Dementia in Africa: An Unprecedented Crisis Approaches
The global burden of dementia is a growing public health priority in 2025. Over the next 25 years, the number of cases is expected to triple, reaching 152 million by 2050.1 Notably, two-thirds of new cases will emerge in low- and middle-income countries (LMICs). The situation is even more alarming in Africa where cases are projected to rise by 330% within the same period—including increases of 387% in Nigeria and 443% in Ethiopia. In contrast, Central Europe and North America expect comparatively lower increases of 82% and 102%, respectively.1
This disparity is partially explained by rapid demographic transitions in African countries, where aging populations are expanding at unprecedented rates.1 In addition, the rising prevalence of modifiable risk factors plays a significant role.2 However, in more developed regions, a decreasing prevalence of these risk factors has contributed to a decline in dementia incidence.1–4 Thus, this approaching crisis demands urgent and collective action.
Approximately half of dementia cases are attributable to 14 modifiable risk factors.5 A systematic review identified 48 observational studies that estimated the population attributable fraction for modifiable risk factors for dementia worldwide.6 Only 3 studies had data from Africa, whereas 17 focused on Europe and North America.6 The proportion of preventable cases in Africa ranged from 24.4% (Mozambique)7 to 45% (South Africa).8 In the most conservative estimates, there will be 4.8 million incident cases by 2050 attributable to modifiable risk factors. This represents 424 daily cases until 2050 and an economic burden of US $3.8 billion. However, current evidence on modifiable risk factors is primarily based on studies conducted in high-income countries, which may not fully account for region-specific risks in African nations.
Oversimplifying the anticipated burden of dementia as a natural consequence of population aging and growth contradicts evidence linking dementia to modifiable risk factors, undermines the urgency of developing public health policies for dementia prevention, and perpetuates harmful stigma by framing dementia as an inevitable part of aging.
Physical Activity and Dementia: The Missing Evidence
Every 45 seconds, there is 1 new case of dementia in the world that could be potentially prevented through physical activity (PA).9 Previous cross-sectional surveys suggested that cases attributable to physical inactivity may be higher in African countries.7,8 However, the lack of culturally and regionally specific longitudinal data limits our understanding of the true burden of dementia linked to physical inactivity in Africa,10–12 posing challenges to the development of effective public health policies.13,14 The prospective design allows a more accurate consideration of place and time to ensure accurate and impactful public health planning.
The context in which PA occurs must be considered when assessing its impact on health outcomes.15 For instance, 7 of the 10 most active countries in the world, based on the average minutes per week in moderate to vigorous PA, are found in Africa.16 In Malawi, the prevalence of physical inactivity (<150 min/wk of moderate to vigorous PA) was 1.7% in 2017, whereas the median time in moderate to vigorous PA was 2160 minutes per week.16 However, most of this time was spent in work or household (median: 77%) and commuting PA (median: 16%), with a median of 0 minutes per week in leisure PA. We observed a similar scenario in other African nations and LMICs.16 A comprehensive meta-analysis found that high levels of PA were associated with reduced risks of all-cause dementia (20%; 16%–23%), Alzheimer’s disease (14%; 7%–20%), and vascular dementia (21%; 5%–34%).17 However, only 1 out of 58 studies included data from an African country. The study in Nigeria involved 612 older adults with an average age of 74.5 years (SD: 8.4) who were followed for 3 years. It included leisure and work-related activities and found no significant association between PA and dementia risk.17
Based on the available evidence, we cannot accurately estimate the burden of dementia attributable to physical inactivity in Africa and countries with similar PA profiles. We recognize that occupational PA is associated with a high risk of all-cause mortality, particularly for men.18 Evidence from the Copenhagen Male Study showed that individuals with high levels of occupational PA had a 48% (5%–110%) higher risk of all-cause dementia compared with participants in sedentary jobs.19 Household PA has also been linked to an increased risk of depression, which is a risk factor for dementia, in the Brazilian population.20 However, leisure PA has been associated with a lower risk of all-cause and cardiovascular mortality regardless of occupational PA levels.21 This document does not intend to alarm readers about the harmful effects of nonleisure PA and shift the continent’s population toward a predominantly inactive lifestyle. Instead, it highlights the urgent need for longitudinal studies in the African continent and in LMICs to understand how different PA profiles are associated with the current and forecasted burden of dementia.
The 2022 Nairobi Declaration,22 the African Dementia Consortium,13 and the Africa-FINGERS project23 are prime examples of initiatives to mitigate the situation. The Nairobi Declaration emphasizes the urgent need for a global approach to dementia that focuses on underserved populations and reallocates investments toward LMICs to tackle challenges and seize opportunities related to dementia prevention, care, and treatment. Other points raised in the declaration urged policymakers to promote diverse, population-level risk reduction strategies. Despite considerable efforts in recent years to conduct population-based surveys, prospective cohorts remain scarce in low-income regions such as sub-Saharan Africa, limiting our ability to develop targeted interventions.14
Although current initiatives are promising, more urgent action is needed to address the approaching dementia crisis. Failure to act now may mean losing a unique opportunity to prevent millions of cases of a disease that imposes significant social and economic burdens on families, caregivers, and communities. Strengthening health care and social support systems in African nations, alongside culturally specific cohort studies, will be essential to shaping effective intervention strategies over the next 25 years.
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