Experimental evidence suggests that vitamin D might play a role in the development of breast cancer. Although the results of case-control studies indicate that circulating 25-hydroxyvitamin D [25(OH)D] is inversely associated with the risk of breast cancer, the results of prospective studies are inconsistent. A case-control study embedded in the European Prospective Investigation into Cancer and Nutrition (EPIC) was carried out comprising 1,391 incident breast cancer cases and 1,391 controls. Multivariable conditional logistic regression models did not reveal a significant overall association between season-standardized 25(OH)D levels and the risk of breast cancer (ORQ4-Q1 [95% CI]: 1.07 [0.85-1.36], ptrend = 0.67). Moreover, 25(OH)D levels were not related to the risks of estrogen receptor positive tumors (ORQ4-Q1 [95% CI]: 0.97 [0.67-1.38], ptrend = 0.90) and estrogen receptor negative tumors (ORQ4-Q1 [95% CI]: 0.97 [0.66-1.42], ptrend = 0.98). In hormone replacement therapy (HRT) users, 25(OH)D was significantly inversely associated with incident breast cancer (ORlog2 [95% CI]: 0.62 [0.42-0.90], p = 0.01), whereas no significant association was found in HRT nonusers (ORlog2 [95% CI]: 1.14 [0.80-1.62], p = 0.48). Further, a nonsignificant inverse association was found in women with body mass indices (BMI) < 25 kg/m(2) (ORlog2 [95% CI]: 0.83 [0.67-1.03], p = 0.09), as opposed to a borderline significant positive association in women with BMI ≥ 25 kg/m(2) (ORlog2 [95% CI]: 1.30 [1.0-1.69], p = 0.05). Overall, prediagnostic levels of circulating 25(OH)D were not related to the risk of breast cancer in the EPIC study. This result is in line with findings in the majority of prospective studies and does not support a role of vitamin D in the development of breast cancer.

Original publication

DOI

10.1002/ijc.28172

Type

Journal article

Journal

Int J Cancer

Publication Date

01/10/2013

Volume

133

Pages

1689 - 1700

Keywords

25-hydroxyvitamin D, breast cancer, estrogen receptor status, prospective study, vitamin D, Body Composition, Body Mass Index, Breast Neoplasms, Case-Control Studies, Europe, Female, Hormone Replacement Therapy, Humans, Nutritional Status, Prospective Studies, Receptors, Estrogen, Risk Factors, Vitamin D