中国新疆地区哈萨克族7～18岁中小学生体重指数分布和超重肥胖筛查参考值的建立

The study on body mass index centile curves and the reference norm for screening overweight and obesity in Kazak primary and middle school students aged 7-18 years in Xinjiang,China

目的建立中国新疆地区哈萨克族7～18岁中小学生超重和肥胖的体重指数(BMI)百分位曲线和界值点参考标准。方法采用横断面调查研究,在中国新疆阿勒泰市及其所属乡镇的中小学采用整群随机抽样方法抽取4所学校(共49个班级)同意参加调查的哈萨克族7～18岁中小学生为调查对象。采集性别、年龄、身高和体重测量资料;应用偏度-中位数-变异系数法建立哈萨克族7～18岁中小学生的BMI百分位曲线;利用儿童青少年超重和肥胖的BMI百分位数曲线在18岁通过国际肥胖工作小组(IOTF)定义的成人超重和肥胖BMI界值点(25kg.m-2/30kg.m-2)和中国肥胖问题工作组(WGOC)定义的界值点(24kg.m-2和28kg.m-2)的方法,计算出哈萨克族7～18岁各年龄超重和肥胖的BMI界值点。结果共采集7～18岁中小学生2487名,其中男1158名,女1329名。①按照IOTF标准,超重和肥胖的BMI百分位曲线:男性分别为P88.63和P98.28,女性分别为P84.41和P98.12;按照WGOC标准,超重和肥胖的BMI百分位数曲线:男性分别为P92.96和P99.28,女性分别为P90.53和P99.38。②哈萨克族男性超重和肥胖BMI标准曲线低于WGOC和IOTF标准;女性肥胖标准曲线13～14岁前低于WGOC和IOTF标准,之后略高于WGOC和IOTF标准。③哈萨克族男性超重、肥胖的界值百分位曲线均低于或接近的汉族和维吾尔族水平;哈萨克族女性超重界值百分位曲线在14岁前介于汉族和维吾尔族间,之后接近或达到汉族水平;肥胖界值百分位曲线在10岁前低于汉族和维吾尔族水平,14岁后达到或接近汉族水平。结论儿童青少年BMI分布有显著的地域差异和民族差异,哈萨克族中小学生超重和肥胖BMI界值标准不同于IOTF和WGOC所建议的相应标准。因此哈萨克族中小学生超重、肥胖人群的筛查可以参考本研究建立的标准。

Objective To construct centile curves and cutoff points of body mass index（BMI）for overweight and obesity screening among Kazak children aged 7 to 18 years in Xinjiang,China.Methods The cross-sectional study was conducted in urban and rural areas of Altai city,using random cluster sampling to select 4 schools（a total of 49 classes）.Enrolled students who agreed to take part in the study were investigated for demographic and anthropometric data.The BMI centile curves for Kazak children aged 7-18 years were constructed by λ-median-coefficient of variation method.Based on BMI cutoff points for adult overweight and obesity recommended by IOTF and WGOC,the centile curves passing through 25 and 30 kg·m^-224 and 28 kg·m^-2at age 18 were identified as overweight and obesity cutoff curves for Kazak children,by which the cutoffs of BMI for each age were computed.Results Overall 2 487 students,including 1 158 boys and 1 329 girls were investigated.The cutoff curves for identifying overweight and obesity were P88.63 and P98.28 for boys,and P84.41 and P98.12 for girls based on WGOC cutoffs of adults＇ BMI,and were P92.96 and P99.28 for boys,P90.53 and P99.38 for girls based on IOTF cutoffs.The cutoff curves for Kazak children differed from that recommended by IOTF and WGOC,as well as differed from cutoff curves for Han and Ugyur children recommended by our earlier studies.The cutoff curves for overweight and obesity for Kazak girls were lower than that of Ugyurs＇ and Hans＇ but increased quickly and exceeded Ugyur curves and reached Han curves around age of 14.Conclusions Norms of BMI for screening overweight and obesity in Kazak school-aged children differ from that recommended by IOTF and WGOC,and appear ethnic difference.For Kazak students,the cutoffs of BMI proposed by this study for screening overweight and obesity are recommended.