Diet and physical activity in the association between depression and metabolic syndrome: Constances study

The association between depression and the metabolic syndrome remains poorly understood. Diet and physical activity may partly explain this association.

Baseline data on 64,861 subjects from the French population-based Constances cohort was analyzed. Depressive symptoms were determined with the Center of Epidemiologic Studies Depression (CES-D) scale. A CES-D score ≥ 19 combined with self-reported limitations related to depressive symptoms was used to define depression. The metabolic syndrome was defined according to the International Diabetes Federation criteria. Dietary patterns were determined with a food frequency questionnaire and a principal component analysis. Physical activity was measured with 3 questions resulting in a composite 6-point scale. Associations between depression and the metabolic syndrome were estimated through logistic regression and path analysis.

The odds-ratios (95% confidence interval) for the association between depression and the metabolic syndrome, adjusting for age, sex, education and income, was 1.75 (1.57-1.96). The path analysis showed that 23% of this association was explained by diet and physical activity, 67% being attributed to physical activity.

The cross-sectional nature of the analyses warrants the results to be confirmed by longitudinal analyses.

Diet and physical activity might partially explain the association between depressive symptoms and metabolic syndrome but other factors (e.g. inflammatory factors) are involved.