Specific depressive symptoms, body mass index and diabetes in middle-aged and older Chinese adults: Analysis of data from the China Health and Retirement Longitudinal Study (CHARLS)

Background: This study examined the association between specific depressive symptoms and incident diabetes, and whether overweight or obesity mediates this relationship among middle-aged and older adults in China. Methods: In a nationally representative prospective cohort study of 11,893 middle-aged and older Chinese adults without baseline diabetes, we used Cox models to assess the association between depressive symptoms and diabetes. The quantile g-computation (qgcomp) model evaluated the contribution of 10 specific depressive symptoms to diabetes risk, and a two-stage regression method explored the mediation effect of overweight or obesity. Results: Over a median follow-up of 7.1 years, 1,314 cases of diabetes were identified. Elevated depressive symptoms were associated with increased diabetes risk (HR 1.23; 95 % CI 1.09-1.38). Eight out of 10 depressive symptoms were significantly associated to diabetes, with loneliness (weight = 18 %; HR 1.23; 95 % CI 1.10-1.39), restless sleep (weight = 17 %; HR 1.16; 95 % CI 1.04-1.29), and bother (weight = 15 %; HR 1.19; 95 % CI 1.07-1.33) being the primary contributors. Mediation analysis showed that overweight and obesity reduced the depression-diabetes risk association by 8.21 % and 12.61 %, respectively. Limitations: Diagnosis of diabetes was self-reported. Conclusions: Eight out of ten specific depressive symptoms were associated to diabetes, overweight and obesity may partially mitigate the effect of depressive symptoms on diabetes among middle-aged and older adults in China. Clinical implications: Our results highlight the importance of tailoring diabetes prevention and management strategies according to specific depressive symptoms among middle-aged and older adults in China.