关键词: 高中生, BMI, 膳食宝塔知识, 静坐时长

Abstract: Background There were relatively few multicenter national sample size studies on the correlation between dietary knowledge mastery level, average sitting time per day, and BMI among high school population in China. Against the backdrop of the current widespread implementation of a blended online and offline teaching model, it was worth exploring how the current situation of BMI, dietary knowledge mastery level, and sitting time among high school students in China has changed. Objective To investigate and analyze the current situation and influencing factors of BMI, dietary pagoda knowledge level, and sitting time of high school students in seven urban and rural areas in China, in order to provide valuable empirical references for promoting the development of physical and mental health levels of high school students. Method From January 2019 to March 2019, a stratified random cluster sampling method was used to investigate the BMI, dietary pagoda knowledge level (according to the "Chinese Dietary Guidelines for Residents (2016)"), and sitting time status of 6213 students in grade one and two of high school. Non parametric tests and multiple linear regression were used to analyze the relationship and influencing factors between BMI, dietary pagoda score, and sitting time.Results (1) There were statistically significant differences in BMI among different provinces, cities, regions, family populations, fathers' educational backgrounds, and grades of study (P<0.05). (2) The scores of "dietary pagoda knowledge" were compared among different provinces, cities, regions, family populations, annual income, and parents' educational backgrounds, and the differences were statistically significant (P<0.05). The score of "dietary pagoda knowledge" was negatively correlated with BMI, and positively correlated with sitting time, father's education, family annual income, and family population. Standardization coefficient β Comparison: Sitting time (0.07)>Father's education (0.05)=Family annual income (0.05)=BMI (-0.05)>Family population (0.03). (3) There were statistically significant differences in the length of sitting time among different provinces, cities, regions, urban and rural areas, age, family population, annual income, and parents' educational background (P value<0.05). The duration of sitting still was positively correlated with the score of dietary pagoda knowledge and father's educational background, while negatively correlated with the number of family members. Standardization coefficient β Comparison: Dietary pagoda knowledge score (0.07)>Father's education level (0.04)>Family population (-0.03). Conclusion The median BMI level of high school students in the seven major regions of China was generally within the normal range, but the overall score of dietary pagoda knowledge was low, and the problem of "overall longer sitting time" was prominent. The score of dietary pagoda knowledge and the duration of meditation were the biggest influencing factors for each other, and the educational background of the father was the main social factor that affected the score of dietary pagoda knowledge and the duration of meditation, followed by the number of family members.

Key words: High school student, BMI, Diet pagoda knowledge, Sitting time