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 natural-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.