Influencing factors of forced vital capacity/weight index of Chinese students in 2019

Objective To investigate the variation pattern of forced vital capacity/weight index (FWI) with age heterogeneity among Han students aged 7-22 and 26 ethnic minority students aged 7-18 in 30 provinces of China and its potential influencing factors.Methods A total of 256 032 Han Chinese students aged 7-22 and 89 763 ethnic minority students aged 7-18 were selected as subjects in 2019. We compared the FWI level of all provinces of China with the Chinese average level and we compared the FWI level of Chinese minority students with Chinese Han students. Besides, the FWI age trajectories of Han students in different provinces and FWI age trajectories of students of different Chinese minorities were drawn. Moreover, Spearman correlation analysis was used to analyze the relationship between FWI and age, area, height, GDP per capita, urbanization rate, longitude, latitude, PM2.5 and park green area.Results The heterogeneity of FWI of Han nationality students in 30 provinces of China showed four situations: higher than average level in all age groups; higher than average level first and then lower than average level; lower than average level first and then higher than average level; lower than average level in all age groups. The FWI of economically developed coastal areas was generally higher than that of backward northwest areas. The FWI level of Han students was correlated with physiological, economic, geographical and environmental factors. The heterogeneity between 26 minority students and Han students showed three situations: higher than the average level of Han nationality in all age groups; first higher and then lower than the average level of Han nationality; lower than the average level of Han nationality in all age groups. Most minority students had lower FWI.Conclusion There were significant regional and ethnic differences in FWI of Chinese student in 2019, which were jointly influenced by physiological, socio-economic and environmental factors. Differentiated measures are needed to address respiratory health problems in different provinces, and effective policies are needed to strengthen physical exercise to improve cardiopulmonary function in underdeveloped provinces and ethnic autonomous regions.