Abstract 4255: Associations of coffee consumption and caffeine intake with mammographic breast density

Abstract

Abstract Purpose: Previous studies suggest that coffee consumption and caffeine intake may be associated with reduced breast cancer risk which may result from stimulating effect of coffee on estrogen metabolism enzymes and subsequent changes in bioavailable estrogen. We investigated the association of coffee consumption and caffeine intake with mammographic density by woman’s menopausal status and, in postmenopausal women, by hormone therapy (HT). Methods: This study included 4,130 cancer-free women within the Nurses’ Health Study and Nurses’ Health Study II cohorts. Percent breast density (PD), absolute dense and non-dense areas were measured from digitized film mammograms using a computer-assisted thresholding technique; all measures were square-root transformed for the analysis to improve normality. Diet was assessed with a food frequency questionnaire; average cumulative coffee/caffeine consumption was calculated using data available from all the questionnaires preceding the mammogram date. Information regarding breast cancer risk factors was obtained from baseline or biennial questionnaires closest to the mammogram date. We used generalized linear regression to quantify associations between exposures and breast density measures, adjusted for potential confounders. Associations were examined separately for regular coffee, decaffeinated coffee, total coffee, and energy-adjusted caffeine intake. Results: In multivariable analyses, decaffeinated coffee was positively associated with PD in premenopausal women (2+ cups/day: β=0.23, p-trend=0.03). In postmenopausal women, decaffeinated and total coffee were inversely associated with PD (decaffeinated coffee 2+ cups/day: β=-0.24, p-trend=0.04; total coffee 4+ cups/day: β=-0.17). These associations appeared to be driven by the inverse associations of these exposures with absolute dense area. Among current HT users (n=980), regular coffee and caffeine intake were inversely associated with PD (regular coffee 4+ cups/day: β=-0.29, p-trend<0.01; caffeine 4th vs. 1st quartile: β=-0.32, p-trend<0.01). Among past users (n=430), decaffeinated coffee was inversely associated with PD (2+ cups/day β=-0.70, p-trend=0.02). Conclusions: Our findings suggest that among current HT users, regular coffee and caffeine are inversely associated with mammographic percent breast density. Citation Format: Lusine Yaghjyan, Graham Colditz, Bernard Rosner, Aleksandra Gasparova, Rulla Tamimi. Associations of coffee consumption and caffeine intake with mammographic breast density [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4255. doi:10.1158/1538-7445.AM2017-4255