Serum Vitamin D and Breast Density in Breast Cancer Survivors

Background: Vitamin D influences cellular proliferation and proliferation-related breast tissue characteristics, such as mammographic breast density. Little is known about vitamin D status, assessed by serum 25-hydroxyvitamin D [25(OH)D], and its relationship to breast density in breast cancer survivors. Methods: Participants were 426 postmenopausal breast cancer survivors from the Health, Eating, Activity, and Lifestyle Study. Women from New Mexico, Los Angeles, and western Washington were enrolled post-diagnosis. Data for this report are from an examination conducted 24 months postenrollment. Participants completed health-related questionnaires, gave fasting blood samples, and completed height and weight measurements. Serum [25(OH)D] was assayed by radioimmunoabsorbant assay. Breast dense area and percent density were measured from postdiagnosis-digitized mammograms. Multivariate linear regression tested associations of serum [25(OH)D] with mammographic breast density measures. Results: Of the 426 participants, 22.8% were African-American, 11.3% were Hispanic, and 62.8% were non-Hispanic white. We observed no associations of serum [25(OH)D] with either breast density or breast dense area. Among women with vitamin D deficiency (serum [25(OH)D], <16.0 ng/mL; n = 103), mean percent breast density was 8.0%, and among those with sufficient status (n = 99; serum [25(OH)D], >= 32.0 ng/mL), mean percent density was 8.5%. Breast dense area averaged 27.2 and 26.2 cm(2) for women with vitamin D deficiency and sufficiency, respectively. Conclusion: Data from this multiethnic cohort of breast cancer survivors do not support the hypothesis that serum vitamin D, [25(OH)D], is associated with breast density in cancer survivors. Cancer Epidemiol Biomarkers Prev; 19(2); 412-7. (c) 2010 AACR.