Usefulness of the Waist Circumference-to-Height Ratio in Screening for Obesity and Metabolic Syndrome among Korean Children and Adolescents: Korea National Health and Nutrition Examination Survey, 2010-2014

Appropriate neck circumference and waist-to-height ratio cut-off points as predictors of obesity and cardiovascular risk in adolescents

OBJECTIVE

To determine neck circumference (NC) and waist-to-height ratio (WHtR) cut-off points as predictors of obesity and cardiovascular risk in adolescents.

METHODS

Cross-sectional study developed with a subsample of 634 adolescents aged 18 and 19 years belonging to the third phase of the "RPS" cohort (Ribeirão Preto, Pelotas and São Luís) carried out in 2016. The area under the ROC curve (AUC) was identified to assess the predictive capacity of NC and WHtR in relation to the percentage of body fat (%BF), obtained by air displacement plethysmography (ADP), and the cardiovascular risk estimated by the Pathobiological Determinants of Atherosclerosis in Youth (PDAY).

RESULTS

The prevalence of obesity by %BF was 7.6% in males and 39.4% in females (p-value <0.001), and the high PDAY risk was 13.8% and 10.9%, respectively. For males, NC cut-off point was 44.0 cm and the AUCs were 0.70 (95%CI 0.58-0.83) to predict obesity and 0.71 (95%CI 0.62-0.80) to predict high cardiovascular risk; for females, NC cut-off point was 40 cm and the AUCs were 0.75 (95%CI 0.69-0.80) and 0.63 (95%CI 0.53-0.73), respectively. WHtR cut-off point was 0.50 for both sexes; for males, the AUCs to predict obesity and high risk according to PDAY were 0.90 (95%CI 0.80-0.99) and 0.73 (95%CI 0.63-0.82), respectively; for females, they were 0.87 (95%CI 0.83-0.90) and 0.55 (95%CI 0.45-0.65), respectively.

CONCLUSION

WHtR and NC are good discriminators to assess obesity and cardiovascular risk in adolescents, especially in males.

Optimal cut-off value of waist circumference-to-height ratio to predict central obesity in children and adolescents: A systematic review and meta-analysis of diagnostic studies

Introduction

Waist circumference-to-height ratio (WHtR) is a simple anthropometric index with good screening power and fast interpretation for early detection of childhood abdominal obesity. This systematic review and meta-analysis aims to determine the best cut-off value of WHtR to use in clinical setting.

Methods

Comprehensive searches were conducted in PubMed, Scopus, and Web of Science by the end of March 2021. Observational studies investigated the best WHtR cut-off to detect abdominal obesity in children and adolescents were included. Thirteen articles (n = 180,119) were included in this systematic review and eight documents were included in the meta-analysis.

Results

The overall optimal cut-off was 0.49 with pooled sensitivity, specificity and diagnostic odds ratio (DOR) of 0.93 (95% confidence interval (CI): 0.93-0.96), 0.88 (95% CI: 0.85-0.91) and 102.6 (95% CI: 50.7-207.5), respectively. The optimal WHtR cut-off to predict abdominal obesity in girls and boys were both 0.49.

Discussion

The current study shows that we could use this cut-off as a simple index for predicting abdominal obesity in children and adolescents without the need for any charts in practice.

Adiposity measures in screening for metabolic syndrome among Chinese children and adolescents

BACKGROUND

Existing various and complicated metabolic syndrome (MetS) definitions have contributed to the difficulty in assessing MetS in children and adolescents, and therefore it is urgently needed to develop a convenient and effective screening tool for pediatric MetS. This study aimed to identify the optimal adiposity measure to screen for pediatric MetS.

METHODS

The cross-sectional data was collected from 8,150 children and adolescents aged 7-17 y living in southern China. Anthropometric indices, blood lipids, and serum glucose were determined. Results of two commonly used MetS definitions were compared: International Diabetes Federation (IDF) and National Cholesterol Education Program Adult Treatment Panel Ⅲ (NCEP-ATP) modified by Cook. Receiver operating characteristic curve analyses were performed and areas under the curve (AUCs) were calculated to determine the optimal index for MetS screening.

RESULTS

MetS prevalence assessed by NCEP-ATP was significantly higher than that by IDF (6.2% vs. 1.5%, p<0.001). Waist-to-height ratio (WHtR) showed the highest screening power for MetS defined by both IDF and NCEP-ATP (AUC 0.932 and 0.900, respectively), and its optimal cut-off point was 0.48 by both IDF and NCEP-ATP definition (sensitivity 0.944 and 0.847, specificity 0.800 and 0.830, respectively), regardless of age or sex. When taking sex diversity into account, the optimal WHtR cut-off point was 0.49 (IDF) or 0.50 (NCEP-ATP) in boys, and 0.46 (both definitions) in girls.

CONCLUSIONS

Among children and adolescents aged 7-17 y in southern China, a WHtR greater than 0.48 can be a simple but effective screening tool for MetS.

Accuracy of different cutoffs of the waist-to-height ratio as a screening tool for cardiometabolic risk in children and adolescents: A systematic review and meta-analysis of diagnostic test accuracy studies

The present systematic review with meta-analysis sought to estimate the accuracy of different waist-to-height ratio (WHtR) cutoff ranges as risk indicators for cardiometabolic health in different populations of children and adolescents. Systematic searches were undertaken to identify studies in apparently healthy participants aged 3-18 years that conducted receiver operating characteristic curve analysis and reported area under the receiver operating characteristic curves for WHtR with any cardiometabolic biomarker. Forty-one cross-sectional studies were included in the meta-analysis, including 138,561 young individuals (50% girls). Higher area under summary receiver operating characteristic (AUSROC) values were observed in cutoffs between 0.46 and 0.50 (AUSROC = 0.83, 95%CI: 0.80-0.86) and ≥0.51 (AUSROC = 0.87, 95%CI: 0.84-0.90) (p < 0.001 in comparison with cutoffs 0.41 to 0.45), with similar results in both sexes. The AUSROC value increased in the East and Southeast Asian regions using a WHtR cutoff of ≥0.46 (AUSROC = 0.90, 95%CI: 0.87 to 0.92). A cutoff of ≥0.54 was optimal for the Latin American region (AUSROC = 0.96, 95%CI: 0.94-0.97). Our meta-analysis identified optimal cutoff values of WHtR for use in children and adolescents from different regions. Despite the widely accepted WHtR cutoff of 0.50, the present study indicated that a single cutoff value of WHtR may be inappropriate.

Gender and age differences in the prevalence and associated factors of metabolic syndrome among children and adolescents in South Korea

Purpose

This study examined the prevalence of metabolic syndrome (MetS) in South Korean children and adolescents by gender and age and analyzed gender-specific factors associated with MetS.

Methods

This study used data on children aged 10-18 years from the Korea National Health and Nutrition Examination Survey (KNHANES) from 2010 to 2015. Analyses included descriptive statistics, the independent t-test, the x² test, and univariate logistic regression analysis (p<.050).

Results

The prevalence of MetS was 4.8% in boys and 3.4% in girls. The prevalence was higher in girls up to the age of 12, but higher in boys who were 13 or older. Abdominal obesity was frequent in girls, whereas low high-density lipoprotein cholesterol (HDL-C) and elevated blood pressure were more common in boys. Higher body mass index, waist-to-height ratio, waist circumference, blood pressure, triglycerides, HDL-C, perceived "fat" body shape, and weight loss efforts were associated with MetS in both genders. Increasing age, having one meal per day, and weight maintenance were associated factors unique to boys. Fasting plasma glucose, familial medical history of low HDL-C, and perceived "thin" body shape were associated factors in girls.

Conclusion

Gender and age differences should be considered in the risk assessment and prevention of MetS.

Performance of different adiposity measures for predicting left ventricular remodeling in Chinese hypertensive youth

There is no consistent conclusion on which adiposity measure is best to predict cardiovascular risk factors in youth. The present study aims to assess the performance of body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) in predicting abnormal left ventricular structure in Chinese hypertensive youth. A total of 1180 youth aged 6–17 years with hypertension from the China Child and Adolescent Cardiovascular Health Study were included in this study. Logistic regression model, receiver operator characteristic (ROC) curve analysis and net reclassification improvement (NRI) method were used to assess performance of BMI, WC, and WHtR in predicting left ventricular hypertrophy (LVH) and left ventricular geometry (LVG). A 1-standard deviation increment in any of three indexes in predicting LVH and LVG were similar, e.g., with the odds ratios and 95% confidence intervals of 1.34 (1.16–1.55), 1.25 (1.08–1.45) and 1.40 (1.20–1.62), respectively. In addition, ROC analysis and NRI method confirmed the similar performance of three adiposity indexes in predicting LVH and LVG. In conclusion, BMI, WC and WHtR had similar performance in predicting abnormal left ventricular structure in Chinese hypertensive youth, but all three indexes had limited value in prediction. WHtR is a simple and convenient adiposity index for screening youth at high risk of target organ damage.

Waist-to-Height Ratio Is a Good Predictor of Metabolic Syndrome in Adolescents: A Report From the Thai National Health Examination Survey V, 2014

This study aimed to assess the performance of waist-to-height ratio (WHtR) in the prediction of metabolic syndrome and to determine the appropriate cutoff value in Thai adolescents. Demographic data, blood pressure, fasting blood glucose, and lipid profile were obtained from the Thai National Health Examination Survey V database. The performances of WHtR, waist circumference, body mass index (BMI), and BMI z-score were analyzed by the receiver operating characteristics. Among 2644 adolescents, metabolic syndrome was identified in 4.27%. The areas under the receiver operating characteristic curves of WHtR, waist circumference, BMI, and BMI z-score were comparable (0.924-0.960). Performance of WHtR was more constant across age groups compared with other parameters. Using the cutoff value of WHtR at 0.5 resulted in the sensitivity and specificity of 98.5%/83.4% and 88.9%/86.0% in males and females, respectively. In conclusion, the cutoff value of WHtR at 0.5 provided good sensitivity and specificity for identifying metabolic syndrome in both genders. However, the other clinical risk factors or more definite scores should be considered when further assessment.

Dietary intake and nutritional status of Korean children and adolescents: a review of national survey data

In Korea, several national cross-sectional surveys monitor the diet, nutritional status, and health status of children. This continual dedicated national surveillance system contributes to the identification of nutritional and health issues, establishment of public health policies, and development of nutrition recommendations. This paper provides recent information about the Korea National Health and Nutrition Examination Survey and the Korean Youth Risk Behavior Web-based Survey and describes key nationwide survey findings published in the last 5 years on infant feeding practices and the dietary intake and nutritional status of Korean infants, children, and adolescents. There have been increasing trends in children, and teenagers who skip breakfast, eat fast food, consume sugary drinks, have vitamin D deficiency, and are obese. This review will inform pediatricians, nutritionists, and other health care practitioners who track children's growth and development. It may also help researchers and policymakers identify diet-related policies and strategies for chronic disease prevention in Korean infants, children, and adolescents.

Distribution of waist-to-height ratio and cardiometabolic risk in children and adolescents: a population-based study

This study was performed to evaluate the waist-to-height ratio (WHtR) distribution and assess its relationship with cardiometabolic risk in children and adolescents. A total of 8091 subjects aged 10–18 years were included from a nationally representative survey. Participants were classified into three groups: (1) < 85th, (2) ≥ 85th and < 95th, and (3) ≥ 95th percentile of WHtR. The WHtR distribution varied with sex and age. Whereas WHtR decreased from age 10–15 years in boys and from age 10–12 years in girls, it slightly increased thereafter. Compared to the < 85th percentile group, the WHtR ≥ 85th and < 95th percentile group had an odds ratio (OR) of 1.2 for elevated blood pressure (BP), 1.89 for elevated triglycerides (TGs), 1.47 for reduced high-density lipoprotein cholesterol (HDL-C) and 4.82 for metabolic syndrome (MetS). The ≥ 95th percentile group had an OR of 1.4 for elevated BP, 2.54 for elevated glucose, 2.22 for elevated TGs, 1.74 for reduced HDL-C, and 9.45 for MetS compared to the < 85th percentile group. Our results suggest that sex- and age-specific WHtR percentiles can be used as a simple clinical measurement to estimate cardiometabolic risk.

Waist circumference-to-height ratio and body mass index for obesity classification in Irish children

AIM

Waist circumference-to-height ratio (WHt) has been proposed as an alternative measure to BMI due to its focus on central weight distribution and its basic threshold for increased cardiometabolic risk. This study aimed to compare prevalence of overweight including obesity using BMI and WHt, and assess 10-year trends of WHt prevalence, in a representative sample of Irish children.

METHODS

Children measured during rounds 2-5 of the Childhood Obesity Surveillance Initiative (n = 20037) were classified as healthy weight or overweight including obesity (International Obesity Task Force age and sex BMI cut-offs), and low or high WHt (WHt ≥ 0.5). Differences in prevalence of BMI and WHt classifications were determined for round five in younger (<9 years) and older (≥9 years) children. The prevalence of high WHt was assessed across rounds.

RESULTS

Differences in prevalence between overweight including obesity and high WHt were apparent in younger (BMI: 16.7%, WHt: 8.9%; p < .001) and older (BMI: 21.3%, WHt: 12.1%; p < .001) children. An inverse trend for prevalence of high WHt was identified across rounds (p < .001).

CONCLUSION

BMI overestimates overweight including obesity prevalence compared to WHt. Given its ease of use, consideration of the WHt as an additional measure in childhood surveillance and screening is warranted.

Prevalence of Metabolic Syndrome among Children and Adolescents in High-Income Countries: A Systematic Review and Meta-Analysis of Observational Studies

Introduction. Metabolic syndrome (MetS) is an assemblage of interconnected cardiovascular risk factors that are prevalent among children and adolescents in high-income countries (HICs). Despite the presence of several studies on the issue, the study findings are incongruent due to the absence of a gold standard diagnostic method of MetS in children. Thus, the findings of the original studies are inconclusive for policy makers and other stakeholders. This systematic review and meta-analysis is aimed at giving conclusive evidence about MetS among children and adolescents in HICs. Methods. We conducted searches using electronic databases (PubMed, Scopus, Web of Science, CINAHL (EBSCOhost), EMBASE (Elsevier), and Medline (EBSCOhost)) and other sources (Google Scholar and Google) up to September 2020. Observational studies reporting the prevalence of MetS were eligible in this study. The pooled estimates were computed in fixed and random effect models using six diagnostic methods (IDF, ATP III, de Ferranti et al., WHO, Weiss et al., and Cruz and Goran). Publication bias was verified using funnel plots and Egger’s regression tests. Subgroup and sensitivity analysis were performed in case of higher heterogeneities among the included studies. Result. In this study, 77 studies with a total population of 125,445 children and adolescents were used in the final analysis. Metabolic syndrome among the overweight and obese population was computed from 28 studies with the pooled prevalence of 25.25%, 24.47%, 39.41%, 29.52%, and 33.36% in IDF, ATP III, de Ferranti et al., WHO, and Weiss et al. criteria, respectively. Likewise, 49 studies were eligible to compute the pooled prevalence of MetS in the general population of children and adolescents. Hence, MetS was found in 3.70% (IDF), 5.40% (ATP III), 14.78% (de Ferranti et al.), 3.90% (WHO), and, 4.66% (Cruz and Goran) of study participants. Regarding the components of MetS, abdominal obesity in the overweight and obese population, and low HDL-C in the general population were the most common components. Besides, the prevalence of Mets among males was higher than females. Conclusion. This study demonstrates that MetS among children and adolescents is undoubtedly high in HICs. The prevalence of MetS is higher among males than females. Community-based social and behavioral change communications need to be designed to promote healthy eating behaviors and physical activities. Prospective cohort studies could also help to explore all possible risk factors of MetS and to design specific interventions accordingly.

Novel Insights into the Pathogenesis and Management of the Metabolic Syndrome

The metabolic syndrome, by definition, is not a disease but is a clustering of individual metabolic risk factors including abdominal obesity, hyperglycemia, hypertriglyceridemia, hypertension, and low high-density lipoprotein cholesterol levels. These risk factors could dramatically increase the prevalence of type 2 diabetes and cardiovascular disease. The reported prevalence of the metabolic syndrome varies, greatly depending on the definition used, gender, age, socioeconomic status, and the ethnic background of study cohorts. Clinical and epidemiological studies have clearly demonstrated that the metabolic syndrome starts with central obesity. Because the prevalence of obesity has doubly increased worldwide over the past 30 years, the prevalence of the metabolic syndrome has markedly boosted in parallel. Therefore, obesity has been recognized as the leading cause for the metabolic syndrome since it is strongly associated with all metabolic risk factors. High prevalence of the metabolic syndrome is not unique to the USA and Europe and it is also increasing in most Asian countries. Insulin resistance has elucidated most, if not all, of the pathophysiology of the metabolic syndrome because it contributes to hyperglycemia. Furthermore, a major contributor to the development of insulin resistance is an overabundance of circulating fatty acids. Plasma fatty acids are derived mainly from the triglycerides stored in adipose tissues, which are released through the action of the cyclic AMP-dependent enzyme, hormone sensitive lipase. This review summarizes the latest concepts in the definition, pathogenesis, pathophysiology, and diagnosis of the metabolic syndrome, as well as its preventive measures and therapeutic strategies in children and adolescents.

Predictive Ability of Seven Anthropometric Indices for Cardiovascular Risk Markers and Metabolic Syndrome in Adolescents

PURPOSE

The aim of the study was to evaluate the reliability of 7 anthropometric indices in predicting cardiovascular risk markers (CRMs) and metabolic syndrome (MetS) in Brazilian adolescents.

METHODS

A cross-sectional study conducted with 1,069 participants of the Cardiovascular Risk in Adolescents Study aged 12-17 years. Receiver operating characteristics curves were plotted, and area under curve (AUC) was calculated for body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHR), conicity index (CoI), body shape index (BSI), adjusted BSI for adolescents (adjusted BSI), and body roundness index (BRI).

RESULTS

In girls, reliability of BMI, WC, WHR, and BRI was sufficient (≥.6 AUC <.7) only to predict high blood pressure. Among boys, reliability of BMI, WC, WHR, BRI, and adjusted BSI ranged from good to sufficient (≥6 AUC <.8) to predict insulin resistance and high blood pressure, but poor to sufficient (≥.5 AUC <.7) for high total cholesterol, triglycerides, and low-density lipoprotein. For both sexes, CoI and BSI presented AUC ≤.5 for all CRM. A majority of the anthropometric indices showed AUC ≥.9 for MetS.

CONCLUSION

Reliability of CoI, BSI, adjusted BSI, and BRI is not superior to BMI, WC, and WHR in predicting CRM and MetS. All the anthropometric indices had excellent predictive capacity for MetS, but limited accuracy for CRM. Among the evaluated indices, we recommend the use of cutoff point WHR ≥.55 to screening MetS in girls and boys because of its easy to measure and interpretation.

Association between Fatty Liver Index and Periodontitis: the Korea National Health and Nutrition Examination Survey

It has been suggested that periodontitis is associated with metabolic abnormalities including non-alcoholic fatty liver disease (NAFLD). The fatty liver index (FLI) is a non-invasive surrogate marker and predictor of NAFLD. We aimed to determine whether FLI itself would be associated with periodontitis through a secondary analysis of previously reported nationally representative probability sample data of the Korean population. FLI was calculated from a previously developed algorithm which combines measures of body mass index (BMI), waist circumference, triglyceride, and gamma-glutamyl transferase (GGT). Periodontitis was diagnosed based on the Community Periodontal Index (CPI) developed by the World Health Organization. Of 4,272 participants, 26.1% were diagnosed with periodontitis. Higher FLI was associated with a higher prevalence of periodontitis (Odds ratio (OR) _{highest vs. lowest quartile of FLI},1.63; 95% confidence interval (CI), 1.23–2.16; P = 0.001 for trend) adjusting for confounding factors. In the highest FLI quartile, prevalence of periodontitis was higher in individuals with diabetes (OR _{highest vs. lowest quartile of FLI}, 2.89; 95% CI, 1.01–8.27 for diabetic subgroup; OR _{highest vs. lowest quartile of FLI}, 1.45; 95% CI, 1.07–1.96 for non-diabetic subgroup). In summary, FLI was associated with prevalent periodontitis.

Identification of metabolic syndrome using phenotypes consisting of triglyceride levels with anthropometric indices in Korean adults

BACKGROUND

The metabolic syndrome (MetS) has shown strong associations with the hypertriglyceridemic waist (HW) phenotype. The best anthropometric indicator of MetS remains controversial. Furthermore, no studies have investigated alternative indices that could replace waist circumference in the HW phenotype. The objectives of this study were to find the best indicator of MetS among anthropometric indices and to examine the predictive power of phenotypes consisting of triglyceride levels with anthropometric indices.

METHODS

A total of 12,025 subjects participated in this retrospective cross-sectional study. All subjects were recruited between November 2016 and August 2007 from hospitals in 28 urban and rural regions in South Korea. The data analyzed in this study were obtained from the Korean Health and Genome Epidemiology Study database and the Korea Institute of Oriental Medicine.

RESULTS

The proportion of patients with MetS ranged from 9 to 57% according to age and gender groups. Waist circumference (WC) was best indicator of MetS in men of all age groups. However, in women aged 40-49 years, the waist-to-height ratio (WHtR) was the best indicator of MetS. Rib circumference and chest circumference were the strongest indicators in women aged 50-59 years and 70-79 years, respectively. The combination of WC and triglyceride (TG) was the best indicator of MetS in men and women overall. However, interestingly, the best indicator was TG + WHtR in women aged 40-49 years and TG + forehead-to-waist ratio in women aged 70-79 years.

CONCLUSIONS

The best indicator of MetS in terms of individual anthropometric indices and the various phenotypes combining a single anthropometric index with TG may differ subtly according to age group in women, but not in men. Our findings provide insight into a simple and inexpensive method that could be used to identify MetS in initial health screening efforts in epidemiology and public health.

The utility of anthopometric indicators to identify cardiovascular risk factors in Vietnamese children

BMI, waist circumference (WC) and waist-to-height ratio (WHtR) can be used for discriminating children and adolescents at risk of CVD. However, consensus on how to use these anthropometric indicators is lacking for children and adolescents in Asia. Discrete criteria are promoted internationally, but continuous variables could be used. Data from a survey of 10 949 Vietnamese school-aged children (6-18 years) were used to evaluate the performance of anthropometric indicators to identify elevated blood pressure (BP), dyslipidaemia or at least three cardiovascular risk factors (CVRF). Weight, height, WC and BP were measured using standardised protocols; 1009 participants who had blood lipids were analysed. AUC was used to assess the performance, and the Youden index to identify optimal cut-offs. The prevalence of elevated BP, dyslipidaemia and CVRF was 26·5, 49·3 and 12·2 %, respectively. BMI, WC and WHtR had low capacity to identify elevated BP and dyslipidaemia (AUC range 0·61-0·66) but moderate capacity to identify CVRF (0·72-0·74). Optimal BMIZ cut-offs to identify elevated BP, dyslipidaemia and CVRF were 0·40, 1·01 and 1·1 sd; for WC z-score, they were 0·06, 0·49 and 0·62 sd; for WHtR, optimal cut-offs were close to 0·5. A BMIZ cut-off of 1·0 sd and a WHtR cut-off of 0·5 would, therefore, be useful criteria to identify Vietnamese children who are likely to have CVRF. However, further validation of these criteria in other studies of Asian children and adolescents is needed.

A simple cut-off for waist-to-height ratio (0·5) can act as an indicator for cardiometabolic risk: recent data from adults in the Health Survey for England

The National Institute for Health and Care Excellence (NICE) has acknowledged the value of waist-to-height ratio (WHtR) as an indicator for ‘early health risk’. We used recent UK data to explore whether classification based on WHtR identifies more adults at cardiometabolic risk than the ‘matrix’ based on BMI and waist circumference, currently used for screening. Data from the Health Survey for England (4112 adults aged 18+ years) were used to identify cardiometabolic risk, indicated by raised glycated Hb, dyslipidaemia and hypertension. HbA1c, total/HDL-cholesterol and systolic blood pressure (BP) were more strongly associated with WHtR than the ‘matrix’. In logistic regression models for HbA1c ≥ 48 mmol/mol, total/HDL-cholesterol > 4 and hypertension (BP > 140/90 mmHg or on medication), WHtR had a higher predictive value than the ‘matrix’. AUC was significantly greater for WHtR than the ‘matrix’ for raised HbA1c and hypertension. Of adults with raised HbA1c, 15 % would be judged as ‘no increased risk’ using the ‘matrix’ in contrast to 3 % using WHtR < 0·5. For hypertension, comparative values were 23 and 9 %, and for total/HDL-cholesterol > 4, 26 and 13 %. Nearly one-third of the ‘no increased risk’ group in the ‘matrix’ had WHtR ≥ 0·5 and hence could be underdiagnosed for cardiometabolic risk. WHtR has the potential to be a better indicator of cardiometabolic risks associated with central obesity than the current NICE ‘matrix’. The cut-off WHtR 0·5 in early screening translates to a simple message, ‘your waist should be less than half your height’, that allows individuals to be aware of their health risks.

Increased prevalence of hypertensive-level blood pressure using the American Academy of Pediatrics 2017 guidelines: a cross-sectional study in a primary school in Thailand

Background: In 2017, the American Academy of Pediatrics (AAP) launched a new clinical practice guideline for diagnosis of hypertension in children and adolescents. The new cut-off values were 2-3 mmHg lower than those of the previous 2004 guidelines. Aims: This study was conducted to evaluate the effects of the new cut-off values on the prevalence of hypertensive-level blood pressure (BP) in children in a primary school in Bangkok, Thailand. Subjects and methods: BP, weight, height and waist circumference were recorded in 536 school children aged 8-13 years (270 boys, 50.3%) in grades 4-6. For analysis, BP was classified by the two different cut-off values (the 2004 AAP and the 2017 AAP guidelines). Demographic data for the children whose BP was hypertensive according to the 2017 guidelines but not the 2004 guidelines were compared with those of the children with normal BP according to both guidelines. Logistic regression analysis was performed to evaluate the factors associated with hypertensive-level BP. Results: Fifty-eight children (10.8%) had hypertensive-level BP according to the 2017 guidelines but only 37 (6.9%) with the 2004 guidelines. Twenty-one children who would not have had hypertensive-level BP with the 2004 AAP guidelines had greater Z-scores for body mass index and a greater proportion had obesity than the normotensive children. Body mass index was the only independent factor associated with hypertensive-level BP. Conclusions: The prevalence of hypertensive-level BP in children was increased using the 2017 guidelines. Children with hypertensive-level BP using the 2017 AAP guidelines but not the 2004 AAP guidelines had greater BMI Z-scores and a greater proportion were obese than the in the normotensive children. Body mass index was the only independent factor associated with hypertensive-level BP. Abbreviations: AAP: American Academy of Pediatrics; BMI: body mass index; BP: blood pressure; cm: centimeter; DBP: diastolic blood pressure; HT: hypertension; kg: kilograms; m: meter; NHANES: National Health and Nutrition Examination Survey; ROC: receiver operating characteristic curve; SBP: systolic blood pressure; SBPHR: systolic blood pressure-to-height ratio; SD: standard deviation; WC: waist circumference; WHR: waist-to-height ratio.

Utility of waist circumference-to-height ratio as a screening tool for generalized and central obesity among Iranian children and adolescents: The CASPIAN-V study

BACKGROUND

Waist-to-height ratio (WHtR) is regarded as a simple anthropometric index for evaluating central adiposity because of its independence of age, gender, and ethnicity.

OBJECTIVE

The purpose of this study was to determine the optimal WHtR cutoff value in screening obesity and to compare it with other obesity indicators including body mass index (BMI) and waist circumference (WC) in Iranian children and adolescents.

METHODS

This large survey was conducted on 14 274 Iranian children and adolescents as a national school-based surveillance study (CASPIAN) in 2015. The receiver operating characteristic curve analysis was performed to estimate the optimal cut-off points of WHtR for the prediction of general and central obesity. The area under curve (AUC) was used to compare the ability of WHtR cut-off points, BMI and WC percentiles to discriminate students with and without obesity according to age and sex.

RESULTS

The optimal WHtR cutoff value for predicting general obesity was 0.49 and 0.48 for boys and girls, respectively and for central obesity according to WC ≥ 90th percentile was 0.50 for both genders. AUC values of WHtR for predicting general and central obesity were 87% and 96%, which indicates its strong predictive ability. For central obesity, the AUCs of WHtR were superior to those of WC percentiles. The kappa agreement coefficient was 0.55 between WC ≥ 90th percentile and WHtR ≥ 0.5.

CONCLUSIONS

The WHtR ≥ 0.5 as a simple and useful screening tool is better than WC, for predicting general and central obesity in different age and sex groups of Iranian children and adolescents.

Using height-corrected definition of metabolic syndrome in children and adolescents

Metabolic syndrome (MS) is common among children and adolescents. Age- and gender-specific references or age-, gender- and height-specific references were used in pediatric MS definitions. More recently, an increasing number of studies documented that the ratio of waist circumference (WC) to height (WHtR) and blood pressure to height (BPHR) were easy anthropometric indexes for detection of obesity and hypertension in children and adolescents. For these reasons, height-corrected MS definition was proposed. WHtR and BPHR were used as alternatives to WC and BP in the definition of MS. In the present review, we discuss the possibility of the height-corrected MS definition for identifying MS in children.

The National After-School Athletics Program Participation as a Tool to Reduce the Risk of Obesity in Adolescents after One Year of Intervention: A Nationwide Study

Regular exercise during school hours is encouraged; however many children and adolescents fail to meet the recommendations during this time. Extracurricular activities may be a more appealing way for youth to achieve guidelines, and it is recommended that they attend two sessions each week. The aim of the study was to assess the influence of participation in a national physical activity program accompanied by nutritional education for trainers on the risk of obesity and body composition in a nationwide sample of boys and girls, after one year of intervention. The #goathletics Study was conducted in a group of 1014 adolescents aged 12⁻13: 507 individuals for the Athletics for All program (210 boys, 297 girls) and 507 pair-matched individuals not participating in any physical activity program (matching including: gender, age, city of residence). The body mass (kg), Body Mass Index (BMI) (kg/m²), waist circumference (WC) (cm), waist-to-height ratio (WHtR) (-) and body composition (%) (measured using bioelectrical impedance method) were compared in a gender-related sub-groups using t-Student test (for parametric distributions) or Mann-Whitney U test (for nonparametric distributions) and chi² test (for the share of sub-groups). After one year of intervention, lower body mass percentile, BMI percentile, WC, WHtR and fat mass share, higher muscle mass share, as well as lower frequency of overweight/obesity and abdominal fat distribution were observed both for boys and girls participating in the physical activity intervention compared to the pair-matched controls. The after-school physical activity program accompanied by nutritional education for trainers may be a highly effective method for reducing the risk of obesity both for boys and girls, as regular participation is ensured.

Body mass index classification misses to identify children with an elevated waist-to-height ratio at 5 years of age

BACKGROUND

Abdominal adiposity is an important risk factor in the metabolic syndrome. Since BMI does not reveal fat distribution, waist-to-height ratio (WHtR) has been suggested as a better measure of abdominal adiposity in children, but only a few studies cover the preschool population. The aim of the present study was to examine BMI and WHtR growth patterns and their association regarding their ability to identify children with an elevated WHtR at 5 years of age.

METHODS

A population-based longitudinal birth cohort study of 1540 children, followed from 0 to 5 years with nine measurement points. The children were classified as having WHtR standard deviation scores (WHtR_SDS) <1 or ≥1 at 5 years. Student's t-tests and Chi-squared tests were used in the analyses.

RESULTS

Association between BMI_SDS and WHtR_SDS at 5 years showed that 55% of children with WHtR_SDS ≥1 at 5 years had normal BMI_SDS (p < 0.001). Children with WHtR_SDS ≥1 at 5 years had from an early age significantly higher mean BMI_SDS and WHtR_SDS than children with values <1.

CONCLUSIONS

BMI classification misses every second child with WHtR_SDS ≥1 at 5 years, suggesting that WHtR adds value in identifying children with abdominal adiposity who may need further investigation regarding cardiometabolic risk factors.

Low Muscle Mass and Depressed Mood in Korean Adolescents: a Cross-Sectional Analysis of the Fourth and Fifth Korea National Health and Nutrition Examination Surveys

BACKGROUND

Muscle mass and muscle function are related to depressed mood in studies of adults. Like adults, Korean students are highly likely to suffer from decreased muscle mass due to social conditions. In this study, we evaluated the muscle mass status of Korean adolescents and assess the effect of muscle on depressive mood.

METHODS

A total of 1,233 adolescent boys and girls participants from the Korea National Health and Nutrition Examination Survey were enrolled in our study. Participants underwent dual-energy X-ray absorptiometry for assessment of appendicular muscle mass and completed questionnaires regarding depressed mood, stress, suicidal ideations, and attempts.

RESULTS

There was no difference in depressive mood according to muscle mass among boys (P = 0.634); girls with decreased muscle mass had a greater tendency for depressed mood compared to girls with optimal muscle mass (P = 0.023). After adjusting for age, waist circumference-to-height ratio, smoking status, alcohol consumption, frequency of physical activity, self-reported obesity, weight-loss efforts, and monthly household income, girls with low muscle mass (LMM) were 2.60 times more at risk of developing depression than girls with normal muscle mass (95% confidence interval [CI], 1.05-6.49; P = 0.040). This trend was similar for girls with LMM with obesity (95% CI, 1.00-11.97; P = 0.049).

CONCLUSION

Adolescent girls who have insufficient muscle mass are more likely to report depressed mood than girls who have ideal muscle mass. Interventions for maintaining proper muscle mass are required.

Secular change in waist circumference and waist-height ratio and optimal cutoff of waist-height ratio for abdominal obesity among Korean children and adolescents over 10 years

PURPOSE

This study aimed to evaluate the time trends of waist circumference (WC) and waist-height ratio (WHR), and to present WC and WHR distributions with optimal WHR cutoff for abdominal obesity in Korean children and adolescents.

METHODS

We performed a retrospective cross-sectional analysis of data from 13,257 children and adolescents (6,987 boys and 6,270 girls) aged 6-18 years who were included in the third to sixth Korea National Health and Nutrition Examination Survey (KNHANES, 2005-2015). Linear regression analyses were used to identify secular changes in WC and WHR by age, sex, and KNHANES waves. A receiver operating characteristic curve analysis was used to determine the optimal WHR cutoff values for abdominal obesity and cardiometabolic risk factors.

RESULTS

The mean WC and WHR distributions from 2005 to 2015 showed no significant secular changes between the KNHANES 4 waves (P for trend ≥0.05 in all ages and both sexes). The mean WCs in the present study were lower than those in the 2007 Korean National Growth Charts. The mean WHR at ages <13 years was statistically higher in the boys than in the girls, but did not significantly differ between the sexes among those aged 13 to 18 years. The optimal WHR cutoff for abdominal obesity was 0.48 (area under the curve, 0.985; 95% confidence interval, 0.985-0.985) in the 13- to 18-yearold adolescents.

CONCLUSION

WC and WHR showed no secular changes over 10 years. The optimal WHR cutoff for abdominal obesity of 0.48 is useful for diagnosing and managing obesity and thus preventing obesityrelated cardiometabolic complications in 13- to 18-year-old Korean adolescents.

Performance of Waist-To-Height Ratio, Waist Circumference, and Body Mass Index in Discriminating Cardio-Metabolic Risk Factors in a Sample of School-Aged Mexican Children

The most common tools used to screen for abdominal obesity are waist circumference (WC) and waist-to-height ratio (WHtR); the latter may represent a more suitable tool for the general non-professional population. The objective of this study was to evaluate the association of WHtR, WC, and body mass index with lipidic and non-lipidic cardio-metabolic risk factors and the prediction capability of each adiposity indicator in a sample of school-aged Mexican children. Overall, 125 children aged 6 to 12 years were analyzed. Anthropometric, biochemical, and dietary parameters were assessed. Receiving operating characteristic (ROC) analysis and univariate and multivariate linear and logistic regression analyses were performed. All the three adiposity indicators showed significant areas under the ROC curve (AURC) greater than 0.68 for high low-density lipoprotein cholesterol (LDL-c), triglycerides, and atherogenic index of plasma, and low high-density lipoprotein cholesterol (HDL-c). A significant increased risk of having LDL-c ≥ 3.4 mmol/L was observed among children with WHtR ≥ 0.5 as compared to those with WHtR < 0.5 (odds ratio, OR: 2.82; 95% confidence interval, CI: 0.75–7.68; p = 0.003). Fasting plasma glucose was not associated with any of the adiposity parameters. WHtR performed similarly to WC and z-BMI in predicting lipidic cardio-metabolic risk factors; however, a WHtR ≥ 0.5 was superior in detecting an increased risk of elevated LDL-c.

Association of dietary fiber intake with general and abdominal obesity in children and adolescents: The Weight disorder survey of the CASPIAN-IV Study

BACKGROUND: Dietary fiber intake might have a protective role against obesity. The aim of this study is to explore the association of dietary fiber intake with general and abdominal obesity in Iranian children and adolescents. MATERIAL AND METHODS: This cross-sectional nationwide study was conducted on 5187 students aged 6–18 years, living in 30 provinces of Iran. They were selected randomly through cluster sampling method. Data on demographic and anthropometric indices including weight, height and waist circumference (WC) were collected by trained interviewers. A valid and reliable 168-item semi-quantitative food frequency questionnaire (FFQ) was used to assess student’s usual dietary intake including total dietary fiber. All dietary reports were converted to daily consumption (g/day) using household measures for different portion sizes. Food items were then converted to their nutrient content. Energy-adjusted dietary fiber intake (g/1000 kcal/day) was also calculated using the energy density method. Multivariate regression models were applied to explore the association between dietary fiber intake and anthropometric indices. RESULTS: The mean and standard deviation (SD) for age of participants were 11.40 (3.20) years. Of 5187 students, 52.6% were boys and 72.5% were from urban areas (participation rate: 79.7%). White bread (32.5%), white rice (17.1%) and potato (11.7%) were the most common sources of dietary fiber intake. Each 1 g/1000 Kcal increase in dietary fiber intake was significantly associated with lower weight and waist circumference (P = 0.006 and P = 0.008, respectively). CONCLUSION: Higher fiber intake was associated with lower anthropometric indices including weight and WC. Increased fiber intake should be encouraged for children and adolescents.

Is single-child family associated with cardio-metabolic risk factors: the CASPIAN-V study

BACKGROUND

In the present study, the association of the cardio-metabolic risk factors and the status of single-child family were studied in a national representative sample of Iranian children and adolescents.

METHODS

This cross sectional study was conducted as the fifth round of "Childhood and Adolescence Surveillance and PreventIon of Adult Non- communicable disease" surveys. The students' questionnaire was derived from the World Health Organization-Global School Student Health Survey. Using survey data analysis methods, data from questionnaires'; anthropometric measures and biochemical information analyzed by logistic regression analysis.

RESULTS

Overall, 14,274 students completed the survey (participation rate: 99%); the participation rate for blood sampling from students was 91.5%. Although in univariate logistic regression model, single child students had an increased risk of abdominal obesity [OR: 1.37; 95% CI: 1.19-1.58)], high SBP [OR: 1.58; 95% CI:1.17-2.14)], high BP [OR: 1.21; 95% CI:1.01-1.45)] and generalized obesity [OR: 1.27; 95% CI:1.06-1.52)], in multiple logistic regression model, only association of single child family with abdominal obesity remained statistically significant [OR: 1.28; 95% CI:1.1-1.50)]. Also in multivariate logistic regression model, for each increase of a child in the family the risk of abdominal obesity [OR: 0.95; 95% CI: 0.91-0.97), high SBP [OR: 0.88; 95% CI: 0.81-0.95)] and generalized obesity [OR: 0.95; 95% CI: 0.91-0.99)] decreased significantly.

CONCLUSION

The findings of this study serve as confirmatory evidence on the association of cardio-metabolic risk factors with single-child family in children and adolescents. The findings of study could be used for better health planning and more complementary research.

Estimated Prevalence of Adolescents with Nonalcoholic Fatty Liver Disease in Korea

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) has become prevalent worldwide in the last decade. However, the recent prevalence of NAFLD in adolescents has not yet been investigated in Korea.

METHODS

Data were obtained from 1,416 participants aged 10-18 years from the Korea National Health and Nutrition Examination Survey conducted in 2010 and 2015. Systolic blood pressure (SBP), diastolic blood pressure (DBP), height, weight, waist circumference (WC), body mass index (BMI), fasting glucose, total cholesterol, high-density lipoprotein (HDL), aspartate aminotransferase (AST), alanine aminotransferase (ALT) level, waist-to-height ratio (WHtR), and pediatric NAFLD fibrosis index (PNFI) were analyzed.

RESULTS

SBP, weight, WC, BMI, WHtR, and total cholesterol level were significantly higher in 2015 than in 2010. Prevalence of NAFLD (BMI ≥ 85th percentile plus ALT > 30 U/L for boys and ALT > 19 U/L for girls) were 4.7% in 2010 and 5.9% in 2015 (P = 0.360). Using various cutoffs for the ALT level (> 40, > 30, > 25.8 U/L for boys and >22.1 U/L for girls) NAFLD prevalence rates were 3.0%, 4.1%, and 5.5% in 2010; 2.9%, 5.0%, and 7.1% in 2015, respectively (P = 0.899, 0.469, and 0.289). Boys had a higher SBP, DBP, height, weight, WC, BMI, WHtR, fasting glucose, total cholesterol, ALT, and lower HDL level than girls. The probability of liver fibrosis using the PNFI varies between 21.3% and 24.5% among NAFLD participants (P < 0.001).

CONCLUSION

The Korean society needs to quickly control the increasing prevalence of NAFLD in adolescents and reduce its complications.

Validation of surrogate markers for metabolic syndrome and cardiometabolic risk factor clustering in children and adolescents: A nationwide population-based study

Prevalence of metabolic syndrome (MetS) in children is increasing and identifying the risk factors for MetS during childhood is an important first step to prevent chronic diseases later in life. The aim of the present study was to evaluate the prevalence of MetS and cardiometabolic risk factor (CMRF) clustering among Korean children and adolescents and to validate the associated anthropometric and laboratory surrogate markers. We used data from the 2011–2014 Korean National Health and Nutrition Examination Survey. In total, data for 2,935 subjects (1539 boys, 52.6%) aged 10–19 years were assessed. MetS was defined by central obesity plus any two or more of CMRFs such as abdominal obesity, hypertension, hyperglycemia, hypertriglyceridemia, and decreased high density lipoprotein cholesterol (HDL-C) using the International Diabetes Federation criteria for children and adolescents. The presence of two or more CMRFs was classified as CMRF clustering. The prevalence of MetS and CMRF clustering in this group was found to be 1.8% and 8.9%, respectively. The receiver operating characteristic analysis of MetS and CMRF clustering, and the area under the curve (95% confidence interval) of surrogate markers revealed that the waist circumference to height ratio [0.960 (95% CI 0.959–0.960), cut-off 0.491] showed the highest predictability for MetS whereas triglyceride to HDL-C ratio [0.891 (95% CI 0.891–0.892), cut-off 2.63] showed the highest predictability for CMRF clustering. Long-term follow-up is needed for further validation.