Prevalence and Clinical Characteristics of Metabolically Healthy Obesity in Korean Children and Adolescents: Data from the Korea National Health and Nutrition Examination Survey

Abstract

Metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) are differentiated by the presence of cardiometabolic risk factors (CMRFs) and insulin resistance (IR). This study aimed to evaluate the prevalence and clinical characteristics of MHO in Korean children and adolescents and to investigate the anthropometric, laboratory, and lifestyle predictors of MHO. This study included data from 530 obese subjects, aged 10-19 years, obtained from the Fourth Korea National Health and Nutrition Examination Survey. Subjects were classified into MHO and MUO groups according to the presence of CMRF (MHO(CMRF)/MUO(CMRF)) and degree of IR (MHO(IR)/MUO(IR)). Demographic, anthropometric, cardiometabolic, and lifestyle factors were compared between the groups. Logistic regression analysis and receiver operating characteristic curve analysis were performed to identify factors that predicted MHO. The prevalence of MHO(CMRF) and MHO(IR) in obese Korean youth was 36.8% (n = 197) and 68.8% (n = 356), respectively. CMRF profiles were significantly less favorable in MUO children. Longer and more vigorous physical activity and less protein intake were associated with MHO(CMRF) phenotype. The best predictors of MHO(CMRF) and MHO(IR) were waist circumference (odds ratio [OR], 0.82; 95% confidence interval [CI], 0.77-0.88; P < 0.001) and body mass index (BMI) standard deviation score (OR, 0.24; 95% CI, 0.15-0.39; P < 0.001), respectively. The prevalence of MHO differed depending on how it was defined. To adequately manage obesity in youth, the approach to individuals with MHO and MUO should be personalized due to variation in clinical characteristics. Longitudinal studies are needed to evaluate long-term consequences of MHO.

Keywords: Children; Korea; Metabolically Healthy Obesity; Prevalence.

Fig. 1

Distribution of the number of CMRFs by MHO and MUO phenotype defined according to different criteria. MHO = metabolically healthy obesity, MUO = metabolically unhealthy obesity, CMRF = cardiometabolic risk factor, IR = insulin resistance.

Fig. 2

Proportion of CMRFs in children and adolescents with MUO. MHO = metabolically healthy obesity, MUO = metabolically unhealthy obesity, CMRF = cardiometabolic risk factor, IR = insulin resistance, HDL = high density lipoprotein.

Fig. 3

ROC curve for BMI SDS, WHR, and WC to detect MUO by definition. (A) MUO_CMRF with an AUC (95% CI) of 0.699 (0.698–0.700) for BMI SDS, 0.744 (0.743–0.745) for WHR, and 0.761 (0.760–0.761) for WC (P < 0.001), (B) MUO_IR with an AUC (95% CI) of 0.676 (0.675–0.677) for BMI SDS, 0.635 (0.634–0.636) for WHR, and 0.593 (0.592–0.594) for WC (P < 0.001). ROC = receiver operating characteristic, BMI = body mass index, SDS = standard deviation score, WHR = waist-height ratio, WC = waist circumference, MUO = metabolically unhealthy obesity, CMRF = cardiometabolic risk factor, AUC = area under the curve, CI = confidence interval, IR = insulin resistance.