Depression, treatable cardiovascular risk factors and incident cardiac events in the Gazel cohort.

Background: Depression is an important risk factor of cardiovascular disease (CVD), a leading cause of death worldwide. One of the reasons underlying this association may be that depression modifies the association between treatable cardiovascular risk factors and cardiac events (angina pectoris or myocardial infarction). We tested this hypothesis in a cohort study of middle-aged men and women in France followed for 20 years.

Methods: 10,541 Gazel working men and women free of cardiovascular disease at baseline (1993) were followed-up over 20 years for validated incident cardiac events. Depression was measured at baseline and every three years with the Center for Epidemiological Studies-Depression (CES-D). We used time-dependent Cox regression models to calculate hazard ratios (HR) of cardiac events associated with depression, main treatable cardiovascular risk factors (hypertension, diabetes, and dyslipidemia), and their interactions, adjusting for demographic, lifestyle and clinical characteristics.

Results: Over 20 years of follow-up, 592 incident cases of cardiac events were identified. Depression was significantly associated with incident cardiac events (HR 1.55, P = 0.002), as was hypertension (HR 1.49, P = 0.02), diabetes (HR 2.54, P = 0.001), and dyslipidemia (HR 1.55, P = 0.003). No statistically significant interactions were observed between depression and hypertension, diabetes or dyslipidemia in relation to incident cardiac events (all P ≥ 0.16).

Conclusions: The association between depression and cardiac events is unlikely to be explained by a heightened impact of hypertension, diabetes or dyslipidemia.