Reducing the Number of People with Dementia Through Primary Prevention in Mozambique, Brazil, and Portugal: An Analysis of Population-Based Data

BACKGROUND: Most people with dementia live in low- and middle-income countries and little is known about the potential for reducing these numbers by reducing key risk factors. OBJECTIVE: To investigate the potential for dementia incidence reduction in Brazil, Mozambique, and Portugal (a culturally related, high-income country). METHODS: We replicated previously published methods and based on the relative risks from previous studies, we estimated the population-attributable risk (PAR) of dementia in Mozambique, Brazil, and Portugal for seven modifiable risk factors associated with dementia (low educational attainment, physical inactivity, midlife hypertension, midlife obesity, depression, smoking, and diabetes mellitus). The combined PAR was calculated and adjusted for associations between risk factors. The potential for risk factor reduction was assessed by examining the effect of relative reductions of 10% and 20% per decade for each of the risk factors on projections for dementia cases for each decade until 2050. RESULTS: After adjusting for non-independence of risk factors, 24.4%, 32.3%, and 40.1% of dementia cases could be related to seven potentially modifiable risk factors in Mozambique, Brazil, and Portugal, respectively. Reducing the prevalence of each risk factor by 20% per decade could, by 2050, potentially reduce the prevalence of dementia in Mozambique, Brazil, and Portugal by 12.9%, 16.2%, and 19.5%, respectively. CONCLUSION: There is a substantial difference between the countries in the percentage of dementia cases that could be attributable to the seven potentially modifiable risk factors. The proportion of cases that could be prevented by 2050 if measures were taken to address these main risk factors was higher in Portugal than in Brazil and Mozambique. Each country or region should consider their unique risk factor profile when developing dementia risk reduction programs.