OBJECTIVES: To examine the temporal relationship between sarcopenia and disability in elderly men and women.
DESIGN: Cardiovascular Health Study, a longitudinal study of cardiovascular disease and its risk factors in older people.
SETTING: Four U.S. communities.
PARTICIPANTS: Five thousand thirty-six men and women aged 65 and older.
MEASUREMENTS: Whole-body skeletal muscle mass was measured at baseline, and subjects were classified as having normal muscle mass, moderate sarcopenia, or severe sarcopenia based on previously established thresholds. Disability was measured via questionnaire at baseline in up to eight annual follow-up examinations. The cross-sectional relationship between sarcopenia and prevalent disability at baseline was examined using logistic regression models. The longitudinal relation between sarcopenia and incident disability over 8 years of follow-up was examined using Cox proportional hazards models.
RESULTS: At baseline, the likelihood of disability was 79% greater in those with severe sarcopenia (P<.001) but was not significantly greater in those with moderate sarcopenia (P=.38) than in those with normal muscle mass. During the 8-year follow-up, the risk of developing disability was 27% greater in those with severe sarcopenia (P=.006) but was not statistically greater in those with moderate sarcopenia (P=.23) than in those with normal muscle mass.
CONCLUSION: Severe sarcopenia was a modest independent risk factor for the development of physical disability. The effect of sarcopenia on disability was considerably smaller in the longitudinal analysis than in the cross-sectional analysis.