Predictors of Bone Health in Post-Menopausal Women

Osteoporosis, a skeletal disorder characterized by compromised bone-strength and an increased risk of bone fracture, is becoming increasingly prevalent, and the health and economic burden of osteoporosis is only expected to increase as the population ages. Osteoporosis disproportionately effects women, and past studies looking at exercise as a preventative factor have primarily focused on white women. Through the FIERCE study, total body bone mineral density (BMD) measurements of 213 post-menopausal African- American women living in the Washington D.C. area were collected via dual-energy x-ray absorptiometry (DXA), the gold standard in the field. Additionally, medical histories and anthropometric measurements were recorded. Participants were assigned to one of three exercise groups after the baseline visit- Supervised exercise, home based exercise, or control. We hypothesized that participants assigned to an exercise group would experience improvements or preservation in BMD levels among postmenopausal Black women at increased risk for breast cancer, as prior studies have showed exercise affecting hip BMD and resistance training preventing spine bone loss. After six months of maintaining their exercise assignments, BMD measurements were taken via DXA once again. Age at baseline had a significant effect on BMD level (p=0.0049) as did total percent body fat at baseline (p<0.0001). The average change in BMD levels in supervised, home-based, and control assignments were -0.001, 0.008, and -0.003 g/cm2 respectively (p=0.24). There was no significant difference in these change of BMD levels among exercise assignments (p= 0.93), after controlling for repeated measures, age and total percent body fat (p= 0.71). Further studies are needed to see if a longer time in an exercise intervention is needed to see improvements in BMD levels, as exercise represents a low cost and noninvasive possible intervention for osteoporosis.