Reported associations between genetic polymorphisms in
folate-metabolizing
enzymes and lymphoid
malignancies suggest etiologic involvement of one-
carbon metabolism and its related dietary exposures. We examined dietary factors of one-
carbon metabolism in relation to
non-Hodgkin lymphoma (NHL) and
multiple myeloma (MM) among 27,111 healthy male smokers who completed baseline dietary questionnaires in the
Alpha-Tocopherol Beta-Carotene Cancer Prevention Study cohort. During a follow-up of up to 16.4 years (1985-2001), 195 NHL and 32 MM cases were ascertained. Cox proportional hazard models were used to estimate multivariable-adjusted hazard ratios (HR) and 95% confidence intervals (95% CI). There was no significant association between dietary
folate and NHL (HR comparing fourth to first quartile, 1.03; 95% CI, 0.68-1.55). Dietary
vitamin B12 was inversely associated with NHL (HR, 0.61; 95% CI, 0.37-1.00; P(trend) = 0.06). The inverse association of
vitamin B12 was evident for diffuse subtype but did not reach statistical significance. There were no significant associations of dietary
vitamin B6 or B2,
methionine, or alcohol with NHL. None of the dietary or supplemental one-
carbon nutrients were associated with MM, although the power of these analyses was limited. Our results suggest that high intake of
vitamin B12 among heavy smokers may be protective against NHL but warrant further studies, including among nonsmokers.