Serum pyridoxal concentrations and depressive symptoms among Japanese adults: results from a prospective study

Abstract

Vitamin B6 is suggested to have a protective role against depression. However, the association between vitamin B6 intake and depression remains inconclusive, and few studies have examined the relationship between circulating vitamin B6 concentrations and depressive symptoms. Here, we investigated the cross-sectional and prospective associations between serum pyridoxal concentrations and depressive symptoms among Japanese workers. Participants were 422 municipal employees (aged 21-67 years) who participated in a baseline survey in 2006 for cross-sectional analysis, and 210 subjects without depressive symptoms at baseline (2006) who completed both baseline and follow-up (2009) surveys for prospective analysis. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Logistic regression analysis was used to estimate the odds ratio of depressive symptoms (CES-D scale of ≥ 19) according to tertile of serum pyridoxal with adjustment for potential confounding variables. In the cross-sectional analysis, serum pyridoxal concentrations were significantly associated with a decreased prevalence of depressive symptoms (P for trend=0.03); the multivariable-adjusted odds ratio of depressive symptoms for the highest tertile of pyridoxal was 0.54 (95% confidence interval 0.30-0.96) compared with the lowest tertile. In longitudinal analyses, higher serum pyridoxal concentrations at baseline were associated with a trend toward reduced depressive symptoms after 3 years; the multivariable-adjusted odds ratio of depressive symptoms for the highest versus the lowest tertile of pyridoxal concentration was 0.55 (95% confidence interval 0.13-2.32). A higher vitamin B6 status may be associated with a decreased risk of depressive symptoms in Japanese.