Abdominal obesity is a major risk factor for chronic diseases. Yet there are no waist circumference (WC) cut-offs for children in the Arabian Gulf. We developed smoothed WC percentiles for 5–19-year-old Kuwaiti children and adolescents, which could be used in clinical and public health practice. We also examined the percentages of children who had WC ≥ 90th percentile, a value commonly associated with an elevated risk of CVD.

This is a cross-sectional study that was conducted by the Kuwait National Nutrition Surveillance System.

Data were collected from representative primary-, intermediate- and secondary-school children as part of the yearly nutrition and health monitoring. Least mean square regression was used to develop smoothed WC curves.

A total of 9593 healthy 5·0–18·9-year-old children of both sexes were studied from all areas of Kuwait. Age, gender, residency, education level, weight, height and WC were collected for all participants.

We developed the first smoothed WC curves for Kuwaiti children. Male children had higher WC than female children. WC increased with age in both genders, but larger percentages of male children had WC ≥ 90th percentile. Male children aged >10 years have higher WC percentiles than do female children at the 50th, 75th, 90th and 97th percentiles.

Male children (especially those aged >10 years) are at higher risk than female children. Few health-care professionals routinely measure WC. WC measurement should be promoted as an important tool in paediatric primary care practice. The use of these age- and gender-specific percentiles can impact public health recommendations for Kuwaiti and other Arab children from the Gulf.

To derive age- and sex-specific reference values for waist circumference (WC) and waist-to-height ratio (WHtR) for Han Chinese children and adolescents and to establish the prevalence of excess central adiposity in our study population.

Cross-sectional study of schoolchildren attending randomly selected primary and secondary schools in south-west China in October 2003 and April 2004. Anthropometry was measured using standard procedures. The LMS method was used to construct smoothed WC and WHtR percentile curves. Overweight and obesity were defined by the International Obesity Task Force (IOTF) criteria and the Working Group on Obesity in Children. Excess central adiposity fat was defined by previously published WC cut-points and a WHtR ≥ 0·5.

Primary and secondary schools in Chongqing, south-west China.

A total of 7326 (49·2 % boys) Han Chinese students at 5–17 years old.

On the basis of the IOTF criteria, 26·4 % of boys were overweight or obese compared with 16·4 % of girls (P < 0·001). WC cut-points identified 31 % of boys and 28 % of girls as having excess central adiposity, whereas using the WHtR criterion, 14·8 % of boys and 5·6 % of girls were identified. Young boys (5–12 years) had a significantly (P < 0·001) higher WHtR than girls.

We have constructed WC and WHtR percentile curves for Han Chinese children and adolescents living in Chongqing. Our measurements were based on a student population with a relatively high rate of overweight and obesity. These data will provide a point of reference for future studies measuring the prevalence of overweight and obesity in China.