Normative values of hand grip strength in a large unselected Chinese population: Evidence from the China National Health Survey.

BACKGROUND: Hand grip strength (HGS) is a powerful indicator of sarcopenia and other adverse health outcomes. Normative values for HGS for general Chinese people with a broad age spectrum are lacking. This study aims to establish normative values of HGS and explore the correlations between HGS and body composition among unselected people aged 8-80 in China. METHODS: From 2012 to 2017, 39 655 participants aged 8-80 years in the China National Health Survey were included. Absolute HGS was measured using a Jamar dynamometer. The relative HGS was normalized by body mass index. Body composition indexes included body mass index, body fat percentage, muscle mass, fat mass index (FMI) and muscle mass index (MMI). Sex-specific smoothed centile tables for the P(1) , P(5) , P(25) , P(50) , P(75) , P(95) and P(99) centiles of HGS and body composition were generated using lambda-mu-sigma method. The correlations between muscle strength and body composition were estimated by partial Spearman correlation analysis. RESULTS: The median values (25th and 75th percentile) of HGS in boys and girls (8-19 years old) were 22 (14, 34) kg and 18 (12, 22) kg, respectively; in men and women aged 20-80 were 39 (33, 44) kg and 24 (20, 27) kg, respectively. Values of upper and lower HGS across ages had three periods: an increase to a peak in the 20 s in men (with the 5th and 95th values of 30 and 55 kg, respectively) and 30 s in women (with the 5th and 95th values of 18 and 34 kg, respectively), preservation through midlife (20s-40 s), and then a decline after their 50 s. The lowest HGS values in both sexes were in the 70- to 80-year-old group, with the 5th and 95th percentile values of 16 and 40 kg in men, and 10 and 25 kg in women. There were substantial sex differences in body composition in the life course (all P values <0.001). In ageing, the decrease of muscle strength was faster than that of muscle mass in both sexes. The correlations between muscle mass and HGS were most robust than other correlations, especially in women (0.68 vs. 0.50), children and adolescents. CONCLUSIONS: Our study established the age- and sex-specific percentile reference values for hand grip strength in an unselected Chinese population across a broad age-spectrum. The rich data can facilitate the practical appraisal of muscle strength and promote early prediction of sarcopenia and other impairments associated with neuromuscular disorders.