Depressive symptoms and incident osteoporosis in older adults: A cohort study with competing?risk and mediation analyses in English Longitudinal Study of Aging

Abstract

Background: Evidence on depressive symptoms and skeletal health is largely cross-sectional and rarely addresses competing risk, dose-response, or potential behavioral pathways. We examined the association between baseline depressive symptoms and incident osteoporosis in older adults, accounting for competing mortality and exploring mediation by physical activity.

Materials and Methods: We analyzed 4920 adults aged ? 60 years from the English Longitudinal Study of Ageing with Wave 1 8?item Center for Epidemiologic Studies Depression Scale (CES?D?8) scores and follow?up osteoporosis ascertainment. Incident
physician?diagnosed osteoporosis was the outcome. Cox models estimated hazard ratios (HRs) per 1?point higher CES?D?8 score. Restricted cubic splines assessed dose?response, Fine–Gray models accounted for death as a competing event, and exploratory  atural?effects models assessed baseline physical activity as a potential mediator.

Results: During a median follow?up of 16.0 years, 502 participants developed incident osteoporosis and 1138 deaths occurred. Higher CES?D?8 scores were associated with greater
osteoporosis risk in the fully adjusted Cox model (HR, 1.05; 95% confidence interval [CI], 1.01–1.10; P = 0.020), with consistent results in Fine–Gray models (subdistribution HR, 1.05; 95% CI, 1.01–1.10; P = 0.019). The dose–response appeared approximately
linear. Exploratory subgroup analyses did not show robust effect modification, and mediation by baseline physical activity was not statistically supported.

Conclusion: Baseline depressive symptoms were associated with a small increase in incident osteoporosis risk among older adults. The individual?level effect size was modest, and mediation findings should be interpreted as exploratory
rather than causal.