Common mental disorders associated with 2-year diabetes incidence : the Netherlands Study of Depression and Anxiety (NESDA)

Background: Few prospective cohort studies describe the risk of type 2 diabetes mellitus associated with depression or anxiety. The aim of this study was to determine the 2-year diabetes incidence and pattern of explanatory factors associated with depressive and/or anxiety disorders. Methods: A prospective cohort of 2981 participants (aged 18-65 years, 66 women) recruited in the Netherlands Study of Depression and Anxiety (NESDA) from community, primary care and outpatient psychiatric clinics were followed-up for two years. Complete data were analyzed from 2460 participants without baseline diabetes. Lifetime or current (past 6-month) depressive and/or anxiety disorders at baseline were assessed using the Composite Interview Diagnostic Instrument (CIDI) and classified by the DSM-IV. Diabetes was classified by either self-report, medications, or fasting plasma glucose ≥ 7.0mmol/L. Baseline covariates included age, gender, lifestyle factors, and medical conditions. Odds ratios (OR [95 confidence intervals]) for diabetes were determined using exact logistic regression. Results: The unadjusted 2-year diabetes incidence was 0.2 (1/571), 1.1 (6/548), and 1.8 (24/1340) for no, remitted, and current depressive and/or anxiety disorders, respectively. In comparison to those without psychopathology, current depressive and/or anxiety disorders was associated with diabetes incidence in unadjusted (OR 10.4 [1.7, 429.0]) and age-adjusted (OR 11.9 (1.9, 423.0]) analyses. The strength of this association (beta coefficient) was slightly changed after further adjustments for impaired fasting glucose (11.4), high triglycerides (-7.8), and lifestyle cumulative risk score (-5.0), in contrast to other covariates when assessed in separate models. Limitations: The low incidence of diabetes resulted in considerable uncertainty for the odds ratios and low statistical power that limited covariate adjustments. Conclusions: The relative odds of developing diabetes within two years was increased for persons with current depressive and/or anxiety disorders, which was partially explained by, but remained independent of, lifestyle cumulative risk factors.