Assessing the prevalence of compromised bone health among overweight and obese African-American breast cancer survivors: a case-control study.

Abstract

Osteoporosis increases the risk of fracture and is often considered a late effect of breast cancer treatment. We examined the prevalence of compromised bone health in a sample of exclusively African-American (AA) breast cancer survivors since bone mineral density (BMD) varies by race/ethnicity in healthy populations. Using a case-control design, AA women in a weight loss intervention previously diagnosed and treated for stages I-IIIa breast cancer were matched 1:1 on age, race, sex, and BMI with non-cancer population controls (n = 101 pairs) from National Health and Nutrition Examination Survey (NHANES). Questionnaires and dual-energy x-ray absorptiometry (DXA) scanning were completed, and participants were categorized as having normal bone density, low bone mass, or osteoporosis using the World Health Organization (WHO) definition for femoral neck T-scores. The majority of these overweight/obese survivors were 6.6 (±4.7) years post-diagnosis, had stage II (n = 46) or stage III (n = 16) disease, and treated with chemotherapy (76 %), radiation (72 %), and/or adjuvant hormone therapies (45 %). Mean femoral neck BMD was significantly lower in cases vs. matched non-cancer population controls (0.85 ± 0.15 vs. 0.91 ± 0.14 g/cm(2), respectively; p = 0.007). However, the prevalence of low bone mass and osteoporosis was low and did not significantly differ between groups (n = 101 pairs; p = 0.26), even when restricted to those on adjuvant hormone therapies (n = 45 pairs; p = 0.75). Using conditional logistic regression, controlling for dietary factors and education, the odds of developing compromised bone health in AA breast cancer survivors was insignificant (OR 1.5, 95 % CI 0.52, 5.56). These null case-control findings challenge the clinical assumption that osteoporosis is highly prevalent among all breast cancer survivors, providing foundational evidence to support differences by race/ethnicity and body weight. Routine bone density testing and regular patient-provider dialogue is critical in overweight/obese AA breast cancer survivors to ensure that healthy lifestyle factors (e.g., ideal weight, regular weight-bearing exercises, dietary adequacy of calcium and vitamin D) support optimal skeletal health.