四川省羌族中小学生BMI变化趋势分析

Secular trend in body mass index among Qiang ethnic children and adolescents in Sichuan Province

目的分析四川省羌族儿童青少年7～18岁学生体质量指数(body mass index,BMI)变化趋势,为儿童青少年生长发育监测提供科学依据。方法从国家教育部官方公布的中国学生体质与健康调研报告中,抽取羌族7～18岁学生身高、体重数据指标,选取2017年分层抽取羌族7～18岁儿童青少年的样本,运用LMS法拟合儿童青少年BMI相对应的百分位数,观察32年间BMI增长率的整体发展趋势。结果 7～18岁BMI均值男生>女生; BMI正态分布系数L男、女生分别在-2.84～-1.79,-1.85～-1.39区间,BMI中位数M男、女生分别在16.08～20.79,15.55～20.35 kg/m^2,BMI变异系数男、女生分别在0.10～0.14,0.11～0.14区间; 1985—1995年男生7～11岁增长率位于-42.94～-21.33区间,女生负增长趋势不一,其他3个大区间男生7～12岁增长均大于5,男、女生17～18岁负增长均小于-7.13。结论四川省7～18岁羌族儿童青少年BMI增长率呈现出低年龄段(7～11岁)持续上升,中年龄段(12～16岁)突增,高年龄段(17～18岁)增长值急剧下降的特征,整体增长值曲线呈现出锯齿状。

Objective To investigate secular trend in body mass index（ BMI） among Qiang ethnic children and adolescents aged 7-18 years in Sichuan Province. Methods Data came from Chinese National Survey on Student ＇s Constitution and Health（ CNSSCH）. Height and weight of Qiang ethnic children and adolescents aged 7-18 years were analyzed by using the lambda mu sigma（ LMS） method. BMI percentiles were constructed to follow secular changes over the past 32 years. Results Boys had higher BMI than girls in 7-12-year-old group. Coefficient of BMI was between -2.84--1.79 and -1.85--1.39,and the median BMI ranged between 16.08-20.95 and 15.55-20.35 kg/m^2,for boys and girls respectively. The BMI coefficient of variation ranged 0.10-0.14,0.11-0.14,for boys and girls,respectively. The increasing rate of BMI among boys aged 7-11 years in 1985-1995 ranged in -42.94 and -21.33 kg/m^2. The decreasing trend of BMI growth rate among girls was observed. Growth rate was above 5 kg/m^2 among 7-12-year-old boys during the year of 1995-2005,2005-2014 and 2014-2017. For girls and boys aged 17-18 years,negative growth negative was observed and no less than -7.13 kg/m^2. Conclusion BMI in Qiang ethnic children and adolescents aged 7-18 years in Sichuan Province shows continued increasing trend among younger age group（ 7-11 years old）,unexpected accelerated trend among 12-16 years old group,as well as abrupt decreasing trend for 17-18-year-old adolescents,which fits ＂ zigzag pattern＂.