Social contexts and cross-national differences in association between adverse childhood experiences and frailty index.

Cross-national differences in the health implication of adverse childhood experiences have been documented. The differences may be shaped by macro- and micro-social context. However, previous studies failed to consider the role of micro-level social contexts, where adverse childhood experiences happen, in affecting the cross-national differences. The study aims to estimate the association between adverse childhood experiences and Frailty Index across countries and micro-social contexts, and then reveal how cross-national difference in the association between adverse childhood experiences and Frailty Index were shaped by social contexts. Adulthood information were collected from three waves of the Survey of Health, Ageing and Retirement in Europe in 2010, 2013, and 2015, and the China Health and Retirement Longitudinal Study data from in 2013, 2015 and 2018, respectively. Frailty index was measured based on 35 health measurements. Eleven adversities, including intrafamilial aggression and neglect, family dynamics, and socioeconomic status etc, were extracted from the life history survey of the two datasets, conducted in 2017 and 2014, respectively. Weighted Linear regression models and the smoothing-differencing method were applied. Experiencing three or more adversities was associated with increase in frailty index level in Europe and China. The effect size ranged from 0.015 (95%CI: 0.011-0.019) in China to 0.030 (95%CI: 0.025-0.034) in Germanic countries. Poor parent-child relationship, parental absence/death were ACEs in terms of frail in European countries but not in China. In a context where adversities were moderately likely to happen, the association between experiencing adverse childhood experiences and Frailty Index were greatest. Cross-national differences of adverse childhood experiences effects were most derived from this social context. These findings highlight the importance of micro-social contexts while mitigating early life stress to promote life-course health. Individuals who were moderately likely to experience adversity should be paid special attention in terms of health implication of adverse childhood experiences.