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Objective: 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. Design: 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. Setting: Primary and secondary schools in Chongqing, south-west China. Subjects: A total of 7326 (49?2 % boys) Han Chinese students at 5-17 years old. Results: 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. Conclusions: 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.

Transcription factor retinoid acid-related orphan receptor gamma t (RORγt) transcriptionally regulates the genes required for differentiation of T helper 17 (Th17) cells that mediate both protective and pathogenic immunity. However, little is known about the function of post-translational modifications in the regulation of RORγt activity. Mass spectrometric analysis of immunoprecipitated RORγt from Th17 cells identified multiple phosphorylation sites. Systematic mutation analysis of the identified phosphorylation sites find that phosphorylation of serine 376 (S376) enhances whereas phosphorylation of serine 484 (S484) inhibits Th17 differentiation. IKKα binds and phosphorylates RORγt at S376 but not S484. Knockdown of IKKα, dominant negative IKKα and RORγt mutants incapable of interacting with IKKα all decrease Th17 differentiation. Furthermore, nonphosophorylatable RORγt mutant (S376A) impairs whereas phosphomimetic mutant (S376E) stimulates Th17 differentiation independent of IKKα. Therefore, IKKα-dependent phosphorylation of S376 stimulated whereas IKKα-independent phosphorylation of S484 inhibited RORγt function in Th17 differentiation.

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