The aim is to determine the disparity between the overweight and obesity prevalence of Chinese American school-aged children and adolescents as measured by the Centers for Disease Control and Prevention (CDC) growth reference and the prevalence as measured by international and ethnic-specific-growth references.

This retrospective, cross-sectional study measured overweight and obesity prevalence among a paediatric population using the CDC, International Obesity Task Force (IOTF), World Health Organization (WHO) and an ethnic Chinese growth curve.

A community health centre in New York City, USA.

Chinese American children aged 6–17 years in 2017 (N 9160).

The overweight prevalence was 24 % (CDC), 23 % (IOTF), 30 % (WHO) and 31 % (China). The obesity prevalence was 10 % (CDC), 5 % (IOTF), 10 % (WHO) and 10 % (China). When disaggregated by age and sex, the difference was the most prominent in girls; using the China reference compared with using the CDC reference almost doubles the overweight prevalence (school-aged: 31 v. 17 %, P < 0·001, adolescent: 27 v. 14 %, P < 0·001) and the obesity prevalence (school-aged: 11 v. 5 %, P < 0·001, adolescent: 7 v. 4 %, P < 0·001).

Use of the CDC reference compared with the Chinese ethnic-specific reference results in lower overweight and obesity prevalence in Chinese American girls. Almost half of the girls who were overweight and half of the girls who were obese were not identified using the CDC reference. Using ethnic-specific references or ethnic-specific cut-points may help improve overweight identification for Chinese American children.

To establish BMI percentile curves that describe the contemporary BMI distribution among Chinese children, and to compare their BMI percentile curves with those in two recently developed international references: the WHO and the US Centers for Disease Control and Prevention (US CDC) growth references.

A cross-sectional national survey.

Thirty provinces, municipalities and autonomous regions in China.

Nationally representative sample of 232 140 school students aged 7–18 years.

BMI percentile curves were established using the LMS method, and were compared with the percentiles of the WHO and the US CDC references. BMI distributions and growth patterns in Chinese children were dramatically different from those in the two international reference populations. Compared with the international reference populations, younger Chinese boys (7–12 years of age) had higher values of the percentiles above the median and lower values of the percentiles below the median, suggesting that they had larger proportions of extreme BMI values in both directions. Chinese girls and older Chinese boys (15–18 years of age) had substantially lower BMI percentiles than their counterparts in the reference populations, particularly those high percentiles among older age groups.

The present study described the unique patterns of BMI curves at the national level, and these curves are useful as a reference for comparing different regions and for monitoring changes over time in Chinese children. Higher proportions of children with extreme values in both directions indicate that China is currently facing both an increasing level of obesity and a high level of undernutrition, simultaneously.