南京市中小学生身高、体重和超重肥胖自我报告值的准确性

Accuracy of self-reported body height,weight and excess body weight among school students in Nanjing City

目的评价南京市中小学生身高、体重和体重状况的自我报告值的准确性及其影响因素。方法采用多阶段随机整群抽样方法,抽取南京市12个区小学4年级至高中3年级的在校学生进行面对面问卷调查及体格检查。采用配对t检验分析客观测量值与自我报告值之间差异,不同方法所收集数据之间的一致性比较采用kappa和Bland-Altman法进行分析。结果南京地区中小学生人群中依据客观测量数据所得的超重和肥胖比例分别为16.70%和10.97%。调查对象的身高自我报告值被高估1.33 cm,体重和体重指数(body mass index,BMI)分别被低估1.16 kg和0.76 kg/m^2,差异均具有统计学意义(均有P<0.05)。性别、年级、父母文化程度、城乡情况和体重状况均可影响自我报告值的准确性。自我报告与客观测量参数的体重状况分类的总体一致率为83.89%(κ=0.662)。Bland-Altman分析显示身高、体重和体BMI自我报告与客观测量数据的差值超出95%一致性限范围的点均小于5%。结论南京市中小学生身高和体重自我报告值与客观测量数值之间存在较好的一致性,适用于儿童青少年人群的大样本流行病学调查。

Objective To assess the accuracy of self-reported body height and weight as well as body weight status among school students in Nanjing,and further to explore the factors affecting the accuracy.Methods With a multistage cluster sampling approach,students of grade four to twelve were randomly selected from 12 districts of Nanjing.All the data were gathered via face-to-face interview and physical examination.Cohen’s kappa and Bland Altman plots were used to assess the agreement between self-reported and objectively-measured body height and weight as well as body weights status.Results The proportion of objectively-measured overweight and obesity was 16.70%and 10.97%,respectively,among these students.Participants’body height was significantly over-estimated with an average of 1.33 cm by self-report,while their body weight and body mass index(BMI)value were significantly under-estimated with 1.16 kg and 0.76 kg/m^2(all P<0.05),respectively.The accuracy of self-reported body height and weight might be influenced by participant’s gender,grade,parent’s educational level,residence location and body weight status.The concordance rate between self-reported and objectively-measured BMI categories was 83.89%(κ=0.662).For each anthropometric characteristic,fewer than 5%of subjects were out of 95%confidence interval of agreement based on Bland-Altman analysis.Conclusions The accuracy of self-reported body height and weight as well as body weight status was acceptable for primary and high school students in Nanjing.It suggests that self-reported anthropometric measurements could be used for population-based epidemiologic surveys among school-aged children and adolescents.