Contributions of life-course circumstances to the cognitive function in later life: A retrospective study among Chinese older adults

OBJECTIVE: Cognitive deterioration in older age could stem from a variety of factors during an individual's lifetime. This study aims to investigate contributions of life-course circumstances to cognitive function of Chinese older adults aged 60 years and above. METHODS: We used data on 12,394 older adults from the China Health and Retirement Longitudinal Study 2011-2020. Fixed-effects multivariable linear regressions accounted for repeated measures and within-person characteristics. Nested sequential regression models decomposed cognitive function, estimating relative contributions of distinct life-course domains. Blinder-Oaxaca decomposition quantified group differences in cognitive performance, while heterogeneity analysis was conducted by gender, age, and residence. RESULTS: Early-life factors directly accounted for 28.36 % of cognitive function. For cumulative associations, the marginal association of early-life factors with cognitive function, episodic memory, and executive function generally became larger. Adulthood socioeconomic status accounted for the largest proportion (36.05 %) of cognitive function. Differences in cognitive performance were observed between males/females, pre-old/older population, and people residing in urban/rural areas. CONCLUSIONS: Unfavorable life-course factors appeared to be associated with lower late-life cognitive function. These associations were exacerbated by cumulative socioeconomic inequalities. The results will offer insights for policy initiatives designed to reduce health inequities by focusing on multiple exposures throughout an individual's lifespan.