Dietary patterns and suicide in Japanese adults: the Japan Public Health Center-based Prospective Study.

BACKGROUND Although dietary patterns have been linked to depression, a frequently observed precondition for suicide, no study has yet examined the association between dietary patterns and suicide risk. AIMS To prospectively investigate the association between dietary patterns and death from suicide. METHOD Participants were 40 752 men and 48 285 women who took part in the second survey of the Japan Public Health Center-based Prospective Study (1995-1998). Dietary patterns were derived from principal component analysis of the consumption of 134 food and beverage items ascertained by a food frequency questionnaire. Hazard ratios of suicide from the fourth year of follow-up to December 2005 were calculated. RESULTS Among both men and women, a 'prudent' dietary pattern characterised by a high intake of vegetables, fruits, potatoes, soy products, mushrooms, seaweed and fish was associated with a decreased risk of suicide. The multivariable-adjusted hazard ratio of suicide for the highest v. lowest quartiles of the dietary pattern score was 0.46 (95% CI 0.28-0.75) (P for trend, 0.005). Other dietary patterns (Westernised and traditional Japanese) were not associated with suicide risk. CONCLUSIONS Our findings suggest that a prudent dietary pattern may be associated with a decreased risk of death from suicide.