Purpose: The aims of this study were to identify the secular changes of WC and WHR, to compare WC with the prior Korean reference, to confirm the distribution of mean WHR values by age and sex, and to determine if WHR cutoff value of 0.5 is an appropriate predicting factor of cardiometabolic risk in childhood, using nationally representative data in children and adolescents.
Methods: We performed a retrospective, cross-sectional analysis of data from 13,257 children and adolescents (boys 6,987 and girls 6,270) aged 6-18 years who were included in the 3rd to 6th Korea National Health and Nutrition Examination Survey (KNHANES, 2005-2015). Receiver operating characteristic (ROC) curve analysis was used to identify the optimal threshold of WHR between 13 to 18 years of age in predicting the cardiometabolic risk factor including abdominal obesity, elevated BP, hyperglycemia, elevated HbA1c, High triglyceride, and low HDL cholesterol. The areas under the ROC curves (AUC) were obtained for each parameter.
Results: There were no secular change of mean WC and WHR by age between KNHANES 4 waves without significant difference. Mean WC increased with age in both sexes. Mean WC was significantly higher in boys than girls in all ages (P<0.001). Compared with previous 2007 Korean National Growth Charts, the mean WC tended to be lower for all ages. Mean WHR falls within the range of 0.421-0.451 for each sex and age. Mean male WHR was significantly greater than that of females aged 6 to 12 years (P<0.001). However, after 13 years old, there was no difference between WHR of boys and girls. The ROC curve analysis was performed between 13 to 18 years. The optimal WHR cutoff values capable of predicting all cardiometabolic risk factors were under 0.5 with higher sensitivity and negative predictive values. The optimal cutoff value for abdominal obesity was the highest as 0.480 with an AUC of 0.985 (sensitivity, 97.6%; specificity, 91.3%). The other optimal WHR cutoff values for cardiometabolic risk factors ranged from 0.442 to 0.462 with AUC from 0.545 to 0.735.
Conclusion: There was no secular change in WC and WHR over 10 years. The optimal WHR cutoff for abdominal obesity, 0.48 would be helpful to diagnose and to manage obesity in Korean 13-18 years old adolescents, preventing obesity related cardiometabolic complications.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology