Life course socioeconomic position and cognitive ageing trajectories: A cross-national cohort study in China and England

Background and Objectives Cross-national research on cognitive aging inequality has largely concentrated on Western countries. It is unclear whether socioeconomic position (SEP) has similar effects on cognitive decline in emerging economies. We compared the association between life course SEP and cognitive function trajectories between China and England, the largest nation under state socialism and one of the oldest capitalist countries. Research Design and Methods This cross-cohort study examined participants aged 50 years and older from the China Health and Retirement Longitudinal Study (n = 12,832) and the English Longitudinal Study of aging (n = 8,875). Cognition z-scores were derived using comparable measures of memory and time orientation on 4 occasions. Life course SEP was self-reported by participants at baseline. Seven- to 8-year trajectories of cognition z-scores were estimated using latent growth curve modeling. Country- and gender-specific associations between childhood/adolescent deprivation, education, material wealth, and home ownership were evaluated in relation to model intercept (baseline level) and linear slope (annual rate of change) of cognition. Results After multivariable adjustment, education was positively associated with the greatest differences in baseline cognition across country and gender. Education was further linked to a slower rate of cognitive decline (z-score units per year); but compared with those with low education, Chinese men (b = 0.032) and women (b = 0.065) with high education had significantly slower declines than English men (b = −0.004) and women (b = 0.010) with high education. Discussion and Implications Despite substantial between-cohort differences in downstream and upstream determinants of dementia, education provided the greatest benefits to cognitive aging in England but particularly in China.