Over the last decades, in addition to the improvement of pathophysiological knowledge regarding the role and mechanisms of action of Vitamin D, there has been a progressive advancement in analytical technologies for its determination, as well as in methodological standardization. A significant number of scientific works, meta-analyses, and guidelines have been published on the importance of Vitamin D and the need for supplementation in deficient individuals. However, it appears necessary to clarify the fundamental elements related to the determination of Vitamin D (both at the strictly analytical and post-analytical levels) and the scientific evidence related to the efficacy/safety of supplementation. Additionally, given the important interrelations between Vitamin D, parathyroid hormone (PTH), and fibroblast growth factor-23 (FGF23), the analytical issues and clinical utility of these biomarkers will be discussed.

Background: To determine vitamin D supplementation frequency among infants, factors that influence adherence, and reasons for discontinuation of initiated vitamin D. Methods: This cross-sectional study was conducted using a questionnaire administered to the mothers via a face-to-face interview on 560 infants aged from 1 to 24 months admitted to outpatient clinics from June to December 2017. Results: A total of 351 infants were administered vitamin D, and the rate of supplementation in the first year of life was 83%, while it was only 28% between 13 and 24 months. The rate of vitamin D supplementation was higher among infants who were exclusively formula-fed (p<.05). When the data were analyzed using logistic regression analysis, only visit family physicians seems to be a statistically significant independent variable in increasing supplementation (p<.05). Compared with family refusal, the rate of discontinuation of vitamin D by the healthcare providers was higher after the first year of life (p<.05). The rates of vitamin D discontinuation by healthcare providers, especially by nurses who considered the duration of supplementation adequate, were statistically significantly higher when compared with the fontanel closure and other reasons (p<0.05). Conclusions: The rate of vitamin D supplementation was higher among families who visited family physicians, which suggests the importance of well-baby visits. Since vitamin D supplementation was less common among exclusively breastfed infants, mothers should be educated. Healthcare professionals need further education about the importance of vitamin D supplementation and indications for discontinuation.

Appropriate supplementation of vitamin D can affect infections, allergy, and mental and behavioral development. This study aimed to assess the effectiveness of monitored vitamin D supplementation in a population of preterm infants. 109 preterm infants (24 0/7–32 6/7 weeks of gestation) were randomized to receive 500 IU vitamin D standard therapy (n=55; approximately 800-1000 IU from combined sources) or monitored therapy (n=54; with an option of dose modification). 25(OH)D concentrations were measured at birth, 4 weeks of age, and 35, 40, and 52±2 weeks of post-conceptional age (PCA). Vitamin D supplementation was discontinued in 23% of infants subjected to standard treatment due to increased potentially toxic 25(OH)D concentrations (&gt;90 ng/mL) at 40 weeks of PCA. A significantly higher infants’ percentage in the monitored group had safe vitamin D levels (20–80 ng/mL) at 52 weeks of PCA (p=0.017). We observed increased vitamin D levels and abnormal ultrasound findings in five infants. Biochemical markers of vitamin D toxicity were observed in two patients at 52 weeks of PCA in the control group. Inadequate and excessive amounts of vitamin D can lead to serious health problems. Supplementation with 800–1000 IU of vitamin D prevents deficiency and should be monitored to avoid overdose.

Vitamin D plays an essential role in embryogenesis and the course of intra- and postnatal periods and is crucially involved in the functioning of the mother-placenta-fetus system. Low quantity of Vitamin D during pregnancy can lead to the elevated risk for preeclampsia occurence. Despite the numerous studies on the association of Vitamin D deficiency and preeclampsia development, the current research on this theme is contradictory. In this review we summarize and analyze study data on the effects of vitamin D deficiency and supplementation on pregnancy, labor, fetal and neonatal outcomes.

Vitamin D is a nutrient with anti-inflammatory properties whose role is currently being evaluated in COVID-19. Although studies are conflicting, they seem to suggest a role for vitamin D in reducing disease susceptibility but not in improving clinical outcome. In order to understand why vitamin D does not seem to have much effect on decreasing disease severity, it is essential to appreciate pulmonary vitamin D metabolism. To reach the pulmonary compartment, vascular endothelial cells would need to take up vitamin D from the blood stream, but they lack vitamin D receptor (VDR) and the activating enzyme CYP27B1. Endothelialitis – an important disease manifestation of COVID-19 – is therefore not expected to be directly affected by vitamin D. Bronchial epithelial cells are usually among the first to be infected with SARS-CoV-2. They do express both VDR and CYP27B1, but circulating vitamin D may not reach bronchial epithelial cells without transportation from the blood stream through the blood vessel wall. Inhalation therapy with vitamin D has therefore been suggested as an alternative for oral administration to bypass endothelial cells and efficaciously target bronchial epithelium. In conclusion, based on the principles of pulmonary vitamin D metabolism, it is not expected that vitamin D administration has a significant effect on COVID-19 severity. Vitamin D is more likely to reduce SARS-CoV-2 susceptibility, but reaching the airways with oral supplementation will be difficult and vitamin D inhalation therapy should be considered.

Asthma is a common chronic respiratory disease that affects millions of people worldwide, and its prevalence continues to increase. Vitamin D has been proposed as a potential environmental factor in asthma pathogenesis, due to its immunomodulatory effects. This systematic review aimed to evaluate the effect of vitamin D supplementation on airway remodeling in asthma. We conducted a comprehensive search of electronic databases and identified experimental studies and randomized controlled trials that investigated the impact of vitamin D supplementation on airway remodeling in asthma. The studies included in this review suggest that vitamin D inhibits airway smooth muscle cell contraction and remodeling, reduces inflammation, and regulates collagen synthesis in the airways, and modulates the action of bronchial fibroblasts. However, one study suggests that TGF-β1 can impair vitamin D-induced and constitutive airway epithelial host defense mechanisms. Overall, vitamin D appears to influence many of the pathways central to asthma progression, indicating a promising potential in asthma management and prevenation of asthma progression.

Vitamin D is crucial for athletes' health and performance. Although the exact vitamin D requirements for athletes have not been established, maintaining 25(OH)D levels of at least 40 ng/ml is considered beneficial. This study aimed to determine whether an individual loading dose formula for vitamin D supplementation is suitable to meet a target value of 40 ng/ml and is more effective than standardized supplementation. In a 10-week supplementation study during the winter months in Germany, 90 athletes with insufficient vitamin D levels (25(OH)D<30ng/ml) were randomly assigned to receive either a universal dose of 2000 IU/day of vitamin D or a loading dose of 4000 IU/day, followed by a maintenance dose of 1000 IU/day. Total 25(OH)D concentration was measured from dried blood spots at three time points: at baseline, at the computed date of 40ng/ml, and after the 10-week period. Additionally, a vitamin D-specific questionnaire was issued. On the day when 25(OH)D blood concentrations of 40 ng/ml were calculated to prevail, the individualized group had a significantly higher 25(OH)D level than the standardized group (41.1+-10.9 ng/ml vs. 32.5+-6.4 ng/ml, p<0.001). This study demonstrated that the examined formula is suitable for athletes to achieve a 25(OH)D concentration of 40 ng/ml. This indicates that a personalized approach is more effective than a one-size-fits-all approach in restoring adequate vitamin D levels in athletes.

Abstract: Hyperuricemia is commonly diagnosed in subjects with abnormal purine metabolism. Prolonged hyperuricemia often associated with gout, which is a vital risk factor for joint dysfunction. The current study was designed to determine the efficacy of vitamin C supplements for treatment of high serum uric acid (UA) among hyperuricemic and gouty patients, and finding-out the effect of supplementation on serum creatinine (Cr) level and glomerular filtration rate (GFR). This intervention study was started in April, 2013, till two months. A convenient sample of 30 adults aged between 24-75 years of both genders was assigned into two study groups: hyperuricemic (n=15) and gouty (n=15) groups. Each participant supplemented with 500 mg/day vitamin C chewable tablets for 2 months. Serum UA, Cr, and GFR were measured before and after treatment. At the end of this study, Cr and GFR enhanced insignificantly in both groups. UA increased insignificantly in gouty group after 2 months by about 0.31 mg/dl. On the other hand, hyperuricemic group showed significant (P ≤0.05) decrease in UA (-0.78 mg/dl) after 2 months duration. In conclusion, supplementation with 500 mg/day vitamin C for 2 months significantly attenuated serum UA for hyperuricemic patients and insignificantly affected serum UA in gouty patients. The uselessness of vitamin C supplements on gouty patients could be associated to a number of possible reasons.

The world is in the grips of the COVID-19 pandemic. Public health measures that can reduce the risk of infection and death in addition to quarantines are desperately needed. This article reviews the roles of vitamin D in reducing risk of respiratory tract infections, knowledge about the epidemiology of influenza and COVID-19, and how vitamin D supplementation might be a useful measure to reduce risk. Through several mechanisms, vitamin D can reduce risk of infections. Those mechanisms include inducing cathelicidins and defensins that can lower viral replication rates and reducing concentrations of pro-inflammatory cytokines that produce the inflammation that injures the lining of the lungs, leading to pneumonia, as well as increase concentrations of anti-inflammatory cytokines. Several observational studies and clinical trials reported that vitamin D supplementation reduced risk of influenza, whereas others did not. Evidence supporting the role of vitamin D in reducing risk of COVID-19 includes that the outbreak occurred in winter, a time when 25-hydroxyvitamin D [25(OH)D] concentrations are lowest; that the number of cases in the Southern Hemisphere near the end of summer are low; that vitamin D deficiency has been found to contribute to acute respiratory distress syndrome, and that case-fatality rates increase with age and with chronic disease comorbidity, both of which are associated with lower 25(OH)D concentration. To reduce risk of infection, it is recommended that people at risk of influenza and/or COVID-19 consider taking 10,000 IU/d of vitamin D₃ for a few weeks to rapidly raise 25(OH)D concentrations, followed by 5000 IU/d. The goal should be to raise 25(OH)D concentrations above 40–60 ng/ml (100–150 nmol/l). For treatment of people who become infected with COVID-19, higher vitamin D₃ doses might be useful. Randomized controlled trials and large population studies should be conducted to evaluate these recommendations.

Background: Vitamin D was studied in regards to its possible impact on body mass reduction and metabolic changes in adults and children with obesity yet there were no studies assessing the impact of vitamin D supplementation during a weight management programme in children and adolescence. The aim of our study was to assess the influence of 26 weeks of vitamin D supplementation in overweight and obese children undergoing an integrated 12-months’ long weight loss programme on body mass reduction, body composition and bone mineral density. Methods: A double-blind randomized placebo-controlled trial. Vitamin D deficient patients ( <30 ng/ml level of vitamin D) aged 6-14, participating in multidisciplinary weight management programme were randomly allocated to receiving vitamin D (1200 IU) or placebo for the first 26 weeks of the intervention. Results: Out of the 152 qualified patients, 109 (72%) completed a full cycle of four visits scheduled in the programme. There were no difference in the level of BMI change. Although the reduction was greater in the vitamin D vs. placebo group (-4.28 ± 8.43 vs. -2.53 ±6.10) the difference was not statistically significant (p=0.319). Similarly the reduction in fat mass – assessed both using bioimpedance and DEXa was achieved, yet the differences between the groups were not statistically significant. Conclusions: Our study ads substantial results to support the thesis on no effect of vitamin D supplementation on body weight reduction in children and adolescents with vitamin D insufficiency undergoing a weight management programme. Trial registration no: NCT 02828228; trial registration date: 8 June 2016 registered in: ClinicalTrials.gov.

Objetives/Background: Vitamin D Binding Protein (VDBP) and free vitamin D are new markers that are being studied as a possible markers of vitamin D status. The main aim of our study was to analyse the VDBP genotype and quantify the levels of VDBP and free vitamin D in a sample of cystic fibrosis (CF) patients. Methods: Multicentre, cross-sectional and prospective study including patients with CF, exocrine pancreatic insufficiency who were clinically stable. We investigated vitamin D levels (total and free) and the different VDBP haplotypes. Free vitamin D levels were measured using an electro-chemiluminescence assay. Results: A sample of 48 patients was obtained (52% male; median age 13.8 years). The most common allele of VDBP was Gc1s (72%)>Gc2 (52%)>Gc1f (27%). Median calcidiol was 21.2 ng/ml (IR 15.3 - 26.9), 81% had levels in the insufficiency range: 23 patients (48%) below 20 ng/ml, and 16 (33%) between 20 and 30 ng/ml. The median free vitamin D level was 4.2 pg/ml (IR 3.9 – 5.6). A positive correlation was observed between calcidiol and free vitamin D levels (r=0.871; p<0.0001). After adjustment for season, vitamin D supplementation, sex and CFrelated diabetes, patients with Gc1f polymorphism had a lower risk of vitamin D deficiency, OR 0.22 (95% CI 0.05 – 0.99), p=0.027. A negative linear trend was observed between the polymorphisms grouped into 3 categories (Gc1/Gc1, Gc1/Gc2, and Gc2/Gc2, in that order) and vitamin D and free vitamin D levels (p=0.025 and p=0.033, respectively). Conclusion: In CF, as in the general population, the most common VDBP haplotype in Caucasian race is Gc1s. VDBP polymorphisms influence serum vitamin D and free vitamin D levels in CF patients. There is a good correlation between free vitamin D and calcidiol levels, suggesting that measuring the latter in CF does not seem to provide any additional benefit.

Background: According to newly published studies, patients with Coronavirus Disease 2019 (COVID-19) have significantly lower serum 25-hydroxyvitamin D 25(OH)D levels than those without the SARS-CoV-2 infection. Vitamin D insufficiency may be a predictor of poor prognosis in COVID-19 patients. Vitamin D supplementation is related to improved clinical outcomes in terms of intensive care unit (ICU) admission and death, particularly in individuals with moderate-to-severe forms of COVID-19 requiring hospitalization. Materials and methods: This placebo-controlled five-day study was performed on 100 hospitalized COVID-19 patients with vitamin D insufficiency randomized into two groups. Vitamin D in the form of a sublingual sprayable microemulsion (LYL love your life® sunD3 LYLmicro™) was given three times daily after breakfast, lunch, and dinner (daily dose 12,000 IU) to 52 patients with blood vitamin D levels below 30 ng/ml. 48 patients in the control group received a placebo spray in the same daily regiment. Results: We observed a statistically significant increase by 8.6 ng/ml in median vitamin D level after five days of high-dose vitamin D3 spray therapy. 90.2% of subjects reached normal serum levels of vitamin D. There was a strong correlation between changes in vitamin D and C-reactive protein (CRP) levels in individuals with moderately severe disease (p<0.05), while mild and severe cases showed no statistical significance comparing case and control groups. There were no statistically significant changes in ferritin and interleukin-6 (IL-6) levels. Conclusions: In this study, we demonstrated the possibility to rapidly increase circulating levels of vitamin D just in 5 days of high-dose intervention and found a statistically significant decrease of CRP levels in patients with moderately severe COVID-19. We were not able to detect statistically significant changes in ferritin and IL-6 levels during the 5-day vitamin D intervention.

Hashimoto's thyroiditis (HT) is essentially featured by self-tissue destruction by means of the adaptive immune responses that evade immune regulation. Vitamin D carries out an immunomodulatory role that appears to promote immune tolerance. The aim of this study is to elaborate a narrative review about the relationship between vitamin D status and HT and the role of vitamin D supplementation to reduce HT risk by modulating the immune system. There is an extensive literature confirming that vitamin D levels are significantly lower in HT patients compared to healthy people. On the other hand, after the supplementation with cholecalciferol in patients with HT and vitamin D deficiency, thyroid autoantibody titer decreased significantly, However, there are no conclusive results on the effect of vitamin D supplementation on the thyroid function. The confirmation of the beneficial effects of vitamin D in the prevention and treatment of autoimmune thyroid diseases require additional randomized, double-blind, placebo-controlled trials with longer follow-up.

In December 2019, the so-called “coronavirus disease 2019” (COVID-19) began. This disease is characterized by heterogeneous clinical manifestations, ranging from an asymptomatic process to life-threatening conditions associated with a “cytokine storm”. This article (narrative review) summarizes the epidemiologic characteristics and clinical manifestations of COVID-19 and multi-system inflammatory syndrome in children (MIS-C). The effect of the pandemic confinement on vitamin D status and the hypotheses proposed to explain the age-related difference in the severity of COVID-19 are discussed. The role of vitamin D as a critical regulator of both innate and adaptive immune responses and the COVID-19 cytokine storm are analyzed. Vitamin D and its links to both COVID-19 (low levels of vitamin D appear to worsen COVID-19 outcomes) and the cytokine storm (anti-inflammatory activity) are detailed. Finally, the efficacy of vitamin D supplementation in COVID-19 is evaluated, but the evidence supporting vitamin D supplementation as an adjuvant treatment for COVID-19 remains uncertain.

Vitamin D, unlike the micronutrients, vitamins A, E and K, is largely obtained, not from food, but by the action of solar UV light on its precursor, 7-dehydrocholesterol, in skin. With the decline in UV light intensity in winter, most skin production of vitamin D occurs in summer. Because no defined storage organ or tissue has been found for vitamin D, it has been assumed that adequate vitamin D status in winter can only be maintained by oral supplementation. Skeletal muscle cells have now been shown to incorporate the vitamin D-binding protein (DBP) from blood into the cell cytoplasm where it binds to cytoplasmic actin. This intracellular DBP provides an array of specific binding sites for 25-hydroxyvitamin D (25(OH)D) which diffuses into the cell from the extracellular fluid. When intracellular DBP undergoes proteolytic breakdown, the bound 25(OH)D is then released and diffuses back into blood. This uptake and release of 25(OH)D by muscle, accounts for the very long half-life of this metabolite in the circulation. As 25(OH)D concentration in blood declines in winter, its cycling in and out of muscle cells appears to be upregulated. Parathyroid hormone is the most likely factor enhancing the repeated cycling of 25(OH)D between skeletal muscle and blood. This mechanism appears to have evolved to maintain adequate vitamin D status in winter.

Vitamin D, unlike the micronutrients, vitamins A, E and K, is largely obtained, not from food, but by the action of solar UV light on its precursor, 7-dehydrocholesterol, in skin. With the decline in UV light intensity in winter, most skin production of vitamin D occurs in summer. Because no defined storage organ or tissue has been found for vitamin D, it has been assumed that adequate vitamin D status in winter can only be maintained by oral supplementation. Skeletal muscle cells have now been shown to incorporate the vitamin D-binding protein (DBP) from blood into the cell cytoplasm where it binds to cytoplasmic actin. This intracellular DBP provides an array of specific binding sites for 25-hydroxyvitamin D (25(OH)D) which diffuses into the cell from the extracellular fluid. When intracellular DBP undergoes proteolytic breakdown, the bound 25(OH)D is then released and diffuses back into blood. This uptake and release of 25(OH)D by muscle, accounts for the very long half-life of this metabolite in the circulation. As 25(OH)D concentration in blood declines in winter, its cycling in and out of muscle cells appears to be upregulated. Parathyroid hormone is the most likely factor enhancing the repeated cycling of 25(OH)D between skeletal muscle and blood. This mechanism appears to have evolved to maintain adequate vitamin D status in winter.

Vitamin D (VD) is a pro-hormone essential for life in higher animals. It is present in few types of foods and is produced endogenously in the skin by a photochemical reaction. The final step of VD activation occurs in the kidneys involving a second hydroxylation reaction to generate the biologically active metabolite 1,25(OH)₂-VD. Extrarenal 1α-hydroxylation has also been described to have an important role in autocrine and paracrine signaling. Vitamin D deficiency (VDD) has been in the spotlight as a major public health-care issue with an estimated prevalence of more than a billion people worldwide. Among individuals with chronic kidney disease (CKD), VDD prevalence has been reported to be as high as 80%. Classically VD plays a pivotal role in calcium and phosphorus homeostasis. Nevertheless, there is a growing body of evidence supporting the importance of VD in many vital nonskeletal biological processes such as endothelial function, renin-angiotensin-aldosterone system modulation, redox balance and innate and adaptive immunity. In individuals with CKD, VDD has been associated with albuminuria, faster progression of kidney disease and increased all-cause mortality. Recent guidelines support VD supplementation in CKD based on extrapolation from cohorts conducted in the general population. In this review, we discuss new insights on the multifactorial pathophysiology of VDD in CKD as well as how it may negatively modulate different organs and systems. We also critically review the latest evidence and controversies of VD monitoring and supplementation in CKD patients.

Vitamin D status may impact acute affective symptomatology and the severity of symptoms in patients with bipolar disorder (BD). Therefore, this cross-sectional study analyzed 25(OH)D, 24,25(OH)2D, and the vitamin D metabolite ratio (VMR) in BD and correlated the results with clinical affective symptomatology and functionality. The inactive precursor 25(OH)D and its principal catabolite 24,25(OH)2D were measured simultaneously with a validated liquid chromatography tandem mass-spectrometry method in 170 BD outpatients and 138 healthy controls. VMR was calculated as follows: VMR=100*(24,25(OH)2D/25(OH)D). The psychometric assessment enclosed: Beck Depression Inventory-II, Hamilton Depression Rating Scale, Young Mania Rating Scale, Global Assessment of Functioning, and number of suicide attempts. We did not find a significant difference between patients and controls in the concentrations of 25(OH)D and 24,25(OH)2D. Additionally, the VMR was comparable in both groups. The calculations for the clinical parameters showed a negative correlation between the Young Mania Rating Scale and 24,25(OH)2D (r = -.154, p = .040). Based on the small effect size and the predominantly euthymic sample, further exploitation in individuals with manic symptoms would be needed to confirm this association. In addition, long-term clinical markers, and an assessment in different phases of the disease may provide available additional insights.

The different cell subsets of the immune system express vitamin D receptor (VDR). Through VDR, vitamin D exerts different functions which influences on immune responses, as previously shown in different preclinical models. Based on this background, retrospective studies have explored the impact of vitamin D levels on the outcome of patients undergoing allogeneic hematopoietic stem cell transplantation, showing that vitamin D deficiency is related to an increased risk of complications, especially graft-versus-host disease. These results have been confirmed in a prospective cohorts trial, although further studies are required to confirm this data. In addition, the role of vitamin D on the treatment of hematologic malignancies has also been explored. Considering this dual effect both on the immune system as well as on tumor cells in patients with hematologic malignancies, vitamin D might be useful in this setting both to decrease graft-versus-host disease and relapse rates.

The discovery that vitamin D2 is being generated by anaerobic microbial metabolism in the alimentary tract, raises the question whether such a source of vitamin D could contribute to vitamin D supply for the animal hosting this microbial production system. In ruminants, this microbial generation in the forestomach allows vitamin D2 to be readily absorbed when it reaches the small intestine, contributing to vitamin D2 and 25-hydroxyvitamin D2 [25(OH)D2] found in their tissues. In monogastric animals like humans, the microbial generation of vitamin D2 is occurring in the large intestine. There is evidence that vitamin D hydroxy metabolites, delivered to the lumen of the colon can be absorbed. However, the parent vitamin D is more lipophilic than its metabolites, and like lipophilic vitamin K2 being produced by bacteria in the hindgut, may be poorly absorbed by the colon mucosa. It is now apparent that colon mucosal cells have the proteins megalin and cubilin in their basal membrane. These glycoproteins perform endocytosis of circulating proteins including vitamin D binding protein [DBP]. Inside the cell, DBP binds to cytoplasmic actin and thus provides an array of high affinity binding sites for vitamin D and its functional metabolites. Any traces of vitamin D2 that may diffuse into the colon mucosal cells from the lumen would thus be retained and accumulate on the DBP-actin. It would then be a substrate for functional hydroxylase metabolism for local endocrine action in these cells, and subsequent delivery of 25(OH)D2 by diffusion to apo-DBP in the circulation.

Vitamin A and E are important during pregnancy, the neonatal period, and childhood. The objective of this study was to assess whether maternal RRR-a-tocopherol supplementation affects serum and breast milk retinol. Serum was collected at baseline and twenty days later, and breast milk, at baseline, and on days 1, 7, and 20 after delivery. After the baseline serum collection, the supplemented group (n=16) received a single 400 IU of RRR-α-tocopherol. The control group (n=18) was only performed collections. Retinol and alpha tocopherol levels were determined by liquid chromatography. Serum retinol and alpha tocopherol at baseline and 20 days after delivery indicated proper vitamin A (> 20 µg/dL) and E (> 516 μg/dL) statuses in the control and supplemented groups (p > 0.05). Colostrum retinol levels on days 1 and 7 after delivery were significantly higher in the supplemented group (p = 0.018 and p = 0.012, respectively). Maternal vitamin E supplementation increased colostrum retinol by 52.23% and 111.2%, 24 hours and 7 days, respectively. However, retinol in mature milk did not differ between the groups (p > 0.05). In conclusion, the supplementation with 400 IU of RRR-α-tocopherol improved vitamin A bioavailability in breast milk.

1) Background: The aim was to evaluate the bioefficacy of vitamin D (VitD) encapsulated in nanoemulsions developed by sonication and pH-shifting of pea protein isolate in restoring VitD status in VitD-deficient rats. 2) Methods: Weaned (3-week old), male albino rats (n = 35) were initially divided into two groups: control sufficient group (VDS; n = 7) fed on a normal AIN-93G diet and a VitD-deficient group (n = 28) fed a VitD-deficient diet for six weeks. VitD-deficient rats were divided into four subgroups: two treatment groups (Nano+VitD and Oil+VitD) and two control groups (Nano-VitD and Oil-VitD), receiving seven rats in each sub-group. Nano+VitD and Oil+VitD groups received VitD dispersed in PPI-nanoemulsions and in canola oil, respectively, while the control groups received the respective delivery vehicles without VitD. Serum 25-hydroxyvitamin D [25(OH)VitD], parathyroid hormone (PTH), calcium (Ca), phosphorus levels (P), and alkaline phosphatase (ALP) activity were measured. Femur bone was used to prepare histopathological sections. 3) Results: After one week of treatment, the VitD-deficient rats consuming Nano+VitD recovered from VitD deficiency (serum 25(OH)VitD 34.38 ± 7.00) compared to the sufficient control (36.84 ± 9.16; p > 0.05) and the deficient control consuming VitD+Oil (14.05 ± 3.08; p < 0.01). Enhancement in VitD status was followed with expected changes in serum PTH, Ca, P, and ALP levels, no difference in similar biomarkers against the sufficient control, and an improvement of the osteoid area and reduction of trabecular separation in bone. 4) Conclusions: Stabilization of VitD within PPI-based nanoemulsions enhances its absorption and restores its status and biomarkers of bone resorption in VitD-deficient rats.

Idiopathic pulmonary fibrosis remains a relevant problem in the field of healthcare with an unfavorable prognosis for patients due to progressive fibrous remodeling of the pulmonary parenchyma. Starting with the reactions damaging the epithelial lining of alveoli, pulmonary fibrosis is implemented through a cascade of complex mechanisms, the crucial of which is the TGF-β/SMAD mediated pathway, involving various cell populations. Considering that a number of the available drugs (pirfenidone and Nintedanib) have only limited effectiveness in slowing the progression of fibrosis, the search and justification of application of other approaches aimed at regulating the immune response, cellular aging processes, programmed cell death and transdifferentiation of cell populations remains relevant. This literature review presents the key modern concepts concerning molecular genetics and cellular mechanisms of lung fibrosis development, based mainly on in vitro and in vivo studies in experimental models of bleomycin-induced pulmonary fibrosis, as well as the latest data on metabolic features, potential application points and effects of vitamin D and its metabolites.

Vitamin D has important anti-inflammatory, anti-microbial properties and plays a central role in host immune response. Due to the crucial role of the kidneys in the metabolism of vitamin D, patients with chronic kidney disease (CKD), are prone to vitamin D deficiency. The resultant reduction in the production of calcitriol, the activated form of vitamin D in patients with CKD is responsible for exacerbating the existing renal impairment and periodontal inflammation. Recent evidence suggests a bidirectional, causal relationship between periodontitis and renal functional status. Both conditions have shared pathophysiologic mechanisms including oxidative stress, increases in the systemic inflammatory burden and impaired host response. This review explores the association between vitamin D, CKD and periodontitis. The review summarises the current evidence base for the classical and non-classical vitamin D metabolic pathways, the biological mechanisms linking vitamin D deficiency, CKD and periodontitis, as well as the bidirectional relationship between the two chronic inflammatory conditions. Finally, the paper explores the impact of vitamin D deficiency on CKD, periodontitis, and related co-morbidities.

It is a well-established fact that inadequate Vitamin D (Vit-D) levels have negative effects on the development and progression of malignant diseases, mainly cancer. The purpose of this paper was to elucidate the effects of Vit-D intake and serum 25-hydroxyvitamin-D (25(OH)D) levels on cancer incidence and mortality, the current evidence in this field, and the biases of this evidence using the meta-meta-analysis method. Meta-analyses focusing on Vit-D intake, serum 25(OH)D levels, and cancer risk/mortality were identified. A structured computer literature search was performed in PubMed/Medline, Web of Science (WoS), and Scopus electronic databases using predetermined keyword combinations. Primary and secondary meta-meta-analyses were carried out, combining odds ratios (ORs), risk ratios (RRs), and hazard ratios (HRs) for outcomes reported in selected meta-analyses. A total of 35 eligible meta-analyses assessing the association between Vit-D and cancer incidence and/or mortality were included in this study. In the pooled analysis, higher Vit-D intake and serum 25(OH)D levels were associated with lower cancer risk (OR = 0.93, 95% CI: 0.90-0.96, p < 0.001; OR = 0.80, 95% CI: 0.72-0.89, p < 0.001, respectively) and cancer-related mortality (RR = 0.89, 95% CI: 0.86-0.93, p < 0.001; RR = 0.67, 95% CI: 0.58-0.78, p < 0.001, respectively). When meta-analyses whose primary reports included only randomized controlled trials were pooled, there was no significant association between Vit-D intake and cancer risk (OR = 0.99, 95% CI: 0.97-1.01, p = 0.320). In subgroup analysis, Vit-D consumption was associated with a significant decrease in colorectal and lung cancer incidence (OR = 0.89, 95% CI: 0.83-0.96, p = 0.002; OR = 0.88, 95% CI: 0.83-0.94, p < 0.001, respectively). Taken together, both Vit-D intake and higher 25(OH)D levels may provide remarkable benefits in terms of cancer incidence and mortality, however, careful evaluation according to cancer types is critically important and recommended.

Although vitamin D deficiency has been correlated with an increased risk of cardiovascular disease (CVD), there are few data on the association between 25-hydroxyvitamin D (25(OH) D) and atherogenic indices predictive of CVD. This study aimed to investigate the relationship of vitamin D status with lipid profile and atherogenic indices in adult women in Morocco. Three hundred healthy women, aged 18 to 50 years, from Meknes were included. Fasting 25(OH) D and lipid concentrations were determined using a one-step electrochemiluminescence-based immunoassay and an enzymatic method, respectively. Atherogenic indices (Atherogenic index of plasma (AIP), non-HDL cholesterol (Non-HDL-C), Atherogenic coefficient (AC), Castelli risk indices I and II (CRI-I and II), and CHOLIndex (CI)) were calculated using conventional lipid parameters. Logistic regression models and operating characteristic curve (ROC) analysis were used to assess the relationship of the variables and estimate the threshold of 25(OH) D levels associated with high atherogenic indices. 25(OH) D below 20 ng/ml was significantly associated with an enhanced risk of hypertriglyceridemia and elevated values of AIP, AC, Non-HDL-C, and CRI-I with an OR (95% CI) of 4.904 (1.856-12.959); 3.637(2.149-6.158); 3.589(1.673-7.700); 2.074(1.215-3.540), and 2.481(1.481-4.123), respectively. According to ROC analysis, the likelihood of hypertriglyceridemia and high values of AIP, AC, Non-HDL-C, and CRI-I were associated with 25(OH)D thresholds ≤15.15 ng/ml, ≤ 17.5 ng/ml, ≤ 19.8 ng/ml, ≤ 20.1 ng/ml and ≤ 19.5 ng/ml, respectively, all p &lt; 0.01. Based on atherogenic indices, this study indicates that vitamin D below 20 ng/ml may increase the risk of cardiovascular disease in adult women. Additional health efforts are needed to raise awareness among women and healthcare providers in preventing and controlling cardiovascular risk factors.

Superoxide, a form of reactive oxygen species (ROS), is catabolized by superoxide dismutase (SOD) and contributes to carcinogenesis via the oxidative damage it inflicts on cells. The aim of this research was to analyze the potential vitamin D-mediated regulation of the antioxidative “SOD1-to-SOD2 switch” within the human MG-63 osteosarcoma model. For this study; real-time PCR analysis was performed using MG-63 cells exposed to metabolically active 1,25(OH)₂D₃. Frist; a sustained statistically significant >2-fold suppression of proliferating cell nuclear antigen (PCNA) transcripts was observed after 10nM but not at 100nM of 1,25(OH)₂D₃ treatment; suggesting a cytostatic effect. In order to assess regulators of mitochondrial oxidative phosphorylation; gene expression of COX2 and COX4l1 of the mitochondrial complex IV and antioxidative enzymes (SOD1; SOD2 and Catalase (CAT)) were monitored. For COX2 and COX4l1; no changes in gene expression were observed. However; a concomitant decrease in CAT and SOD1 mRNA; and increase in SOD2 mRNA after 24 hours of 10nM 1,25(OH)₂D₃ treatment were observed. A ~8-fold increase in SOD2 mRNA was apparent after 48 hours. The significant increase in SOD2 activity in the presence of vitamin D indicates an antioxidant potential and sensitization of vitamin D during osteosarcoma transformation and mitochondrial detoxification over time.

Background: A Few preclinical studies have shown that Knee osteoarthritis (KOA) is linked to gut microbiome dysbiosis and chronic inflammation. This pilot study was designed to look at the gut microbiome composition in KOA patients and normal individuals with or without vitamin D deficiency (VDD, serum vitamin D <30 ng/ml). Methods: This pilot study was conducted prospectively in 24 participants. The faecal samples of all the participants were taken for DNA extraction. The V3-V4 region of 16s rRNA was amplified and the library was prepared and sequenced on the Illumina Miseq platform. Results: The mean (±SD) age was 45.5 (±10.2) years with no defined co-morbidities. Of 447 total Operational Taxonomic Units (OTUs), a differential abundance of 16 nominally significant OTUs between the groups were observed. Linear discriminate analysis (LEfSe) revealed a significant difference in bacteria among the study groups. Pseudobutyrivibrio and Odoribacter were specific for VDD while Parabacteroides, Butyricimonas, and Gordonibacter were abundant in the KOA_VDD group and Peptococcus, Intestimonas, Delftia, and Oribacterium were abundant in the KOA group. About 80% of bacterial species were common among different groups and hence labeled as core bacterial species. However, the core microbiome of KOA and VDD groups were not seen in the KOA_VDD group, suggesting that these bacterial groups were affected by the interaction of the KOA and VDD factors. Conclusion: Parabacteroides, Butyricimonas, Pseudobutyrivibrio, Odoribacter, and Gordonibacter are the predominant bacteria in vitamin D deficient patients with or without KOA. Together these results indicate an association between the gut microbiome, vitamin D, and knee osteoarthritis.

(1) Background: To investigate the effect of phosphohistone H3 (PHH3) and vitamin D receptor (VDR) in the risk assessment of endometriosis, in two cohorts of women with this pathology, those receiving hormonal treatment, and those without treatment; (2) Methods: In 60 cases of women with endometriosis, the paraffin-embedded endometriosis tissue samples, retrieved after surgery, were immunohistochemically (IHC) analyzed aiming to determine the expression status of PHH3 and VDR; (3) Results: The IHC positive index of PHH3 and VDR of these two groups were compared. PHH3 levels were positively correlated with vitamin D levels, both being increased in patients without treatment. Within the group without treatment, PHH3 and VDR expressions were positively associated; (4) Conclusions: IHC analysis of PHH3 and VDR can be used as an additional tool for risk stratification and prognostic assessment in patients with endometriosis.

Coronavirus disease (COVID-19) is an infectious disease caused by a new virus which causes respiratory illness. Older adults and people who have previous chronic medical conditions are at higher risk for more serious complications from COVID-19.Hypovitaminosis D is attributed to the increased risk of lung injury and acute respiratory distress syndrome (ARDS) as well as diabetes, Cardiovascular event and associated comorbidities, which are the main causes of severe clinical problem in COVID-19 patients. Considering the protective role of vitamin D through modulating the innate and adaptive immune system as well as inhibition of Renin Angiotensin System (RAS), vitamin D supplementation might boost the immune system of COVID-19 patients and reduce severity of the disease in vitamin D deficient individuals.

A recent systematic review for 19 selected articles after searching through to 30 September 2017 showed vitamin D deficiency was associated with ischemic stroke (IS), not hemorrhagic stroke (HS). But a heterogeneity would be introduced with comparing the lowest and highest category of vitamin D. The aim of this article was to conduct an updated meta-analysis (UMA) with searching through to 31 March 2019. An interval collapsing method as information extraction was applied in order to decrease a heterogeneity among studies. Additional articles were selected from cited lists from 19 selected articles using citation discovery tools. Random effect model was applied if I-squared value was over 50%. A funnel plot and Egger’s test were used to detect a publication bias. After 5 new studies were added, the summary RRs [and their 95% confidence intervals] (I-squared value) were 1.52 [1.33–1.74] (0.0%) in IS, and 2.44 [1.34–4.46] (69.7%) in HS. This UMA supported the hypothesis that serum vitamin D deficiency was associated with an increased risk of HS as well as IS. Diverse public health programs against vitamin D deficiency status would be needed for higher risk group, especially elderly people.

Chronic kidney disease (CKD) is a major non-communicable disease associated with high rates of premature morbidity and mortality. The prevalence of hypovitaminosis D (deficiency of 25(OH)D or 25D) is greater in racial/ethnic minorities and in patients with CKD than the general population. Low 25D is associated with bone and mineral disorders as well as immune, cardiometabolic and cardiovascular (CV) diseases. Thus, it has been suggested low 25D contributes to the poor outcomes in patients with CKD. The prevalence of hypovitaminosis D rises progressively with advancing severity of kidney disease with over 30% of patients with CKD stage 3 and 70% patients with CKD stage 5 estimated to have low levels of 25D. This report describes several of the abnormal physiologic and counter-regulatory actions related to low 25D in CKD such as those in oxidative stress and inflammatory systems, and some of the preclinical and clinical evidence or lack of thereof of normalizing serum 25D levels to improve outcomes in patients with CKD, and especially for the high risk subset of racial/ethnic minorities who suffer from higher rates of advanced CKD and hypovitaminosis D.

Recent studies have demonstrated a relationship between poor vitamin D status and respiratory infections and diarrhea among young children. Acute lower respiratory infections (ALRI) and diarrhea are among the two most important causes of death in under-5 children. In this analysis, we examine the extent to which vitamin-D deficiency (<10 ng/ml) predicts these outcomes using data from a randomized controlled trial (RCT) of daily folic acid and/ or vitamin B12 supplementation for six months in 6 to 30 months old children conducted in Delhi, India. Of the 960 subjects who had vitamin-D concentrations measured, 331(34.5%) were vitamin-D deficient. We found, after controlling for relevant potential confounders (age, sex, breastfeeding status, wasting, stunting, underweight, anemia status at base line and season), the risk of ALRI was significantly higher among vitamin-D deficient (OR 1.26; 95% CI: 1.03 to 1.55) compared to vitamin-D-replete children in the six months follow-up period. Vitamin-D status was not significantly associated with episodes of diarrhea and clinical pneumonia. The extent of causal relationship of vitamin-D status and ALRI needs to be explored in further studies.

(1) Background: Many malignancies are driven by mutations which affect the gene for fibroblast growth factor receptor (FGFR) 1. Previously we have documented that signal transduction from FOP2–FGFR1 fusion protein in KG1 cells downregulated the expression of vitamin D receptor (VDR) gene. In this paper we investigated if also other FGFRs were responsible for the regulation of the VDR expression. (2) Methods: We used human myeloid leukemia cells U937, and bone cancer cell line U2OS, and cell transfection methods in order to address the above questions. (3) Results: In myeloid leukemia cells overexpression of FGFR 1-4 caused shift to granulocytic differentiation, upregulated expression of VDR, and sensitized these cells to 1,25-dihydroxyvitamin D (1,25D)-induced monocytic differentiation, while in bone cells, signal transduction activated by FGF1 was not responsible for regulation of VDR expression and activity. (4) Conclusions: Since the overexpression of FGFRs occurs in many neoplasms, it may be reasonable to use 1,25D analogs in these cancers, in which overexpression of FGFRs leads to VDR upregulation.

Background: Hypovitaminosis D is a public health problem due to its implications for various diseases. Vitamin D has numerous functions, such as modulating the metabolism of some cellular tissues, and is expressed through the VDR gene that may influence gene expression modulation, which plays an important role in vitamin D metabolism. Objective: To evaluate the effect of the genotypes of single nucleotide polymorphism (SNP) BsmI of the vitamin D receptor (VDR) gene on VDR, SOD2, and CYP24A1 gene expression in individuals with low serum vitamin D levels. Methods: This was a cross-sectional analytical study. Individuals were invited to participate and, after signing the informed consent form, answered a structured questionnaire with identification data. Blood was collected for biochemical analysis, and vitamin D was measured by chemiluminescence; BsmI polymorphism was determined using real-time polymerase chain reaction (PCR) assays with TaqMan allelic discrimination, and gene expression was conducted by qRT-PCR using QuantiFast SYBR® Green PCR Master Mix. Data were analyzed using the SPSS 20.0 software, and differences were considered significant at p&lt;0.05. Results: 98 individuals with vitamin D ≤20 ng/dL were evaluated, and the SNP BsmI of the VDR gene showed CYP24A1 overexpression and low SOD2 expression. Conclusion: SNP Bsm I of the VDR gene can modulate the expression of the genes evaluated without interfering with serum levels.

Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal0 tract (GIT), including Crohn’s disease (CD) and ulcerative colitis (UC), which differ in the location and lesion extensions. Both diseases are associated with microbiota dysbiosis, with a reduced population of butyrate-producing species, abnormal inflammatory response, and micronutrient deficiency (e. g. vitamin D hypovitaminosis). Vitamin D (VitD) is involved in immune cell differentiation, gut microbiota modulation, gene transcription, and barrier integrity. Vitamin D receptor (VDR) regulates the biological actions of the active VitD (1α, 25-dihydroxyvitamin D3), and is involved in the genetic, environmental, immune, and microbial aspects of IBD. VitD deficiency is correlated with disease activity and its administration targeting a concentration of 30 ng/mL may have the potential to reduce disease activity. Moreover, VDR regulates functions of T cells and Paneth cells and modulates release of antimicrobial peptides in gut microbiota-host interactions. Meanwhile, beneficial microbial metabolites, e.g. butyrate, upregulate the VDR signaling. In this review, we summarize the clinical progress and mechanism studies on VitD /VDR related to gut microbiota modulation in IBD. We also discuss epigenetics in IBD and the probiotic regulation of VDR. Furthermore, we discuss the existing challenges and future directions. There is a lack of well-designed clinical trials exploring the appropriate dose and the influence of gender, age, ethnicity, genetics, microbiome, and metabolic disorders in IBD subtypes. To move forward, we need well-designed therapeutic studies to examine whether enhanced vitamin D will restore functions of VDR and microbiome in inhibiting chronic inflammation.

Background and Objectives: Previous studies revealed anti-angiogenic, antiproliferative and anti-inflammatory effects of Vitamin D on cancer cells. Although this body of evidence supported the correlation of high Vitamin D levels with reduced incidence rates for various malignancies, contradictory results were reported regarding non-melanoma skin cancer (NMSC). Aim of this overview was to summarize the available evidence from the existing pool of systematic reviews and meta-analyses, focusing on Vitamin D serum status, dietary intake, and Vitamin D receptor (VDR) polymorphisms in correlation to NMSC incidence. Materials and Methods: A literature search in electronic databases was conducted from inception to January 2023. Inclusion criteria were systematic reviews and meta-analyses published in peer-reviewed journals, evaluating Vitamin D serum levels, dietary and/or supplementary intake, or VDR gene polymorphisms, and reporting data on NMSC. Results: A total of 10 studies were included in the data analysis models. A positive association between Vitamin D serum levels and NMSC is highlighted. However, dietary/supplementation of Vitamin D doesn’t exhibit a likewise strong linkage to NMSC. Despite the contradictory findings, VDR polymorphisms may play a crucial role in the intricate NMSC pathogenesis. Conclusions: This umbrella review showed that high Vitamin D levels are associated with increased NMSC incidence, potentially due to its direct correlation with increased sun exposure. Further research on VDR polymorphisms is suggested to explore their true effect size on NMSC risk.

Aging is the results of several complex and multifactorial processes, where several agents contribute to increase intrinsic vulnerability and susceptibility to age-related diseases. The hallmarks of aging are a set of biological mechanisms, finely regulated and strictly interconnected, initiating or contributing to biological changes anticipating several age-related diseases. The complex network of cellular and intercellular connections between the hallmarks might represent a possible target for the research of agents with pleiotropic affects. Vitamin D (VitD) is known to have positive impact not only on muscle and bone health, but also on several extra-skeletal districts, due to the widespread presence of VDRs (VDR). VitD and VDR could be molecules potentially targeting the hallmark of aging network. To date, evidence about the potential effect of VitD on the hallmark of aging is scarce in humans and mainly based on preclinical models. Although underpowered and heterogeneous, in-human studies seems to confirm the modulatory effect of VitD on some hallmarks aging and diseases. However, more investigations are needed to clarify the pleiotropic effects of VitD and its impact on the hallmark of aging, hopefully highlighting the courses for translational applications and potential clinical conclusions.

This study aimed to examine the vitamin D status of professional volleyball athletes and to determine its correlation with shoulder muscle strength. We finally included 52 healthy male professional volleyball players (23.2 ± 4.5 years), who were categorized by vitamin D status (<20 ng/mL: deficiency, 20-30 ng/mL: insufficiency, and >30 ng/mL: sufficiency). We examined the strength of the internal rotator (IR) and external rotator (ER) muscles of the shoulder by using isokinetic dynamometer. Fourteen players (26.9%) had vitamin D deficiency, 24 players (46.2%) were vitamin D insufficient, and 14 players (26.9%) were vitamin D sufficient. There was no significant correlation between the vitamin D level and shoulder muscle strength at 60°/s (IR, r = 0.159, p = 0.26; ER, r = 0.245, p = 0.08), and at 180°/s (IR, r = - 0.093, p = 0.51; ER, r = - 0.037, p = 0.79). Moreover, the isokinetic shoulder strengths were not significantly different across the three groups in all settings. In conclusion, vitamin D insufficiency was common in elite volleyball players. Though not being associated with isokinetic muscle weakness, vitamin D should be regularly monitored and supplemented in young elite athletes, considering its importance on musculoskeletal health.

The Vitamin D Receptor (VDR) mediates the actions of vitamin D, which has important roles in bone homeostasis, growth/differentiation of cells, immune functions and reduction of inflammation. Emerging evidences suggest that epigenetic modifications of the VDR gene, particularly DNA methylation, may contribute to the onset and progression of many human disorders. This review aims to summarize the available information on the role of VDR methylation signatures in different pathological contexts, including autoimmune diseases, infectious diseases, cancer and others. The reversible nature of DNA methylation could enable the development of therapeutic strategies, offering new avenues for the management of these worldwide diseases.

(1) Background: Obesity and its comorbidities can cause burdens and limitations. Bariatric surgery (BS) is indicated as a safe procedure to reduce body mass and improve present comorbidities. Yet, several complications were reported, like vitamin D [25(OH)D] deficiency. We evaluated if 25(OH)D serum levels relate to clinical characteristics, symptoms, or habits in women after their BS and whether the vitamin D receptor (VDR) gene's TaqI and FokI polymorphisms affected 25(OH)D levels and the total body bone mineral density (TBBMD). (2) Methods: This cohort cross-sectional comparative analytical prospective study consisted of 27 women, 61.6 ± 5.0 years, submitted to BS one year prior at a public reference hospital, DF-Brazil. All participants were asked to follow the physical and dietary activity recommendations and received vitamin D3 supplements. Their anthropometric, biochemical, and immunological measurements and blood samples were obtained. (3) Results: 73.3% of participants had low 25(OH)D levels, and their levels correlated positively with TBBMD and negatively with systolic pressure. VDR TaqI did not affect 25(OH)D levels, whereas VDR FokI's allele f presence correlated to a median rise in 25(OH)D levels. Neither polymorphism correlated to TBBMD. (4) Conclusions: 25(OH)D levels were positively correlated with TBBMD, negatively with systolic blood pressure, and were higher in those with the VDR FokI allele f.

5-Pentadecylresorcinol (C15) is a natural alkylresorcinol that has been shown to protect against complications caused by imbalanced nutrition. Although the exact mechanisms of beneficial activity of C15 are not known, we assume that the protective effects of C15 on metabolic health are mediated by their modulatory influence on the composition of the intestinal microbiota and functional activity. Cobamides and vitamin B12 are believed to be crucial modulators of mammalian gut ecosystems. We proposed that C15 may influence the representation of enzymes and pathways for vitamin B12 synthesis in the gut microbiome, providing compositional and functional changes in the microbial community. High-throughput metagenome sequencing of the contents of the small and large intestines of C57Bl6 mice fed a regular or high-fat diet with or without C15 supplementation was performed followed by reconstruction of the metabolic activity of the microbiota to clarify the role of C15 in vitamin B12 synthesis by the gut microbiota. It has been established that C15 significantly increases the representation of the cobalamin salvage pathway and enzymes in the microbiome of the large intestine of mice fed a high-fat diet. The genera Clostridium, AF12, and [Ruminococcus] had shown the highest number of correlations with enzymes for B12 synthesis and were negatively associated with the representation of probiotic bacteria. Therefore, the beneficial effect of C15 on the gut microbiota community can be achieved by modulating B12 synthesis that, in turn, serves as one of the key regulators of gut microbiota ecology.

Severe infection from the SARS-CoV-2 virus is associated with various clinical findings, including hematological manifestations. Thrombotic events or a tendency to develop thrombotic events also characterize severe COVID-19 disease and may lead to death. Vitamin D is known to have immunomodulating properties and to enhance the body defense system against invading pathogens and to have immunostimulatory properties as far as the innate immune response is concerned. The aim was to measure 25(OH)D3 levels in patients hospitalized for severe COVID-19 infection, to explore the relationship between 25(OH)D3 and outcome and to investigate the relationship between 25(OH)D3 levels, CRP, ferritin, d-dimers and fibrinogen levels in this cohort. In a cohort of 88 patients hospitalized for severe infection from the SARS-CoV-2 virus and a control group matched for age and sex the levels of 25(OH)D3 were measured. In the same cohort CRP, ferritin, d-dimer and fibrinogen levels were also analyzed. Levels of 25(OH)D3 were 17.36±8.80 ng/ml (mean±SD) as compared with 24.34±10.34 ng/ml, in patients with severe SARS-CoV-2 infection and the control group, respectively, p<0.001 (Student’s t test). The levels of 25(OH)D3 were found to be significantly related to outcome, i.e. survival as opposed to non-survival, as more patients with 25(OH)D3 deficiency (0-10 ng/ml) and insufficiency (10-20 ng/ml) had a fatal outcome as compared with those with vitamin D sufficiency, p<0.001, chi-square test, p<0.001, Fischer’s exact test. Levels of 25(OH)D3 were inversely related to CRP, ferritin, d-dimer and fibrinogen levels, p<0.001, linear regression analysis, beta coefficient of variation, -0.176, -0,160, -0.178, -0.158, respectively. Vitamin D deficiency observed in severe SARS-CoV-2 infection was related to the disease outcome. Increased ferritin levels, and increased thrombotic markers, namely d-dimer and fibrinogen levels were observed in the patients and their concentration was also inversely related to vitamin D. We showed that vitamin D levels were low in hospitalized patients with severe SARS-CoV-2 infection and also inversely related to CRP, ferritin, d-dimer and fibrinogen concentration. It is proposed that vitamin D levels may be an index of severity in the context of SARS-CoV-2 infection.

Background: Diabetic retinopathy (DR) is one of the most prominent pathological microvascular complications in diabetes. A series of studies reported that vitamin D deficiency was associated with increased prevalence of retinopathy in diabetic patients but the results were inconsistent. In this study we focused on evaluating the relationship between vitamin D deficiency and DR by conducting a meta-analysis of observational studies. Methods: Systematic computerized searches were performed in PubMed, MEDLINE, and the Cochrane Library for relevant original articles till November 20, 2016. The pooled odds ratios (ORs) with corresponding confidence intervals (CIs) were calculated to assess the associated value of vitamin D deficiency to the risk of DR. 9 studies including 6332 participants were subjected to final analysis. Results: The results indicated that vitamin D deficiency increases the risk of DR (OR = 1.57, 95% CI 1.32-1.87) with a little heterogeneity (I2 = 23%). In addition, the subgroup analysis demonstrated that there were obvious heterogeneities in T2DM (I2 = 47.8%). Sensitivity analysis showed that the results were relatively stable and reliable. Conclusion: our meta-analysis demonstrated that vitamin D deficiency could increase the risk of DR.

The aim of this study was to develop a valid and reliable questionnaire to assess vitamin D-related knowledge, attitude and practice (KAP) in Iranian adults who may be at increased risk of vitamin D deficiency. This study was conducted on 527 subjects, aged ≥20 years from Public health care centers in Tehran, Iran. Based on results of literature review and in-depth interviews, the 38-item vitamin D-related KAP questionnaire with four subscale was developed: 1) general knowledge; 2) nutritional knowledge; 3) attitudes; 4) behaviors. Validity of the developed vitamin D-KAP questionnaire was assessed, utilizing face, content, and construct validity methods. Internal consistency was calculated to assess reliability of the current developed questionnaire. A total of 572 (54.1% female) adults, aged 30.2±7.9 years, participated in the study. All items were perceived as relevant and comprehendible by participants. Content validity was confirmed by the panel of experts. The internal consistency, as measured by Cronbach’s alpha coefficients, exceeded the minimum reliability standard of 0.60 for four subscales. The EFA suggested a four-factor construct and the results of the CFA indicated acceptable fit indices for the proposed model. No ceiling effects were observed except for general knowledge (1.2%). Floor effects detected were 0, 1.1, 2.4, and 8.7% for practice, attitude, general knowledge, and nutrition knowledge, respectively. General knowledge had the highest score (79.59±14.52) and nutrition knowledge, the lowest score (42.58±20.40) among the four sub-scales. Results confirm the initial validity and reliability of the vitamin D-related knowledge, attitude and practice questionnaire. Further investigations in different urban and rural population are recommended.

Age-related declines in vitamin D receptor (VDR) expression have been implicated in the onset of sarcopenia. The increased expression of VDR in muscle is known to increase muscle mass, whereas VDR knockout in the muscle decreases muscle mass in rats. Similar to VDR, the age-related decline in protein deacetylase sirtuin (SIRT) expression is linked to the development of sarcopenia and age-related muscle dysfunction. This study aimed to investigate whether the VDR agonist 1,25-dihydroxyvitamin D3 (1,25VD3) exerts beneficial effects on muscles through interactions with sirtuins and, if so, the underlying molecular mechanisms. 1,25VD3 treatment increases the expression of VDR, SIRT1, and SIRT3 in C2C12 myotubes. Additionally, it stimulates the differentiation of C2C12 myoblasts into myotubes. Furthermore, 1,25VD3 significantly enhanced the expression of key myogenic markers, including myosin heavy chain (MyHC) proteins (MyHC I and II), MyoD, and MyoG, and increased the phosphorylation of AMPK and AKT. Conversely, VDR knockdown in myoblasts induces myotube atrophy by downregulating SIRT1 and SIRT3 expression. Furthermore, 1,25VD3 ameliorated muscle atrophy and apoptosis induced by IFN-γ/TNF-α co-treatment to C2C12 myotube. Moreover, 1,25VD3 downregulated the increased expression of muscle atrophy-associated proteins, including FoxO3a, MAFbx, and MuRF1 in IFN-γ/TNF-α induced atrophy model. Importantly, IFN-γ/TNF-α significantly reduced the mtDNA copy number in C2C12 myotube, whereas the presence of 1,25VD3 effectively prevented this decrease. These results indirectly suggest that 1,25VD3 has the potential to develop as a therapeutic or preventive agent for age-mediated muscle atrophy by enhancing the VDR/SIRT1/SIRT3 axis and inhibiting the FoxO3-mediated atrophy pathway.

Chronic kidney disease (CKD) and cardiovascular disease (CVD) are highly prevalent conditions, each significantly contributing to the global burden of morbidity and mortality. CVD and CKD share a great number of common risk factor, such as hypertension, diabetes, obesity, and smoking among others. Their relationship extends beyond these factors, encompassing intricate interplay between the two systems. Within this complex network of pathophysiological processes, vitamin D has emerged as a potential linchpin, exerting influence over diverse physiological pathways implicated in both CKD and CVD. In recent years, scientific exploration has unveiled a close connection between these two prevalent conditions and vitamin D, a crucial hormone traditionally recognized for its role in bone health. This article aims to provide an extensive review of vitamin D's multifaceted and expanding actions concerning its involvement in CKD and CVD.

Background: Vitamin D and calcium are important dietary compounds that affect bone mass, even if other minerals (potassium, zinc, etc.) and other vitamins (A, C and K) are also involved. Vitamin D and other minerals, in fact, play an important role in calcium homeostasis and calcium absorption. Hip fractures incidence is higher in western countries, where calcium is frequently included in human diet, while the occurrence of these fractures is lower in developing countries, where diets are often poor in calcium. This situation is known as the “calcium paradox”, and may be partially explained considering phosphate toxicity, that can induce a disorder of mineral metabolism. It is important to maintain adequate dietary calcium-phosphate balance in order to perform a healthy life, reducing the risk of osteoporotic fracture in older people. Vitamin D can also act as a hormone; vitamin D2 (ergocalciferol) is derived from the UV-B radiation of ergosterol, the vitamin D precursor naturally found in plants, fungi, and invertebrates. Vitamin D3 (cholecalciferol) is originated by sunlight exposure from 7-dehydrocholesterol, a precursor of cholesterol that can also act as a provitamin D3. Dietary intake of vitamin D3 is very important when skin is exposed for short times to ultraviolet B light (UV-B) one of the three kinds of invisible light rays together with UV-A and UV-C. This can be considered the usual situation in northern latitudes and in winter season, or the typical condition for older people and/or for people with very white delicate skin. Actually, the recommended daily intake of dietary vitamin D is strictly correlated with age, ranging from 5 μg for infants, children, teen-agers and adults, including women during pregnancy and lactation, to 15 μg for people over 65 years.

Celiac disease is a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten, affecting approximately 1% of the global population and two million Americans. An increasing number of studies have identified a link between celiac disease and adverse maternal and fetal outcomes during pregnancy and after birth. Additionally, both celiac disease and pregnancy are associated with an increased risk for nutrient deficiencies, specifically vitamin B12 and folate. Deficiencies in these key nutrients are linked with several negative maternal and fetal health outcomes including preeclampsia, gestational diabetes, spontaneous abortion/miscarriage, preterm birth, NTDs, Intrauterine Growth Restriction, and low gestational age and birthweight. This review examines the current literature related to the folate trap and vitamin B12 deficiency in patients with celiac disease and pregnant women independently, and to provide rationale for future research to explore the correlation between the folate to B12 ratio in pregnant woman with celiac disease.

Background: The utilization of nutrient supplementation as a tool to address issues such as iron and vitamin A deficiencies among children in Sub–Saharan Africa (SSA) has been beneficial. Nevertheless, there is a dearth of evidence on the effect of vitamin A and iron supplementation on infectious diseases in pre–school children in SSA. We aimed to assess the association of vitamin A and iron supplementation on the incidence of major clinical features of infectious diseases (diarrhea, cough, and fever) in children aged 6–59 months in Ghana. Methods: A cross–sectional study that utilized data from the Ghana Demographic and Health Survey, involving a sample size of 2,408 children. The collected data was analyzed using binomial logistic regression. Results: Dual supplementation with vitamin A and iron was associated with an increased risk of fever (OR: 1.68 95% CI: 1.22–2.32) and cough (OR: 1.43, 95% CI: 1.02–1.99) in children 6–59 months. Iron supplementation alone was associated with an increased risk of fever (OR: 1.32, 95% CI: 1.01–1.72) while Vitamin A alone significantly increased the risk of diarrhea (OR: 1.73, 95% CI: 1.03–2.92). Conclusions: Dual supplementation of vitamin A and iron is associated with an increase in childhood morbidity, endorsement of combined supplementation should be done with caution.

Relapses and resistance to therapeutic agents are major barriers for treatment of acute myeloid leukemia (AML) patients. This unfavorable circumstance emphasizes the need for new strategies targeting drug-resistant cells. As IDH mutation is present in the preleukemic stem cells and systematically conserved at relapse, targeting mutant IDH cells would be essential to achieve a long-term remission in the AML subgroup with IDH mutation. Here, using a panel of human AML cell lines and primary AML patient specimens harboring IDH mutation, we showed that the presence of IDH mutation through the production of an oncometabolite (R)-2-HG induces vitamin D receptor related transcriptional programs, priming these AML cells to differentiate with pharmacological doses of ATRA or/and VD. This activation occurs in a CEBP-dependent manner. Accordingly, our findings illuminate potent and cooperative effects of IDH mutation and vitamin D pathway to differentiate in AML, revealing a novel therapeutic approach easily transferable/immediately applicable in clinics for this subgroup of AML patients.

The aim of this study was to detect seasonal and species differences in serum 25-hydroxy vitamin D (25(OH)D) concentrations during summer and winter months in Asian (Elephas maximus) and African elephants (Loxodonta africana), black (Diceros bicornis) and Indian rhinoceroses (Rhinoceros unicornis) and Malayan tapirs (Tapirus indicus) - when kept in captivity in (Western) Europe. Both elephant species had a low circulating level of serum 25(OH)D while African elephants (median 33.2 nmol/l – range: 21.2-58.8 nmol/l,) did not show a seasonal variation. Asian elephants had significant higher circulating levels of serum 25(OH)D compared to their African counterparts, but also did not show a seasonal difference (median 68.7, – range 55.5-110.6 nmol/l). Both rhinoceros species investigated had higher serum 25(OH)D levels compared to both elephant species; the Indian rhinoceros had high circulating levels year around (median 107.9 – range: 106.3-132.8 nmol/l), while the black rhinoceroses showed significant lower 25(OH)D levels in winter (summer median 109.0– range 51.5-251.0 nmol/l; winter median 58.3 nmol/l - range 23.5-226.0 nmol). Malayan tapirs have very low levels of serum 25(OH)D (median &lt; 20.3 – range &lt; 20.3-33.5 nmol/l), which is comparable to horses. Higher levels of circulating 25(OH)D of elephants and rhinoceroses compared to horses, could indicate that elephants and rhinoceroses are capable of producing vitamin D. However, this requires further testing. If this is indeed the case, this might indicate that the Indian rhinoceros are capable of producing enough endogenous vitamin D year around at latitudes around 52°N, while both elephant species and the black rhinoceros are not. To the author’s knowledge, this is the first report of vitamin D levels in tapirs.

Study Objectives: The aim of this study is to explore the association between serum 25-hydroxyvitamin D [25(OH)D] levels, a marker of Vitamin D status, and excessive daytime sleepiness (EDS), expressed as increased scores of Epworth Sleepiness Scale (ESS), in a group of prospectively enrolled patients with obstructive sleep apnea (OSA). Methods: Newly diagnosed patients with OSA, divided into two groups, those with EDS (ESS>10) and those without EDS (ESS

Vitamin D and iron deficiencies are the most prevalent micronutrient deficiencies among women of reproductive age (WRA) in Morocco. Recent studies suggest that Vitamin D deficiency (VDD) may reduce iron bioavailability necessary for erythropoiesis, potentially leading to iron deficiency (ID) and anemia. This study investigates the association between vitamin D status, iron levels, and anemia risk among Moroccan WRA aged 18-49 years. A cross-sectional study was conducted with 463 participants. Serum levels of 25(OH)D, blood count parameters, iron, ferritin, C-reactive protein, and creatinine were measured. Lifestyle factors, including dietary intake, sun exposure, and physical activity, were evaluated using validated questionnaires, and anthropometric data were collected. Linear and logistic regression models assessed the relationships between variables, while Receiver Operating Characteristic (ROC) curve analysis evaluated the predictive accuracy of VDD for ID and anemia. VDD (25(OH)D &lt; 20 ng/ml) was significantly associated with lower levels of hemoglobin, hematocrit, red blood cells, and ferritin (all p &lt; 0.01), suggesting a role of vitamin D in erythropoiesis and iron storage. Multivariate logistic regression showed that VDD increased the risk of anemia (OR: 7.17, 95% CI: 3.19-19.28, p &lt; 0.001), ID (OR: 2.20, 95% CI: 1.32-3.77, p = 0.007), and IDA (OR: 4.10, 95% CI: 1.73-12.08, p = 0.004). Dietary iron intake was inadequate among all participants, with minimal protective effect against anemia and ID (β(SE): -0.08(0.03), p = 0.030 and β(SE): -0.05(0.02), p=0.037 respectively). ROC analysis demonstrated moderate discriminative power for VDD in diagnosing IDA and anemia (AUC: 0.643 and 0.603) but reduced accuracy for ID (AUC: 0.575). This study identifies VDD as a significant risk factor for impaired iron status and anemia among Moroccan WRA, underscoring the need for targeted nutritional interventions and further research to explore effective prevention strategies.

This review examines the challenges faced by the pig industry, with a specific emphasis on improving the health and growth of weaned pigs. It emphasises the immediate necessity of investigating alternative approaches to managing pig nutrition and health due to restrictions on the use of antibiotics and the prohibition of zinc oxide in weaned pig diets. The weaning phase is identified as a critical stage in piglet development, characterized by stressors that affect their gastrointestinal health, immune responses, and overall physiology. The primary challenge during weaning arises from transitioning piglets from a digestible milk-based diet to a less digestible cereal-based feed, causing nutritional stress. This manifests as reduced feed intake, leading to gastrointestinal disturbances, intestinal inflammation, and adverse effects on intestinal structure and microbiota. To address these challenges and optimise piglet development, various nutritional strategies have been explored. Notably, glucans, particularly β-glucans from fungi, cereals, algae, and yeast, show promise in alleviating weaning-related issues. Furthermore, it's important to highlight the critical roles played by vitamin D and selenium in piglet nutrition. These essential nutrients can be sourced naturally from enriched mushrooms that are specifically enriched with vitamin D and selenium, providing a valuable dietary option. In conclusion, effective nutritional strategies, including glucans, vitamin D, selenium, and enriched mushrooms, are beneficial for addressing weaning-related challenges.

The purpose of this research was two-fold: (a) to observe whether highly trained adolescent swimmers abide to vitamin D supplement recommendations; and (b) to monitor changes in circulating 25-hydroxyvitamin D (25(OH)D) that occur between the autumn and winter months. Twenty swimmers (age: 17 ± 2 years) from a UK high-performance swimming club volunteered to complete two blood spot cards to determine 25(OH)D concentration: the first in an autumn training phase (October) and the second during winter training (January). All swimmers were advised to consume vitamin D3 supplements across the assessment period; however, only 50% of swimmers adhered to this recommendation. Resultantly, a winter decline in 25(OH)D was observed in non-supplementing swimmers (79.6 ± 25.2 to 52.6 ± 15.1 nmol·L-1, p = 0.005), with swimmers either displaying an ‘insufficient’ (60%) or ‘deficient’ (40%) vitamin D status. In comparison, greater maintenance of 25(OH)D occurred in supplementing swimmers (92.0 ± 25.5 to 97.2 ± 38.3 nmol·L-1, p = 0.544), although variable outcomes occurred at the individual level (four increased, three maintained, three declined). These findings highlight possible risks of vitamin D insufficiency during the winter for swimmers in the UK, possibly requiring standardised supplement practices. Moreover, alternative educational strategies may be required for swimmers to transfer knowledge to practice in order to improve supplement adherence in future.

Background: Vitamin D is essential for bone health, influencing bone mineral density (BMD) and the prevention of bone-related disorders. Despite its importance, Vitamin D deficiency remains prevalent among young adults, raising concerns about its impact on skeletal health. Objective: This review aims to summarize the current understanding of Vitamin D's role in bone health, focusing on its effects on BMD in young adults, and to identify gaps in the existing literature. Methods: A comprehensive narrative review of recent studies and guidelines was conducted, covering Vitamin D synthesis, its impact on bone health, dietary recommendations, and public health implications. Data were sourced from PubMed, Google Scholar, and relevant clinical guidelines.

Objective: In this study, we investigated vitamin D, inflammatory hematologic ratios such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), MHR and plasma atherogenic index (PAI) and possible relationships with insulin resistance in children. Methods: A total of 210 individuals, including 96 children with insulin resistance and 114 children without insulin resistance, aged 6-18 years, who were admitted to the Pediatric Endocrinology Outpatient Clinic at Medicine Hospital, Istanbul Atlas University were included in our study. Result: NLR, PLR, SII and MHR were significantly higher in patients with insulin resistance compared to those without. Fasting insulin, PAI, HOMA-IR, HOMA- were significantly higher and QUICKI was significantly lower in patients with insulin resistance compared to those without insulin resistance. NLR, SII and MHR were lower in normal vitamin D groups than the others were (p

It is widely known that vitamin D receptors have been found in neurons and glial cells and their highest expression is in the hippocampus, hypothalamus, thalamus and subcortical grey nuclei, and substantia nigra. The vitamin D helps the regulation of neurotrophin, neural differentiation and maturation, through the control operation of growing factors synthesis (ie NGF and GDNF), the trafficking of the septo-hyppocampal pathway, and the control of the synthesis process of different neuromodulators (such as Ach, DA, and GABA). Based on these assumptions, we have written this review in order to summarize the potential role of vitamin D in neurological pathologies. The work could be titanic, and might result very fuzzy and even incoherent, if we would not have conjectured to taper our first intentions and devoted our interests towards three mainstreams: demyelinating pathologies, vascular syndromes and neurodegeneration. Due to the lack of effective therapeutic options, a part from the disease modifying strategies, the role of different risk factors should be investigated in neurology, as far as their correction may lead to the improvement of the cerebral conditions. We have explored the relationships between the gene-environmental influence and long term vitamin D deficiency, as a risk factor for the development of different types of neurological disorders, along with the role and the rationale of therapeutic trials with vitamin D implementation.

COVID-19 is a pandemic triggered by the coronavirus SARS-CoV-2 whose peak occurred in the years 2020 and 2021. The main target of the virus is the lung and infection is associated to an accentuated inflammatory process involving mainly the innate arm of the immune system. Here, we described the induction of a pulmonary inflammatory process triggered by the intranasal (IN) instillation of UV-inactivated SARS-CoV-2 in C57BL/6 mice and then the evaluation of vitamin D (VitD) ability to control this process. The assays used to estimate the severity of lung involvement included total and differential number of cells in the BALF, histopathological analysis, quantification of T cell subsets and inflammatory mediators by RT-PCR, cytokine quantification in lung homogenates and flow cytometric analysis of cells recovered from lung parenchyma. IN instillation of inactivated SARS-CoV-2 triggered a pulmonary inflammatory process, consisting of various cell types and mediators, resembling the typical inflammation found in COVID-19 patients. This inflammatory process was significantly decreased by IN delivery of vitD, but not by its IP administration, suggesting that this hormone has therapeutic potential in COVID-19 if locally applied.

Vitamin D has previously been quantified in some plants and algae, particularly in leaves of the Solanaceae family. We measured the vitamin D content of Australian native food plants and Australian-grown edible seaweed. Using liquid chromatography with triple quadrupole mass spectrometry, 13 samples (including leaf, fruit and seed) were analysed in duplicate for vitamin D₂, vitamin D₃, 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃. Five samples contained vitamin D₂: raw wattleseed (Acacia victoriae) (0.03 µg/100 g dry weight (DW)); fresh and dried lemon myrtle (Backhousia citriodora) leaves (0.03 and 0.24 µg/100 g DW, respectively); dried leaves and berries of Tasmanian mountain pepper (Tasmannia lanceolata) (0.67 and 0.05 µg/100 g DW, respectively). Fresh kombu (Lessonia corrugata) contained vitamin D₃ (0.01 µg/100 g DW). Detected amounts were low; however, it is possible that exposure to ultraviolet radiation may increase the vitamin D content of plants and algae if vitamin D precursors are present.

The aim of this single-center, open-label, non-controlled randomized study was to evaluate which formulation of vitamin D between cholecalciferol and calcifediol is most effective in the treatment of hypovitaminosis D in older adults. Demographic characteristics, clinical history and comprehensive geriatric assessment were recorded at admission. Eligible patients randomly received an equivalent vitamin D supplement either with cholecalciferol or calcifediol from hospital admission to three months after discharge. Among the 140 older patients included (mean age 83±6.6, 57.8% females), 69 received cholecalciferol and 71 calcifediol. The mean plasma values of 25OH-Vitamin D3 found at the enrollment were 16.8 ± 9.9 ng/mL in patients receiving cholecalciferol and 18.8 ± 13.3 ng/mL in those treated with calcifediol (p =0.31). At the 3-month follow up, the mean concentration of 25OH-Vitamin D3 was significantly higher in patients treated with calcifediol than in patients treated with cholecalciferol (respectively, 30.7 ± 8.4 vs 45.4 ± 9.8 ng/mL, p &lt;0.001). Supplementation with cholecalciferol or calcifediol results in both cases effective in reaching optimal circulating values of 25OH-VitaminD3 in the older patients suffering from hypovitaminosis D. However, supplementation with calcifediol led to average circulating values of 25OH- VitaminD3 significantly higher (over 50%) than those obtained with cholecalciferol.

Treatment with calcitriol, the hormonal form of vitamin D, has shown beneficial effects in ex-perimental models of acute lung injury. In this study we aimed to analyze the associations be-tween calcitriol supplementation and the risk of SARS-CoV2 infection or COVID-19 mortality. Individuals ≥18 years old living in Catalonia and supplemented with calcitriol from April 2019 to February 2020 were compared with propensity score matched controls. Outcome variables were SARS-CoV2 infection, severe COVID-19 and COVID-19 mortality. Associations between calcitriol supplementation and outcome variables were analyzed using multivariable Cox proportional regression. A total of 8076 patients were identified as being on calcitriol treatment. Advanced chronic kidney disease and hypoparathyroidism were the most frequent reasons for calcitriol supplementation in our population. Calcitriol use was associated with reduced risk of SARS-CoV2 infection (HR 0.78 [CI 95% 0.64-0.94], p=0.010), reduced risk of severe COVID-19 and reduced COVID-19 mortality (HR 0.57 (CI 95% 0.41-0.80), p=0.001) in patients with advanced chronic kidney disease. In addition, an inverse association between mean daily calcitriol dose and COVID-19 severity or mortality was observed in treated patients, independently of renal function. Our findings point out that patients with advanced chronic kidney disease could benefit from calcitriol supplementation during the COVID-19 pandemic.

The use of vitamin D (VitD) supplements has become widespread in the last decade due not only to the dissociation between the blood levels recommended as "optimal" and those shown by the healthy population, but also to its presumed beneficial effects on multiple disorders. This work evaluated the levels of 25-hydroxyvitamin D [25(OH)D] in a healthy population of European origin living in a region with high solar irradiation. In serum samples from a population-based study conducted in the Canary Islands, levels of 25(OH)D were analyzed. In 876 individuals who had no history of kidney or malabsorption disorders and who had not been treated with calcium and/or VitD supplementation, the median 25(OH)D level was 26.3 (5th;95th percentile, 14.3;45.8)ng/mL. Notably, 65.4% of the population had 25(OH)D blood levels below 30ng/mL, 23.4% below 20ng/mL and 6.4% below 15ng/mL. Based on the lack of evidence supporting causality between 25(OH)D levels below what is recommended as optimal (≥20ng/mL, or even ≥30ng/mL) and major skeletal and non-skeletal diseases, and in light of the distribution of the concentration of this vitamin in healthy adults living under optimal conditions of solar irradiation, it seems reasonable to consider 25(OH)D levels below 20ng/mL and close to 15ng/mL as adequate for the general population.

The post-hoc analysis presented here aimed to address the influence of endogenous vitamin D in the immunological mechanism underlying effective mite allergoid-immunotherapy (AIT). Previously, we have shown that one subpopulation of T regulatory cells results in phenotypically identifiable as functionally potentiated and memory cells in allergic children after 12 months of this immunoactive treatment. Indeed, AIT is the only known treatment able to reshape the detrimental immune response against the allergen into a not noxious one. Besides, VD is widely considered an immunoregulatory molecule endogenously produced and exogenously provided with foods and supplements that might interact with AIT mechanism and affect its outcome. Therefore, a post-hoc analysis of the clinical and immunological data of three different cohorts of allergic patients was performed. One cohort (N=70) was on standard symptoms-controlling pharmacological treatment while the other two (N=60 and N=35, respectively) were treated with AIT for 12 months. Among the first were observed a lower mean endogenous VD level (&lt;22 ng/ml) along with worse symptoms and higher use of medications. Remarkably, the comparison between two sub-cohorts of patients with serum VD above (N=32) or below (N=28) a cut-off value set at mean value (27 ng/ml) revealed that optimal improvement of all clinical and immune parameters was achieved (as expected by effective AIT), irrespective of the VD level. Notably, the third analysis, carried out on one cohort of AIT patients also taking concomitantly VD3 as food supplement (N=19), was distinguished by uppermost overall treatment outcome (amelioration of symptoms, lowest medications requirement, and reduction of total and allergen-specific IgE) as well as the increase of allergen-specific tolerogenic memory T regulatory cells. These findings suggest that endogenous VD level affects allergy severity and allergen immunotherapy effectiveness. Also, VD3 might be investigated as an add-on supplement to get the best out of immunotherapy in VD deficient/insufficient allergic patients. The immunogenic but low-allergenic mite allergoid used as bioactive agent might have contributed to minimize allergic and highlight immunological effects described here.

Abstract: COVID-19 in 2020 brought challenges to the Brazilian public health system with an emerging virus with respiratory contagion called SARS-CoV-2. There are few studies in Brazil and in some countries, on the increased incidence of certain viral respiratory infections, includ-ing H1N1 and coronavirus and their association with low levels of vitamin D, zinc and iron. The aim of this study was to demonstrate that the deficit of vitamin D, zinc and iron has an impact on the infectious process of patients with COVID-19 and to establish new forms of prevention for the worsening of COVID-19 in the human body. Data were collected from medical records and test results from patients being followed up during the treatment period for COVID-19. Patients with low blood levels of vitamin D, zinc and iron during the treatment period of COVID-19 had a higher percentage of worsening and complications requiring hospitalization in intensive care beds. The ingestion of vitamin D, zinc and iron in the treatment period of patients with COVID-19 in addition to being an immunological protector against SARS-CoV-2 and alleviating the process of worsening the disease can also act as a biomarker in cases of this disease.

Observational studies have linked vitamin D insufficiency to pediatric type 2 diabetes (T2D) , but evidence from vitamin D supplementation trials is sparse. Given the rising prevalence of pediatric T2D in all ethnicities, determining a protective role of vitamin D has significant public health importance. We tested whether serum 25-hydroxyvitamin D (25OHD) levels are causally linked to youth-onset T2D risk using Mendelian randomization (MR). We selected 54 single nucleotide polymorphisms (SNPs) associated with 25OHD in a European genome-wide association study (GWAS) on 443,734 individuals and obtained their effects on pediatric T2D from the multi-ethnic PRODIGY GWAS (3,006 cases/6,061 controls). We applied inverse variance weighted (IVW) MR, and a series of MR methods to control for pleiotropy. We undertook sensitivity analyses in ethnic sub-cohorts of PRODIGY, and using SNPs in core vitamin D genes or ancestry-informed 25OHD SNPs. Multivariable MR accounted for mediating effects of body mass index. We found that a standard deviation increase in 25OHD in the logarithmic scale did not affect youth-onset T2D risk (IVW MR odds ratio (OR) = 1.04, 95% CI=0.96-1.13, P=0.35) in the multi-ethnic analysis, and sensitivity, ancestry-specific and multivariable MR analyses showed consistent results. Our study had limited power to detect small/moderate effects of 25OHD (OR of pediatric T2D < 1.39 to 2.1). In conclusion, 25OHD levels are unlikely to have large effects on risk of youth-onset T2D across different ethnicities.

The appropriate concentration of vitamin D in the athlete’s body is essential for its proper functioning, especially in terms of muscular health, by enhancing recovery and oxygen consumption. Soccer players are required to perform frequent sprints and change of directions during training and competition. The aim of the present study was to establish whether the level of vitamin D (measured by 25-hydroxyvitamin D concentrations- 25(OH)D) in blood serum has any influence on speed (s) and change of direction (COD, s) performance. Material and methods: Twenty male soccer players from the top league in Poland participated in the study. All subjects' were evaluated for the serum concentration of 25(OH)D at the beginning of the preseason. . The linear sprint test was performed at 5m and 30m and COD (time and deficit), was evaluated at 30m at the beginning and after 6 weeks of preparatory period. Results: The results revealed that 50% of soccer players had an insufficient level or a deficit of 25(OH)D (≤ 30 ng/ml), with 20% having a significant deficiency of 30 ng/ml).There were no statistically significant correlations between the training effect for the variables ∆5m (before - after) and ∆30m (before - after). Statistically significant positive correlations were found between the training effect for the variables ∆COD (before - after) (R=0.62/p=0.003) and ∆deficit (before-after) (R=0.47/p=0.039). With a higher concentration of vitamin D in the blood, the training effect for COD and the deficit increased, which was visible in the faster performance of the COD test. No statistically significant differences were found for the mean values of the variables ∆5m (before - after) and ∆30m (before - after) in the group of subjects whose 25(OH)D concentration was 30mg /ml. Significant differences were noticed for the variables ∆COD (m=0.60 [s]) and ∆deficit (m=0.56[s]) in the group of subjects whose 25(OH)D concentration was 30mg /ml. The training effect was significantly higher for the group of subjects whose 25(OH)D concentration was above 30 mg/ml, which was observed by the faster performance of the COD test in this group of subjects. Conclusions: The serum concentration of vitamin D affects training adaptations of muscles. A lower concentration of Vitamin D seems to have a detrimental effect on the change of direction performance. Soccer players whose blood serum 25(OH)D concentrations were >30mg/ml achieved better results in the applied fitness tests.

The role of vitamin D in the prevention and treatment of non-skeletal health issues has received significant media and research attention in recent years. Costs associated with clinical management of low vitamin D (LVD) have increased exponentially. However, no clear evidence supports vitamin D screening to improve health outcomes. Authoritative bodies and professional societies recommend against population-wide vitamin D screening in community-dwelling adults who are asymptomatic or at low risk of LVD. In order to assess patterns of physician management of LVD in this conflicting environment, we conducted a scoping review of three electronic databases and gray literature. Thirty-eight records met inclusion criteria and were summarized in an evidence table. Results from seven countries showed a consistent increase in vitamin D lab tests and related costs. Many vitamin D testing patterns reflected screening rather than targeted testing for individuals at high risk of vitamin D deficiency or insufficiency. Interventions aimed at managing inappropriate clinical practices related to LVD were effective in the short term. Variability and controversy were pervasive in many aspects of vitamin D management, shining light on physician practices in the face of uncertainty. Future research is needed is needed to inform better clinical guidelines and to assess implementation practices that encourage evidence-based management of LVD in adult populations.

Background: Shorter leukocyte telomere length (LTL) is observed in multiple age-related diseases, which are also associated with vitamin D deficiency (i.e., osteosarcopenia, neurocognitive disorders, cancer, osteoarthritis, etc.), which suggests a close association. In this study, we examined the relationship between vitamin D levels and LTL in older participants of the UK Biobank. Methods: Data were collected from the UK Biobank. Participants aged 60 and older (n=148,321) were included. Baseline LTL was measured using a multiplex qPCR technique and expressed as the ratio of the telomere amplification product (T) to that of a single-copy gene (S) (T/S ratio). Se-rum 25-hydroxyvitamin D (25OHD) was stratified by z score and linked to LTL in a linear regression model adjusting for covariates. Results: Compared to the medium level, a low (in the range of 16.6 nmol/L, 29.7 nmol/L) or extremely low (≤ 16.6 nmol/L) level of serum 25OHD was associated with shorter LTL: 0.018 SD (standardized β= -0.018, 95% CI -0.033 to -0.003, P=0.022) and 0.048 SD (standardized β= -0.048, 95% CI -0.083 to -0.014, P=0.006), respectively. Additionally, the high serum 25OHD groups (> 95.9 nmol/L) had 0.038 SD (standardized β= -0.038, 95% CI -0.072 to -0.004, P=0.030) shorter mean LTL than the group with medium 25OHD levels. The associations above were adjusted for multiple variables. Conclusion: In this population-based study, we identified an inverted U-shape relationship between LTL and vitamin D status. Whether high or low vitamin D-associated shorter LTL is mechanistically related to age-related conditions remains to be elucidated.

Certain micronutrients exhibit immunomodulatory effects. However, no intervention has yet investigated the effect of an individualized supplementation on the severity of upper respiratory tract infections (URI). Therefore, we investigated whether a personalized supplementation moderates the incidence and severity of URI. Selenium, zinc, and vitamin D was measured from 59 healthy participants ) in dried blood spots. Accordingly, a personalized supplement was provided with or without the respective micronutrients. We used WURSS-21 questionnaires to assess the disease status. The blood values converged during the intervention and micronutrients no longer differed at the end of the intervention period between treated and untreated volunteers. The incidence and severity of the illness did not significantly differ between the groups. However, when analyzing the WURSS-21 score by the intention to treat, the initially randomized treatment arm revealed a significantly higher score than the placebo arm. Upon acute administration, individualized combination of selenium, zinc and vitamin D does not reduce the number or contribute to a milder course of URIs. Therefore, supplementation in acute infectious situations seems questionable. Further studies must address the habitual diet in more detail to better understand the impact of individual micronutrient status on the prevention of URI.

Background/Objectives: Type 1 Diabetes Mellitus (T1DM) is the reduction or non-production of insulin. As T1DM increases cardiovascular risk, in addition to glycemic control, the monitoring of other risk factors, such as lipid profile, has gained attention. Vitamin D deficiency has been associated with the pathophysiology of T1DM, metabolic syndrome, and cardiovascular diseases. This study investigated the relationship between vitamin D, glycemic control, and lipid profiles in children and adolescents with T1DM. Methods: This observational study consisted of 81 patients with T1DM. Laboratory test data were collected to determine the lipid profile. Glycated hemoglobin (HbA1c) and fasting glucose levels assessed glycemic control. Results: A significant association was observed between serum vitamin D levels and a pubertal stage and a moderate negative correlation between vitamin D, age, and HbA1c. There is a negative correlation between vitamin D levels and age, as well as with HbA1c, and a positive correlation of HbA1c with glucose, total cholesterol, triglycerides, Low-density lipoprotein (LDL-c), non-HDL cholesterol (non-HDL cholesterol), apolipoprotein B (apoB), and the apolipoprotein B/apolipoprotein A ratio. Finally, the study indicated that vitamin D levels, insulin administration method, and total cholesterol, when considered together, explained approximately 43.6% of the observed variation in HbA1c, highlighting the complex interdependence of these factors in regulating glycemia. Conclusions: Our results show that Vitamin D levels are associated with glycemic control and other biochemical parameters and its control can bring benefits to the patient with T1DM.

Studies shows that, normal to high serum 25(OH)D status appears to have some beneficial influence on the incidence and severity of some, though not all, types of infections. However, studies with vitamin D supplementation on young children produced conflicting results with respect to the level of vitamin D deficiency among common medical illnesses among children. Method: A systematic review of literatures from PubMed, CINAHL, Web of science, global health and Google scholar electronic databases was conducted to assess the pooled prevalence of vitamin D deficiency among healthy and sick children in sub-Saharan Africa. The data was extracted by two authors independently using standard data extraction format and STATA Version 14 was used for analysis. The heterogeneity of the studies was assessed by using I2 test. A random-effects model was used to estimate the pooled prevalence among both healthy and sick children. Presence of publication bias was checked using Funnel plot and Egger's test. Result: A total of 1212 articles were identified by the total search of utilized data bases of which 13 papers fulfilled the inclusion criteria and accessible with full document. The meta-analysis revealed that the pooled prevalence of vitamin D deficiency among healthy children in this study was 50.06% (95%CI 33.46%, 66.67%) with mean serum vitamin D level of 41.06 nm/L (CI range from 23.82nm/L to 58.31nm/L). The pooled prevalence among the sick children was 39.36% (CI 20.57%, 57.96%) with 66.96nm/L (95% CI 54.81nm/L, 79.11nm/L) mean concentration of vitamin D. Comparing the two level of the pooled prevalence, the prevalence among the healthy children was significantly higher compared to those who have common medical illnesses and the pooled mean concentration among the sick was much higher than the mean concentration among healthy children. Conclusion: The level of pooled prevalence among both group of population was significantly of public health concern and the prevalence among the healthy children was much higher among the sick children implying the need for reconsideration of available recommendations for the prevention of vitamin D deficiency

Background: The immunomodulatory role of 1,25-Dihydroxy vitamin D3 (1,25(OH)2D3) is exerted through its interaction with the Vitamin D receptor (VDR) present on pancreatic and immune cells. While a deficiency in Vitamin D has been linked to Type 1 Diabetes Mellitus (T1DM), the exact molecular mechanism driving this down-regulation in T1DM is yet to be fully understood. This study aimed to decipher differences in the expression of genes associated with Vitamin D metabolism in T1DM patients and to ascertain if there is a correlation between serum 1,25(OH)2D3 levels and the expression of these genes. We also sought to understand the influence of specific microRNAs (miRNAs) on the expression of Vitamin D metabolism genes in peripheral blood mononuclear cells (PBMCs) of T1DM patients. Furthermore, the study delved into the potential implications of altered Vitamin D metabolism genes and miRNAs on autoimmune processes. Methods: Utilizing real-time PCR, we assessed the expression profiles of genes encoding for 1-hydroxylases (CYP27B1) and 24-hydroxylases (CYP24A1), as well as related miRNAs, in PBMCs from 30 T1DM patients and 23 healthy controls. ELISA tests facilitated the measurement of 1,25(OH)2D3, GAD65, and IA-2 levels. Results: Our findings showcased down-regulated CYP27B1 mRNA levels, while CYP24A1 expression remained stable compared to healthy subjects (CYP27B1, p = 0.0005; CYP24A1, p = 0.205, respectively). In T1DM patients, the levels of has-miR-216b-5p were found to be increased, while the levels of has-miR-21-5p were decreased in comparison to the control group. Notably, no correlation was identified between the expression of CYP27B1 in T1DM patients and the levels of has-miR-216b-5p, has-miR-21-5p, and 1,25(OH)2D3. A significant negative correlation was identified between CYP27B1 mRNA levels in PBMCs of T1DM and IA2, but not with GAD65. Conclusions: The study highlights there were reduced levels of both CYP27B1 mRNA and has-miR-21-5p, along with elevated levels of has-miR-216b-5p in the PBMCs of T1DM. However, the absence of a correlation between the expression of CYP27B1, levels of has-miR-216b-5p, and the status of 1,25(OH)2D3 suggests the possible existence of other regulatory mechanisms. Additionally, the inverse relationship between IA2 autoantibodies and CYP27B1 expression in T1DM patients indicates a potential connection between this gene and the autoimmune processes inherent in T1DM.

The global population is at risk of vitamin D deficiency due to low exposure to sunlight and low intake of the vitamin through diet. The aim was to investigate in women the association between vitamin D status and parathyroid hormone (PTH), ultraviolet radiation, lifestyle, ethnicity, social conditions, and residential greenness. A 1-year longitudinal study assessed vitamin D status in 309 women, latitude 51° 14' N. Blood samples were taken four times throughout the year for analysis of 25(OH)D and serum PTH concentration. After each seasonal visit, the individuals completed 4-day diet diaries and used two dosimeter badges for 1 week to estimate weekly UVR exposure. A questionnaire was applied to provide information about lifestyle and their ethnicity. Residential greenness was measured by Normalized Difference Vegetation Index (NDVI), within a 1000 m radius around each participant’s home address. Women living in greener spaces were more likely to have improved vitamin D status (RR: 1.51; 95%CI: 1.13 – 2.02), as well as those who were more exposed to UVR (RR: 2.05; 95%CI: 1.44 – 2.92). Our results provided a first insight into the connection between vitamin D, residential greenness, and lifestyle in a region of temperate climate and with a high degree of urbanization.

Vitamin D plays an important role in maintaining healthy mineralized skeleton. It is also consid-ered an immunomodulatory agent that regulate the innate and adaptive immune systems. Multi-ple observational studies have demonstrated the association between low level of serum 25-hydroxyvitamin D [25(OH)D] and presence and severity of several rheumatic diseases, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), spondyloarthropathies and oste-oarthritis (OA). Nevertheless, the specific benefits of vitamin D supplement for treatment and prevention of rheumatic diseases are less accepted as the results from randomized clinical trials are inconsistent, although some conceivable benefits of vitamin D for improvement of disease ac-tivity of RA, SLE and OA have been demonstrated in meta-analyses. It is also possible that some individuals might benefit from vitamin D differently from others since inter-individual difference in responsiveness to vitamin D supplementation has been observed in genomic studies. Although the optimal level of serum 25(OH)D is still debatable, it is advisable it is advisable that patients with rheumatic diseases should maintain serum 25(OH)D level at least 30 ng/mL (75 nmol/L) to prevent osteomalacia, secondary osteoporosis and fracture, and possibly 40 – 60 ng/mL (100 – 150 nmol/L) to achieve maximal benefit from vitamin D for immune health and overall health.

The present study was aimed to evaluate the levels of oxidative stress markers in breast diseases by measuring the 8-hydoxy-2-deoxyguanosine (8-OHdG), vitamin A, vitamin C, vitamin E and total antioxidant status (TAS) alterations in relation to cell proliferation activity and disease progression. Significant increases in the level of oxidative damage marker 8-OHdG and cell proliferation activity were observed in breast carcinoma patients in comparison to benign and normal controls, which were accompanied by significant decrease in non enzymatic antioxidants and TAS concentrations. 8-OHdG and cell proliferation level were negatively correlated with non enzymatic antioxidants viz., Vitamin A, Vitamin C, vitamin E level and total antioxidant activity. Altered levels of biomarkers of oxidative stress and cell proliferation activity amongst the malignant, benign and controls suggest a correlation of increased oxidative stress and cell proliferation activity in the progression of disease in breast carcinoma patients. Among the oxidative stress markers and cell proliferation index, decreased level of vitamin A, vitamin C, vitamin E, TAS and increased level of 8-OHdG, cell proliferation index emerged as best predicted biomarkers for subjects with malignancy and benign breast disease.

The nuclear hormone family of receptors regulates gene expression. The androgen receptor (AR) shuttles upon ligand binding and homodimerization from the cytosol into the nucleus to activate gene expression. Thyroid hormone receptors(TR), retinoic acid receptors (RAR), and the vitamin D receptor (VDR) are present in the nucleus bound to chromatin as a heterodimer with the retinoid X receptors (RXR) and repress gene expression. Ligand binding leads to transcription activation. The hormonal ligands for these receptors play crucial roles to ensure the proper conduct of very many tissues and exert effects on prostate cancer (PCa) cells. Androgens support PCa proliferation and deprivation alone or with chemotherapy is the standard therapy for PCa. RAR activation and 3,5,3'-triiodo-L-thyronine (T3) stimulation of TR support the growth of PCa cells. Ligand stimulation of VDR drives growth arrest, differentiation, and apoptosis of PCa cells. Often these receptors are explored as separate avenues to find treatments for PCa and other cancers. However, there is accumulating evidence to support receptor interactions and crosstalk of regulatory events whereby a better understanding might lead to new combinatorial treatments.

Abstract The aim of the present review is to discuss the roles of vitamin K and vitamin K-dependent proteins, and the combined action of the vitamins K and D, for maintenance of bone health. The most relevant vitamin K-dependent proteins in this respect are osteocalcin and matrix Gla-protein (MGP). When carboxylated these proteins appear to have the ability to chelate and import calcium from the blood to the bone, thereby reducing the risk of osteoporosis. Carboxylated osteocalcin appears to contribute directly to bone quality and strength. Adequate vitamin K status is required for carboxylation of MGP and osteocalcin. In addition, vitamin K acts on bone metabolism by other mechanism, such as a ligand for the nuclear steroid and xenobiotic receptor (SXR). In this narrative review, we examine the evidence for increased bone mineralization through dietary adequacy of vitamin K (phylloquinone or menaquinone). Summarizing the evidence for a synergistic effect of vitamin K and vitamin D3 we find that an adequate supply of vitamin K on top of an optimal vitamin D status seems to add to the benefit for maintaining bone health. More research related to synergism and possible mechanisms of vitamins D3 and K interaction in bone health is needed.

If environmental exposures are shown to cause an adverse health outcome, reducing exposure should reduce the disease risk. Links between exposures and outcomes are typically based on ‘associations’ derived from observational studies, and causality may not be clear. Randomised controlled trials to ‘prove’ causality are often not feasible or ethical. Here the history of evidence that tobacco smoking causes lung cancer – in observational studies – is compared to that of low sun exposure and/or low vitamin D status as causal risk factors for the autoimmune disease, multiple sclerosis. Evidence derives from in vitro and animal studies, as well as ecological, case-control and cohort studies, in order of increasing strength. For smoking and lung cancer, the associations are strong, consistent, and biologically plausible – the evidence is coherent or ‘in harmony’. For low sun exposure/vitamin D as risk factors for MS, the evidence is weaker, with smaller effect sizes, but coherent across a range of sources of evidence, and biologically plausible. The association is less direct – smoking is directly toxic and carcinogenic to the lung, but sun exposure/vitamin D modulate the immune system, which in turn may reduce the risk of immune attack on self-proteins in the central nervous system. Opinion about whether there is sufficient evidence to conclude that low sun exposure/vitamin D increase the risk of multiple sclerosis, is divided. General public health advice to receive sufficient sun exposure to avoid vitamin D deficiency (<50nmol/L) should also ensure any benefits for multiple sclerosis.

Vitamin D deficiencies are very common in pregnant women, raising concerns about adverse health outcomes in children. This issue has hardly been studied in multiple pregnancies, the prevalence of which has been steadily increasing. Therefore, our study investigated the relationship between newborns’ anthropometric parameters and the concentration of 25(OH)D in maternal blood of women with twin pregnancies and umbilical cord blood. The study included 50 women who gave birth after the 36th week of twin gestation. 25(OH)D was determined in maternal blood collected during the antenatal period and in the umbilical cord blood of 100 newborns. Anthropometric parameters of the newborns (birth weight, length, head and chest circumference) were obtained from hospital records. Data on nutrition and lifestyle during pregnancy were collected from the patients during an interview conducted by a dietitian. No relationship between maternal and neonatal cord blood vitamin D concentrations and any of the anthropometric parameters of the newborns was found. However, only 6% of the mothers and 13% of the newborns had vitamin D deficiency (≤20 ng/mL). The type of pregnancy and maternal height were the main factors associated with neonatal size. Newborns from dichorionic pregnancies were on average 202 g heavier (p<0.001) and 1 cm longer (p=0.006) than newborns from monochorionic pregnancies. Newborns of mothers ≤ 160 cm in height had on average 206 g lower birth weight (p=0.006) and were 3.5 cm shorter (p=0.003) compared to newborns of taller mothers. Therefore, in our study, neonatal size of the twins was not related to the vitamin D status but to other factors such as the type of pregnancy and maternal height.

Thyroid hormones have a catabolic effect on bone homeostasis. Hence, this study aimed to evaluate serum vitamin D, calcium, and phosphate and bone marker levels and bone mineral density (BMD) among patients with different thyroid diseases. This cross-sectional study included patients with underlying thyroid diseases (n=64, hyperthyroid; n=53 euthyroid; and n=18, hypothyroid) and healthy controls (n=64). BMD was assessed using z-score and left hip and lumbar bone density (g/cm2). Results showed that the mean serum vitamin D Levels of all groups was low (<50 nmol/L). Thyroid patients had higher serum vitamin D levels than healthy controls. All groups had normal serum calcium and phosphate levels. The bone marker levels were significantly high in the hyperthyroid group and low in the hypothyroid group. The z-score for hip and spine did not significantly differ between thyroid patients and control groups. The hip bone density was remarkably low in the hyperthyroid group. In all groups, the serum vitamin D levels were below the cutoff value. However, thyroid patients had a higher serum vitamin D level than healthy controls. The carboxy terminal collagen crosslink and procollagen type I N-terminal propeptide levels were high in hyperthyroid patients and low in hypothyroid patients. Further, hyperthyroid patients had a low hip BMD.

Vitamin D, sunshine and UVB phototherapy were first reported in the early 1900s to control psoriasis, cure rickets and cure tuberculosis (TB). Vitamin D also controlled asthma and rheumatoid arthritis with intakes ranging from 60,000 to 600,000 International Units (IU)/day. In the 1980s interest in treating psoriasis with vitamin D rekindled. Since 1985 four different oral forms of vitamin D (D2, D3, 1-hydroxyvitaminD3 (1(OH)D3) and 1,25-dihydroxyvitaminD3 (calcitriol)) and several topical formulations have been reported safe and effective treatments for psoriasis—as has UVB phototherapy and sunshine. In this review we show that many pre-treatment serum 25(OH)D concentrations fall within the current range of normal, while many post-treatment concentrations fall outside the upper limit of this normal (100 ng/ml). Yet, psoriasis patients showed significant clinical improvement without complications using these treatments. Current estimates of vitamin D sufficiency appear to underestimate serum 25(OH)D concentrations required for optimal health in psoriasis patients, while concentrations associated with adverse events appear to be much higher than current estimates of safe serum 25(OH)D concentrations. Based on these observations, the therapeutic index for vitamin D needs to be reexamined in the treatment of psoriasis and other diseases strongly linked to vitamin D deficiency, including COVID-19 infections, which may also improve safely with sufficient vitamin D intake or UVB exposure.

Middle East region experiences a high prevalence of hypovitaminosis D, yet most genetic studies on Vitamin D have focused on European populations. Furthermore, there is a lack of research on the genomic risk factors affecting the elderly population, who are more susceptible to health burden. We investigated the genetic determinants of 25-hydroxyvitamin D levels in elderly Lebanese individuals (n=199) through a whole exome-based genome-wide association study. We identified new loci with suggestive evidence of an association with Vitamin D levels, including rs141064014 in the MGAM gene (P-value of 4.40 × 10−06) and rs7036592 in PHF2 (P-value of 8.43 × 10−06). A meta-analysis of the Lebanese data and the largest European genome-wide association study confirmed consistence replication of numerous variants, including rs2725405 in SLC38A10 (P-value of 3.73 x 10-08). Despite the lower performance of European-derived polygenic risk scores compared to the European estimations, it still effectively predicted Vitamin D deficiency among elderly Lebanese individuals. Our findings provide novel insights into the genetic mechanisms of Vitamin D deficiency in Middle Eastern elderly populations, facilitating the development of personalized approaches for more effective management of hypovitaminosis D. Additionally, we demonstrated that whole exome-based genome-wide association study is an effective method for identifying genetic components associated with phenotypes.

COVID-19 has emerged as deadly pandemic worldwide with no vaccine or suitable antiviral drugs to prevent or cure the disease. Because of the time-consuming process to develop new vaccines or antiviral agents, there has been a growing interest in repurposing some existing drugs to combat SARS-CoV-2. Vitamin D is known to be protective against acute respiratory distress syndrome (ARDS), pneumonia and cytokine storm. Recently it has been used as a repurposed drug for the treatment of H5N1 virus-induced lung injury. Circumstantial evidences indicate that people with low level of vitamin D are more susceptible to SARS-CoV-2. Although, vitamin D was suggested to interfere with viral replication, its interaction with any SARS-CoV-2 protein is unexplored yet. Beside this, ivermectin, a well-known anti-parasitic agent, exhibits potent anti-viral activities in vitro against viruses such as HIV-1 and dengue. Very recently, ivermectin has been found to reduce viral load of SARS-CoV-2 in vitro. We have analyzed available structures of SARS-CoV-2 proteins to identify probable binding partner(s) of vitamin D and ivermectin through knowledge-based docking studies and figured out possible implication of their binding in SARS-CoV-2 infection. Our observations suggest that the non-structural protein nsp7 possesses a potential site to house 25-hydroxyvitamin D3 (VDY) or the active form of Vitamin D, calcitrol. Binding of vitamin D with nsp7 likely to hamper the formation of nsp7-nsp8 complex which is required to bind with RNA dependent RNA polymerase (RdRP), nsp12 for optimal function. On the other hand, potential binding site of ivermectin has been identified in the S2 subunit of trimeric spike(S) glycoprotein of SARS-CoV-2. We propose that deeply inserted mode of ivermectin binding at three inter-subunit junctions may restrict large scale conformational changes of S2 helices which is necessary for efficient fusion of viral and host membrane. Our study, therefore, opens up avenues for further investigations to consider vitamin D and ivermectin as potential drugs against SARS-CoV-2.

Several observational studies have indicated the potential associations between calcium, vitamin D(Vit-D) and irritable bowel syndrome (IBS). However, the causal relationship deduced from these studies is subjected to residual confounding factors and reverse causation. Therefore, we aim to explore the bidirectional causal effects between serum calcium, Vit-D, PTH and IBS at the genetic level by a two-sample Mendelian randomization (MR) analysis. Sensitivity analyses were performed to evaluate the robustness. The estimates were presented as odds ratio (OR) with their 95% confidence intervals (CIs). The results of the inverse-variance-weighted method did not re-veal any causal relationship shared between genetically predisposed calcium (OR = 0.92, 95% CI: 0.80-1.06, P = 0.25) and Vit-D (OR = 0.99, 95% CI: 0.83-1.19, P = 0.94) level and the risk of IBS. The bidirectional analysis demonstrated that genetic predisposition to IBS was associated with a de-creased level of PTH (beta: -0.19, 95%CI: -0.34 to -0.04, P = 0.01). In conclusion, the present study indicates no causal relationship between the serum calcium and Vit-D concentrations and the risk of IBS. The potential mechanisms by which IBS affects serum PTH need to be further investigated.

Low 25 OH vitamin D (25(OH)D) in preterm infants is a risk factor of bronchopulmonary dysplasia (BPD), but increased supplementation failed to demonstrate beneficial effect on BPD. In neonatal animal models, deficiency and excessive vitamin D exposure have been associated with increased mortality and lung histological alterations evocative of BPD. Our hypothesis is that 25(OH)D levels ≥ 120nmol/L is also a risk factor for BPD or death. This retrospective single-center cohort study included all infants born <31 weeks gestational age without major malformation with at least a determination of 25(OH)D <36 weeks corrected age and no determination <50 nmol/L. Routine 25(OH)D determination was performed at 1 month and monthly thereafter. A total of 175 infants were included. Infants with BPD or who died had a significantly lower term and weight, but a similar frequency of 25(OH)D ≥120nmol/L (50.5% vs 43.9%, p=0.53). The logistic regression identified weight (OR 0.997, 95%CI [0.995-0.998]) and term (OR 0.737, 95%CI [0.551-0.975]) as significantly associated with BPD or death; the occurrence of excessive 25(OH)D was not significantly associated (OR 1.029, 95%CI [0.503-2.093]). The present study did not demonstrate any significant association between excessive 25(OH)D after one month of age and BPD or death.

(1) Background: The issue of human adaptation to the Arctic environmental factors is relevant. The adaptation can be assessed through dynamic monitoring of the functional state of a person during his/her stay there. The vitamin D level in blood is one of the markers of the functional reserves of the human body and can contribute to more successful adaptation in the Arctic. (2) Methods: The study involved 38 participants in the scientific and educational expeditionary project "Arctic Floating University-2021". Blood collection for determination of vitamin D content was carried out at the beginning of the expedition. A dynamic study was carried out for 20 days in the morning and in the evening during a marine scientific expedition to the Arctic. The main parameters of the functional state of the participants were assessed using instrumental psychophysiological, projective and questionnaire methods. Statistical methods: Mann-Whitney U-test, correlation analysis using the Spearman coefficient. (3) Results: It was found that at the beginning of the expedition, the functional state of participants with severe vitamin D deficiency is characterized by a shorter average duration of RR intervals and reduced SDNN values, which may indicate a higher level of regulatory mechanisms tension. The pronounced differences in the nature of the dynamic series of objective and projective working capacity parameters were manifested most clearly. According to the subjective questionnaire characteristics of well-being, activity and mood, no significant features of the participants with vitamin D deficiency were revealed. (4) Conclusion: The participants with vitamin D deficiency in blood are characterized by a reduced adaptive capacity during the expedition to the Arctic.

Background/Objectives: Vitamin D’s effect on risk health outcomes is often evaluated using prospective cohort studies. Risk ratios (RRs; e.g., hazard ratios or odds ratios) are determined for incidence for participants with baseline serum 25-hydroxyvitamin D [25(OH)D] concentrations below or above specified values. Serum 25(OH)D concentrations vary over time, thereby diluting the effect of 25(OH)D for long follow-up periods. Inverse relationships between RR and follow-up period have been reported for all-cause mortality rate and cancer incidence rates. Here I evaluate the effect for neurological outcomes. Methods: I analyzed how follow-up period affected results from 10 cohort studies of all-cause dementia, 6 studies of Alzheimer’s disease, and 9 for cognitive impairment with respect to vitamin D deficiency. Results: For all-cause dementia, Alzheimer’s disease, and cognitive impairment, respectively, the linear regression fits are RR = 2.9 – 0.14 × years, r = 0.73, p = 0.02; RR = 2.9 – 0.14 × years, r = 0.69, p = 0.13; and RR = 1.8 – 0.066 × years, r = 0.72, p = 0.03. The regression fit to RR for the shortest follow-up period for each outcome is considered the best estimate of vitamin D deficiency’s effect on risk. Those values are approximately twice that found by averaging all RRs without considering the effect of follow-up period. Conclusions: Vitamin D’s effect on risk of neurological conditions should be determined with relatively short follow-up periods after repeated 25(OH)D measurements as warranted during follow-up.

Background: Studies have demonstrated the link between vitamin D-related genetic variations and non-skeletal outcomes. We aimed to identify all available data on the association of vitamin D-related genetic variations with non-alcoholic fatty liver disease (NAFLD). Methods: Potentially eligible studies were identified from Embase and Medline databases from inception to June 2022 using search strategy that comprised terms for “Vitamin D” and “NAFLD”. Eligible study must report the association between vitamin D-related genetic variations and presence, severity or response to treatment of NAFLD. Data were extracted from each eligible study. Results: A total of 3,495 articles were identified. After systematic review, twelve studies were in-cluded. A total of 26 genetic variations were identified. Presence of NAFLD was associated with variations of GC (rs222054, rs222020, rs10011000, rs7041), VDR (rs2228570, rs11168287, rs10783219, rs4752), CYP24A1 (rs3787557, rs6068816, rs2296241, rs2248359) and CYP27B1 (rs4646536). Severity of NAFLD was associated with variations of GC (rs4588), VDR (rs2228570, rs4334089), CYP2R1 (rs10741657), DHCR7 (rs1544410, rs3829251, rs12785878) and CYP24A1 (rs3787557, rs6068816, rs6097809, rs6127119, rs2248359, rs3787554, rs4809960, rs6022999). Response to calcitriol treatment was associated with variation of VDR (rs10735810). Conclusions: Multiple vitamin D-related genetic variations were associated with NAFLD, indi-cating the role of vitamin D in the pathogenesis of NAFLD.

In the last decade, an increasing awareness was directed to the role of Vitamin D in non-skeletal and preventive roles for chronic diseases. Vitamin D is a key hormone involved in the regulation of calcium/phosphorous balance and it has been implicated in the pathogenesis of inflammation, insulin resistance and obesity. Cholecalciferol (Vitamin D3) and Ergocalciferol (Vitamin D2) are the main form of vitamin D: the active form (1,25-dihydroxyvitamin D) is the result of two hydroxylations that take place in liver, kidney, pancreas and immune cells. Some anti-inflammatory cytokines are produced at higher levels by vitamin D, while some pro-inflammatory cytokines are released at lower levels. Toll-Like Receptor (TLR) expression is increased and a pro-inflammatory state is also linked to low levels of vitamin D. Regardless of how it affects inflammation, various pathways suggest that vitamin D directly improves insulin sensitivity and secretion. The level of vitamin D in the body may change the ratio of pro- to anti-inflammatory cytokines, which would impact insulin action, lipid metabolism, and the development and function of adipose tissue. Many studies have demonstrated an inverse relationship between vitamin D concentrations and pro-inflammatory markers, insulin resistance, glucose intolerance, metabolic syndrome, obesity and cardiovascular disease. It's interesting to note that several long-term studies also revealed an inverse correlation between vitamin D level and the occurrence of diabetes mellitus. Vitamin D supplementation in people has controversial effects, in fact while some studies demonstrated improvements in insulin sensitivity, glucose and lipid metabolism, others revealed no significant effect on glycemic control and inflammation. The aim of this review is to provide insight into the molecular basis of the relationship between vitamin D, insulin-resistance, metabolic syndrome, type 1 and 2 diabetes, gestational diabetes, and cardiovascular diseases.

Vitamin D-dependent rickets type 1A (VDDR1A) is a rare autosomal recessive disorder, caused by pathogenic variants in the CYP27B1 gene, typically characterized by growth failure, rickets, leg bowing, fracture, seizures, hyperparathyroidism, hypocalcemia, high alkaline phosphatase, high or normal 25(OH)D3, and low 1,25(OH)2D3. We studied two siblings in a Mexican family with an atypical form of VDDR1A. In addition to the typical features of VDDR1A, the proband showed cafe au lait spots, small teeth and grayish sclera, with hypophosphatemia, normocalcemia and normal 25(OH)D3, the proband´s brother showed grayish sclera. Proband underwent Next Generation Sequencing. Sanger sequencing was performed in the proband, his brother, the parents and 100 healthy controls for validation of detected variant. Both brothers presented a recurrent variant NM_000785.3; c.1319_1325dupCCCACCC and a novel nonsense variant NM_000785.3; c.227G>A in the CYP27B1 gene. Calcitriol treatment had better response in proband´s younger brother. We describe the first Mexican family with an atypical form of VDDR1A associated with novel nonsense variant, the results contribute to the phenotypic spectrum and increases the pool of pathogenic variants in CYP27B1. Data suggesting that nonsense-truncating variants play a significant role in the severity of VDDR1A.

Polymorphism of vitamin D3 receptor (VDR), has been associated with low bone mineral density and other immune and metabolic disorders; however, its impact on mortality of female dialysis patients is not well studied. This study aimed to identify bone mass-related factors, VDR gene polymorphism, and their interaction with morbid conditions that could influence all-cause mortality. In 246 female dialysis patients, age 43±11 years on continuous ambulatory dialysis peritoneal; 48%, haemodialysis; 23% and automated peritoneal dialysis; 29%. Tscore, Ca, PO4, albumin, hs-CRP, osteoprotegerin, fetuin, osteocalcin, iPTH, PINP and β-CTx were measured. PCR products were digested with Bsml to analyze VDR polymorphisms. Patients n=229; were followed for a median of 17 (15-31) months; 42 patients died. Bsml polymorphism, bb=64% and BB+Bb=36%. Hs-CRP was the risk of death in multivariate Cox Analysis. Patients with bb and inflammation had a higher risk of death (HR 2.48, 95% CI 1.08-5.68) persisted after adjustment for age, diabetes and iPTH (HR 2.33; 95% CI, 1.01-8.33) and after further adjustment for vintage, albumin, osteoprotegerin and vitamin D therapy (HR 3.49; 95% CI, 1.20-10.9). We may conclude that the presences of the bb genotype of VDR and inflammation have additive effects on all cause-mortality in females in CAPD, APD, and HD patients.

: Cardiac surgery (CS) with extracorporeal circulation (ECC), induces oxidative stress and systemic inflammatory response, which may seriously affect postoperative lung function. We aimed to test if high parenteral (200mg/kg/24h) perioperative (48h) doses of Vitamin C (VitC) may reduce the incidence and severity of postoperative pulmonary complications (PPC) in selected CS patients. Single centered, prospective, randomized, single-blinded, interventional study included 150 patients, assigned to control group A (n=75) and interventional group B (n=75). Group B intraoperatively received 1/4 of the planned daily Vit C dose (200mg/kg/24h), diluted in 10 ml of normal saline, divided into three parts, while Group A received an equal volume of normal saline at the same time frames. After 6 h from the first intraoperative dose, the following regimen was applied: Group B: 200 mg/kg/24h - 30 min i.v. infusion of VitC in 50 ml of normal saline, every 6h, for the next 48h, and Group A: 30 min i.v. infusion of an equal volume of normal saline every 6 hours, for the next 48h. Modified Kroenke’s score was used to determine the incidence and severity of PPC. The overall incidence of PPC was 36.7% and was significantly lower in Group B (13.3% v.s. 60.0%, p&lt;0.001). The severity of PPC was also significantly lower in Group B [1(1) v.s. 3(2), p&lt;0.001]. Besides, patients from Group B had significantly less damaged lungs and better postoperative renal function, shorter ICU stay, fewer ICU re-admissions, and lower hospital mortality. High parenteral daily VitC doses (200mg/kg/24h) given to selected CS patients for 48h after CS are safe and effective in reducing the incidence and severity of PPC. Further multicenter RCT is needed to confirm these results.

Abstract: A primary action of vitamin D is regulation of gene transcription. Many cell types possess genes that make antimicrobial peptides (AMPS) (endogenous antibiotics), recently discovered to be regulated by vitamin D. Two examples are cathelicidin and beta defensins, both bioactive against many different bacteria, fungi, mycobacteria, parasites and viruses. The signal transduction pathway is triggered by sensing microorganisms via cell surface receptors, causing intracellular production of calcitriol (1,25(OH)2D) and vitamin D receptors, leading to upregulation of AMP production. Serum 25(OH)D concentrations required to sustain adequate AMP production to eradicate infections are unknown. Vitamin D3 is photosynthesized in skin in amounts ranging from 10,000 (250 mcg) to 25,000 (625 mcg) International Units (IU) from 7-dehydrocholesterol after whole-body exposure to one minimal erythemal dose (MED) of ultraviolet B (UVB) radiation, and is impacted by many factors including geographic localities, seasonal changes and skin pigmentation. We and others have reported extended daily oral dosing with these amounts of vitamin D3 safe. We routinely observe serum 25(OH)D concentrations below 20ng/ml on new admissions, which have been reported insufficient to sustain AMP production. In contrast serum 25(OH)D concentrations above 100ng/ml have been reported after serial UVB treatments for psoriasis. Little vitamin D naturally occurs in food, and insufficient sun exposure may be causing worldwide deficiency. We review evidence suggesting that higher daily intakes of vitamin D3 than the currently recommended 600 (15 mcg) IU/day may be necessary to sustain AMP production in the face of an overwhelming infection, particularly in non-Hispanic blacks, a high risk population suffering the worst outcomes from COVID-19. We propose that increased vitamin D supplementation could provide a safe and cost-effective way to protect all populations from infections, in particular those from pandemic COVID-19.

Background: Potential calcium-related adverse events of vitamin D supplement use have not been addressed in large-scale, real-world data so far. Methods: Leveraging data from the UK Biobank, encompassing 445,493 individuals aged 40-69, we examined associations of high 25-hydroxyvitamin (25[OH]D) levels ≥100 nmol/L and vitamin D supplementation with hypercalcemia (plasma calcium >2.6 mmol/L), kidney stones, and atherosclerosis assessments (pulse wave arterial stiffness index and carotid intima-medial thickness). Regression models were comprehensively adjusted for 49 covariates. Results: Approximately 1.5% of the participants had high 25(OH)D levels, 4.3% regularly used vitamin D supplements, and 20.4% reported regular multivitamin use. At baseline, the hypercalcemia prevalence was 1.6%, and 1.1% were diagnosed with kidney stones during follow-up. High 25(OH)D levels were neither associated with calcium-related adverse events nor atherosclerosis assessments. Vitamin D and multivitamin supplementation were associated with an increased prevalence of hypercalcemia (odds ratios and 95% confidence intervals: 1.46[1.32-1.62] and 1.11[1.04-1.18], respectively) but were neither associated with atherosclerosis nor future kidney stones. Conclusion: High 25(OH)D levels observable in routine care were not associated with any adverse outcome. Vitamin D users have a slightly higher prevalence of hypercalcemia, possibly due to co-supplementation with calcium, but without higher atherosclerosis prevalence or risk of kidney stones.

Active vitamin D derivatives (VDDs) – 1α,25-dihydroxyvitamin D3/D2 and their synthetic analogs – are well-known inducers of cell maturation with the potential for differentiation therapy of acute myeloid leukemia (AML). However, their dose-limiting calcemic activity is a significant obstacle to using VDDs as an anticancer treatment. We have shown that different activators of the NF-E2-related factor-2/Antioxidant Response Element (Nrf2/ARE) signaling pathway, such as the phenolic antioxidant carnosic acid (CA) or the multiple sclerosis drug monomethyl fumarate (MMF), synergistically enhance the antileukemic effects of various VDDs applied at low concentrations in vitro and in vivo. This study aimed to investigate whether glutathione, the major cellular antioxidant and the product of the Nrf2/ARE pathway, can mediate the Nrf2-dependent differentiation-enhancing activity of CA and MMF in HL60 human AML cells. We report that glutathione depletion using L-buthionine sulfoximine attenuated the enhancing effects of both Nrf2 activators concomitant with downregulating vitamin D receptor (VDR) target genes and the activator protein-1 (AP-1) family protein c-Jun levels and phosphorylation. On the other hand, adding reduced glutathione ethyl ester to dominant negative Nrf2-expressing cells re-stored both the suppressed differentiation responses and the downregulated expression of VDR protein, VDR target genes, as well as c-Jun and P-c-Jun levels. Finally, using the transcription factor decoy strategy, we demonstrated that AP-1 is necessary for the enhancement by CA and MMF of 1α,25-dihydroxyvitamin D3-induced VDR and RXRα protein expression, transactivation of the vitamin D response element, and cell differentiation. Collectively, our findings suggest that glutathione mediates, at least in part, the potentiating effect of Nrf2 activators on VDDs-induced differentiation of AML cells, likely through the positive regulation of AP-1.

In this work a series of experiments on the retention of B1 (riboflavin), B2 (thiamine) and B3 (nicotinic acid) vitamins in the HILIC and RPLC conditions have been performed involving the effects of organic modifier type and content, pH of the eluent, and buffering salt (ammonium acetate) concentration in the mobile phase, as well as temperature of the system. For the needs of this studies three columns of different features have been chosen: Acclaim™ Mixed-Mode HILIC-1 (Dionex), Eurospher II 100-5 HILIC (Knauer) and the RPLC column Nucleodur® C18 Gravity – SB (Macherey –Nagel). The influence of acetonitrile and methanol content in the eluent and process temperature have been tested and basing on that the most promising systems have been selected regarding the possible separation of the vitamins mixture. Both pH and buffering salt concentrations in the eluent have been adjusted in order to indicate the most effective system which turned out to be the one involving the Nucleodur column and the eluent with 90% methanol, at pH 6 and Cbuff = 20 mmol/dm3 that enables separation of the mixture within the time as short as 2.5 minutes at 1.0 mL/s flowrate in isocratic conditions.

A 24 week-controlled trial was conducted in menopausal women (mean age:61.5) to assess serum 25-hydroyvitaminD (s25OHD) evolution in relation to three interdependent determinants: doses of supplemented (Suppl.) vitamin D₃ (VitD₃); baseline status; seasonality. Participants were randomized into 3 groups (Gr): Gr.Suppl.0, time-controls maintaining dietary habits; Gr.Suppl.5 and Gr.Suppl.10 consuming one and two 125 g servings of VitD₃-fortified yogurts with 5 and 10 µg daily doses, respectively. The 16 intervention-weeks lasted from early-January to mid-August, the 8 follow-up-weeks from late-August to mid-October. Before enrollment, subjects were randomized into two s25OHD strata: “Low stratum (LoStr)“: 25-50 nmol/L; “High stratum (HiStr)“: >50-75 nmol/L. All enrolled participants remained compliant until study end: Gr.Suppl.0 (n=45), Gr.Suppl.5 (n=44) Gr.Suppl.10 (n=44). Over the 16 intervention and 8 follow-up weeks, s25OHD increased in both supplemented groups, more in Gr.Suppl.10 than Gr.Suppl.5. The constant rate of s25OHD per supplemental VitD₃ microgram was greater in LoStr than HiStr. s25OHD increase was greater with late (mid-March) than early (mid-January) inclusion. In conclusion, this randomized trial demonstrates: -a dose-dependent s25OHD improvement related to fortified yogurt consumption; -an inversely baseline-dependent increase in s25OHD; -a seasonal effect that highlights the importance of vitamin D₃ supplementation during winter, even at 5µg/d, in healthy menopausal women.

Background/Objectives: Prospective cohort studies are useful for studying how biomolecular status affects risk of adverse health outcomes. Less well known is that the longer the follow-up time, the lower the apparent effect due to “regression dilution.” Here we evaluate how follow-up time affects the relationship between serum 25-hydroxyvitamin D [25(OH)D] concen-tration and incidence of stroke and major cardiovascular events (MCEs). Methods: Findings re-garding the relative risk (RR) of stroke and MCEs with respect to serum 25(OH)D concentrations at baseline from prospective cohort studies were plotted against mean follow-up time. Fifteen studies from mainly European countries and the United States were used for stroke, with nine studies for MCEs. Linear regression analyses were performed for follow-up periods of up to 10 years. Results: For stroke, the linear regression fit for 1–10 years is RR = 0.34 + (0.065 × follow-up [years]), r = 0.84, adjusted r2 = 0.67, p <0.001. No significant change was evident for studies with follow-up periods of 10–20 years. For MCEs, the linear fir for 1–8.1 years is RR = 1.61 ‒ (0.074 × follow-up [years]), r = 0.75, adjusted r2 = 0.49, p = 0.03. Discussion: The shorter the follow-up period, the greater the apparent effect of vitamin D in reducing risk of stroke and MCEs. In addition, the apparent effect of higher 25(OH)D concentration found for the shortest follow-up time is more than twice as high as the estimate based on averaging the results for all studies without considering follow-up time. Mechanisms have been found to explain how higher serum 25(OH)D concentrations could reduce risk of stroke and MCEs. Randomized controlled trials have not shown that vitamin D supplementation significantly reduces risk of either stroke or MCE, probably because risk of both outcomes increases rapidly below 15 ng/mL (38 nmol/L) and it is difficult in Western developed countries to enroll enough participants with concentrations that low. Nonetheless, vitamin D’s role in reducing risk of stroke and MCE can be considered causal on the basis of an evaluation of the evidence with respect to Hill’s criteria for causality in a biological system. Conclusions: Serum 25(OH)D concentrations above 20 ng/mL are associated with significantly reduced risk of stroke and MCEs in an apparent causal manner. Raising serum 25(OH)D concentrations to >20 ng/mL should be recommended for everyone likely to be at risk for stroke or MCE and indeed in the general population.