Association between body composition and hip fractures in older women with physical frailty.

Abstract

We sought to determine the extent to which higher lean and fat mass as measured by dual X-ray absorptiometry in older adults with frailty are related to total hip bone mass density (BMD) index and the rate of hip fractures. The data are from the Women's Health Initiative Observational Study. We identified 872 participants aged ≥65 years with body composition measures and positive frailty. Frailty was determined using modified Fried's criteria. Linear and Cox regressions were used to model study outcomes. During the follow-up period, 5.6% patients (n = 49) had sustained a hip fracture. Body composition indexes were associated with total hip BMD (P < 0.001 for all). In models adjusted for age, ethnicity, smoking, history of fractures, recurrent falls, number of frailty criteria and corresponding lean mass, the hazard ratio for hip fracture per 1 kg/m2 increase in fat mass was 0.73 (95% confidence interval 0.60-0.88) for appendicular compartment, 0.76 (95% confidence interval 0.65-0.89) for trunk and 0.84 (95% confidence interval 0.77-0.93) for whole-body fat mass. The hazard ratio for hip fracture per 1 kg/m2 increase in appendicular lean mass was 0.63 (95% confidence interval 0.46-0.88). However, after final adjustment for total hip BMD, the only index that remained statistically significant was whole-body fat mass (P for trend = 0.04). We showed that in frail older women, higher fat and lean mass was associated with reduced hip-fracture rates. Higher whole-body adiposity, however, was also associated with lower hip-fracture rate independent of total hip BMD. The present results confirm the importance of weight maintenance in frail populations. Geriatr Gerontol Int 2017; 17: 898-904.