Research article

Vitamin D receptor polymorphisms and breast cancer risk in a large population-based case-control study of Caucasian and African-American women

Britton Trabert^1,2 , Kathleen E Malone^1,2 , Janet R Daling^1,2 , David R Doody¹ , Leslie Bernstein³ , Giske Ursin^3,4 , Polly A Marchbanks⁵ , Brian L Strom⁶ , Mariela C Humphrey⁷ and Elaine A Ostrander^7,8

¹  Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Fairview Ave N, Seattle, Washington 98109-1024, USA

²  Department of Epidemiology, University of Washington School of Public Health and Community Medicine, NE Pacific St, Seattle, Washington 98195, USA

³  Department of Preventive Medicine, Keck School of Medicine and Norris Comprehensive Cancer Center, University of Southern California, Zonal Ave, Los Angeles, California 90089, USA

⁴  Department of Nutrition, University of Oslo, Sognsvannsveien, 0372 Oslo, Norway

⁵  National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Clifton Rd, Atlanta, Georgia 30333, USA

⁶  Center for Clinical Epidemiology and Biostatistics and Department of Biostatistics and Epidemiology, University of Pennsylvania, Guardian Drive, Philadelphia, Pennsylvania 19104, USA

⁷  Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, Washington 98109-1024, USA

⁸  Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, South Drive, Bethesda, Maryland 20892, USA

author email corresponding author email

Breast Cancer Research 2007, 9:R84doi:10.1186/bcr1833

Published:	7 December 2007

Abstract

Introduction

The involvement of vitamin D receptor (VDR), which is a key mediator in the vitamin D pathway, in breast cancer etiology has long been of interest.

Methods

We examined the association between polymorphisms in the 3' end of the VDR gene, specifically BsmI and Poly(A), and breast cancer risk within a large, population-based, case-control study of breast cancer. Cases (n = 1,631) were Caucasian and African-American women, aged 35 to 64 years, who were diagnosed with incident, invasive breast cancer between July 1994 and April 1998. Control individuals (n = 1,435) were women without breast cancer ascertained through random digit dialing.

Results

Accounting for age, study site, and sampling weights, we observed a significantly increased risk for breast cancer among Caucasian, postmenopausal carriers of the bb genotype of BsmI (odds ratio = 1.53, 95% confidence interval = 1.04 to 2.27). However, no associations with the bb genotype were observed in African-American women. Overall, there were no significant associations between the Poly(A) genotype and breast cancer risk in either racial group. Smoking status (ever/never) modified the association between both the BsmI and Poly(A) genotypes and breast cancer risk. The respective associations between these genotypes and breast cancer risk did not significantly vary by oral contraceptive use, hormone replacement therapy, or body mass index.

Conclusion

Our results provide additional support for an increased risk for breast cancer in postmenopausal Caucasian women with the BsmI bb genotype and shed light on possible differential effects by menopausal status and race.