Background/objectives: The objectives of this study were to determine the prevalence of muscle weakness using the two 2014 Foundation for the National Institutes of Health (FNIH) Sarcopenia Project criteria and its relationship with physical limitations, basic activities of daily living (ADL) and instrumental ADL.
Subjects/methods: We performed a cross-sectional analysis of community-dwelling adults from the Health and Retirement Study 2006-2008 and identified a subsample of 5092 adults aged ⩾60 years with grip strength (GS) data. Self-reported physical limitations, basic ADL and instrumental ADL were assessed. Criteria for GS (men<26 kg; women <16 kg) and GS adjusted for body mass index (GS/BMI; men <1.0; women <0.56) were applied to the sample. We determined the prevalence of muscle weakness in each sex. Multivariable logistic regression was used to calculate the association of physical limitations, basic ADL and instrument ADL with weakness definitions in each sex.
Results: Mean age was 72.1 years (54.9% female). Mean GS was 38.3 and 22.9 kg and mean BMI was 29 kg/m2, respectively, in men and women. Weakness prevalence using GS and GS:BMI definitions were 7.8 and 15.2 (P<0.001), respectively, in men and 11.4 and 13.3% (P=0.04) in women. Overall prevalence of physical limitations, basic ADL limitations and instrumental ADL limitations was 52.9, 28.1 and 35.9%, respectively. In those with weakness, prevalence of physical limitations, basic ADL and instrumental ADL was 78.5, 42.3 and 65.3%, respectively, using the GS definition, and 79.7, 40.7 and 58.8%, respectively, using the GS/BMI definition. GS and the GS/BMI definitions of weakness were strongly associated with physical limitations (odds ratio (OR) 2.19 (95% confidence interval (CI): (1.67-2.87)) and 2.52 (2.01-3.17)), basic ADL (OR 1.59 (1.22-2.07) and 1.66 (1.32-2.07)) and instrumental ADLs (OR 1.98 (1.28-2.54) and 1.78 (1.44-2.20)).
Conclusions: The new FNIH guidelines for weakness are associated with higher prevalence of physical limitations, basic ADL impairments and instrumental ADL impairments as compared with individuals without weakness.