Portions of the analyses in this paper were presented as a poster at the American Geriatrics Society Meeting in Washington, DC, May 2008.
Do Muscle Mass, Muscle Density, Strength, and Physical Function Similarly Influence Risk of Hospitalization in Older Adults?
Article first published online: 29 JUL 2009
© 2009, Copyright the Authors. Journal compilation © 2009, The American Geriatrics Society
Journal of the American Geriatrics Society
Volume 57, Issue 8, pages 1411–1419, August 2009
How to Cite
Cawthon, P. M., Fox, K. M., Gandra, S. R., Delmonico, M. J., Chiou, C.-F., Anthony, M. S., Sewall, A., Goodpaster, B., Satterfield, S., Cummings, S. R., Harris, T. B. and for the Health, Aging and Body Composition Study (2009), Do Muscle Mass, Muscle Density, Strength, and Physical Function Similarly Influence Risk of Hospitalization in Older Adults?. Journal of the American Geriatrics Society, 57: 1411–1419. doi: 10.1111/j.1532-5415.2009.02366.x
- Issue published online: 29 JUL 2009
- Article first published online: 29 JUL 2009
- lean mass;
- physical function;
- muscle fat infiltration;
- walking speed
OBJECTIVES: To examine the association between strength, function, lean mass, muscle density, and risk of hospitalization.
DESIGN: Prospective cohort study.
SETTING: Two U.S. clinical centers.
PARTICIPANTS: Adults aged 70 to 80 (N=3,011) from the Health, Aging and Body Composition Study.
MEASUREMENTS: Measurements were of grip strength, knee extension strength, lean mass, walking speed, and chair stand pace. Thigh computed tomography scans assessed muscle area and density (a proxy for muscle fat infiltration). Hospitalizations were confirmed by local review of medical records. Negative binomial regression models estimated incident rate ratios (IRRs) of hospitalization for race- and sex-specific quartiles of each muscle and function parameter separately. Multivariate models adjusted for age, body mass index, health status, and coexisting medical conditions.
RESULTS: During an average 4.7 years of follow-up, 1,678 (55.7%) participants experienced one or more hospitalizations. Participants in the lowest quartile of muscle density were more likely to be subsequently hospitalized (multivariate IRR=1.47, 95% confidence interval (CI)=1.24–1.73) than those in the highest quartile. Similarly, participants with the weakest grip strength were at greater risk of hospitalization (multivariate IRR=1.52, 95% CI=1.30–1.78, Q1 vs. Q4). Comparable results were seen for knee strength, walking pace, and chair stands pace. Lean mass and muscle area were not associated with risk of hospitalization.
CONCLUSION: Weak strength, poor function, and low muscle density, but not muscle size or lean mass, were associated with greater risk of hospitalization. Interventions to reduce the disease burden associated with sarcopenia should focus on increasing muscle strength and improving physical function rather than simply increasing lean mass.