Association between folate, vitamin B6 and vitamin B12 intake and depression in the SUN cohort study

An association between low blood levels of folate, vitamins B-6 and B-12 and a higher prevalence of depressive symptoms has been reported in several epidemiological studies. The present study aimed to assess the association between folate, vitamins B-6 and B-12 intake and depresion prevalence in the SUN cohort study. The study comprised a cross-sectional analysis of 9670 participants. A validated semi-quantitative food frequency questionnaire was used to ascertain vitamin intake. The association between the baseline intake of folate, vitamins B-6 and B-12 categorised in quintiles and the prevalence of depression was assessed. The analyses were repeated after stratifying by smoking habits, alcohol intake, physical activity and personality traits. Among women, odds ratios (OR) [95% confidence interval (CI)] for the third to fifth quintile for vitamin B-12 intake were 0.58 (0.41-0.84), 0.56 (0.38-0.82) and 0.68 (0.45-1.04), respectively. Among those men with a low level of anxiety and current smokers, a significant positive association between low folate intake and the prevalence of depression was found. The OR (95% CI) for the first quintile of intake was 2.85 (1.49-5.45) and 2.18 (1.08-4.38), respectively, compared to the upper quintiles of intake (Q2-Q5) considered as a group. Low folate intake was associated with depression among currently smoking men and men with low anxiety levels. Low intake of vitamin B-12 was associated with depression among women. No significant associations were found for vitamin B-6 intake.