Stressful life events in childhood and incident stroke: cross-national, longitudinal cohort analyses of HRS and CHARLS

Childhood stressful life events may contribute to later-life stroke risk, but it remains unclear whether this association is consistent and of similar magnitude across different sociocultural and institutional settings. We analyzed data from two nationally representative cohorts: the U.S. Health and Retirement Study (HRS, 2010–2020) and the China Health and Retirement Longitudinal Study (CHARLS, 2011–2020). Stressful life events in childhood—financial hardship, parental unemployment, parental substance abuse, foster home, parental separation or divorce, and parental death—were retrospectively assessed. Incident stroke was self-reported during follow-up. Adjusting for demographic, behavioral, and clinical variables, hazard ratios (HRs) and 95% confidence intervals (CIs) were obtained using Cox proportional hazards regression. Between-cohort heterogeneity was assessed using a cohort-by-exposure interaction term, and additional sensitivity and subgroup analyses were conducted to evaluate robustness. The analytic samples included 9,839 participants in HRS and 11,343 in CHARLS. In HRS, stroke incidence was 6.9% in the exposed group and 1.7% in the unexposed group; fully adjusted HR = 2.56 (95% CI: 1.26–5.17). In CHARLS, incidence was 10.2% versus 7.8%; fully adjusted HR = 1.24 (95% CI: 1.10–1.41). A significant cohort-by-exposure interaction was observed (P for interaction = 0.008), indicating heterogeneity in effect magnitude between cohorts. Findings were robust across multiple sensitivity analyses. Childhood stressful life events were associated with elevated risk of incident stroke across two nationally representative cohorts in the United States and China. The consistent direction of association across settings, together with between-cohort differences in magnitude, underscores the relevance of early-life adversity to stroke prevention from a life-course perspective.