Risk of Fracture in Women with Sarcopenia, Low Bone Mass, or Both

Abstract

Objectives: To determine whether women with sarcopenia and low bone mineral density (BMD) are at greater risk of clinical fractures than those with sarcopenia or low BMD alone.

Design: Women's Health Initiative (WHI) Observational and Clinical trials.

Setting: Three U.S. clinical centers (Pittsburgh, PA; Birmingham, AL; Phoenix/Tucson, AZ).

Participants: Women (mean age 63.3 ± 0.07) with BMD measurements (N = 10,937).

Measurements: Sarcopenia was defined as appendicular lean mass values corrected for height and fat mass. Low BMD was defined as a femoral neck T-score less than -1.0 based on the Third National Health and Nutrition Examination Survey reference database for white women. Cox proportional hazards analysis was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). We followed women for incident fractures over a median of 15.9 years.

Results: Participants were classified into mutually exclusive groups based on BMD and sarcopenia status: normal BMD and no sarcopenia (n = 3,857, 35%), sarcopenia alone (n = 774, 7%), low BMD alone (n = 4,907, 45%), and low BMD and sarcopenia (n = 1,399, 13%). Women with low BMD, with (HR = 1.72, 95% CI = 1.44-2.06) or without sarcopenia (HR = 1.58, 95% CI = 1.37-1.83), had greater risk of fracture than women with normal BMD; the difference remained statistically significant after adjustment for important covariates. Women with low BMD, with (HR = 2.78, 95% CI = 1.78-4.30 and without (HR = 2.42, 95% CI = 1.63-3.59) sarcopenia had higher risk of hip fractures. Women with sarcopenia alone had similar HRs to women with normal BMD.

Conclusion: Compared to women with normal BMD.

Keywords: epidemiology; fracture; low bone mineral density; osteoporosis; sarcopenia.

Figure 1. Survival Curve in years by BMD and Body Composition Group

Solid Line = Referent Small Dash Line = Sarcopenia Only Dotted Line = Low BMD Only Large Dash Line = Combination of low BMD & Sarcopenia