中国九年级学生身体发育状况及其相关因素

目的  分析九年级学生身体发育状况及其相关因素，为制定青春期学生体质健康促进方案提供参考依据。 方法  使用多元线性回归和二元Logistic回归分析方法对2016年中国教育追踪调查中7 840名九年级学生相关数据进行比较分析。 结果  学生身高、体重在城乡、性别上分布存在差异。在14~16岁男生均高于女生（身高cm：171.69±6.95 vs 161.54±5.58，体重kg：60.43±13.19 vs 53.21±11.69），城市均高于农村（身高cm：167.93±8.16 vs 165.80±7.94；体重kg：58.18±13.16 vs 55.94±12.78）。男生体能水平达标率低于女生（51.8%vs 87.8%），城市男生低于农村男生（45.7%vs 58.9%），城市女生高于农村女生（92.0%vs 84.6%）。男生首次遗精平均年龄13.62±1.23岁，女生月经初潮平均年龄12.87±1.07岁，城市男女生性发育均比农村早。多元线性回归显示身高和体重均与独生子女、睡眠时间相关；身高与父母身高、民族、家庭经济、锻炼时间等相关，体重还与父母体重相关（均有P < 0.05）。二元Logistic回归显示，体能水平与性别、民族、营养、体重、高热量饮食、锻炼时间相关（均有P < 0.05）。男生首次遗精与民族、城乡、是否独生、睡眠时间、体能水平相关；女生月经初潮与锻炼时间、午饭方式、营养相关（均有P < 0.05）。 结论  中国九年级学生身体发育状况整体良好，但男生体能水平亟待提升，因身体发育状况受多种因素影响，所以需要多部门合作采取针对性措施，促进学生健康生长发育。

The physical development and associated factors of ninth grade students in China

  Objective  To analyse the status and related factors of physical development of ninth grade students in China, so as to provide reference and scientific basis for the development of adolescent' physical health promotion programs.  Methods  Multiple linear regression and binomial Logistic regression models were used to analyse the data from 7 840 ninth grade students in the 2016 China Education Panel Survey.  Results  There were differences in the distribution of height and weight between urban and rural and between boys and girls.From the age of 14 to 16, boys were taller and heavier than girls(height cm: 171.69±6.95 vs 161.54±5.58, weight kg: 60.43±13.19 vs 53.21±11.69), and urban students were taller and heavier than rural students(height cm: 167.93±8.16 vs 165.80±7.94;weight kg: 58.18±13.16 vs 55.94±12.78). The rate of physical fitness of boys was lower than that of girls(51.8% vs 87.8%), and that of urban boys was lower than that of rural boys(45.7% vs 58.9%), and that of urban girls was higher than that of rural girls(92.0% vs 84.6%). The average age of first spermatorrhea was 13.62±1.23 years for boys and 12.87±1.07 years for girls. Sexual development of urban students appeared earlier than rural students. Multivariate linear regression analysis showed that height and weight were related to bring single-child and sleep time. Height was also related to parents'height, nationality, family economic level and exercise time, weight was also related to parents' weight (all P < 0.05). Binomial Logistic regression analysis showed that physical fitness level was related to gender, nationality, nutritional status, weight, high calorie intake, exercise time, etc (all P < 0.05). Correlative factors of male first spermatorrhea were nationality, urban residence, singleton, sleep time, physical fitness level, while female menarche was related to exercise time, lunch spot and nutritional status (all P < 0.05).  Conclusions  Comprehensive efforts and cooperation are needed to promote the normal development and physical health of the students.