Vitamin D and Breast Cancer.
Final rept. 1 Jul 94-30 Jun 96,
STANFORD UNIV CA
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Few epidemiologic studies to date have addressed the hypothesis that Vitamin D reduces breast cancer risk. We analyzed interview data obtained from a cohort of white women aged 25-74 years who participated in the first National Health and Nutrition Examination Survey NHANES I from 1971 to 1975 and were followed until 1987. We performed Cox proportional hazards analysis to assess the relationship between sunlight exposure, dietary vitamin D intake, and supplement use and breast cancer risk. The analytic cohort comprised 133 women diagnosed with breast cancer during follow-up and 4,748 women without a self-reported history of breast cancer. Reduced breast cancer risk was associated with high sunlight exposure assessed by the examining physician RR0.60, 95 Cl 0.33-1.09 and self-report RR0.54, 95 Cl 0.28-1.02, high solar radiation in state of longest residence RR0.59, 95 Cl 0.36-0.94, residence in the South at baseline RR0.59, 95 Cl 0.35-0.98, and dietary intake of more than 206 IU assessed by 24-hour dietary recall RR0.67, 95 Cl0.40-1.11. Actinic skin damage, an indirect measure of sunlight exposure, and regular use of multivitamins were not associated with breast cancer risk. Adjustment for other risk factors only minimally changed the relative risk estimates. These findings support the hypothesis that vitamin D may reduce breast cancer risk and warrant future epidemiologic studies.
- Anatomy and Physiology
- Medicine and Medical Research