The association between longitudinal social stress trajectories and all–cause mortality among older adults in China: a prospective cohort study

This study aimed to investigate the association between longitudinal social stress (SS) and all–cause mortality among older adults in China. Data were obtained from the Chinese Longitudinal Healthy Longevity Survey. SS and healthy lifestyle were assessed at baseline and first follow–up, and longitudinal trajectories reflecting changes in these factors over time were identified using group–based trajectory modeling. Cox proportional hazards models were applied to evaluate the associations between SS trajectories and mortality, adjusting for sociodemographic characteristics, lifestyle trajectories, and chronic conditions, with stratified and interaction analyses performed. Among 10,938 Chinese older adults, 5,920 deaths occurred during follow–up. Two SS trajectories were identified: a low–high trajectory, characterized by relatively low baseline SS followed by an increasing trend, and a high–high trajectory, characterized by consistently high SS levels with further increases over time. Compared with the low–high trajectory, participants in the high–high SS trajectory had a significantly higher risk of all–cause mortality in the fully adjusted model (HR = 1.10, 95% CI: 1.04–1.17). Stratified analyses showed that this association was evident among individuals with high–low and moderate–stable healthy lifestyle trajectories, but not among those with a persistently low–low lifestyle trajectory. This study provides novel evidence that persistently high and increasing SS is associated with elevated all–cause mortality risk among Chinese older adults. The findings emphasize the importance of considering the dynamic nature of psychosocial stress and lifestyle behaviors in aging research.