Longitudinal Association between n-3 Long-Chain Polyunsaturated Fatty Acid Intake and Depressive Symptoms: A Population-Based Cohort Study in Japan.

It remains unclear whether n-3 long-chain polyunsaturated fatty acids (LCPUFA) have a preventive effect on depression in the general population. This study investigated the longitudinal association between n-3 LCPUFA intake and depressive symptoms in community-dwelling Japanese participants. The participants were aged 40⁻79 years at baseline in the cohort study; wherein examinations; including the assessment of depressive symptoms and nutritional status; were biennially conducted from 1997 to 2012. The subjects (n = 2335) who had a Center for Epidemiologic Studies Depression Scale (CES-D) score < 16 at the first examination and who participated in the follow-up study at least once were included in the analysis. The follow-up end point was the first onset (CES-D ≥ 16) or the last examination participation. Hazard ratios (95% CIs) for CES-D ≥ 16 were estimated using the adjusted Cox proportional hazards model. Overall; 22.1% participants showed depressive symptoms during follow-up (average; 8.1 years). Compared with the lowest tertile; the highest HR for EPA was 0.74 (0.60⁻0.93), and highest and middle HRs for DHA were 0.79 (0.63⁻0.98) and 0.80 (0.65⁻0.99) (P for trend = 0.009 and 0.032), respectively. Among populations with high fish consumption; higher n-3 LCPUFA intake may be associated with a low risk of depressive symptoms.