Depression and all-cause and coronary heart disease mortality among adults with and without diabetes

OBJECTIVE - The aim of this study was to evaluate the effect of depression on all-cause and coronary heart disease (CHD) mortality among adults with and without diabetes. RESEARCH DESIGN AND METHODS - We studied 10,025 participants in the population-based National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study who were alive and interviewed in 1982 and had complete data for the Center for Epidemiologic Studies Depression Scale. Four groups were created based on diabetes and depression status in 1982: 1) no diabetes, no depression (reference group); 2) no diabetes, depression present; 3) diabetes present, no depression; and i4) diabetes present, depression present. Cox proportional hazards regression models were used to calculate multivariate-adjusted hazard ratios (HRs) of death for each group compared with the reference group. RESULTS - Over 8 years (83,624 person-years of follow-up), 1,925 deaths were documented, including 522 deaths from CHD. Mortality rate per 1,000 person-years of follow-up was highest in the group with both diabetes and depression. Compared with the reference group, HRs for all-cause mortality were no diabetes, depression present, 1.20 (95% CI 1.03-1.40); diabetes present, no depression 1.88 (1.55-2.27); and diabetes present, depression present, 2.50 (2.04-3.08). HRs for CHD mortality were no diabetes, depression present, 1.29 (0.96-1.74); diabetes present, no depression 2.26 (1.60-3.21); and diabetes present, depression present, 2.43 (1.66-3.56). CONCLUSIONS - The coexistence of diabetes and depression is associated with a significantly increased risk of death from all causes, beyond that due to having either diabetes or depression alone.