Validity of simple, novel measures of generalized and central obesity among young Asian Indian women.

Objective: The study examined the validity of simple and novel measures of generalized obesity- [body mass index (BMI, kg/m 2 ), fat mass index (FMI, kg/m 2 ), and body fat percent (BF%)] and central obesity- [waist circumference (WC, cm), waist-hip ratio (WHR), and waist-to-height ratio (WC/ht ratio)] against BF% and BMI as criteria. It also aimed to predict fat-free mass index (FFMI, kg/m 2 ), FMI, and BF% ranges for various BMI categories. Design: Cross-sectional study. Materials and Methods: Weight, BF%, fat mass (FM), and fat-free mass (FFM) were measured using leg-to-leg bioelectrical impedance in 183 women. Height, hip, and waist circumferences were taken using standard methods. The indices [FMI, FFMI, WHR, W/ht ratio] were computed. Results: The study revealed that FMI, BMI, WC, and WC/ht ratio were highly correlated with BF% (r = 0.978; r = 0.939; r = 0.894; r = 0.890, respectively, P < 0.01), whereas WHR had the least correlation (r = 0.497, P < 0.01). The FMI showed a higher positive predictive value (PPV) in diagnosing generalized obesity compared to BMI with BF% as criterion and higher PPV than BF% with BMI as criterion. Considering only the indices of central obesity, WC was the most predictive in identifying women with high BF% (≥30% and ≥35%), whereas WC/ht ratio proved to be a better index in identifying women with BMI greater than 23 and 25 kg/m 2 . The normal BMI for Asians (18.5-23 kg/m 2 ), the at-risk group (23- 25 kg/m 2 ), and the obese class I (25-30 kg/m 2 ) corresponded to FFMI values of 14.1-15.1 kg/m 2 , 15.1-15.5 kg/m 2 , 15.5-16.1 kg/m 2 , respectively, and to FMI values of 4.4-7.9 kg/m 2 , 7.9-9.5 kg/m 2 , 9.5-13.9 kg/m 2 , respectively. The BMI cutoff of 18.5, 23, 25, 27.5, and 30 kg/m 2 corresponded to BF% of 23.6, 34.3, 38.3, 42.6, and 46.3%, respectively. Conclusion: FMI was a better predictor of generalized obesity compared to BMI and BF%. Considering abdominal obesity as an independent risk factor for insulin resistance, both WC and WC/ht ratio were able to predict central obesity better than WHR. Finally, the study presents ranges for FFMI and FMI for various BMI categories.

Waist-to-height Ratio, a Simple and Practical Index for Screening of Adolescent Metabolic Syndrome Aged 17~19 Years / 대한소아소화기영양학회지

PURPOSE: To evaluate the validity and usefulness of the waist circumference-to-height ratio (WHtR) in screening for metabolic syndrome in Korean adolescents aged 17~19 years. METHODS: Data (body mass index, waist circumference, and height) and blood samples were obtained from adolescents in A University Hospital in 2011. This study included 554 adolescents (176 boys and 378 girls) aged 17~19 years. Dependent variables were systolic and diastolic blood pressure, fasting blood glucose (FBS), total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C) and low density lipoprotein-cholesterol (LDL-C). Using the Pearson's correlation analysis and logistic regression analysis, we measured the WHtR against Body mass index (BMI). RESULTS: An assessment was carried out of the ability of the 2 indexes to 1) account for the variability in each metabolic risk factor and 2) correctly identify adolescents with metabolic risk factors. The results revealed that the predictive abilities of the waist-to-height ratio index were better values. The waist-to-height ratio showed superior values in predicting concentrations of DBP, FBS, TC, TG and LDL-C. However, BMI showed better values in identifying adolescents with high systolic blood pressure and HDL-C. 3) Normal weight adolescents (BMI: 5th or =0.51 in male, > or =0.49 in female). WHtR was better than the BMI index for signaling metabolic risk in the normal-weight adolescents. CONCLUSION: The WHtR is a better predictor for finding metabolic risk factors in adolescents aged 17~19 years with normal BMI. The WHtR is proposed as an alternative, convenient measure of screening metabolic syndrome for adolescents aged 17~19 years independent of age and sex.

Usefulness of the Waist Circumference-to-Height Ratio in Screening for Obesity in Korean Children and Adolescents / 대한소아소화기영양학회지

PURPOSE: To evaluate the feasibility and usefulness of the waist circumference-to-height ratio (WHTR) in screening for obesity in Korean children and adolescents. METHODS: Data, including body mass index (BMI), waist circumference (WC), and height, were obtained from the national growth surveys for children and adolescents in 2005. The WHTR was calculated dividing WC by height in subjects 2~18 years of age. Overweight and obese were defined by BMI percentiles for age and gender. The receiver operating characteristic (ROC) analysis was performed to find out the optimal cutoff values of WHTR that matched BMI-determined overweight and obesity using the STATA program. The area under the curve (AUC), a measure of diagnostic power, of WHTR was compared to WC. The influence of age on WHTR was analyzed by the SAS program. RESULTS: The WHTR significantly decreased with age, and had less correlation with age in the 6~18-year-old age group than the 2~5-year-old age group. Furthermore, the WHTR also had less correlation with age than WC in the 6~18-year-old age group. The AUC of WHTR in identifying overweight and obesity was significantly higher than the AUC of WC in the 6~18-year-old age group. The optimal cutoff values were 0.51 in boys and 0.49 in girls for obesity, and 0.48 in boys and 0.47 in girls for overweight, with all having the AUC>0.9. The optimal cutoff values of WHTR had a higher sensitivity for diagnosing obesity than WC> or =90th percentiles. CONCLUSION: The WHTR is an easy, accurate, and less age-dependent index with high applicability in screening for obesity in children and adolescents.

Usefulness of the Waist Circumference-to-Height Ratio in Screening for Obesity in Korean Children and Adolescents / 대한소아소화기영양학회지

PURPOSE: To evaluate the feasibility and usefulness of the waist circumference-to-height ratio (WHTR) in screening for obesity in Korean children and adolescents. METHODS: Data, including body mass index (BMI), waist circumference (WC), and height, were obtained from the national growth surveys for children and adolescents in 2005. The WHTR was calculated dividing WC by height in subjects 2~18 years of age. Overweight and obese were defined by BMI percentiles for age and gender. The receiver operating characteristic (ROC) analysis was performed to find out the optimal cutoff values of WHTR that matched BMI-determined overweight and obesity using the STATA program. The area under the curve (AUC), a measure of diagnostic power, of WHTR was compared to WC. The influence of age on WHTR was analyzed by the SAS program. RESULTS: The WHTR significantly decreased with age, and had less correlation with age in the 6~18-year-old age group than the 2~5-year-old age group. Furthermore, the WHTR also had less correlation with age than WC in the 6~18-year-old age group. The AUC of WHTR in identifying overweight and obesity was significantly higher than the AUC of WC in the 6~18-year-old age group. The optimal cutoff values were 0.51 in boys and 0.49 in girls for obesity, and 0.48 in boys and 0.47 in girls for overweight, with all having the AUC>0.9. The optimal cutoff values of WHTR had a higher sensitivity for diagnosing obesity than WC> or =90th percentiles. CONCLUSION: The WHTR is an easy, accurate, and less age-dependent index with high applicability in screening for obesity in children and adolescents.

Relationships with Alanine Aminotransferase Activity, and Anthropometric and Biochemical Measures in Obese Children / 대한소아소화기영양학회지

PURPOSE: To investigate the physical and biochemical parameters related with elevated serum alanine aminotransferase (ALT) levels in obese children. METHODS: One hundred forty-two obese or overweight children who visited the out-patient clinics of Chungnam National University Hospital between January 2006 and August 2008 were enrolled. Physical measures and biochemical tests were performed in all patients. Liver sonography was performed in 43 patients. They were divided into the following 2 groups based on ALT levels: group I, normal ALT levels (n=65); and group II, elevated ALT levels (n=77). We compared the physical measures, biochemical results, and ultrasonographic findings of the livers in both groups. Other causes of elevated serum ALT levels were ruled out. RESULTS: The male-to-female ratios were 1.6:1 in group I and 7.6:1 in group II. Among physical parameters, the waist circumference-to-height ratio and hip circumference-to-height ratio were significantly higher in group II (p=0.001 and 0.046, respectively). Among biochemical parameters, aspartate aminotransferase (AST), gamma-glutamyltransferase (gamma-GT), and total cholesterol levels were significantly higher in group II (p<0.001, 0.001, and 0.001, respectively). The AST/ALT ratio was <1 (mean, 0.55) and statistically lower in group II. There was a positive correlation between the serum ALT level and gamma-GT (p<0.001, r=0.750), and a positive correlation between the serum ALT level and the waist circumference-to-height ratio in group II (p<0.001, r=0.401). CONCLUSION: The results suggest that the waist circumference-to-height ratio and gamma-GT may be associated with elevated alanine aminotransferase activity in obese children.