Source
Centre For Molecular Epidemiology, National University of Singapore, Blk MD3, 16 Medical Drive, Singapore 117597, Singapore.
Abstract
BACKGROUND:
Joint effects of mammographic density and other risk factors on breast cancer risk remain unclear.
METHODS:
From The Singapore Breast Screening Project, we selected 491 cases and 982 controls. Mammographic density was measured quantitatively. Data analysis was by conditional logistic regression.
RESULTS:
Density was a significant risk factor, adjusting for other factors. Density of 76-100% had an odds ratio of 5.54 (95% CI 2.38-12.90) compared with 0-10%. Density had significant interactions with body mass index and oral contraceptive use (P=0.02).
CONCLUSIONS:
Percent density increases breast cancer risk in addition to effects of other risk factors, and modifies the effects of BMI and OCs.