Waist circumference percentile in children from municipalities of developed and developing countries

Abstract Aims: to design reference percentile curves of waist circumference (WC) in children aged 6-10 from municipalities of developed (Portugal) and developing (Brazil) countries and to compare these results with other international references. Methods: this cross-sectional study enrolled a 6-10-year-old probability sampling. Univariate analysis of covariance adjusted by height was carried out to test the main effects of age, sex, countries, and interactions. WC percentile curves were performed with the LMS Chart Maker. Results: The sample comprised 6,475 children. Portuguese children presented a curvilinear increase in WC curves and Brazilian WC curves have shown a linear increase with age both for boys and girls. Overweight and obesity prevalence was 15.9 % and 4.7 % for Portuguese children and 12.9 % 4.5% for Brazilian children, respectively. There was a main effect (p<0.0001) for age and countries, and an interaction effect for sex*age (p=0.001) and countries*age (p<0.0001). Portuguese boys and girls have shown higher values for the 50th, 75th, and 95th percentiles than Brazilian boys and girls. Conclusions: WC reference percentile curves were drawn for 6-10-year-old Portuguese and Brazilian children. Portuguese children have higher WC values than Brazilian children and other children from developed countries.

摘要
研究目的：构建发达国家葡萄牙与发展中国家巴西6~10岁儿童腰围（waist circumference, WC）的参考百分位曲线，并将该结果与其他国际参考标准进行对比。
研究方法：本横断面研究采用概率抽样方法招募了6~10岁儿童受试者。采用以身高为协变量进行校正的单因素协方差分析，检验年龄、性别、国家的主效应及各因素间的交互效应。使用LMS Chart Maker工具绘制腰围百分位曲线。
研究结果：本研究共纳入6475名儿童。葡萄牙男女儿童的腰围曲线随年龄呈曲线型增长，巴西男女儿童的腰围曲线则均随年龄呈线性增长。葡萄牙儿童的超重与肥胖患病率分别为15.9%和4.7%，巴西儿童则分别为12.9%和4.5%。统计分析显示，年龄与国家均存在主效应（p<0.0001），性别×年龄（p=0.001）及国家×年龄（p<0.0001）存在显著交互效应。葡萄牙男女儿童的50th、75th、95th百分位腰围值均高于巴西男女儿童。
研究结论：本研究绘制了葡萄牙与巴西6~10岁儿童的腰围参考百分位曲线。葡萄牙儿童的腰围值高于巴西儿童及其他发达国家儿童。