Life course circumstances contribute to the acceleration of phenotypic and functional aging in Chinese middle-aged and older adults

Accelerated aging implies health inequalities in late life and consequently, poses a huge challenge to society. With two well-validated aging measures, this study aimed to evaluate the relative contributions of life course circumstances to variance in these aging measures with policy implications. We assembled data for 6224 middle-aged and older adults (≥45 years) who participated in the 2014 life course survey, the 2015 biomarker collection, and the 2015 main survey of the China Health and Retirement Longitudinal Study (CHARLS). Two aging measures, including physiological dysregulation (PD) and frailty index (FI), were calculated. Life course circumstances, i.e., 70 circumstances variables involving childhood and adulthood circumstances, demographics, and behaviors, were categorized into 11 study domains for simplicity. The Shapley value decomposition, hierarchical clustering, and general linear regression models were performed. The Shapley value decomposition revealed that all 11 study domains accounted for about 6.3% and 29.7% of the variance in PD and FI, respectively. We then identified six subpopulations who shared similar patterns in terms of childhood and adulthood circumstances. One subpopulation (i.e., disadvantaged) who reported experiencing more childhood and adulthood adversity consistently exhibited accelerated aging indicated by the two aging measures. We conclude that life course circumstances contribute differently to the acceleration of phenotypic and functional aging in Chinese middle-aged and older adults. Special attention should be given to promoting health for the disadvantaged subpopulation and narrowing their health gap with advantaged counterparts. Our findings highlight the role of life course circumstances in ameliorating health inequalities in late life.