title: Alcohol consumption and breast cancer risk in Japanese women: the Miyagi Cohort study.
abstract: Alcohol consumption is known to be a risk factor for breast cancer in Western countries, but few epidemiologic data have been available in Japan. This population-based prospective cohort study evaluated the associations of alcohol consumption with breast cancer risk in a Japanese population. A total of 19,227 women aged 40-64 years were followed from 1990 to 2003. During 246,703 person-years of follow-up, 241 breast cancer cases were identified. Hazard ratios (HRs) were estimated by the Cox proportional-hazard regression model. After adjustment for potential risk factors of breast cancer and nutritional factors, the HR and 95% confidence interval (CI) for current drinkers was 1.00 (0.74-1.34) compared with never drinkers. According to the amount of alcohol intake per day, a higher amount (≥15.0 g/day) had no significant relation to breast cancer risk (HR = 0.87, 95% CI: 0.40-1.91; P for trend = 0.85). Age upon starting to drink, and the frequency of drinking, were not associated with breast cancer risk. In analysis stratified according to exogenous female hormone use, a higher alcohol intake (≥15.0 g/day) was associated with an increased risk of breast cancer among hormone users (HR = 1.67, 95% CI: 0.17-16.73); however, this was not statistically significant. Stratification according to folate intake with energy adjustment (<219, ≥ 219 μg/day) found that breast cancer risk tended to increase with increasing alcohol consumption among women with a low intake of folate (P for trend = 0.09). Our findings suggest that alcohol consumption has no overall effect on breast cancer risk among Japanese women, whereas nutritional factors such as folate intake may modify the alcohol-breast cancer risk relationship.
authors.affiliation: Department of Surgical Oncology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kawai
authors.forename: Yuko
authors.initials: Y
authors.lastname: Minami
authors.forename: Masako
authors.initials: M
authors.lastname: Kakizaki
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Kakugawa
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Nishino
authors.forename: Akira
authors.initials: A
authors.lastname: Fukao
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tsuji
authors.forename: Noriaki
authors.initials: N
authors.lastname: Ohuchi
mesh_terms: D000328:Adult; D000428:Alcohol Drinking / Q000009:adverse effects*; D001943:Breast Neoplasms / Q000453:epidemiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008875:Middle Aged; D018570:Risk Assessment; D012307:Risk Factors