The objective of the current study was to examine the associations between dietary folate, vitamin B6, vitamin B12, and methionine intake and the risk of breast cancer by estrogen receptor (ER) and progesterone receptor (PR) status among Chinese women. A hospital-based case–control study was conducted from June 2007 to August 2008, with 438 cases and 438 age (five-year interval)- and residence (rural/urban)-matched controls. Dietary intake information was assessed using a validated food frequency questionnaire administered through an interview. A significant inverse association was found between dietary folate and vitamin B6 intake and breast cancer risk. The adjusted odds ratio of the highest versus the lowest quartile was 0.32 (95 % CI: 0.21-0.49; P< 0.001) for dietary folate and 0.46 (95 % CI: 0.30-0.69; P< 0.001) for vitamin B6. No associations were observed for vitamin B12 and methionine intake. A significant inverse association between dietary folate intake and breast cancer risk was observed in all subtypes of ER and PR status. These findings suggest that dietary folate and vitamin B6 intakes were inversely associated with breast cancer risk but this inverse association did not differ by ER and/or PR status. Br J Nutr. 2011 Sep;106(6):936-43. PMID: 21736840.
