Association of the metabolic syndrome with depression and anxiety in Japanese men: A 1-year cohort study

Background: Recent studies on the association between the metabolic syndrome (MetS) and depression have reported conflicting findings. This 1-year cohort study aims to evaluate the association of MetS with the development of both depression and anxiety. Methods: The cohort comprised 956 Japanese male employees of an enterprise (mean age, 42.7 years; SD, 10.2 years). MetS was diagnosed according to the International Diabetes Federation criteria. The psychological conditions of depression and anxiety were assessed in 2 successive years by using the profile of mood states (POMS) questionnaire and by conducting clinical interviews as per the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). We evaluated the temporal and doseresponse relationships between MetS and the development of depression and anxiety, controlling for potential confounding factors like age and lifestylerelated factors. Results: We identified a positive relationship between MetS at baseline and new-onset depression in the subsequent year (OR 2.14, 95% CI 1.10-4.17). Of the fiveMetS components examined, only waist circumference was significantly related to new-onset depression (OR 2.08, 1.23-3.50). Trend analysis revealed a significant positive trend of association between the number of MetS components identified and new-onset depression (P_trend < 0.01), but not between Mets and new-onset anxiety. Conclusions: Our results suggest that MetS is a predictive factor for the development of depression, and that waist circumference largely contributes to the association between MetS and depression.