Methionine and vitamin B6 intake and risk of pancreatic cancer:: A prospective study of Swedish women and men

Background & Aims: It has been hypothesized that dietary factors involved in methyl group metabolism, such as methionine, folate, and vitamin B-6, may modify cancer risk. We have previously reported an inverse association between folate intake and pancreatic cancer risk in a prospective population-based cohort of Swedish women and men. In the present study, we used data from this prospective study to examine whether methionine and vitamin B6 intakes were associated with the incidence of exocrine pancreatic cancer. Methods: Our study population comprised 81,922 Swedish women and men, aged 45-83 years, who were free from cancer and completed a self-administered food-frequency questionnaire in 1997. We used Cox proportional hazards models to estimate rate ratios with 95% confidence intervals (CI), adjusted for age, sex, education, smoking, body mass index, diabetes, and intakes of total energy and dietary folate. Results: During a mean follow-up of 7.2 years, through June 2005, 147 incident cases of pancreatic cancer were diagnosed. Methionine intake was significantly inversely associated with risk of pancreatic cancer, whereas no significant association was observed for dietary or total vitamin B6 intake. The multivariate rate ratios comparing the highest with the lowest quartile of methionine intake were 0.44 (95% CI, 0.26-0.73; P for trend = .0005) in women and men combined, 0.59 (95% CI, 0.28-1.21; P for trend = .07) in women, and 0.32 (95% CI, 0.15-0.65; P for trend = .002) in men. Conclusions: These findings suggest that higher methionine intake may reduce the risk of pancreatic cancer.