Low skeletal muscle mass and risk of functional decline in elderly community-dwelling women: the prospective EPIDOS study.

OBJECTIVES

To assess relationships between low skeletal muscle mass (SMM) and functional decline in community-dwelling elderly women.

DESIGN

Secondary analysis of data from EPIDOS, a French prospective observational multicenter cohort study of osteoporosis epidemiology.

SETTING

One center in France between 1992 and 1994.

PARTICIPANTS

Women aged 75 years or older without disability and with available baseline SMM measurements.

MEASUREMENTS

SMM was assessed using dual-energy X-ray absorptiometry and functional decline was defined as loss of at least one Instrumental Activity of Daily Living component. Associations linking low SMM to functional decline were estimated using the Cox proportional hazards model.

RESULTS

Of 975 women followed for 4 years, 452 (46.4%) experienced functional decline. Factors independently associated with functional decline were decreased SMM (adjusted hazard ratio [aHR] per SD decrease, 1.12; 95% confidence interval [95% CI], 1.01-1.24), older age (aHR per SD increase, 1.28; 95% CI, 1.17-1.39), one or more comorbidities (aHR, 1.65; 95%CI, 1.05-2.59), and impaired chair-stand test (aHR, 1.35; 95% CI, 1.01-1.82). The second SMM quartile was associated with functional decline (aHR, 1.39; 95% CI, 1.06-1.84) and the lowest quartile showed a nearly significant association (aHR, 1.29; 95% CI, 0.98-1.72). Factors negatively associated with functional decline were living alone (aHR, 0.76; 95% CI, 0.59-0.96), higher handgrip strength (aHR per SD increase, 0.88; 95% CI, 0.78-0.88), and walking speed (aHR per SD increase, 0.86; 95% CI, 0.77-0.96).

CONCLUSION

Low SMM was independently associated with functional decline within 4 years after adjustment for age, muscle strength, physical performance, and comorbidities in community-dwelling elderly women.