Liu et al. BMC Public Health 2010, 10:82 http://www.biomedcentral.com/1471-2458/10/82 R E S E A R C H A R T I C L E Open Access Waist circumference cut-off values for the prediction of cardiovascular risk factors clustering in Chinese school-aged children: a cross-sectional study Ailing Liu1,2, Andrew P Hills2, Xiaoqi Hu1, Yanping Li1, Lin Du3, Ying Xu4, Nuala M Byrne2, Guansheng Ma1* Abstract Background: Waist circumference has been identified as a valuable predictor of cardiovascular risk in children. The development of waist circumference percentiles and cut-offs for various ethnic groups are necessary because of differences in body composition. The purpose of this study was to develop waist circumference percentiles for Chinese children and to explore optimal waist circumference cut-off values for predicting cardiovascular risk factors clustering in this population. Methods: Height, weight, and waist circumference were measured in 5529 children (2830 boys and 2699 girls) aged 6-12 years randomly selected from southern and northern China. Blood pressure, fasting triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and glucose were obtained in a subsample (n = 1845). Smoothed percentile curves were produced using the LMS method. Receiver-operating characteristic analysis was used to derive the optimal age- and gender-specific waist circumference thresholds for predicting the clustering of cardiovascular risk factors. Results: Gender-specific waist circumference percentiles were constructed. The waist circumference thresholds were at the 90th and 84th percentiles for Chinese boys and girls respectively, with sensitivity and specificity ranging from 67% to 83%. The odds ratio of a clustering of cardiovascular risk factors among boys and girls with a higher value than cut-off points was 10.349 (95% confidence interval 4.466 to 23.979) and 8.084 (95% confidence interval 3.147 to 20.767) compared with their counterparts. Conclusions: Percentile curves for waist circumference of Chinese children are provided. The cut-off point for waist circumference to predict cardiovascular risk factors clustering is at the 90th and 84th percentiles for Chinese boys and girls, respectively. Background The global prevalence of overweight and obesity has increased dramatically in North America, some Eur- opean countries, and Australia in recent decades [1-4], however evidence suggests that a greater potential pro- blem exists for China, South America and some coun- tries in North Africa [4,5]. Higher than desirable levels of body fat pose an increased risk of ill-health, however the location of * Correspondence: mags@chinacdc.net.cn 1National Institute for Nutrition and Food Safety, China Center for Disease Control and Prevention, Beijing, China excess fat appears to have particular implications [6-8]. For example, a greater concentration of adipose tissue in the abdomen, specifically in the visceral area, is directly related to metabolic and cardiovascular risk in adults [9]. Visceral adiposity is best quantified using sophisticated imaging techniques however such approaches are not feasible at the population level [10]. Recent attention has been paid to the applicability of anthropometric markers to measure abdominal obesity and the waist circumference is consistently identified as a better measure of cardiovascular risk than the body mass index [6,11,12]. Waist circumference is also © 2010 Liu et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.