Dietary B vitamin intake and risk of ulcerative colitis: a case-control study.

OBJECTIVES: A meta-analysis showed that serum folate concentrations, but not vitamin B12 concentrations, are lower in patients with ulcerative colitis compared to healthy controls. However, no epidemiological study has investigated the association between dietary intake of folate, vitamin B12, vitamin B6, vitamin B2, and vitamin B1 and the risk of ulcerative colitis. This study examines this association using data from a multicenter, hospital-based, case-control study.

METHODS: The study included 384 cases of ulcerative colitis diagnosed within the past 3 years and 665 controls. Data were collected through a self-reported questionnaire. Dietary information was obtained using a 169-item semi-quantitative food frequency questionnaire. Adjustment was made for sex, age, pack-years of smoking, alcohol consumption, history of appendicitis, family history of ulcerative colitis, education level, and BMI.

RESULTS: Higher dietary intakes of folate and vitamin B1 were independently associated with a decreased risk of ulcerative colitis after adjusting for confounding factors. The adjusted odds ratio for extreme quartiles was 0.60 [95% confidence interval (CI): 0.39 - 0.91, P for trend = 0.009) for folate and 0.54 (95% CI: 0.36 - 0.81, P for trend = 0.004) for vitamin B1. Dietary intake of vitamins B12, B6, or B2 was not independently associated with ulcerative colitis risk.

CONCLUSION: This is the first study to demonstrate significant inverse relationships between dietary intake of folate and vitamin B1 and the risk of ulcerative colitis. Our results should be interpreted as exploratory and require validation through further, more focused studies.