Higher waist-to-height ratio and waist circumference are predictive of metabolic syndrome and elevated serum alanine aminotransferase in adolescents and young adults in mainland China

Objectives: The prevalence of overweight and obesity continue to increase among children and adolescents worldwide. This study examined whether waist circumference (WC), waist-to-hip ratio (WHpR) and waist-to-height ratio (WHtR) are predictive of metabolic syndrome and elevated serum alanine aminotransferase (ALT) among adolescents and young adults in mainland China. Study design: Cross-sectional study. Methods: In total, 6997 students aged 12-24 years from nine Chinese cities participated in this study. Anthropometric and biochemical data were collected. A logistic regression model was performed to determine the association between anthropometric indicators and metabolic syndrome components and abnormal liver function. Results: This study found prevalence rates for the metabolic syndrome and elevated ALT of 1.4% and 3.1%, respectively, among adolescents and young adults in mainland China. A multivariate logistic regression model found that WHtR >= 0.50 was more strongly associated with metabolic syndrome components and elevated ALT than WC values at or above the 90th percentile (P-90) or WHpR >= P-90. Odds ratios for elevated ALT were 2.03 [95% confidence interval (CI) 1.46-2.81], 4.56 (95% CI 3.07-6.78) and 13.43 (95% CI 7.67-23.51) in adolescents and young adults with one, two and three or more components of metabolic syndrome, respectively (P < 0.001 for all). Conclusions: Higher WC and WHtR were found to be predictive of metabolic syndrome components and elevated ALT among adolescents and young adults in mainland China, and the association was stronger for WHtR. Furthermore, adolescents and young adults with more metabolic syndrome components were more likely to suffer from elevated ALT. (C) 2011 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.