Bidirectional association between depressive symptoms and type 2 diabetes mellitus: The China Health and Retirement Longitudinal Study

Objective: To prospectively examine the bidirectional relationship between depressive symptoms and type 2 diabetes mellitus (T2DM) among middle-aged and elderly Chinese. Methods: Participants were enrolled in 2011-2012 (Wave 1) and followed up in 2013-2014 (Wave 2) and 2015-2016 (Wave 3) in the China Health and Retirement Longitudinal Study. Depressive symptoms were evaluated by the Chinese language version of 10-item Center for Epidemiological Studies Depression Scale (CESD-10) at three waves. T2DM was assessed by biochemical biomarkers at Wave 1 and reported physician-diagnosis at Wave 2 and 3. Cox proportional hazards regression was applied to calculate hazard ratio (HR) and 95% confidence intervals (CIs) for the bidirectional association. Results: Participants with baseline depressive symptoms were 1.33 times as likely to develop T2DM (HR, 133; 95% CI: 1.06, 1.66), compared to their counterparts after adjusting for demographic characteristics and T2DM risk factors. The risk of T2DM increased linearly with higher severity of depression as determined by a higher CESD-10 score (P for trend << 0.001). In addition, baseline T2DM was associated with increased risk of incident depressive symptoms (1.15; 1.00,1.31) and persistent depressive symptoms (1.35; 1.03, 1.77). Conclusion: There is a positive bidirectional association between depressive symptoms and T2DM in middle-aged and elderly Chinese. (C) 2019 Elsevier Inc. All rights reserved.