Life-course stress exposure and cognitive decline in middle-aged and older Chinese adults: The role of sex differences and educational protection.
BACKGROUND: Stressful life events (SLEs) across the life course have been associated with cognitive decline, but evidence on their cumulative impact and potential modifiers remains limited. We aimed to examine the associations between SLE exposure in childhood, adulthood, or both life stages and cognitive trajectories, and to investigate whether these associations vary by sex and education. METHODS: We used data from the China Health and Retirement Longitudinal Study, a nationally representative cohort of adults aged ≥45 years. Participants with complete data on SLEs, cognition, and covariates were included (n = 5922). SLEs were retrospectively assessed for childhood and adulthood. Cognitive function was measured using a composite score (range 0-21) across three waves (2011-2015). Linear mixed-effects models examined longitudinal associations, adjusting for sociodemographic factors, health behaviors, and chronic conditions, with interaction analyses for sex and education. RESULTS: Compared with participants reporting no SLEs, cumulative exposure showed the strongest association with cognitive decline (β = -0.52, 95% CI -0.69 to -0.35), followed by childhood-only (β = -0.34, -0.48 to -0.20) and adulthood-only exposure (β = -0.22, -0.37 to -0.07). Sex significantly moderated the associations for childhood and cumulative exposure, with women exhibiting greater cognitive vulnerability. Higher educational attainment attenuated the associations between single-period stress and cognitive decline, with only partial protection observed against cumulative adversity. CONCLUSION: Cumulative life-course stress is associated with accelerated cognitive decline in Chinese middle-aged and older adults. Women appear more vulnerable to stress-related cognitive effects, whereas higher education confers partial resilience, highlighting the need for sex-sensitive and education-informed prevention strategies.