Longitudinal bidirectional association of biological aging acceleration with depressive symptoms in mid-to-late life: evidence from the China Health and Retirement Longitudinal Study.

The longitudinal directionality between depressive symptoms and biological aging acceleration has yet to be thoroughly investigated. This study included 5442 Chinese adults aged 45-80 years from the 2011 and 2015 survey waves of China Health and Retirement Longitudinal Study. Multiple biomarker-based biological age was estimated using the Klemera and Doubal method, and biologically older was defined as biological age larger than chronological age. Depressive symptoms were identified using a threshold of ≥ 10 on the 10-item Center for Epidemiological Studies Depression Scale. Multivariate logistic regression was employed to explore two unidirectional associations between biological aging and depression. Cross-lagged panel models (CLPM) were also constructed to simultaneously examine the bidirectional relationship and the strength of the association. In the logistic regression model adjusted for potential confounders, biologically older at baseline was associated with a higher risk of subsequent depression (OR = 1.202, 95% CI: 1.020, 1.417) compared with biologically younger; conversely, individuals with baseline depression had a higher risk of being biologically older later (OR = 1.372, 95% CI: 1.148, 1.639) when compared to those without depression. CLPM identified bidirectional relationship over time, with standardized coefficients of 0.03 (P < 0.01) for both longitudinal directional pathways, suggesting an equal contribution of biological aging acceleration and depression to their dynamic interplay. This study reveals a reciprocal interaction between biological aging acceleration and depression in mid-to-late life, suggesting that targeted interventions aimed at decelerating biological aging or alleviating depressive symptoms may confer reciprocal benefits over time.