Cognitive aging across the life course in a low-income context: evidence from Malawi.

BACKGROUND

We investigated heterogeneity in cognitive aging trajectories in rural Malawi-a low-income country in sub-Saharan Africa in which the current understanding of cognitive aging is limited.

METHODS

We used longitudinal data on 1214 adults aged ≥45 years from the Mature Adults Cohort of the Malawi Longitudinal Study of Families and Health from 2012 to 2022 and employed latent-class trajectory models to identify distinct trajectories of cognition. We estimated associations between sociodemographic variables and group membership probabilities by using fractional multinomial logit regression models.

RESULTS

Three cognitive trajectory groups were identified: 36% of the respondents belonged to the "high" cognition group characterized by a stable relative decline in cognition over time, 46% belonged to the "medium" cognition group experiencing intermediate relative decline by age 80 years, and 18% of respondents belonged to the "low" cognition group experiencing the largest relative decline in cognition by age 80 years. Individuals on higher cognition trajectories were more likely to be men, have completed a primary or secondary level of schooling, be living in a house with a metal roof, and have been born in younger cohorts.

CONCLUSION

Heterogeneity exists in cognitive aging trajectories in Malawi-while some individuals experience healthy cognitive aging, a nontrivial subgroup also experience accelerated cognitive decline over the life course. The results provide guidance for policymakers and practitioners in developing targeted programs to prevent or reduce the burden of cognitive decline among high-risk groups and seek to enhance healthy cognitive aging among older adults in Malawi, where resources for treatment and care are limited.