Bone mineral density and the risk of breast cancer: a case-control study of Korean women

Abstract Purpose Bone mineral density (BMD) may be useful as a surrogate marker reflecting lifetime exposure to estrogen in a woman. Our study aimed to investigate an association between BMD and breast cancer risk. Methods A case-control study was conducted using 253 breast cancer cases and 506 age and menopausal status–matched controls from the same institution. Cases were ascertained through medical record review of the women with abnormal mammographic findings. BMD was measured at the lumbar spine and femoral neck using a dual-energy X-ray absorptiometry. The association was estimated by conditional logistic regression analysis with an adjustment for covariates. Results Although there was no difference in the association between pre- and postmenopausal disease, the association between BMD and breast cancer was evident for postmenopausal breast cancer. One standard deviation in age and menopausal status adjusted BMD at lumbar spine and femur neck was associated with 1.35-fold (standard error = 0.19, P = .04) and 1.34-fold (standard error = 0.20, P = .05) increased likelihood of breast cancer risk, respectively, for postmenopausal women. Conclusion After adjusting for covariates, higher BMD at lumbar spine and femur neck are associated with increased likelihood of breast cancer risk for postmenopausal women. These findings suggest that BMD could be included in breast cancer risk prediction models for postmenopausal Korean women.