Population-Based Cohort Analyses of the Bidirectional Relationship Between Type 2 Diabetes and Depression

  1. Chung-Yi Li, PHD6,7
  1. 1Institute of Epidemiology and Preventive Medicine, National Taiwan University College of Public Health, Taipei, Taiwan
  2. 2Department of Health, Centers for Disease Control, ROC Executive Yuan, Taipei, Taiwan
  3. 3Department of Endocrinology, Far Eastern Memorial Hospital, Panchiao, New Taipei City, Taiwan
  4. 4School of Medicine, Fujen Catholic University, New Taipei City, Taiwan
  5. 5Department of Surgery, Taipei City Hospital City, Taipei, Taiwan
  6. 6Department and Institute of Public Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan
  7. 7Department of Public Health, College of Public Health, China Medical University, Taichung, Taiwan
  1. Corresponding author: Ming-Chung Ko, mingchung77{at}
  1. M.-C.K. and C.-Y.L. contributed equally to this study.


OBJECTIVE This study addresses the strength of association for the bidirectional relationship between type 2 diabetes and depression.

RESEARCH DESIGN AND METHODS We used two cohort studies with the same source of database to determine the link between depression and type 2 diabetes. The data analyzed included a random sample of 1 million beneficiaries selected from the National Health Insurance claims in 2000. The analysis of diabetes predicting the depression onset consisted of 16,957 diabetic patients and the same number of sex- and age-matched nondiabetic control subjects. The analysis of depression predicting diabetes onset included 5,847 depressive patients and 5,847 sex- and age-matched nondepressive control subjects. The follow-up period was between 2000 and 2006, and onset of end points was identified from ambulatory care claims. The Cox proportional hazards regression model adjusted for potential confounders was used to estimate relative hazards.

RESULTS The first cohort analysis noted an incidence density (ID) of 7.03 per 1,000 person-years (PY) and 5.04 per 1,000 PY for depression in diabetic and nondiabetic subjects, respectively, representing a covariate-adjusted hazard ratio (HR) of 1.43 (95% CI 1.16–1.77). The second cohort analysis noted an ID of 27.59 per 1,000 PY and 9.22 per 1,000 PY for diabetes in depressive and nondepressive subjects, respectively. The covariate-adjusted HR was stronger at 2.02 (1.80–2.27) for incident diabetes associated with baseline depression.

CONCLUSIONS The two cohort studies provided evidence for the bidirectional relationship between diabetes and depression, with a stronger association noted for the depression predicting onset of diabetes.

  • Received March 9, 2012.
  • Accepted August 2, 2012.

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  1. Diabetes Care
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