Anthropometric Cut Points for Definition of Sarcopenia Based on Incident Mobility and Physical Limitation in Older Chinese People

Background: The Foundation of the National Institutes for Health (FNIH) Sarcopenia Project derived cut points in appendicular lean mass (ALM) and grip strength, in relation to mobility limitation defined as a walking speed less than 0.8 m/s. Methods: Using data from the Mr and Ms Os cohort of 4,000 community-dwelling Chinese men and women aged 65 years and older and a similar data-driven approach, we examined whether the cutoff values are the same for Chinese people using baseline walking speed, incident physical limitation, and incident slow walking speed at 4 years. Physical limitation was determined by interviewer-administered questionnaire. Height, weight, body composition (using dual-energy X-ray absorptiometry), grip strength, and walking speed were measured. Results: Cutoff values identified by Classification and Regression Tree (CART) analysis for grip strength were less than 27 kg for men and less than 17 kg for women. The values for ALM were less than 15.61 kg in men and less than 12.42 kg in women; the values for ALM/body mass index (BMI) were less than 0.72 in men and less than 0.47 in women. Using presence of physical limitation at 4 years as the outcome measure, cutoff values identified by CART analysis for grip strength were less than 27 kg for men and less than 19 kg for women; for ALM, less than 15.65 kg for men and less than 11.26 kg for women; for ALM/BMI, less than 0.69 for men and 0.52 for women. Cutoff values for grip strength were less than 28.5 kg for men and less than 19 kg for women; for ALM, less than 17.61 kg for men and less than 10.84 kg for women; for ALM/BMI, less than 0.81 for men and less than 0.53 for women. Conclusions: Cutoff values may differ between ethnic groups as a result of differences in body size and lifestyles.