title: Alcohol and dietary folate intake and the risk of breast cancer: a case-control study in Japan.
abstract: Owing to its interaction with alcohol, folate has been suggested to be a potential factor for many types of cancer. The impact of these factors on the risk of breast cancer among Asian populations has not been fully examined, however, particularly with respect to receptor status. We carried out a case-control study in premenopausal and postmenopausal Japanese women, including 1754 breast cancer patients and 3508 noncancer controls. We determined the association between self-reported alcohol drinking, dietary folate intake, and the risk of breast cancer. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using logistic models adjusted for potential confounders. Alcohol consumption was associated with the risk of breast cancer, with the OR for a drinker consuming 23 g or more per day relative to a nondrinker of 1.39 (95% CI: 1.07-1.80). A significant inverse association was observed between folate intake and overall risk of breast cancer, with an OR of 0.79 (95% CI: 0.68-0.93; Ptrend=0.004) for the highest tertile relative to the lowest. The OR of a drinker consuming 23 g or more per day relative to a nondrinker with a low folate intake was 1.58 (95% CI: 1.06-2.33). However, a significantly increased risk was not observed in tertile 2 and tertile 3 folate in taker with any amount of alcohol consumption. Higher folate intake decreases the risk of breast cancer among Japanese, whereas alcohol intake increases the risk. These two factors interact with each other, and the excess risk of breast cancer with alcohol consumption might be attenuated by increasing the intake of folate. In addition, the effects of folate/alcohol may vary according to the tumor subtype.
authors.affiliation: Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, Nagoya, Japan.
authors.forename: Tania
authors.initials: T
authors.lastname: Islam
authors.forename: Hidemi
authors.initials: H
authors.lastname: Ito
authors.forename: Aiko
authors.initials: A
authors.lastname: Sueta
authors.forename: Satoyo
authors.initials: S
authors.lastname: Hosono
authors.forename: Kaoru
authors.initials: K
authors.lastname: Hirose
authors.forename: Miki
authors.initials: M
authors.lastname: Watanabe
authors.forename: Hiroji
authors.initials: H
authors.lastname: Iwata
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tajima
authors.forename: Hideo
authors.initials: H
authors.lastname: Tanaka
authors.forename: Keitaro
authors.initials: K
authors.lastname: Matsuo
mesh_terms: D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects*; D001943:Breast Neoplasms / Q000737:chemistry / Q000209:etiology*; D016022:Case-Control Studies; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D012306:Risk
chemical_list: D005492:Folic Acid; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human