Plasma folate, vitamin B6, vitamin B12, homocysteine, and risk of breast cancer

intake has appeared to reduce the elevated risk of breast cancer associated with moderate alcohol consumption. How-ever, data relating plasma folate levels to breast cancer risk are sparse. We investigated the association between plasma folate and other vitamins with breast cancer in a prospective, nested case–control study. Methods: Blood samples were ob-tained during 1989 and 1990 from 32 826 women in the Nurses ’ Health Study who were followed through 1996 for the development of breast cancer. We identified 712 breast cancer case patients and selected 712 individually matched control subjects. Dietary information was obtained using food frequency questionnaires given in 1980, 1984, 1986, and 1990. Logistic regression was used to estimate the relative risks (RRs) of breast cancer (after adjustment for potential risk factors), and a generalized linear model was used t