Abstract 2778: Association between mammographic density and serum 25-hydroxyvitamin D levels

Abstract

Abstract Background: Previous studies have demonstrated an inverse association between vitamin D and risk of breast cancer. In addition, dietary vitamin D intake has been associated with lower mammographic density (MD), a strong intermediate marker of breast cancer risk. We examined the relationship between MD and serum 25-hydroxyvitamin D [25(OH)D], an integrated measure of vitamin D status from food, supplements, and sun exposure, in a multi-ethnic cohort of women undergoing screening mammography. Methods: Using a cross-sectional study design, 195 women without a history of breast cancer completed a routine screening mammogram, in-person interviews collecting data on demographics, lifestyle factors, and breast cancer risk factors, and donated a blood sample. We digitized mammograms and evaluated the proportion of dense area on cranial-caudal images using Cumulus software. Serum 25(OH)D was measured in batched, archived specimens by Diasorin radioimmunoassay. We used a multivariate linear regression model to investigate the association of percent density with serum 25(OH)D. We examined confounding by age, race/ethnicity, body mass index (BMI), season of blood draw, and breast cancer risk factors. Results: A total of 195 women enrolled, 116 donated a blood sample and were evaluable for analysis; median age: 49.9 years (range 40.0-60.9); white/African American/African Caribbean/Hispanic Caribbean: 26%/43%/19%/12%. The prevalence of vitamin D deficiency [25(OH)D <20 ng/ml] was 24% among whites, 52% in African Americans, 33% in African Caribbeans, and 43% in Hispanics (Chi-square p-value=.09). Age and BMI were inversely associated with MD (p<0.001). After adjusting for known confounders, we found no association between serum 25(OH)D and percent density. Discussion: In contrast to some previous reports, vitamin D does not appear to be related to MD in this multiethnic cohort. Vitamin D status, a potentially modifiable risk factor, may have a protective effect against breast cancer development which is not mediated by changes in breast density. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2778.