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.