Sarcopenia adds to osteoporotic risk for fractures
Lima RM, de Oliveira RJ, Raposo R, et al. Stages of sarcopenia, bone mineral density, and the prevalence of osteoporosis in older women. Arch Osteoporos. 2019;14:38.
Osteoporotic fractures impose a significant burden on health care costs and increase the risk for disability and mortality, especially as life expectancy increases.7
In 1989, the term sarcopenia was introduced to refer to the age-related decline in skeletal muscle mass.8 Currently, sarcopenia is defined as a progressive decline in muscle mass, strength, and physical function, thus increasing the risk for various adverse outcomes, including osteoporosis.9 Although muscle and bone tissues differ morphologically, their functioning is closely interconnected.
The sarcopenia-osteoporosis connection
Lima and colleagues sought to investigate the relationship between sarcopenia and osteoporosis.10 They measured women's fat free mass with dual-energy x-ray absorptiometry (DXA) scanning, muscle strength using a dynamometer to measure knee extension torque while participants were seated, and functional performance using the timed "up and go test" in which participants were timed as they got up from a chair, walked 3 meters around a cone, and returned to sit in the chair.10,11
The authors used definitions from the European Working Group on Sarcopenia in Older People (EWGSOP). Participants who had normal results in all 3 domains were considered nonsarcopenic. Presarcopenia was defined as having low fat free mass on DXA scanning but normal strength and function. Participants who had low fat free mass and either low strength or low function were labeled as having sarcopenia. Severe sarcopenia was defined as abnormal results in all 3 domains.
Two hundred thirty-four women (mean age, 68.3 years; range, 60-80) underwent BMD testing and were evaluated according to the 3 domains of possible sarcopenia. All were community dwelling and did not have cognitive impairment or functional dependency.
The rates of osteoporosis were 15.8%, 19.2%, 35.3%, and 46.2% for nonsarcopenia, presarcopenia, sarcopenia, and severe sarcopenia, respectively (P=.002). Whole-body and femoral neck BMD values were significantly lower among all sarcopenia stages when compared with nonsarcopenia (P<.05). The severe sarcopenia group showed the lowest lumbar spine T-scores (P<.05). When clustered, sarcopenia and severe sarcopenia presented a significantly higher risk for osteoporosis (odds ratio, 3.4; 95% confidence interval [CI], 1.5-7.8).
Consider sarcopenia a risk factor
The authors concluded that these "results provide support for the concept that a dose-response relationship exists between sarcopenia stages, BMD, and the presence of osteoporosis. These findings strengthen the clinical significance of the EWGSOP sarcopenia definitions and indicate that severe sarcopenia should be viewed with attention by healthcare professionals."
Osteoporotic fractures are defined as fragility fractures. While "frailty" has been a risk factor for such fractures in the past, increasing evidence now suggests that what we previously called frailty includes a significant component of loss of muscle mass, strength, and function—referred to as sarcopenia. While it is not likely that many ObGyns will perform objective testing for sarcopenia, conducting even a subjective assessment of such status should be considered in addition to BMD determinations in making decisions about pharmacotherapy.
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