Life-course multidimensional social determinants of health, social mobility, and loneliness in older adulthood: evidence from three national ageing cohorts

Loneliness is a growing public health concern in ageing societies. Although socioeconomic disadvantage has been linked to loneliness in later life, less is known about associations of life-course social determinants of health (SDOH) and social mobility with loneliness across national contexts. We analysed longitudinal data from CHARLS in China ( N = 9,621), HRS in the United States ( N = 17,362), and ELSA in England ( N = 3,719). Early-life and later-life SDOH profiles were identified using latent class analysis, and life-course SDOH trajectories were defined by stability or change between SDOH classes. Repeated loneliness was measured using a harmonised single CES-D loneliness item. Associations were estimated using cohort-specific generalised estimating equations and random-effects meta-analysis. In the primary five-category trajectory analyses, stable low trajectories were consistently associated with higher odds of loneliness than upward mobility across all three cohorts, whereas associations for downward mobility varied across cohorts. Stable high trajectories were not associated with higher odds of loneliness, while findings for stable middle trajectories were inconsistent. Supplementary three-category analyses indicated that the elevated odds observed for the aggregate no-change category were concentrated primarily among individuals with stable low trajectories rather than being uniformly observed across stable trajectories. Low early-life and low later-life SDOH were also associated with higher odds of loneliness, with generally larger association estimates for later-life SDOH. In pooled analyses, stable low trajectories (OR = 2.23, 95% CI 1.84–2.71), downward mobility (OR = 1.46, 95% CI 1.22–1.75), and low later-life SDOH (OR = 2.72, 95% CI 2.15–3.44) were associated with higher odds of loneliness. Life-course SDOH trajectories and stage-specific SDOH profiles were associated with loneliness in older adulthood, with persistent disadvantage reflected by stable low trajectories showing the most consistent association. These findings support life-course and context-sensitive approaches to loneliness prevention.