Depression and cardiovascular mortality: a role for n-3 fatty acids?

BACKGROUND Recent studies indicate that depression plays an important role in the occurrence of cardiovascular diseases (CVDs). The underlying mechanisms are not well understood. OBJECTIVE We investigated whether dietary intake of the n-3 fatty acids (FAs) eicosapentaenic acid and docosahexaenoic acid could explain the relation between depressive symptoms and cardiovascular mortality. DESIGN The Zutphen Elderly Study is a prospective cohort study conducted in the Netherlands. Depressive symptoms were measured in 1990 with the Zung Self-rating Depression Scale in 332 men aged 70-90 y and free from CVD and diabetes. Dietary factors were assessed with a cross-check dietary history method in 1990. Mortality data were collected between 1990 and 2000. Logistic and Cox regression analyses were performed, with adjustment for demographics and CVD risk factors. RESULTS Compared with a low intake (x: 21 mg/d), a high intake (x: 407 mg/d) of n-3 FAs was associated with fewer depressive symptoms [odds ratio: 0.46; 95% CI: 0.22, 0.95; P for trend = 0.04] at baseline and no significant reduced risk of 10-y CVD mortality [hazard ratio (HR): 0.88; 95% CI: 0.51, 1.50]. The adjusted HR for an increase in depressive symptoms with 1 SD for CVD mortality was 1.28 (95% CI: 1.03, 1.57) and did not change after additional adjustment for the intake of n-3 FAs. CONCLUSION An average intake of approximately 400 mg n-3 FA/d may reduce the risk of depression. Our results, however, do not support the hypothesis that the intake of n-3 FAs explains the relation between depression and CVD.