Objective To investigate the relationship between impaired fasting glucose(IFG) and the distribution of body fat in adolescents.Methods Stratified cluster sampling was used to select 3874 adolescents aged 13-18 years for this cress-sectional study.Measurements included height,weight,waist circumference,hip circumference and fasting plasma glucose (FPG).Family history of diabetes was determined by using a serf-administered questionnaire.Participants were divided into normal fasting glucose group(FPG＜5.6 mmol/L,n=3738) and impaired fasting glucose group (5.6 mmol/L≤FPG ＜ 7.0 mmoL/L,n=136) according to their FPG levels. Results (1) After adjusting for age and sex using covariance analysis,the impaired fasting glucose group showed increased levels of body mass index,weight circumference,waist/hip ratio,waist/height ratio,as compared to the normal fasting glucose group (P＜ 0.05).(2) After the age and gender were adjusted,body mass index,weight circumference,waist/hip ratio and waist/height ratio were positively correlated with FPG level (P＜0.05).Among the partial relation coefficients, that between waist/height ratio and FPG(r'=0.0925) was the highest (3) In multiple regression analyses,age (β=-0.102,P＜0.05),family history of diabetes (β=0.186,P＜0.05) and waist/height ratio (β=0.842,P＜0.05) were consistently associated with FPG.Conclusion Central obesity was an important predictor of IFG in adolescents.Waist/height ratio may be an useful index of central obesity and an important predictor of IFG in adolescents.

Objective To investigate the correlation of anthropometric parameters with alanine aminotransferase (ALT) in Qinhuangdao college students.Methods A total of 789 subjects from two colleges in Qinhuangdao City (369 men and 420 women) were recruited using a cluster-stratified sampling method.Anthropometric measurements included height,body weight,waist circumference,hip circumference,blood pressure.and ALT.Body mass index,waist to height ratio,and waist to hip ratio were calculated.Results Elevated ALT was found in 16.3% of male participants and 4.0% of females(P<0.05).For males,those with elevated ALT showed significantly higher levels of anthropometric parameters (P<0.05).In females,the levels of anthropometric parameters were similar between subjects with or without elevated ALT(P>0.05).Receiver operating characteristie curve analysis also showed that obesity indices predicted elevated ALT only in men [area under the curve:0.8-0.9(P<0.05) in men,0.5-0.6(P>0.05) in wonlen].Blood pressure did not predict elevated ALT in both men and women (area under the curve:0.5-0.7).Conclusion Dender difference of obesity indices could be found in Qinhuangdao college students.Obesity indices may be independent predictors of elevated ALT in men.However,blood pressure seems not to be an independent predictor of elevated ALT.

Objective To explore the best cut-point of waist-to-heisht ratio (WHtR) for identifying metabolic syndrome(MS)in adolescents.Methods A cross-sectional study was conducted in 4 507 adolescents aged 13-18 years in Qinhuangdao.Receiver operating characteristic (ROC) curve analysis was employed to determine the optimal WHtR cut-point for detecting MS.Results The prevalences of MS were higher among higher WHtR in both boys and girls.Odds ratios for MS significantly increased from the WHtR≥0.45 in boys(OR =13.85,95%CI 4.08-46.97)and in girls (OR=12.42,95%CI 2.62-58.96,P<0.01).The ROC curve analysis showed that the optimal WHtR cut-point was 0.45 in boys with the sensitivity of 89.4%and specificity of 81.4%.and in girls with sensitivity of 90.3%and specificity of 86.5%.Conclusion There is a significant correlation between WHtR and MS.Optimal WHtR cut-point for predicting MS is 0.45.