Trends and distributional characteristics in handgrip strength of 1,082,296 children and adolescents in China: an analysis from five representative cross-sectional surveys from 2000 to 2019.

OBJECTIVE: Previous nationally representative health surveys in China found that handgrip strength (HGS) of children and adolescents has declined since 2000. However, these data are not only lacking in updates but also have limitations in identifying high-risk groups. This paper aims to estimate the trends in HGS adjusted for height and weight among Chinese children and adolescents from 2000 to 2019 and to investigate differences in demographic characteristics and distribution. METHODS: Height, weight, and HGS data among Chinese 1,082,296 children and adolescents aged 7-18 years (543,118 boys) were obtained from five waves of the Chinese National Surveillance on Students' Constitution and Health from 2000 to 2019. General linear models were used to estimate trends in absolute HGS and HGS adjusted for height and weight in each sex-region-age group, respectively. Population-based trends were estimated by a post-stratification population weighting procedure. The trends in the distributional characteristics were visually described. RESULTS: For the total population, HGS increased by an average of 2.2 kg (95% confidence interval [CI]: 2.1 to 2.1 kg) or 0.44 effect size (ES) (95% CI: 0.43 to 0.45 ES), with a small but statistically significant improvement. There was a moderate improvement (0.62 ES) among children aged 7-12 years and a small improvement (0.27 ES) among adolescents aged 13-18 years, respectively. However, HGS adjusted for height and weight increased by an average of 0.6 kg (95% CI: 0.5 to 0.7 kg) or 0.05 ES (95% CI: 0.04 to 0.06 ES), with a negligible improvement observed overall. Urban boys aged 7-9 years and urban girls aged 7-12 years experienced small improvements (ranging from 0.22 to 0.38 ES). Urban boys aged 15, 18 years and rural boys aged 15-18 years experienced small decreases (ranging from - 0.31 to -0.23 ES) In general, the distribution of trends was uneven, with decreases primarily observed at higher percentiles but improvements observed at lower percentiles. CONCLUSION: No significant changes were observed in HGS adjusted for height and weight, but there were significant differences in sex, age and distribution. Policies and intervention strategies need to prioritize low-health groups, especially among post-pubertal boys or high-fitness performers.