Bone loss in women with BRCA1 and BRCA2 mutations.

Objective: Estimate the prevalence and identify risk factors for bone loss in women with BRCA mutations.

Methods: Women, age 40 and older, with BRCA mutations identified from the Breast Cancer Surveillance database at Kaiser Permanente Northern California were invited to participate and undergo a dual-energy x-ray absorptiometry scan to assess for bone loss (osteopenia or osteoporosis). Multivariable logistic regression analysis was performed to assess clinical factors associated with bone loss.

Results: Of the 238 women in the final cohort, 20 women had intact ovaries (median age 54.5years) and 218 had undergone risk reducing salpingo-oophorectomy (RRSO) (median age 57). The prevalence of bone loss was 55% in the no RRSO group and 72.5% in the RRSO group (P=0.10). In multivariable analysis, only higher body mass index (OR 0.6 per 5kg/m, 95% CI: 0.4-0.7) and nonwhite race compared to white (OR 0.5, 95% CI: 0.2-0.9) were protective for bone loss while older age (OR 1.5 per 10years, 95% CI: 1.1-2.1) and selective estrogen receptor modulator use (3.1, 95% CI: 1.2-10.1) were associated with increased odds of bone loss. Among women with RRSO, bone loss was more frequent in women who had postmenopausal (n=106) compared to women who had premenopausal RRSO (n=112), (82.1% and 63.4% respectively, P=0.002). In multivariable analysis, only BMI was protective of bone loss (OR 0.5, 95%, CI: 0.4-0.7) but neither age nor menopausal status at RRSO were associated with bone loss.

Conclusion: Bone loss is common in women with BRCA mutations who undergo RRSO.