BOSTON—Circulating 25-hydroxyvitamin D (25(OH)D) levels were not significantly associated with breast cancer risk in a predominantly premenopausal population assessed by researchers at Brigham and Women’s Hospital and Harvard Medical School (Breast Cancer Research 2011, 13:R50).
Experimental evidence indicates vitamin D may play an important role in breast cancer etiology but epidemiologic evidence to date is inconsistent. Vitamin D comes from dietary intake and sun exposure and plasma levels of 25(OH)D are considered the best measure of vitamin D status. Researchers conducted a prospective nested case-control study within the Nurses' Health Study II (NHSII). Plasma samples collected in 1996 to 1999 were assayed for 25(OH)D in 613 cases, diagnosed after blood collection and before June 1, 2007, and 1,218 matched controls.
No significant association was observed between plasma 25(OH)D levels and breast cancer risk. Results were similar when season-specific quartile cut points were used. Results did not change when restricted to women who were premenopausal at blood collection or premenopausal at diagnosis. Results were similar between estrogen receptor (ER)+/progesterone receptor (PR)+ and ER-/PR- tumors. The association did not vary by age at blood collection or season of blood collection, but did vary when stratified by body mass index.
