Prevalence and determinants of probable dementia in rural India: a cross-sectional study in the APCAPS cohort.

Background: Dementia poses a growing public health challenge in India. Despite this, epidemiological data on the condition remain largely restricted to adults >60 years of age, despite the convergence of urbanisation-driven cardiometabolic risks and socioeconomic disadvantage in rural India potentially accelerating dementia onset. We investigated the prevalence and determinants of probable dementia in a transitional rural Indian cohort of adults aged ≥45 years. Methods: In this cross-sectional study, we utilised data from the Andhra Pradesh Children and Parents Study cohort from 29 villages near Hyderabad, South India (2021-2023). We collected sociodemographic, occupational, and household asset data through face-to-face, questionnaire-based interviews. Cardiometabolic diseases (diabetes, hypertension, cardiovascular disease, and stroke) were assessed using validated methods. Dementia screening was performed using the Brief Community Screening Instrument for Dementia. We calculated prevalence estimates for dementia and used multivariable logistic regression to identify independent associations of probable dementia with sociodemographic, socioeconomic (education, occupation, household assets), and cardiometabolic factors (diabetes, hypertension, cardiac disease, and stroke). Results: The final sample included 2,163 adults aged ≥45 years. The prevalence of probable dementia (a positive screen on the BCSI-D) was 3.4% (95% confidence interval (CI) = 2.6-4.6) in the 45-59 age group and 7.4% (95% CI = 6.0-9.4) in the ≥60 age group. In the multivariable model, the odds of probable dementia were 2.2 times higher among unemployed or retired participants than among those working in agriculture or animal rearing (adjusted odds ratio (aOR) = 2.23; 95% CI = 1.26-3.95). The odds of probable dementia among literate participants were 0.5 times those among illiterate participants (aOR = 0.54; 95% CI = 0.31-0.89). The odds of probable dementia were 3.8 times higher among participants with a history of stroke than among those without (aOR = 3.77; 95% CI = 1.67-7.94). Conclusions: Our results indicate that the burden of probable dementia in rural India extends into middle age, and that the condition itself is independently associated with a history of stroke and socioeconomic disadvantages. This suggests a need to extend cognitive and vascular risk assessment to adults aged ≥45 years in rural India. However, as all findings reflect positive screening results rather than confirmed diagnoses, longitudinal studies with diagnostic confirmation are needed before population-level screening recommendations can be made.