Who maintains good health? Contributions of life course circumstances to healthy aging

While the impact of life course circumstances on later-life health is increasingly acknowledged, their specific contributions to healthy aging among Chinese older adults remain insufficiently understood. This study aims to quantify the contributions of key life course domains and identify which factors most significantly influence healthy aging outcomes. Utilizing data from the 2014 Life History Survey, the 2015 main wave, and the 2015 biomarker collection of the China Health and Retirement Longitudinal Study (CHARLS), Healthy Aging Scores (HAS) were constructed using Item Response Theory (IRT) models based on 29 items across seven dimensions. Ten domains of life course circumstances, spanning childhood to adulthood, were examined. Shapley Value Decomposition was used to quantify domain-specific contributions to HAS variance. Hierarchical cluster analysis and multivariable linear regression were also employed to explore subgroup patterns and associations. The ten life course domains explained 26.69% of the variance in HAS. Four distinct life course subgroups were identified. Subgroup 1, characterized by high socioeconomic status (SES) in both childhood and adulthood, exhibited the highest HAS. In contrast, the remaining subgroups, marked by poorer childhood relationships, greater exposure to trauma, lower adulthood SES, and increased adversity, had significantly lower HAS compared to Subgroup 1. These findings underscore the long-term impact of both childhood and adulthood circumstances on healthy aging. Interventions targeting disadvantaged life course trajectories may be critical for promoting healthy aging and reducing later-life health disparities among Chinese older adults. Further research is needed to explore causal mechanisms and design integrated life course-oriented preventive strategies.