Serum polyunsaturated fatty acids are not associated with the risk of severe depression in middle-aged Finnish men: Kuopio Ischaemic Heart Disease Risk Factor (KIHD) study

PURPOSE: The aim of this study is to investigate whether serum n - 3 polyunsaturated fatty acids (PUFAs) or n - 6 to n - 3 ratio is associated with risk of severe depression in middle-aged Finnish men. METHODS: The association between the serum concentrations of fatty acids and depression was investigated in 2077 men aged 42-60 years at baseline in a prospective follow-up setting. The population-based Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study cohort was recruited between 1984 and 1989 and followed until the end of 2007. The baseline levels of serum total n - 3 PUFAs, n - 6 PUFAs and individual fatty acids were determined. Data on hospital treatments due to major depressive disorder were derived from the national hospital discharge register. RESULTS: During the average follow-up time of 18 years, 46 men received a discharge diagnosis of depression. When the Cox proportional hazards model was adjusted for age, examination year, baseline socioeconomic status, alcohol consumption, smoking, maximal oxygen uptake and body mass index, there was no association between serum total n - 3 PUFAs and the risk of depression [relative risk (RR) in the highest compared to the lowest tertile 0.71, 95% confidence interval (CI): 0.38; 1.43]. Serum concentrations of n - 6 PUFAs, n6/n3 PUFA ratio, or individual fatty acids were not associated with the risk of severe depression, either. CONCLUSIONS: We did not find evidence that serum n - 3 PUFA concentration or n - 6/n - 3 ratio would be associated with risk of severe depression in middle-aged Finnish men.