Abstract A123: Serum levels of hormones and breast tissue composition in young women

Abstracts: Frontiers in Cancer Prevention Research 2008 A123 Background Percent mammographic density (PMD) is a strong and heritable risk factor for breast cancer with characteristics that suggest it may be a marker of susceptibility to the disease. We have examined serum hormone levels and other factors associated with breast tissue composition in young women, when susceptibility to breast carcinogens is greatest. Methods In 400 young women aged 15-30 years we obtained quantitative measures of breast water, which reflects fibro-glandular tissue, and breast fat using magnetic resonance (MR), and collected anthropometric and other data. All examinations were performed in the follicular phase of the menstrual cycle and fasting blood samples for hormone assays were obtained on the morning of the MR examination. Results Serum levels of growth hormone (GH) and sex hormone binding globulin (SHBG) were positively associated with percent breast water content in all young women aged 15-30, and the associations remained statistically significant after adjustment for height, weight and other covariates. IGF-I was not associated with any MR breast measures. Serum levels of estradiol, progesterone, and testosterone, were not associated with MR breast measures in all young women, or in those aged 20-30, but did show evidence of positive associations with percent water in those aged 15-19 years. After adjustment for other covariates, interactions of age and serum levels of testosterone (p=0.02) and progesterone (p=0.03) were associated with percent water, and estradiol with total water (p=0.07). Conclusions Serum levels of sex hormones were associated with breast tissue composition in young women aged less than 20, while GH and SHBG were associated with breast tissue composition in all young women. Citation Information: Cancer Prev Res 2008;1(7 Suppl):A123.