Depressive symptoms and cardiometabolic diseases in Chinese middle-aged and older adults: a longitudinal cross-lagged analysis

Depressive symptoms and cardiometabolic diseases (CMDs) are highly prevalent among middle-aged and older adults. However, longitudinal evidence on their reciprocal and time-varying associations remains limited. This study aimed to examine the bidirectional and temporal associations between depressive symptoms and CMDs among Chinese adults aged ≥ 45 years. Data were derived from three waves (2015, 2018, 2020) of the nationally representative China Health and Retirement Longitudinal Study (CHARLS). Depressive symptoms were assessed with the 10-item Center for Epidemiologic Studies Depression Scale (CESD). CMDs included hypertension, diabetes, dyslipidemia, stroke, and heart disease, and were operationalised as continuous counts and alternative categorical definitions. The continuous CMDs count was specified as the primary exposure. Random-intercept cross-lagged panel models (RI-CLPM) were used to examine within-person bidirectional associations while separating stable between-person differences. At baseline (2015, T1), 18,837 participants were included, with 16,832 and 16,204 retained at the 2018 (T2) and 2020 (T3) waves, respectively. Mean depressive symptom scores increased from 7.88 (SD = 6.35) to 8.78 (SD = 6.49), while the mean number of CMDs rose from 0.81 (SD = 1.03) to 1.14 (SD = 1.21) across the study period. RI-CLPM identified strong autoregressive effects for CMDs across both intervals (β = 0.414 and 0.676, p < 0.001), suggesting that CMDs are highly stable across time. A time-dependent asymmetry was observed in the bidirectional associations. During T1–T2, higher depressive symptoms were prospectively associated with increases in CMDs (β = 0.076, p < 0.001), whereas CMDs did not predict subsequent depressive symptoms (β = 0.031, p > 0.05). During T2–T3, CMDs showed a stronger prospective association with later depressive symptoms (β = 0.103, p < 0.001) than the reverse pathway (β = 0.021, p < 0.01). These patterns were consistent across alternative CMDs specifications and sensitivity analyses. This study provides longitudinal evidence of a dynamic and temporally asymmetric association between depressive symptoms and CMDs among middle-aged and older Chinese adults. The findings underscore the importance of considering time-varying and bidirectional processes and support the need for integrated, stage-specific approaches to mental and cardiometabolic health management in ageing populations.