Associations of Muscle Mass and Strength with All-Cause Mortality among US Older Adults
Recent studies suggested that muscle mass and muscle strength may independently or synergistically affect aging-related health outcomes in older adults; however, prospective data on mortality in the general population are sparse.Methods
We aimed to prospectively examine individual and joint associations of low muscle mass and low muscle strength with all-cause mortality in a nationally representative sample. This study included 4,449 participants aged 50 years and older from the National Health and Nutrition Examination Survey (NHANES) 1999-2002 with public-use 2011 linked mortality files. Weighted multivariable logistic regression models were adjusted for age, sex, race, BMI, smoking, alcohol use, education, leisure-time physical activity (LTPA), sedentary time, and comorbid diseases.Results
Overall, the prevalence of low muscle mass was 23.1% defined by appendicular lean mass (ALM) and 17.0% defined by ALM/BMI, and the prevalence of low muscle strength was 19.4%. In the joint analyses, all-cause mortality was significantly higher among individuals with low muscle strength, whether they had low muscle mass (OR 2.03, 95% CI, 1.27-3.24 for ALM; OR 2.53, 95% CI, 1.64-3.88 for ALM/BMI) or not (OR 2.66, 95% CI 1.53-4.62 for ALM; OR 2.17, 95% CI 1.29-3.64 for ALM/BMI). In addition, the significant associations between low muscle strength and all-cause mortality persisted across different levels of metabolic syndrome (MetS), sedentary time, and LTPA.Conclusions
Low muscle strength was independently associated with elevated risk of all-cause mortality, regardless of muscle mass, MetS, sedentary time, or LTPA among US older adults, indicating the importance of muscle strength in predicting aging-related health outcomes in older adults.