Widening or convergence, the trajectories of health inequalities induced by childhood SES across the life course: Evidence from China

This study aims to explore the trajectories of health inequalities induced by childhood SES across the life course in China. There are two competing theories on this subject. Cumulative disadvantage theory contends that health gaps induced by childhood SES tend to widen across the life course as adulthood SES compound or multiply the negative effects of early SES disadvantage. Age-neutral theory draws the opposite inference that the physiological decline due to aging offsets the health gaps at older ages. Based on the data of the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2018, a two-level mixed-effects model was used to analyze the trajectories of health inequalities induced by childhood SES among Chinese individuals aged 45 and above and further distinguished the age and cohort effects in the overall trajectories. Unlike previous studies that unilaterally supported one of these theories, our findings support both of them. In this study, health gaps induced by childhood SES gradually widened before entering old age, which supports the cumulative disadvantage theory. In contrast, the health gaps in older adults gradually converged with age, thus supporting the age-neutral theory. The age effect shows that in the same birth cohort, health gaps induced by childhood SES first increased and then decreased during the survey time. The cohort effect shows that, at the same age, childhood SES has a greater impact on the health of those with later birth cohorts than on those with earlier birth cohorts. The findings of this study support the importance of policy and practices to reduce health inequalities among adolescents for long-term healthy aging in China.