Electronic supplementary material
The online version of this article (doi:10.1186/s12889-015-2447-1) contains supplementary material, which is available to authorized users.
We have no competing interests to declare.
R.M. conceived the original idea for the study, collected the data, and analyzed them; T.I. made the percentile curves; R.T. collected the data from the participants who were obese; E.S., R.Y., K.K., E.N., S.S., and T.N. obtained data to evaluate the percentiles; Y.N., T. Ohzeki, and T. Ogata supervised this project; R.M. and Y.F. wrote the paper; and Y. F. will act as guarantor for the paper. All authors read and approved the final manuscript.
In Japan, waist circumference (WC) percentiles to screen for childhood metabolic syndrome (MetS) are unavailable. The objectives of this study were to develop WC and WC-to-height ratio (WC/Ht) percentile curves by age and sex for Japanese children, and to test their utility in screening for MetS in children with obesity who are otherwise healthy.
The WC and WC/Ht percentiles were developed using the LMS method of summarizing growth standards, which monitors changing skewness (L), medians (M), and coefficients of variation (S) in childhood distributions. A representative dataset was used, which consisted of 3,634 boys and 3,536 girls aged 4.5–12.75 years in Shizuoka prefecture, Japan, between 2010 and 2012. Children who were obese (355 boys and 230 girls) aged 6–12 years from Osaka prefecture, Japan, were screened for childhood MetS using the new percentiles and the International Diabetes Federation’s (IDF’s) definition of MetS.
The number of participants with certain metabolic abnormalities (high systolic and diastolic blood pressure, and a high level of triglycerides) was significantly higher in boys aged 10–12 years, with a WC ≥ 90th percentile, than among those with a WC < 90th percentile. None of the participants with a WC < 90th percentile exhibited two or more metabolic abnormalities, regardless of their age or sex. Among the participants aged 10–12 years, 11.4 % of boys and 4.4 % of girls with a WC ≥ 90th percentile were diagnosed with MetS.
The new percentiles may have a certain level of potential to screen Japanese children for childhood MetS in accordance with the IDF definition.