NaCl: A Determinant Factor in the Pathophysiology of Arterial Hypertension

3. Methodology

A systematic review of the scientific literature was conducted to thoroughly analyze the available evidence on arterial hypertension, its prevalence, pathophysiology, risk factors, prevention and diagnostic methods, as well as its close relationship with metabolic syndrome, obesity, and particularly, excessive sodium chloride consumption. The central focus of the search was to identify studies specifically addressing the impact of NaCl on blood pressure regulation, its role as a modifiable cardiovascular risk factor, and its relation to essential hypertension development. Structured search criteria, a systematic analysis method, and rigorous inclusion and exclusion filters were applied. Source selection was limited to original scientific articles and reviews published between 2010 and 2023, in Spanish and English. Literature available in academic databases and reliable virtual libraries was prioritized, including Google Scholar, San Martín University Foundation database, SciELO, PubMed, and Elsevier. Keywords and specific descriptors were combined using Boolean operators to optimize information retrieval. Some of the terms used were: “arterial hypertension,” “sodium chloride,” “NaCl,” “blood pressure,” “hypertension pathophysiology,” “salt intake,” “metabolic syndrome,” “obesity,” and “cardiovascular disease prevention.” Inclusion criteria encompassed observational studies, clinical trials, and systematic reviews directly addressing the relationship between salt intake and the onset or progression of arterial hypertension. Duplicated articles, non-peer-reviewed publications, studies with non-human populations, or those lacking relevant quantitative data on NaCl exposure were excluded. Finally, selected articles were organized and analyzed based on thematic relevance, methodological quality, and clinical applicability to integrate solid evidence supporting relevant conclusions on sodium chloride’s influence in the genesis, diagnosis, and prevention of arterial hypertension.

4. Results and Analysis

4.1. Prevalence and Current Status

In September 2023, the World Health Organization published a report on global hypertension prevalence, stating it affects one in three adults worldwide. The number of people with hypertension doubled between 1990 and 2019, rising from 650 million to 1.3 billion. The report highlights the importance of understanding hypertension’s silent nature, noting that nearly half of those affected are unaware of their condition. Similarly, higher prevalence exists in low- and middle-income countries due to inadequate treatment and prevention [21]. Incidence among people over 18 years exceeds 20%, being more frequent in older adults. Prevalence in women is lower than men before menopause [2].

A study by the Integral Information System of Social Protection (SISPRO) indicated that hypertension prevalence in Colombia is 40.3% in urban areas and 34.9% in rural zones. The Atlantic coast departments of Sucre and Atlántico reported prevalence above 9%, La Guajira between 3% and 6%, and other coastal departments between 6% and 9% [24].

4.2. Diagnosis and Pathophysiology of Arterial Hypertension

Blood Pressure (BP) corresponds to the tension the blood generates within arterial walls and is determined by myocardial contractility, circulating intrathoracic volume, and arterial wall structural characteristics [1]. BP is measured in millimeters of mercury (mmHg), defined by systolic pressure (SBP) from left ventricular contractions and diastolic pressure (DBP) dependent on arterial resistance [2]. Hypertension diagnosis is based on BP measurements during medical consultation. A patient presenting repeatedly with readings ≥140/90 mm Hg (SBP/DBP) is considered hypertensive, though the number of visits for diagnosis varies among institutions [1]. Dr. Casado Pérez suggests hypertension diagnosis after four visits with sustained elevated readings. BP is a variable parameter influenced by the autonomic nervous system and affected by physical and mental stimuli [2].

The pathophysiology of arterial hypertension involves the (pro)renin receptor (PRR) and the renin-angiotensin-aldosterone system (RAAS), where angiotensin II modulates BP through vasoconstriction, sympathetic nervous system activation, among other mechanisms [12]. An in-depth analysis of the pathophysiology proposed by Patrick Garner in 2018 concluded that hypertension is characterized by endothelial dysfunction due to an imbalance between vasodilatory and vasoconstrictive factors. Endothelin is a potent local vasoconstrictor, undergoing transformations to ET-1 responsible for systemic vasoconstriction, with angiotensin II being the second most potent vasoconstrictor [5]. The RAAS raises BP when the body detects decreased blood flow or pressure, necessary to maintain adequate organ perfusion. However, hyperactivation contributes to hypertension development [4].

4.3. Classification: Prehypertension, Primary and Secondary Hypertension

Hypertension classification is consistent across youth, middle-aged adults, and the elderly [25]. A patient is normotensive or has optimal BP when values are below 120/80 mmHg. Prehypertension or high-normal BP refers to systolic 130-139 mmHg and diastolic 85-89 mmHg. Primary hypertension ranges from 140-159 mmHg systolic and 90-99 mmHg diastolic. Secondary hypertension applies when BP reaches 160-179 mmHg systolic and 100-109 mmHg diastolic; grade 3 hypertension is ≥180/110 mmHg. Table 1 details these classifications [23]. Regarding age, most affected individuals are 40-49 years, with 36.1% men and 32.5% women; young men have higher hypertension prevalence than women, while women have higher prevalence after age 39 [22].

4.4. Risk Factors

BP varies throughout life, progressively increasing with age. A 2020 study by Regino et al. indicates advanced age as a risk factor for hypertension and cardiovascular diseases, along with smoking, physical inactivity, poor diet, dyslipidemia, insulin resistance, and obesity [3]. Studies show hypertension relates to central obesity, which is linked to metabolic syndrome. Physiologically, increased subcutaneous fat leads to more free fatty acid release, increased reactive oxygen species production, and impaired oxidative stress response, reducing vascular endothelial function and ultimately raising BP [8].

Different fat distributions in the body associate with hypertension and metabolic risks [8]. Salt consumption is an important factor in hypertension development and high prevalence, as are sedentary lifestyles and diets high in saturated fats and low in vegetables, contributing to overweight [2]. Bates suggests that hypertension within metabolic syndrome can cause cardiovascular diseases (CVDs) preventable by lifestyle changes [14].

4.6. Preventive Measures

Non-pharmacological preventive measures include awareness campaigns encouraging BP monitoring, especially in individuals with hypertensive relatives, since early detection prevents complications. Dr. Casado Pérez recommends the measures summarized in Table 2 [2].

The reduction of salt intake remains one of the most effective interventions to reduce hypertension prevalence. The American Heart Association recommends less than 2.3 grams of sodium per day (approx. 5.8 grams of salt), with an ideal limit of 1.5 grams per day for most adults, especially hypertensive individuals [20]. High sodium diets contribute to fluid retention, increasing blood volume and cardiac output, causing sustained elevated BP [7]. Education on dietary habits, promoting fruit and vegetable consumption rich in potassium, is also essential, as potassium intake counters sodium’s effects on blood pressure.

5. Conclusions

Arterial hypertension is a prevalent condition worldwide, significantly influenced by excessive sodium chloride consumption. This condition increases cardiovascular disease risk and is closely linked to obesity and metabolic syndrome. Its diagnosis relies on repeated blood pressure measurements, with values ≥140/90 mmHg indicating hypertension. Preventive strategies focusing on reducing salt intake, weight control, and lifestyle modifications are essential to curb its prevalence and complications. Education and awareness programs targeting populations at risk should be prioritized to promote sustainable behavioral changes.