Multidimensional deprivation and brain health in older adults in rural northern Tanzania: a cross-sectional community-based study

Introduction: Dementia and late-life depression are rising rapidly in sub-Saharan Africa, yet prevention frameworks remain focused on individual behaviour. Multidimensional poverty is a plausible structural determinant of brain health but is rarely assessed. Methods: This cross-sectional analysis of the community-based Akili Mali study assessed adults aged 60 years and older in three rural communities in Kilimanjaro, Tanzania. Outcomes were the 15-item Geriatric Depression Scale (GDS-15), IDEA cognitive screen, CERAD ten-word list, and verbal fluency. Deprivation was measured with a nine-indicator Alkire-Foster Multidimensional Deprivation Index. Missing data were multiply imputed; models adjusted for age, sex, education, community, comorbidity, and health behaviours. Results: Of 1054 participants (mean age 70.2 years [SD 9.35]; 629 [59.7%] women), 840 (81.9%) of 1026 were multidimensionally deprived. Each unit increase in deprivation score predicted a higher GDS-15 score (β 4.83, 95% CI 3.82 to 5.83), higher odds of screen-positive depression (odds ratio 17.18, 6.89 to 42.83), lower IDEA score (β −1.97, −2.97 to −0.97), and lower verbal fluency (β −2.57, −3.77 to −1.36; all p<0.001). CERAD measures and self-reported impairment showed no association. At community level this gradient inverted: the most deprived community had the lowest depression and highest cognition, yet perceived social standing did not differ. Conclusion: Multidimensional deprivation was near-universal and independently associated with worse brain health. The community-level inversion, with perceived social standing equivalent across communities of unequal material circumstances, indicates that absolute deprivation alone does not explain the distribution of brain health. Relative position and community resilience are priorities for study