Abstract
BACKGROUND: Sex hormones are important for breast cancer, but it is unclear whether dietary patterns influence hormone concentrations. METHODS: Dietary pattern adherence scores for the alternate Mediterranean diet (aMED), Dietary Approaches to Stop Hypertension (DASH), and Alternative Healthy Eating Index (AHEI) were calculated from semiquantitative food frequency questionnaires administered in 1995 and 1999. Premenopausal plasma concentrations of sex hormones were measured in samples collected in 1996 to 1999. We used generalized linear models to calculate geometric mean hormone concentrations across quartiles of dietary pattern scores among 1,990 women in the Nurses' Health Study II. RESULTS: We did not observe significant associations between sex hormone concentrations and the DASH pattern and only one suggestive association between follicular estrone concentrations and the aMED pattern [top vs. bottom quartile -4.4%, 95% confidence interval (CI), -10.6% to 2.1%; Ptrend = 0.06]. However, women in the top versus bottom quartile of AHEI score had lower concentrations of follicular (-9.1%; 95% CI, -16.1% to -1.4%; Ptrend = 0.04) and luteal (-7.5%; 95% CI, -13.6% to -0.9%; Ptrend = 0.01) estrone, luteal-free (-9.3%; 95% CI, -16.8% to -1.1%; Ptrend = 0.01) and total (-6.7 %; 95% CI, -14.3% to 1.5%; Ptrend = 0.04) estradiol, follicular estradiol (-14.2%; 95% CI, -24.6% to -2.4%; Ptrend = 0.05), and androstenedione (-7.8%; 95% CI, -15.4% to 0.4%; Ptrend = 0.03). CONCLUSION: Diet quality measured by the AHEI is inversely associated with premenopausal estrogen concentrations. Given that we did not observe similar associations with the aMED or DASH patterns, our findings should be interpreted with caution. IMPACT: Given the role of estrogens in breast cancer etiology, our findings add to the substantial evidence on the benefits of adhering to a healthy diet. Cancer Epidemiol Biomarkers Prev; 25(5); 791-8. ©2016 AACR.