Physical activity and mammographic breast density in the EPIC-Norfolk cohort study.

TitlePhysical activity and mammographic breast density in the EPIC-Norfolk cohort study.
Publication TypeJournal Article
Year of Publication2008
AuthorsPeters, TM, Ekelund, U, Leitzmann, M, Easton, D, Warren, R, Luben, R, Bingham, S, Khaw, K-T, Wareham, NJ
JournalAm J Epidemiol
Volume167
Issue5
Pagination579-85
Date Published2008 Mar 01
ISSN1476-6256
KeywordsAdult, Aged, Body Mass Index, Breast, Breast Neoplasms, Cross-Sectional Studies, Exercise, Female, Humans, Mammography, Middle Aged, Motor Activity, Risk Assessment, Surveys and Questionnaires, United Kingdom
Abstract

Physical inactivity and high mammographic breast density have both been associated with increased breast cancer risk. However, the association between physical activity and mammographic breast density remains inconsistent. In the European Prospective Investigation of Cancer (EPIC)-Norfolk population-based cohort study (United Kingdom), the authors investigated the cross-sectional association between physical activity level at baseline during 1993-1997 and breast density among 1,394 postmenopausal, cancer-free women. Usual physical activity was assessed by a brief, validated questionnaire. Percentage breast density was determined visually from mammograms by three trained radiologists using the Boyd six-category scale. The association between physical activity level and breast density risk category was examined. No statistically significant association between physical activity and percentage breast density was observed in the unadjusted or adjusted regression models. A suggested increase in breast density for the most active women in the unadjusted regression analysis (odds ratio = 1.13, 95% confidence interval: 0.71, 1.80) was reversed after inclusion of body mass index and reproductive and lifestyle variables (odds ratio = 0.78, 95% confidence interval: 0.45, 1.34). The lack of an association between physical activity and percentage breast density suggests that an association between physical activity and breast cancer risk is unlikely to be mediated through an effect on mammographic breast density.

DOI10.1093/aje/kwm350
Alternate JournalAm. J. Epidemiol.
Citation Key10.1093/aje/kwm350
PubMed ID18162477
Grant List10118 / / Cancer Research UK / United Kingdom
MC_U106179471 / / Medical Research Council / United Kingdom
MC_U106179473 / / Medical Research Council / United Kingdom
T32 GM008444 / GM / NIGMS NIH HHS / United States