Alcohol consumption and breast cancer risk by estrogen receptor status: in a pooled analysis of 20 studies
2016 (English)In: International Journal of Epidemiology, ISSN 0300-5771, E-ISSN 1464-3685, Vol. 45, no 3, 916-928 p.Article in journal (Refereed) Published
Background: Breast cancer aetiology may differ by estrogen receptor (ER) status. Associations of alcohol and folate intakes with risk of breast cancer defined by ER status were examined in pooled analyses of the primary data from 20 cohorts. Methods: During a maximum of 6-18 years of follow-up of 1 089 273 women, 21 624 ER+ and 5113 ER- breast cancers were identified. Study-specific multivariable relative risks (RRs) were calculated using Cox proportional hazards regression models and then combined using a random-effects model. Results: Alcohol consumption was positively associated with risk of ER+ and ER- breast cancer. The pooled multivariable RRs (95% confidence intervals) comparing amp;gt;= 30 g/d with 0 g/day of alcohol consumption were 1.35 (1.23-1.48) for ER+ and 1.28 (1.10-1.49) for ER+ breast cancer (P-trend amp;lt;= 0.001; Pcommon-effects by ER status: 0.57). Associations were similar for alcohol intake from beer, wine and liquor. The associations with alcohol intake did not vary significantly by total (from foods and supplements) folate intake (P-interaction amp;gt;= 0.26). Dietary (from foods only) and total folate intakes were not associated with risk of overall, ER+ and ER- breast cancer; pooled multivariable RRs ranged from 0.98 to 1.02 comparing extreme quintiles. Following-up US studies through only the period before mandatory folic acid fortification did not change the results. The alcohol and folate associations did not vary by tumour subtypes defined by progesterone receptor status. Conclusions: Alcohol consumption was positively associated with risk of both ER+ and ER- breast cancer, even among women with high folate intake. Folate intake was not associated with breast cancer risk.
Place, publisher, year, edition, pages
OXFORD UNIV PRESS , 2016. Vol. 45, no 3, 916-928 p.
Alcohol; folate; breast cancer; estrogen receptor; progesterone receptor; pooled analyses; epidemiology; cohort study
Cancer and Oncology
IdentifiersURN: urn:nbn:se:liu:diva-132357DOI: 10.1093/ije/dyv156ISI: 000384653200044PubMedID: 26320033OAI: oai:DiVA.org:liu-132357DiVA: diva2:1046183
Funding Agencies|National Institute of Health [CA55075]; Breast Cancer Research Foundation2016-11-122016-11-012016-11-12