Dementia risk and prevention in low and middle-income country settings – focus on Tanzania Mainland

As a result of an increasing population of aged people in sub-Saharan Africa, dementia is predicted to surge up to 90% by 2030. This review is set to assess the prevalence of dementia, for 65+ aged population in sub-Saharan states and particularly in Tanzania. Subsequently, the review will identify the possible risks factors – age, gender, level of education, cardiovascular problems, diabetes and mild cognitive impairment – and will lay out the challenges of reducing the dementia burden in Tanzania. Additionally, the review explores the current approaches in solving dementia disorders, including a general view on the public understanding of dementia. Also, the review recognises the gaps in government funding to mental health, a barrier to service access and the need for further research on Alzheimer’s and other dementias. Lastly, the review links the sustainable development goals (SDGs) addressed and appreciate the impact of coronavirus pandemic on the fight against dementia.


Introduction -the general outline of the context of Tanzania
Over two decades ago, Kilonzo and Simmons (1998) published an insightful paper in which they described the evolution of mental health in Tanzania. However, the evidence reviewed failed to account for any reported measures of risk of dementia in Tanzania.
Following the World Health Report (World Health Organization, 2001) and The Lancet's first global mental health series (Patel et al., 2018), the earliest studies were conducted in Tanzania by a group of researchers from Northumbria Healthcare NHS Foundation Trust and Newcastle University from 2009 to examine the prevalence and nature of dementia in rural Tanzania.
Over time, the basic inherent features surrounding dementia and mild cognitive impairment in Tanzania have been unravelled to enable appropriate health services to be directed to the aged population.
The current Tanzania population is estimated to be 56.7 million; population with 60+ years old (both male and female combined) increased by 28.5% from 1,952,041 in 2002to 2,507,568 in 2012(Ministry of Health, 2020National Bureau of Statistics, 2003). Moreover, in twenty years, the Tanzania population aged 65+ (both male and female combined) was projected to increase by 82.2% from 867,253 in 2000 to 1.58 million in 2020 (United Nations Department of Economic and Social Affairs Population Division, 2019). At birth, the sex ratio is 102.7 males per 100 females born (Chao, Gerland, Cook, & Alkema, 2019;Ministry of Health, 2020). Life expectancy at birth is projected to 75 and 83 years old by 2035 for males and females, respectively (National Bureau of Statistics & Ministry of Finance and Planning, 2018). Domestic government expenditure on health (non-communicable diseases) is 0.42% of the gross domestic product (GDP, $63.2 billion in 2019) (World Health Organization, 2020).
Increasing aged population brings about the need to further work in reducing the risks and burden caused by dementia.

The epidemiology and dementia burden in Tanzania
The prevalence of dementia in Tanzania is as high as that recorded in other places worldwide. In rural Tanzania, the prevalence of dementia was calculated to be 6.4% (95% confidence interval, 4.9 to 7.9) . In this study, which was undertaken in Hai, the rural northern part of Tanzania enrolled 1198 people with 70 or more years of age.
One hundred and eighty-four people tested positive for probable dementia, and 104 tested positive for possible dementia using the Community Screening Instrument for Dementia (CSID). Moreover, higher prevalence was significantly associated with increasing age .

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Furthermore, sub-types of dementia, Alzheimer's (ADD) and vascular dementia (VAD) are present in Tanzania. A different study by the Northumbria Healthcare Foundation Trust and Newcastle University research group demonstrated that in a group of 78 dementia cases, they recorded 38 (48.7%) and 32 (41.0%) ADD and VAD cases respectively .
While there are no recent research studies conducted to determine the changes in prevalence, the most recent survey in Tanzania looked at the out-patients neurological conditions in a private institution and found that 3.5% of the observed cases (41/1186) had Alzheimer's disease (31.7%) and vascular dementia (43.9%) (Adebayo et al., 2020). Also, in another study to diagnose the presence of delirium in 506 patients admitted in a hospital in Tanzania, 18.7% (95/506) had dementia . Although the frequencies reported in these studies do not reflect the prevalence in the general population, they are useful in assessing the evidence-based information on the effect of various combinations of neurocognitive disorders.
Combination of dementia with neuropsychological problems increases mortality rate in Tanzania aged population. Evidence suggests that for people living with dementia (PwD), a combination of age and neuropsychiatric disorders increase mortality. The sampled population of rural northern Tanzania by Longdon et al. (2013) was followed to assess their mortality for a period of four years, with mortality rates being recorded and compared against different levels of dementia severity. Their age-gender-education-adjusted results reported the hazard ratio of 6.33 (95% CI 3.19-12.58) for dementia and 3.57 (95% CI 1.64-7.79) for mild cognitive impairment respective to people without an impaired cognitive state. Mortality rates were also highly recorded in subjects with vascular dementia . The same study laid out a set of frequencies of neuropsychiatric disorders from 78 study participants. Of 78 PwD, 69 (88.4 per cent) reported at least one present behavioural and psychological symptoms, with 40 (51.3 per cent) having three or more symptoms, and anxiety (47.4 per cent), agitation/aggression (38.5 per cent), night-time behavioural illness (34.6 per cent), irritability (33.3 per cent) and depression being the most common symptoms reported (33.3 per cent) .
Generally, the prevalence of dementia in Tanzania corresponds to results from highincome countries (HICs) reported by the 10/66 research group (Fig.1).

Age-standardised prevalence of Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) dementia in Hai, rural Tanzania compared to results from the 10/66 dementia research groups.
Note. Data reproduced from studies Piovezan et al., 2020).
The disability-adjusted life years (DALYs) of Alzheimer's disease and other dementias, in Tanzania, for 65+ aged population, are estimated to contribute to 2.19% of the disease burden 2019 (Global Burden of Disease Collaborative Network, 2020). Moreover, in evaluating the burden in caregivers' terms, a survey has reported caregivers declared burdens of caring (Mushi et al., 2014).

Possible risks factors and challenges
The first risk factor observed in the Tanzanian context is age. As age progresses, the risk of Alzheimer's disease, vascular dementia and many other dementias rises drastically (Adebayo et al., 2020;Paddick et al., 2018;Paddick, Mkenda, et al., 2015).
The third risk factor is the level of education. Evidence indicates that low literacy levels were substantially correlated with higher chances of having probable dementia (Heward et al., 2018;Mushi et al., 2014;.

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The fourth risk factor is a cardiovascular problem related to high blood pressure and diabetes. Through data gathered and analysed in Tanzania, it was reported that higher systolic blood pressure could be potentially preventive against dementia (Gray et al., 2017). Moreover, diabetes has been linked to increased chances of having vascular dementia .
The last risk factor is mild cognitive impairment. It has been established that human immunodeficiency virus (HIV)-associated neurocognitive disorder (HAND) is triggered when individuals are socially isolated (Eaton et al., 2020). More on the subject, the recent study by  accounted for HAND prevalence in Tanzania. Their research has conclusively shown that there has been a reduction in HAND prevalence of 62% in 2018 and 54% in 2019 for combination antiretroviral therapy-treated patients.
The recognisable risk factors aid in structuring the interventions that can be employed in reducing the dementia burden. For instance, focusing assistance on female aged population with cardiovascular and mild cognitive disorders because they are positively affected compared to their male counterparts. In most cases, preventive strategies of dementia depend on avoidable risk factors. This is possible since it has been reported that, the avoidable risk factors contribute to high risk of dementia in LMIC as compared to the global average (Mukadam, Sommerlad, Huntley, & Livingston, 2019). Nevertheless, in the contexts of presented risk factors, Tanzania is faced with various limitations. First, the limited 65+ aged population size with limited local settings in available evidence-based results. All studies mentioned above only sampled less than 1,500 study participants in a limited number of hospitals or local settings. Second, the conditions studied upon might be inadequately represented in a country with 1.6 million 65+ aged population. Therefore, devised mental health interventions might not be useful under these circumstances (Lloyd-Sherlock & Amoakoh-Coleman, 2020).

Current services and approaches in place to dealing with dementia in Tanzania
In system governance, there is a legally endorsed mental health policy plan, approved in 2016, containing specified indicators and targets against which its implementation can be monitored. The elements of the public wellbeing initiative include, first, the transfer of care and funding from mental hospitals to neighbourhood mental health facilities. Second, the incorporation of programs for mental health into primary care. A dedicated law on mental health, introduced in 2008, exists and recently amended. Other regulations also cover legal requirements for mental health (World Health Organization, 2018).

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In financing systems, mental health expenditures by the government are 4% of the total health budget (World Health Organization, 2018).
In mental health care, Table 1 and 2 show the available mental services and workforce.

Public understanding of dementia in the general population
Tanzania public understanding on dementia is discussed according to the World Health Organisation (WHO) global action plan on the public health response to dementia (GAPD) 2017-2025; increasing dementia recognition and prioritisation, reducing the risk of dementia, diagnosis, prevention and care, assisting dementia caregivers, improving dementia information systems, and research and creativity (World Health Organization, 2017). There is a general lack of knowledge and comprehension of dementia that results in stigmatisation, diagnosis and treatment challenges, and physical, psychological and economic effects on patients, communities and populations.
Although mental health policy is incorporated in the national health plan, dementia is given less public priority (id est on 4% of the total health budget). As a result, Tanzanians view dementia as a regular part of the ageing process -"old people disease" and are not sure of the causes of dementia (Mushi et al., 2014). Also, there are neither public awareness campaigns nor programmes of raising awareness on dementia.
For reliable and straightforward dementia diagnosis in Tanzania settings, there is proposed use of CSID in East Africa for non-specialised personnel (Chen et al., 2010). The CSID has been proved to be highly effective in detecting dementia .
Another study assessed 207 elderly individuals aged 60+ using Identification and Intervention for Dementia in Elderly Africans (IDEA) as another alternative for a cognitive screen test and reported its efficacy (receiver operating characteristic curve of 0.92) in detecting dementia . A different and more reliable diagnosis, dementia screening mobile application for non-specialist workers in rural Tanzania has been recently recommended . The mobile app ideally incorporates IDEA cognitive screening functions. In contrast, dementia and cognitive disability screening in LMICs rely mainly on HIC-adapted tools; in these contexts, these frequently lack validation due to low literacy and preconceived cultural ideas (Magklara, Stephan, & Robinson, 2019).
Moreover, treatment and care for PwD has been highly dependent on traditional and spiritual healing. A study by Hindley et al. (2016) found three themes associated with traditional and spiritual wellbeing. First, healers' conceptualisation of dementia as a natural part of the course of ageing and little knowledge of dementia as a particular disorder. Second, PwD and carer reasons for seeking help and experiences of treatment and the role of prayers, plants and witchcraft in diagnosis and treatment. Lastly, the willingness to work with hospital allopathic programs. Traditional healers and PwD shared concern over the partnership with western healers. Similar beliefs were reported by (Mushi et al., 2014). Hence spiritual and traditional healers can be involved in recognising PwD (Hindley et al., 2016). Caregivers of PwD in Tanzania settings have reported their sufferings during the caring (Mushi et al., 2014;.

What is the gap/need?
First, the government should increase the mental health funding on the total budget in health expenditure.
Second, there is a need to add more workforce in order to deal with the issue of limited specialised workforce (Patel et al., 2018). Despite the delayed progress, there have been some improvements in mental health professional workforce from 2011 to 2017 Mental Atlas reports; in terms of the psychiatrist, 0.01 to 0.06, mental health nurses 0 to 0.36, psychologists 0.001 to 0.01, and occupational therapist 0.009 to 0.02 (Table 2).
Third, further research is needed to devise the best possible models that can work in LMIC settings because models developed in HIC are evidenced to hardly work in LMIC (Stephan et al., 2020). The research should be expanded to more comprehensive Tanzania settings.
Lastly, for efficiently managing the challenging behaviour of PwD, new interventions, such as Cognitive Stimulation Therapy (CST), currently under research, should be considered for use. There is evidence from randomised trials in the U.K. that this may have a comparable effect on cognition enhancement with cholinesterase inhibitors; recently performed controlled CST study in Tanzania that found that this was possible and showed cognitive benefits (Stoner et al., 2020).

The SDGs addressed
According to the social determinants of global mental health addressed in The Lancet's Commission on global mental health and sustainable development (Patel et al., 2018),

The impact of the COVID-19 pandemic
The gaps discussed are still applicable during COVID-19 pandemic as numerous implementational and research activities are affected by the pandemic. Globally, cases and deaths due to COVID-19 seem to remarkably correspond to the burden of dementia (Azarpazhooh et al., 2020).
Although there is limited number of studies in Tanzania, reports on the impact of COVID-19 from LMICs have shown that governments need to focus their attention to geriatric populations in order to fix the impaired social cohesion (social and task relations, social unity, and emotions) (De Sousa, Mohandas, & Javed, 2020). Besides, in accessing caregivers experience, in India during the pandemic, relatives of PwD faced several specific challenges that specifically contribute to their position in providing care and another set of concerns that do not directly relate to their role in providing care (Vaitheswaran, Lakshminarayanan, Ramanujam, Sargunan, & Venkatesan, 2020).

Conclusion
In general, therefore, it seems that while dementia has a significant effect on cognitive capacity and functionality, there is a high burden on caregivers of behavioural and psychological symptoms, complex attitudes towards dementia within the population and may seem inconsistent at first glance. Many carers and community members regard dementia as a natural part of ageing and see the care they give as an inevitable part of caring for an elderly relative for their relative. However, if the disorder is followed by apparent behavioural abnormalities, some people interpret the illness in the light of conventional health beliefs such as witchcraft. In such instances, dementia, even with the whole family, is particularly stigmatising, and PwD are often concealed with no social interaction. Moreover, the current approaches in solving dementia disorders from the 2020 World Alzheimer's Report -designing for PwD (Fleming, Zeisel, & Bennett, 2020) could be employed for further changes.
Additionally, in raising public awareness of dementia, Tanzania should consider increasing the budget for mental health yearly, fund researchable interventions aiming at modelling strategies focusing on dementia disorders and seeking technical support from WHO and member states and international associations. There should be available dementia information systems with a shared database to promote research, although challenges in following up and accomplishing the plans are acknowledged widely. Interventions targeting caregivers, during the COVID-19 pandemic of PwD should be sensible, practical and multi-layered for the caregivers during the pandemic, and should consider both their immediate and long-term concerns (Vaitheswaran et al., 2020).

Funding:
No funding was provided for this work.
Institutional Review Board Statement: Not applicable.
Informed Consent Statement: Not applicable.
Data Availability Statement: Not applicable.

Conflicts of Interest:
The author declares no conflict of interest