Waist circumference for the screening of the metabolic syndrome in children

Optimal cutoff of the abdominal skinfold thickness (AST) to predict hypertension among Chinese children and adolescents

Previous studies have shown that the correlation between the abdominal skinfold thickness (AST) and hypertension is better than that observed using the body mass index (BMI) or waist-to-height ratio (WHtR). We aimed to explore the optimal cutoff of the AST to predict childhood hypertension. The AST percentiles were calculated based on 215,223 students from the Chinese National Survey on Students' Constitution and Health (CNSSCH) in 2010 using the LMS method. Logistic regression model and Receiver operating characteristic (ROC) curves were used to evaluate the optimal cutoff of the AST to predict hypertension based on a sample of 683 children aged 8-15 years. The prevalence of hypertension was 5.71% (5.45% in boys and 6.01% in girls). The area under the ROC curve [AUC (95% CI)] values of the BMI, WHtR and AST to predict hypertension were 0.62 (0.47-0.77), 0.61 (0.45-0.76), and 0.67 (0.54-0.80) in boys and 0.59 (0.46-0.71), 0.65 (0.50-0.80), and 0.70 (0.57-0.83) in girls, respectively. The AUC value at P₈₅ of AST in boys and that at P₉₀ of AST in girls to predict hypertension were higher than other percentile values of AST. The OR (95% CI) values of the optimal cutoff of the AST associated with hypertension were 2.90 (1.17-7.20) and 4.91 (1.81-13.31) in boys and girls, respectively, and were higher than those associated with overweight/obesity (based on BMI) and abdominal obesity (based on WHtR).The AST was more effectively associated with hypertension than the BMI and WHtR, and the optimal cutoff to predict hypertension was at P₈₅ for boys and P₉₀ for girls.

Biomarkers and Prevalence of Cardiometabolic Syndrome Among People Living With HIV/AIDS, Addis Ababa, Ethiopia: A Hospital-Based Study

BACKGROUND

While the fast extension of combination antiretroviral therapy (cART) has resulted in significant increases in life expectancy, disorders such as cardiometabolic syndrome (CMetS), which have received less attention, are becoming a major concern in HIV/AIDS patients (PLWHA).

OBJECTIVES

The purpose of this research was to identify biomarkers and determine the prevalence of CMetS in PLWHA using the National Cholesterol Education Program (NCEP) and the International Diabetes Federation (IDF) tools.

METHODS

Between January 2019 and February 2021, a hospital-based study of HIV-infected patients (n = 288) was conducted. The data were analyzed using binary logistic regression. To control the effect of confounders, independent variables with a P-value of <.20 in the bivariate logistic regression were incorporated into multivariate logistic regression. Statistical significance was defined as a 95% confidence interval and a P-value of less than .05.

RESULTS

The risk of CMetS increased twofold as age increased each year (P = .009), 1.2 times as the age at which cART began increased (P = .015), and 6 times with 1 or more co-morbidities (P = .028), according to the NCEP tool. Furthermore, significant NCEP-CMetS correlations were produced by a rise in diastolic blood pressure (P < .001) and cART duration (P = .006). Male gender was 99.9% less likely to be related to CMetS using the IDF tool, and the risk of CMetS increased fourfold with each unit increase in waist circumference (P < .001). Triglycerides and blood type "A" have been found to have substantial relationships with CMetS using both techniques.

CONCLUSION

According to the study, CMetS was found to be common in PLWHA. Age, time on cART, age when cART started, gender, co-morbidities, waist circumference, and diastolic blood pressure were all revealed to be significant predictors of CMetS. Triglycerides and blood type "A" were the only biomarkers found to be significant with CMetS using both the NCEP and IDF tools.

Diagnostic Performance and Appropriate Cut-Offs of Different Anthropometric Indicators for Detecting Children with Overweight and Obesity

In the clinical settings, different anthropometric indicators like neck circumference (NC), waist circumference (WC), midupper arm circumference (MUAC), waist-to-height ratio (WHtR), and arm-to-height ratio (AHtR) have been suggested for evaluating overweight and obesity in children. The comparative ability of these indicators in Pakistan is yet unknown. This study is aimed at examining the validity of different anthropometric indicators of overweight and obesity simultaneously and at determining their superlative cut-off values that would correctly detect overweight and obesity in children. For this purpose, the dataset of anthropometric measurements height, weight, WC, MUAC, and NC of 5,964 Pakistani children, aged 5-12 years collected in a cross-sectional multiethnic anthropometric survey (MEAS), was used. Receiver operating characteristic (ROC) curve analysis was performed to assess the validity of different anthropometric indicators. The most sensitive and specific cut-off points, positive and negative predictive values of each indicator were also calculated. The results of the ROC curve indicated that all the studied indicators had a good performance but the indicators AHtR and WHtR had the highest value of the area under the curve (AUC) for the screening of children with overweight and obesity (AUC > 0.80). In the overall sample, AHtR, WHtR, MUAC, WC, and NC cut-off points indicative of overweight, in both boys and girls, were 0.14, 0.46, 18.41 cm, 62.86 cm, and 26.36 cm and 0.14, 0.47, 18.16 cm, 64.39 cm, and 26.54 cm, respectively; the corresponding values for obesity were 0.14, 0.47, 18.67 cm, 62.10 cm, and 26.36 cm and 0.14, 0.48, 20.19 cm, 64.39 cm, and 25.27 cm. We concluded that the sex-specific cut-off points for AHtR, WHtR, MUAC, WC, and NC can be used to diagnose overweight and obesity in Pakistani children.

Determination of Child Waist Circumference Cut Points for Metabolic Risk Based on Acanthosis Nigricans, the Children's Healthy Living Program

INTRODUCTION

Waist circumference is a common anthropometric measure for predicting abdominal obesity and insulin resistance. We developed optimal waist circumference cut points for children aged 2 to 8 years in the US-Affiliated Pacific (USAP) region based on the relationship of waist circumference and acanthosis nigricans in this population.

METHODS

We conducted a cross-sectional analysis from the Children's Healthy Living Program's 2012-2013 data on 4,023 children. We used receiver-operating characteristic analysis to determine the sensitivity and specificity for acanthosis nigricans across waist circumference, by sex and age. We determined optimal waist circumference cutoff points corresponding to Youden index (J), (equal to [sensitivity + specificity] - 1), with acanthosis nigricans. We compared these cut points with the 90th percentile.

RESULTS

The 90th-percentile cut points for boys aged 2 to 5 years (58.15 cm) and 6 to 8 years (71.63 cm) were slightly higher than for girls in both age groups (aged 2-5 y, 57.97 cm; 6-8 y: 70.37 cm). The optimal cut points (corresponding to the highest sensitivity and specificity) were as follows: for boys aged 2 to 5 years, 90th percentile (58.25 cm; sensitivity, 48.0%; specificity, 91.5%); for boys aged 6 to 8 years, 78th percentile (63.59 cm; sensitivity, 86.8%; specificity, 82.8%); for girls aged 2 to 5 years, 62nd percentile (53.27 cm; sensitivity, 71.4%; specificity, 63.1%), and for girls aged 6 to 8 years, 80th percentile (63.63 cm; sensitivity, 55.4%; specificity, 82.9%).

CONCLUSION

Among USAP children, waist circumference was a reasonable predictor for acanthosis nigricans. Further analysis is warranted to examine causes of acanthosis nigricans at lower-than-expected waist circumference percentiles. The cut points can be used for early detection of metabolic risk.

Prevalence and risk factors for nonalcoholic fatty liver disease in obese children in rural Punjab, India

BACKGROUND

Pediatric nonalcoholic fatty liver disease (NAFLD) is associated with insulin resistance, hypertension, metabolic syndrome, cardiovascular problems, and increased risk of chronic liver disease and Type II diabetes mellitus. The aim of the study was to assess the metabolic profiles and associated risk factors of NAFLD in obese children.

MATERIALS AND METHODS

Children with a body mass index (BMI) of >27 kg/m² an adult equivalent cutoff (Indian Academy of Paediatrics, 2015 guidelines) aged 5-18 years presenting to the pediatric outpatient unit of PGIMER Satellite Centre, Sangrur, India, were retrospectively recruited over a 1-year period. Anthropometry, lipid profile, thyroid levels, liver function test, fasting blood sugar, and blood pressure were measured. Ultrasonography was used to diagnose NAFLD. Logistic regression was used to assess the risk factors.

RESULTS

A total of 100 children participated in the study. The mean age was 10.6 ± 2.6 years and the mean BMI-Z score was 2.6 ± 0.5. The prevalence of NAFLD was 62%. Alanine transaminase (ALT) was significantly elevated in all the children with NAFLD. Lipid levels and BMI Z-score were similar in both groups. Unadjusted odds ratio shows statistically significant association of ALT (2.058 [1.11-1.01]) and waist circumference (1.089 [1.19-0.99]) with NAFLD. With adjusted odds ratio only, ALT (1.12 [1.24-1.01]) was found to be significantly associated with NAFLD.

CONCLUSION

There is quite a high prevalence of nonalcoholic fatty liver in obese Indian children. All children with raised liver enzymes should undergo sonography to rule out NAFLD.

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.

Interaction of the CMTM7 rs347134 Polymorphism with Dietary Patterns and the Risk of Obesity in Han Chinese Male Children

A genome-wide association study (GWAS) in the Han Chinese population had found that single nucleotide polymorphism (SNP) on the CMTM7 gene rs347134 was significantly associated with Body Mass Index (BMI). In the present study, the association of the rs347134 SNP with obesity and its interaction with dietary patterns (DPs) were explored in Han Chinese children. This cross-sectional study group included 1292 children, in whom obesity-related indicators were evaluated, the rs347134 SNP was genotyped by improved Multiple Ligase Detection Reaction (iMLDR), and the DPs were identified by principal component factor analysis. The GG genotype exhibited higher odds of general overweight/obesity (P = 0.038) and central obesity (P = 0.039) than AA + GA genotypes in boys. Four DPs of boys were identified: healthy balanced (HBDP), nuts and sweets-based (NSDP), animal food-based (AFDP), and wheaten and dairy-based (WDDP). Boys with the GG genotype were significantly more inclined to AFDP (P = 0.028) and had a shorter sleep duration (P = 0.031). Significant interactions were observed; boys with the GG genotype displayed a higher LDL in AFDP (P = 0.031) and higher FBG in NSDP (P = 0.038), respectively. Our findings indicate for the first time that the GG genotype of CMTM7 rs347134 is potentially a novel obesity risk factor for Han Chinese male children and is associated with dietary patterns more or less.

Application of ELISA Technique and Human Microsomes in the Search for 11β-Hydroxysteroid Dehydrogenase Inhibitors

The metabolic syndrome is defined by impaired carbohydrate metabolism and lipid disorders and often accompanied by hypertension, all of which will lead to obesity and insulin resistance. Glucocorticoids play a regulatory role in the metabolism of proteins, lipids, and carbohydrates. There is growing evidence for a role of glucocorticoids in the development of the metabolic syndrome. The most important factor that regulates the access of endogenous glucocorticoids to receptors after release of glucocorticoids and their diffusion into the cytoplasm of target cells is the steroid metabolism involving a microsomal enzyme, 11β-hydroxysteroid dehydrogenase (11β-HSD). The changes in intracellular glucocorticoid metabolism in the pathogenesis of obesity indicate the participation of modulation by 11β-HSD1, which may represent a new therapeutic target for the treatment of diseases such as type 2 diabetes, visceral obesity, or atherosclerosis. The aim of our study was to determine the fast and effective method to assess inhibition activity of compounds in relation with 11β-hydroxysteroid dehydrogenase. The material for this study was human liver and kidney microsomes. In this study we used ELISA technique using 96-well microplates coated with antibodies which were specific for analyzed enzymes. The method can quickly and efficiently measure the inhibition of both 11β-HSD1 and 11β-HSD2. This method can be used to search for and determine inhibitors of this enzyme. Cortisone and cortisol were used as the substrates for corresponding enzyme assays. Furthermore, 3-N-allyl-2-thiouracil derivatives were used by us for comparison purposes in developing the method, although, due to their structure, those derivatives have not previously been considered as potential inhibitors of 11β-HSD1. 3-N-Allyl-2-thiouracil derivatives are a group worth considering, because by modifying their structure (e.g., by introducing other substituents into the pyrimidine ring) it will be possible to obtain an increase in the activity of compounds in this regard. In conclusion, this study shows an efficient and fast method of determining inhibition activity of compounds in relation with 11β-hydroxysteroid dehydrogenase.

Feasibility of anthropometric indices to identify dyslipidemia among adults in Jilin Province: a cross-sectional study

Background

Dyslipidemia and other cardiovascular disease (CVD) risk factors have a strong association with obesity. Anthropometric indices have been widely used to evaluate obesity in clinical and epidemiological studies. We aim to investigate association between serum lipid levels and different anthropometric indices.

Methods

Our study included 17,554 participants. We mainly investigated area under the receiver operating characteristic (AUROC) curves and optimal operating points (OOPs) between the anthropometric indices and serum lipid levels or categories of abnormal serum lipid indices.

Results

For predicting one/two categories of abnormal serum lipid indices among the anthropometric indices, AUROC value of WC was the highest in men (0.718), and AUROC values of BRI and WHtR were the highest in women (0.700 and 0.700) (all P < 0.001); OOP of WC was 82.450 in men; OOPs of BRI and WHtR were 3.435 and 0.504 in women. For predicting three/more categories of abnormal serum lipid indices among the anthropometric indices, AUROC value of WC was the highest in men (0.806), and AUROC values of BRI and WHtR were the highest in women (0.783 and 0.783) (all P < 0.001); OOP of WC was 84.150 in men; OOPs of BRI and WHtR were 3.926 and 0.529 in women.

Conclusions

WC was a good predictor for one/two or three/more categories of abnormal serum lipid indices in men. However, BRI and WHtR were good predictors for one/two or three/more categories of abnormal serum lipid indices in women. ABSI showed the weakest predictive power.

Electronic supplementary material

The online version of this article (10.1186/s12944-017-0648-6) contains supplementary material, which is available to authorized users.

Phenol Concentrations During Childhood and Subsequent Measures of Adiposity Among Young Girls

Phenolic compounds represent a class of environmental chemicals with potentially endocrine-disrupting capabilities. We investigated longitudinal associations between childhood exposure to phenols, from both manmade and natural sources, and subsequent measures of adiposity among girls enrolled in the Breast Cancer and the Environment Research Program between 2004 and 2007. Baseline (ages 6-8 years) urinary concentrations were obtained for creatinine and phenol metabolites: enterolactone, genistein, daidzein, benzophenone-3, bisphenol A, the sum of parabens (methyl, ethyl, and propyl parabens), 2,5-dichlorophenol, and triclosan. Body mass index (weight (kg)/height (m)2), waist circumference, and percent body fat were measured at annual or semiannual examinations through 2015 (n = 1,017). Linear mixed-effects regression was used to estimate how baseline concentrations of phenols (tertile groups) were related to changes in girls' adiposity measurements from ages 7 through 15 years. Enterolactone was inversely associated with body mass index, waist circumference, and percent body fat, while 2,5-dichlorophenol was positively associated with these measurements. A nonmonotonic association was observed for triclosan and girls' adiposity; however, it was due to effect modification by baseline overweight status. Triclosan was positively associated with adiposity only among overweight girls. These results suggest that exposure to specific phenols during childhood may influence adiposity through adolescence.

Cumulative Risk Exposure and Waist Circumference in Preschool-Aged Children: the Mediating Role of Television and Moderating Role of Sex

BACKGROUND

Children exposed to multiple stressors are more likely to be overweight, but little is known about the mechanisms explaining this association.

PURPOSE

This cross-sectional study examined whether children exposed to multiple stressors had higher waist circumference, and whether this association was mediated through children's television time.

METHODS

Participants were 319 parent-child dyads. Children were 2-5 years old and had at least one overweight parent (BMI ≥ 25 kg/m2). Data were collected at baseline of a larger childhood obesity prevention study and included information on psychosocial stressors (e.g., parenting stress), demographic stressors (e.g., low income), children's television time, and children's waist circumference. Two cumulative risk scores were created by summing stressors in each domain (demographic and psychosocial). Mediation and moderated mediation analyses were conducted.

RESULTS

Indirect effects of both cumulative risk scores on waist circumference through television time were not significant; however, moderated mediation analyses found significant moderation by gender. The indirect effects of both risk scores on waist circumference through television time were significant and positive for girls, but near-zero for boys.

CONCLUSIONS

Reducing television time should be explored as a strategy for buffering against the negative health effects of exposure to multiple stressors among girls. Longitudinal and intervention research is needed to confirm these results and to identify mediating factors between cumulative risk and body weight among boys.

Different consecutive training protocols to design an intervention program for overweight youth: a controlled study

OBJECTIVE

To find the optimal exercise program to be recommended in reducing adiposity and promoting long-term physical activity adherence in a sample of overweight adolescents.

METHODS

Forty-five overweight adolescents were randomly divided into three exercise groups, to perform two phases of physical activity as follows: in the first phase, the first group performed a 16-week moderate-intensity resistance training (RT), the second group performed a 16-week high-intensity RT, and the third group performed a 16-week aerobic training (AT); in the second phase, all groups performed a 6-week AT. Anthropometric body composition and fitness measures were considered as outcome measures.

RESULTS

After the second protocol, both RT groups showed a significant improvement in percentage of fat mass (F_2,76 = 5.843; p = 0.004; h² = 0.133) and free fat mass (F_2,76 = 6.254; p = 0.003; h² = 0.141), and in fitness tests (p < 0.01). The VO₂max values of the RT groups were significantly higher than those of the AT group (F_2,38 = 4.264; p = 0.021; h² = 0.183). The rate of adherence to exercise was an average of 94% in both RT groups, whereas in the AT group, it was 83%. During the 12-week post-intervention follow-up, the number of participants who continued to perform physical activities was significantly higher in both the RT groups than in the AT group (p < 0.05).

CONCLUSION

The present study provides preliminary evidence that moderate-to-intense RT, followed by AT, can be an effective treatment for overweight adolescents, and the positive effects are maintained even after 12 weeks of follow-up.

Longitudinal Associations of Phthalate Exposures During Childhood and Body Size Measurements in Young Girls

BACKGROUND

Phthalates are environmental chemicals that may play a role in the development of obesity. Few studies have investigated longitudinal associations between postnatal phthalate exposures and subsequent anthropometric measurements in children.

METHODS

We collected data as part of The Breast Cancer and Environment Research Program at three US sites. A total of 1,239 girls, aged 6-8 years, were enrolled in 2004-2007. We categorized baseline phthalate exposures, assessed from creatinine-corrected urinary concentrations of low-molecular weight phthalate metabolites, as low, <78; medium, 78 to <194; and high, ≥194 μg/g creatinine and of high-molecular weight phthalates as low, <111; medium, 111-278; and high, ≥278 μg/g creatinine. Anthropometric measurements were collected through 2012 (n = 1,017). Linear mixed effects regression estimated how baseline low and high-molecular weight phthalate concentrations related to changes in girls' body mass index (BMI), height, and waist circumference at ages 7-13 years.

RESULTS

Low-molecular weight phthalates were positively associated with gains in BMI and waist circumference. Predicted differences in BMI and waist circumference between girls with high versus low concentrations of low-molecular weight phthalates increased from 0.56 (95% confidence interval [CI]: -0.02, 1.1) to 1.2 kg/m (95% CI: 0.28, 2.1) and from 1.5 (95% CI: -0.38, 3.3) to 3.9 cm (95% CI: 1.3, 6.5), respectively. High-molecular weight phthalates were negatively associated with height but only among girls who were normal weight at baseline (BMI ≤ 85th percentile).

CONCLUSION

Phthalates, specifically low-molecular weight phthalates, have small but detectable associations with girls' anthropometric outcomes. Low-molecular weight phthalates showed stronger associations than other types of phthalates.

Gender and urban-rural difference in anthropometric indices predicting dyslipidemia in Chinese primary school children: a cross-sectional study

BACKGROUND

Childhood dyslipidemia is a critical factor of lifelong health. Therefore, screening and controlling dyslipidemia from childhood is a practical healthy strategy. However, few studies have examined the performance of anthropometric predictors of dyslipidemia in Chinese children, let alone the potential gender and urban-rural disparity. Thus, we evaluated anthropometric indices predicting dyslipidemia by genders and living areas in Chinese children.

METHODS

Data were from a health and nutrition survey conducted in seven urban areas and two rural areas in China between 2011 and 2012. The serum lipid levels of the participants were compared between genders and living areas. The body mass index z-score (BMI z-score), waist-hip ratio (WHR), waist-height ratio (WHtR), and mid-upper arm height ratio (MaHtR) were used as predictors. The receiver operating characteristic (ROC) analysis was performed to investigate the ability of anthropometric indices predicting dyslipidemia.

RESULTS

A total of 773 participants (average age = 9.3 ± 1.7 y) were included. The prevalence of dyslipidemia was 10.9%. Anthropometric indices were all significantly related to blood lipid profiles in boys after adjustment for age. The areas under the ROC curves (ACUs) were significantly larger than 0.5 in boys (ranged between 0.66-0.73), and were larger in rural boys (ranged between 0.68 and 0.94). MaHtR and WHR were associated with the highest specificity (93.8%) and highest sensitivity (100%), respectively.

CONCLUSION

Using anthropometric indices, screening for dyslipidemia may be more appropriate in boys than in girls in China, especially in rural boys. The BMI z-score, WHR, WHtR, and MaHtR were all significantly associated with dyslipidemia in boys; using WHR and MaHtR as indicators achieved the highest sensitivity and specificity, respectively.

Waist Circumferences of Chilean Students: Comparison of the CDC-2012 Standard and Proposed Percentile Curves

The measurement of waist circumference (WC) is considered to be an important means to control overweight and obesity in children and adolescents. The objectives of the study were to (a) compare the WC measurements of Chilean students with the international CDC-2012 standard and other international standards, and (b) propose a specific measurement value for the WC of Chilean students based on age and sex. A total of 3892 students (6 to 18 years old) were assessed. Weight, height, body mass index (BMI), and WC were measured. WC was compared with the CDC-2012 international standard. Percentiles were constructed based on the LMS method. Chilean males had a greater WC during infancy. Subsequently, in late adolescence, males showed values lower than those of the international standards. Chilean females demonstrated values similar to the standards until the age of 12. Subsequently, females showed lower values. The 85th and 95th percentiles were adopted as cutoff points for evaluating overweight and obesity based on age and sex. The WC of Chilean students differs from the CDC-2012 curves. The regional norms proposed are a means to identify children and adolescents with a high risk of suffering from overweight and obesity disorders.

Percentile reference values for anthropometric body composition indices in European children from the IDEFICS study

INTRODUCTION

To characterise the nutritional status in children with obesity or wasting conditions, European anthropometric reference values for body composition measures beyond the body mass index (BMI) are needed. Differentiated assessment of body composition in children has long been hampered by the lack of appropriate references.

OBJECTIVES

The aim of our study is to provide percentiles for body composition indices in normal weight European children, based on the IDEFICS cohort (Identification and prevention of Dietary- and lifestyle-induced health Effects in Children and infantS).

METHODS

Overall 18,745 2.0-10.9-year-old children from eight countries participated in the study. Children classified as overweight/obese or underweight according to IOTF (N=5915) were excluded from the analysis. Anthropometric measurements (BMI (N=12 830); triceps, subscapular, fat mass and fat mass index (N=11,845-11,901); biceps, suprailiac skinfolds, sum of skinfolds calculated from skinfold thicknesses (N=8129-8205), neck circumference (N=12,241); waist circumference and waist-to-height ratio (N=12,381)) were analysed stratified by sex and smoothed 1st, 3rd, 10th, 25th, 50th, 75th, 90th, 97th and 99th percentile curves were calculated using GAMLSS.

RESULTS

Percentile values of the most important anthropometric measures related to the degree of adiposity are depicted for European girls and boys. Age- and sex-specific differences were investigated for all measures. As an example, the 50th and 99th percentile values of waist circumference ranged from 50.7-59.2 cm and from 51.3-58.7 cm in 4.5- to <5.0-year-old girls and boys, respectively, to 60.6-74.5 cm in girls and to 59.9-76.7 cm in boys at the age of 10.5-10.9 years.

CONCLUSION

The presented percentile curves may aid a differentiated assessment of total and abdominal adiposity in European children.

Selected anthropometric variables and aerobic fitness as predictors of cardiovascular disease risk in children

The aim of this study was to assess the suitability of body mass index, waist circumference, waist-to-height ratio and aerobic fitness as predictors of cardiovascular risk factor clustering in children. A cross-sectional study was conducted with 290 school boys and girls from 6 to 10 years old, randomly selected. Blood was collected after a 12-hour fasting period. Blood pressure, waist circumference (WC), height and weight were evaluated according to international standards. Aerobic fitness (AF) was assessed by the 20-metre shuttle-run test. Clustering was considered when three of these factors were present: high systolic or diastolic blood pressure, high low-density lipoprotein (LDL) cholesterol, high triglycerides, high plasma glucose, high insulin concentrations and low high-density lipoprotein (HDL) cholesterol. A ROC curve identified the cut-off points of body mass index (BMI), WC, waist-to-height ratio (WHtR) and AF as predictors of risk factor clustering. BMI, WC and WHR resulted in significant areas under the ROC curves, which was not observed for AF. The anthropometric variables were good predictors of cardiovascular risk factor clustering in both sexes, whereas aerobic fitness should not be used to identify cardiovascular risk factor clustering in these children.

Are field measures of adiposity sufficient to establish fatness-related linkages with metabolic outcomes in adolescents?

OBJECTIVE

To examine the associations between the adiposity-related information conveyed by field fatness measures: body mass index (BMI), waist circumference (WC) and sum of triceps and subscapular skinfolds (SUM SF) relative to dual-energy X-ray absorptiometry (DXA), beyond their common intercorrelations, with three important metabolic variables in US adolescents.

METHODS

We analyzed data on adiposity and insulin resistance (HOMA-IR), serum triglycerides (TGs) and total cholesterol (TC) from three US national surveys. In two-stage least-square modeling, we first calculated the common adiposity variance, and then used multivariate linear and quantile regressions to access residual associations with each measure.

RESULTS

Basic associations for each of the adiposity measures were similar but differences emerged in residual adiposity analyses scaled by s.d. units. While a 1 s.d. change in residual variance in DXA total fat beyond that accounted for by BMI (DXA|BMI) was strongly and significantly associated with all outcomes, associations with DXA accounting for SUM SF (DXA|SUM SF) and WC (DXA|WC) were weak or nonsignificant. Contrasted amongst themselves, the residual score association between BMI|SUM SF (β=0.06, P<0.0001) and HOMA-IR was weaker, and half as strong as that for the converse, SUM SF|BMI (β=0.13, P=0.020). SUM SF|WC was stronger than WC|SUM SF (β=0.08, P<0.0001 vs SUM SF|WC β=0.13, P<0.0001). Associations were similar for TGs and TC.

CONCLUSIONS

Laboratory methods like DXA offer minimal explanatory advantage over field methods in assessing adiposity-related contributions to metabolic outcomes in adolescents. Among the simple fatness measures, skinfolds convey additional information beyond BMI and WC when estimating associations both at the population mean and at the upper extremes of metabolic factors.

The effect of low glycemic index diet on body weight status and blood pressure in overweight adolescent girls: a randomized clinical trial

Although several studies have assessed the influence of the glycemic index on body weight and blood pressure among adults, limited evidence exists for the pediatric age population. In the current study, we compared the effects of low glycemic index (LGI) diet to the healthy nutritional recommendation (HNR)-based diet on obesity and blood pressure among adolescent girls in pubertal ages. This 10-week parallel randomized clinical trial comprised of 50 overweight or obese and sexually mature girls less than 18 years of age years, who were randomly assigned to LGI or HNR-based diet. Macronutrient distribution was equivalently prescribed in both groups. Blood pressure, weight and waist circumference were measured at baseline and after intervention. Of the 50 participants, 41 subjects (include 82%) completed the study. The GI of the diet in the LGI group was 42.67 ± 0.067. A within-group analysis illustrated that in comparison to the baseline values, the body weight and body mass index (not waist circumference and blood pressure) decreased significantly after the intervention in both groups (P = 0.0001). The percent changes of the body weight status, waist circumference and blood pressure were compared between the two groups and the findings did not show any difference between the LGI diet consumers and those in the HNR group. In comparison to the HNR, LGI diet could not change the weight and blood pressure following a 10-week intervention. Further longitudinal studies with a long-term follow up should be conducted in this regard.

Adiposity among children in Norway by urbanity and maternal education: a nationally representative study

BACKGROUND

International research has demonstrated that rural residency is a risk factor for childhood adiposity. The main aim of this study was to investigate the urban-rural gradient in overweight and obesity and whether the association differed by maternal education.

METHODS

Height, weight and waist circumference (WC) were measured in a nationally representative sample of 3166 Norwegian eight-year-olds in 2010. Anthropometric measures were stratified by area of residence (urbanity) and maternal education. Risk estimates for overweight (including obesity) and waist-to-height ratio ≥0.5 were calculated by log-binomial regression.

RESULTS

Mean BMI and WC and risk estimates of overweight (including obesity) and waist-to-height ratio ≥0.5 were associated with both urbanity and maternal education. These associations were robust after mutual adjustment for each other. Furthermore, there was an indication of interaction between urbanity and maternal education, as trends of mean BMI and WC increased from urban to rural residence among children of low-educated mothers (p = 0.01 for both BMI and WC), whereas corresponding trends for children from higher educational background were non-significant (p > 0.30). However, formal tests of the interaction term urbanity by maternal education were non-significant (p-value for interaction was 0.29 for BMI and 0.31 for WC).

CONCLUSIONS

In this nationally representative study, children living rurally and children of low-educated mothers had higher mean BMI and waist circumference than children living in more urban areas and children of higher educated mothers.

Alterations in the antioxidant defense system in prepubertal children with a history of extrauterine growth restriction

PURPOSE

The role of oxidative stress is well known in the pathogenesis of acquired malnutrition. Intrauterine growth restriction has been associated with an imbalance in oxidative stress/antioxidant system. Therefore, early postnatal environment and, consequently, extrauterine growth restriction might be associated with alterations in the antioxidant defense system, even in the prepubertal stage.

METHODS

This is a descriptive, analytical, and observational case-control study. The study included two groups; 38 Caucasian prepubertal children born prematurely and with a history of extrauterine growth restriction as the case group, and 123 gender- and age-matched controls. Plasma exogenous antioxidant (retinol, β-carotene, and α-tocopherol) concentrations were measured by HPLC; antioxidant enzyme activities of catalase, glutathione reductase, glutathione peroxidase, and superoxide dismutase were determined in lysed erythrocytes by spectrophotometric techniques.

RESULTS

Catalase and glutathione peroxidase concentrations were significantly lower in extrauterine growth restriction children than in controls (P < 0.001). Lower plasma retinol concentrations were found in the case group (P = 0.029), while concentrations of β-carotene and α-tocopherol were higher (P < 0.001) in extrauterine growth restriction prepubertal children as compared with controls. After correction by gestational age, birth weight, and length, statistically significant differences were also found, except for retinol.

CONCLUSIONS

Prepubertal children with a history of extrauterine growth restriction present alterations in their antioxidant defense system. Knowing these alterations may be important in establishing pharmacological and nutritional treatments as this situation might be associated with higher metabolic disorders in adulthood.

Parental education associations with children's body composition: mediation effects of energy balance-related behaviors within the ENERGY-project

Background

It is well known that the prevalence of overweight and obesity is considerably higher among youth from lower socio-economic families, but there is little information about the role of some energy balance-related behaviors in the association between socio-economic status and childhood overweight and obesity. The objective of this paper was to assess the possible mediation role of energy balance-related behaviors in the association between parental education and children’s body composition.

Methods

Data were obtained from the cross sectional study of the “EuropeaN Energy balance Research to prevent excessive weight Gain among Youth” (ENERGY) project. 2121 boys and 2516 girls aged 10 to 12 from Belgium, Greece, Hungary, the Netherlands, Norway, Slovenia and Spain were included in the analyses. Data were obtained via questionnaires assessing obesity related dietary, physical activity and sedentary behaviors and basic anthropometric objectively measured indicators (weight, height, waist circumference). The possible mediating effect of sugared drinks intake, breakfast consumption, active transportation to school, sports participation, TV viewing, computer use and sleep duration in the association between parental education and children’s body composition was explored via MacKinnon’s product-of-coefficients test in single and multiple mediation models. Two different body composition indicators were included in the models, namely Body Mass Index and waist circumference.

Results

The association between parental education and children’s body composition was partially mediated by breakfast consumption, sports participation, TV viewing and computer use. Additionally, a suppression effect was found for sugared drinks intake. No mediation effect was found for active transportation and sleep duration. The significant mediators explained a higher proportion of the association between parental education and waist circumference compared to the association between parental education and BMI.

Conclusions

Tailored overweight and obesity prevention strategies in low SES preadolescent populations should incorporate specific messages focusing on the importance of encouraging daily breakfast consumption, increasing sports participation and decreasing TV viewing and computer use. However, longitudinal research to support these findings is needed.

Is waist-to-height ratio a useful indicator of cardio-metabolic risk in 6-10-year-old children?

BACKGROUND

Childhood obesity is a public health problem worldwide. Visceral obesity, particularly associated with cardio-metabolic risk, has been assessed by body mass index (BMI) and waist circumference, but both methods use sex-and age-specific percentile tables and are influenced by sexual maturity. Waist-to-height ratio (WHtR) is easier to obtain, does not involve tables and can be used to diagnose visceral obesity, even in normal-weight individuals. This study aims to compare the WHtR to the 2007 World Health Organization (WHO) reference for BMI in screening for the presence of cardio-metabolic and inflammatory risk factors in 6-10-year-old children.

METHODS

A cross-sectional study was undertaken with 175 subjects selected from the Reference Center for the Treatment of Children and Adolescents in Campos, Rio de Janeiro, Brazil. The subjects were classified according to the 2007 WHO standard as normal-weight (BMI z score>-1 and<1) or overweight/obese (BMI z score≥1). Systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting glycemia, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), Homeostatic Model Assessment--Insulin Resistance (HOMA-IR), leukocyte count and ultrasensitive C-reactive protein (CRP) were also analyzed.

RESULTS

There were significant correlations between WHtR and BMI z score (r=0.88, p<0.0001), SBP (r=0.51, p<0.0001), DBP (r=0.49, p<0.0001), LDL (r=0.25, p<0.0008, HDL (r=-0.28, p<0.0002), TG (r=0.26, p<0.0006), HOMA-IR (r=0.83, p<0.0001) and CRP (r=0.51, p<0.0001). WHtR and BMI areas under the curve were similar for all the cardio-metabolic parameters. A WHtR cut-off value of >0.47 was sensitive for screening insulin resistance and any one of the cardio-metabolic parameters.

CONCLUSIONS

The WHtR was as sensitive as the 2007 WHO BMI in screening for metabolic risk factors in 6-10-year-old children. The public health message "keep your waist to less than half your height" can be effective in reducing cardio-metabolic risk because most of these risk factors are already present at a cut point of WHtR≥0.5. However, as this is the first study to correlate the WHtR with inflammatory markers, we recommend further exploration of the use of WHtR in this age group and other population-based samples.

Association of pediatric psoriasis severity with excess and central adiposity: an international cross-sectional study

OBJECTIVE

To investigate the relationship of excess and central adiposity with pediatric psoriasis severity.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, cross-sectional study of 409 psoriatic children. Psoriasis was classified as mild (worst Physician's Global Assessment score ≤3 with body surface area ≤10%) or severe (worst Physician's Global Assessment score ≥3 with body surface area >10%). Children were enrolled from 9 countries between June 19, 2009, and December 2, 2011.

MAIN OUTCOME MEASURES

Excess adiposity (body mass index percentile) and central adiposity (waist circumference percentile and waist to height ratio).

RESULTS

Excess adiposity (body mass index ≥85th percentile) occurred in 37.9% of psoriatic children (n=155) vs 20.5% of controls (n=42) but did not differ significantly by severity. The odds ratio (95% CI) of obesity (body mass index ≥95th percentile) overall in psoriatic children vs controls was 4.29 (1.96-9.39) and was higher with severe (4.92; 2.20-10.99) than with mild (3.60; 1.56-8.30) psoriasis, particularly in the United States (7.60; 2.47-23.34, and 4.72; 1.43-15.56, respectively). Waist circumference above the 90th percentile occurred in 9.3% of the control (n=19), 14.0% of the mild psoriasis (n=27), and 21.2% of the of severe psoriasis (n=43) participants internationally; this incidence was highest in the United States (12.0% [n=13], 20.8% [16], and 31.1% [32], respectively). Waist to height ratio was significantly higher in psoriatic (0.48) vs control (0.46) children but was unaffected by psoriasis severity. Children with severe psoriasis at its worst, but mild at enrollment, showed no significant difference in excess or central adiposity from children whose psoriasis remained severe.

CONCLUSIONS

Globally, children with psoriasis have excess adiposity and increased central adiposity regardless of psoriasis severity. The increased metabolic risks associated with excess and central adiposity warrant early monitoring and lifestyle modification.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00879944

Gender specific effect of major dietary patterns on the metabolic syndrome risk in Korean pre-pubertal children

There is a lack of data on metabolic risk factors during pre-puberty, which is important for identifying the subgroups of youth, at whom early interventions should be targeted. In this study, we evaluated the prevalence of metabolic risk factors and its subsequent relations with dietary patterns in Korean pre-pubertal children through a cross-sectional sample (n = 1,008; boys = 513) of pre-pubertal children (aged 8-9 years) from a sub-study of the Korea Metabolic Syndrome Research Initiatives (KMSRI) in Seoul, Korea. Measures of anthropometry and blood pressure as well as fasting blood samples were used in the analysis. A three-day food records were collected. The metabolic syndrome was defined according to the age-adjusted National Cholesterol Education Program Adult Treatment Panel III guidelines. An added metabolic risk score was calculated for each subject by summing the quintile values of the five individual risk factors. Among the 5 risk components of metabolic syndrome, high waist circumference (WC) was the major factor (P < 0.001). A significant increasing trend of the added metabolic syndrome risk score was observed with the increase of WC (P (trend) < 0.001) among both genders. The cutoff point for high WC for pre-pubertal children was 61.3 cm for boys and 59.9 cm for girls. The prevalence of high triglyceride (TG) values was significantly higher in girls than it was in boys (P < 0.01). Girls in the highest quintile of balanced dietary pattern scores had lower TG values (P (trend) = 0.032) than did those in the lowest quintile. Moreover, girls in the highest quintile of western dietary pattern scores showed increasing trend for the added metabolic risk score (P (trend) = 0.026) compared with those in the lowest quintile. Adverse associations exist between western dietary patterns and the accumulation of metabolic risks among girls, not in boys, even during pre-puberty.

Predictors of metabolic syndrome in the Iranian population: waist circumference, body mass index, or waist to hip ratio?

This study aimed to investigate whether body mass index (BMI), waist circumference (WC), or waist to hip ratio (WHR) could be a better predictor of metabolic syndrome and, if so, what would be the cutoff points for these surrogates to appropriately differentiate metabolic syndrome in different age and sex subgroups. Methods. The present cross-sectional study was conducted on a sample of Isfahan Cohort Study (ICS). In total, 468 individuals (194 with and 274 subjects without metabolic syndrome) according to the National Cholesterol Education Program's Adult Treatment Panel III (ATP-III) criteria were selected. Anthropometric indices were measured and plotted using receiver-operating characteristic (ROC) curves. Results. According to ROC curve analysis, WC and WHR parameters were better indicators of metabolic syndrome compared to BMI in women, whereas in men WHR had a lower discriminating value compared to the other two parameters. Among these three anthropometric parameters, BMI had a lower sensitivity and WC and WHR both had a higher sensitivity for predicting metabolic syndrome in women compared with in men. The cut points for WC were nearly equal in men and women, 90.3 versus 90.0, respectively. Women had higher cut points for BMI (28.5 kg/m(2)) compared to men (26.0 kg/m(2)). Our results showed the highest sensitivity and specificity for WC cut points specially in women. To predict metabolic syndrome, we looked into optimal age-specific cut points for BMI, WC, and WHR. The results indicated that WC had the highest discriminating value compared to other indicators in the different age subgroups. The optimal cut points for all three parameters gradually increased with age. Conclusion. Our results demonstrated that regardless of gender and age variables, WC could be a preferred parameter for predicting metabolic syndrome compared to BMI and WHR in Iranian population.

Waist circumference percentiles among Turkish children under the age of 6 years

Waist circumference, a proxy measure of abdominal obesity, is associated with cardio-metabolic risk factors in childhood and adolescence. Although there are numerous studies about waist circumference percentiles in children, only a few studies cover preschool children. The aim of this study was to develop age- and gender-specific waist circumference smoothed reference curves in Turkish preschool children to determine abdominal obesity prevalence and to compare them with reference curves obtained from different countries. The design of the study was cross-sectional. A total of 2,947 children (1,471 boys and 1,476 girls) aged 0-6 years were included in the study. The subjects were divided according to their gender. Waist circumference was measured by using a standardized procedure. The age- and gender-specific waist circumference reference curves were constructed and smoothed with LMS method. The reference values of waist circumference, including 3rd, 10th 25th, 50th, 75th, 90th, and 97th percentiles, and standard deviations were given for preschool children. Waist circumference values increased with age, and there were differences between genders. The prevalence of abdominal obesity was calculated as 10.1 % for boys and 10.7 % for girls. Having compared our data with two other countries' data, we found that our waist circumference data were significantly lower. This is the first cross-sectional study for age- and gender-specific references of 0- to 6-year-old Turkish children. The gender- and age-specific waist circumference percentiles can be used to determine the risk of central obesity.

Adiposity indices in the prediction of insulin resistance in prepubertal Colombian children

OBJECTIVE

To compare BMI with abdominal skinfold thickness (ASF), waist circumference and waist-to-height ratio in the prediction of insulin resistance (IR) in prepubertal Colombian children.

DESIGN

We calculated age- and sex-specific Z-scores for BMI, ASF, waist circumference, waist-to-height ratio and three other skinfold-thickness sites. Logistic regression with stepwise selection (P = 0·80 for entry and P = 0·05 for retention) was performed to identify predictors of IR and extreme IR, which were determined by age- and sex-specific Z-scores to identify the ≥ 90th and ≥ 95th percentile of homeostasis model assessment (HOMAIR), respectively. We used receiver operating characteristic curves to compare the area under the curve between models.

SETTING

Bucaramanga, Colombia.

SUBJECTS

Children (n 1261) aged 6-10 years in Tanner stage 1 from a population-based study.

RESULTS

A total of 127 children (seventy girls and fifty-seven boys) were classified with IR, including sixty-three children (thirty-three girls and thirty boys) classified with extreme IR. Only ASF and BMI Z-scores were retained as predictors of IR by stepwise selection. Adding ASF Z-score to BMI Z-score improved the area under the curve from 0·794 (95 % CI 0·752, 0·837) to 0·811 (95 % CI 0·770, 0·851; P for contrast = 0·01). In predicting extreme IR, the addition of ASF Z-score to BMI Z-score improved the area under the curve from 0·837 (95 % CI 0·790, 0·884) to 0·864 (95 % CI 0·823, 0·905; P for contrast = 0·01).

CONCLUSIONS

ASF Z-score predicted IR independent of BMI Z-score in our population of prepubertal children. ASF and BMI Z-scores together improved IR risk stratification compared with BMI Z-score alone, opening new perspectives in the prediction of cardiometabolic risk in prepubertal children.

Waist circumference percentiles for Portuguese children and adolescents aged 10 to 18 years

The purposes of this study were to develop age- and sex-specific waist circumference reference data for Portuguese children and adolescents aged 10-18 years and to compare them with those from other countries. This was a school-based study performed in Portugal. A total of 22,003 children and adolescents aged 10-18 years were included in the study. Smoothed sex- and age-specific 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentile curves of waist circumference were estimated using Cole's lambda-mu-sigma method. Waist circumference values increased with age in both boys and girls, and boys had higher values than girls at every age and percentile. In both sexes, the Portuguese values in the 90th percentile were closer to the Bolivian values and considerably lower than those of the American children for all age groups.

CONCLUSION

The data presented provide information for abdominal risk assessment and clinical and lifestyle intervention; our results also provide useful baseline data information for the implementation of a surveillance system required to monitor trends and factors associated with abdominal obesity in children and adolescents.

Waist circumference, waist-hip ratio and waist-height ratio percentiles and central obesity among Pakistani children aged five to twelve years

Background

Central obesity has been associated with the risk of cardiovascular and metabolic disease in children and anthropometric indices predictive of central obesity include waist circumference (WC), waist-hip ratio (WHR) and waist-height ratio (WHtR). South Asian children have higher body fat distribution in the trunk region but the literature regarding WC and related indices is scarce in this region. The study was aimed to provide age- and gender-specific WC, WHR and WHtR smoothed percentiles, and to explore prevalence and correlates of central obesity, among Pakistani children aged five to twelve years.

Methods

A population-based cross-sectional study was conducted with a representative multistage random cluster sample of 1860 primary school children aged five to twelve years in Lahore, Pakistan. Smoothed percentile curves were constructed for WC, WHR and WHtR by the LMS method. Central obesity was defined as having both age- and gender-specific WC percentile ≥90^th and WHtR ≥0.5. Chi-square test was used as the test of trend. Multivariate logistic regression was used to quantify the independent predictors of central obesity and adjusted odds ratios (aOR) with 95% CI were obtained. Linear regression was used to explore the independent determinants of WC and WHtR. Statistical significance was considered at P < 0.05.

Results

First ever age- and gender-specific smoothed WC, WHR and WHtR reference curves for Pakistani children aged five to twelve years are presented. WC increased with age among both boys and girls. Fiftieth WC percentile curves for Pakistani children were higher as compared to those for Hong Kong and British children, and were lower as compared to those for Iranian, German and Swiss children. WHR showed a plateau pattern among boys while plateau among girls until nine years of age and decreased afterwards. WHtR was age-independent among both boys and girls, and WHtR cut-off of ≥0.5 for defining central obesity corresponded to 85^th WHtR percentile irrespective of age and gender. Twelve percent children (95% CI 10.1-13.0) had a WC ≥90^th percentile and 16.5% children (95% CI 14.7-18.1) had a WHtR ≥0.5 while 11% children (95% CI 8.9-11.6) had both WC ≥90^th percentile and WHtR ≥0.5. Significant predictors of central obesity included higher grade, urban area with high socioeconomic status (SES), high-income neighborhood and higher parental education. Children studying in higher grade (aOR 5.11, 95% CI 1.76-14.85) and those living in urban area with high SES (aOR 82.34, 95% CI 15.76-430.31) showed a significant independent association. Urban area with high SES and higher parental education showed a significant independent association with higher WC and higher WHtR while higher grade showed a significant independent association with higher WC.

Conclusions

Comprehensive worldwide reference values are needed to define central obesity and the present study is the first one to report anthropometric indices predictive of central obesity for Pakistani school-aged children. Eleven percent children were centrally obese and strong predictors included higher grade, urban area with high SES and higher parental education. These findings support the need for developing a National strategy for childhood obesity and implementing targeted interventions, prioritizing the higher social class and involving communities.

Waist circumference and risk of elevated blood pressure in children: a cross-sectional study

Background

Increasing childhood obesity has become a major health threat. This cross-sectional study reports associations between schoolchildren's waist circumference (WC) and risk of elevated blood pressure.

Methods

We measured height, weight, neck and waist circumference, and blood pressure in regular health examinations among children in grade 1 (ages 6-7 years) at six elementary schools in Taipei County, Taiwan. Elevated blood pressure was defined in children found to have mean systolic or diastolic blood pressure greater than or equal to the gender-, age-, and height-percentile-specific 95th-percentile blood pressure value.

Results

All 2,334 schoolchildren were examined (response rate was 100% in the six schools). The mean of systolic and diastolic blood pressure increased as WC quartiles increased (p < 0.0001). The prevalence of elevated blood pressure for boys and girls within the fourth quartile of waist circumference was 38.9% and 26.8%, respectively. In the multivariate logistic regression analyses, the adjusted odds ratios of elevated blood pressure were 1.78 (95% confidence interval [CI] = 1.13-2.80), 2.45 (95% CI = 1.56-3.85), and 6.03 (95% CI = 3.59-10.1) for children in the second, third, and fourth waist circumference quartiles compared with the first quartile. The odds ratios for per-unit increase and per increase of standard deviation associated with elevated blood pressure were 1.14 (95% CI = 1.10-1.18) and 2.22 (95% CI = 1.76-2.78), respectively.

Conclusions

Elevated blood pressure in children was associated with waist circumference. Not only is waist circumference easier to measure than blood pressure, but it also provides important information on metabolic risk. Further research is needed on effective interventions to identify and monitor children with increased waist circumference to reduce metabolic and blood pressure risks.

Metabolic syndrome: definitions and controversies

Metabolic syndrome (MetS) is a complex disorder defined by a cluster of interconnected factors that increase the risk of cardiovascular atherosclerotic diseases and diabetes mellitus type 2. Currently, several different definitions of MetS exist, causing substantial confusion as to whether they identify the same individuals or represent a surrogate of risk factors. Recently, a number of other factors besides those traditionally used to define MetS that are also linked to the syndrome have been identified. In this review, we critically consider existing definitions and evolving information, and conclude that there is still a need to develop uniform criteria to define MetS, so as to enable comparisons between different studies and to better identify patients at risk. As the application of the MetS model has not been fully validated in children and adolescents as yet, and because of its alarmingly increasing prevalence in this population, we suggest that diagnosis, prevention and treatment in this age group should better focus on established risk factors rather than the diagnosis of MetS.

Anthropometric risk factors for elevated blood pressure in adolescents in Turkey aged 11-17

To investigate the relationship between anthropometric parameters and elevated blood pressure in adolescents, we measured blood pressure (BP), height, weight, triceps skinfold (TSF) thickness, waist circumference (WC), and mid-upper-arm circumference (MUAC) in 2,860 student volunteers aged 11-17 years in Kayseri, Turkey. Waist-to-height ratio (WHtR), waist-to-arm-span ratio (WASR), body mass index (BMI), arm-fat area (AFA), and fat percentage (FP) were also calculated. Participants were divided into two groups: hypertensive [systolic blood pressure (SBP) or diastolic blood pressure (DBP) ≥  95th percentiles, n = 246] and normotensives (SBP or DBP < 95th percentiles, n = 2614). Multiple logistic regression models were produced within these groups for the examined risk factors, and cutoff points were investigated for SBP or DBP ≥ 95th percentiles using receiver operating characteristics (ROC) analysis. BMI, WC, WHtR, WASR, MUAC, and BMI had statistically significant cutoffs among boys. Whereas BMI, WHtR, WASR, WC, MUAC, AFA, and TSF were statistically significant for girls younger than 15, only BMI and WC were statistically significant for participants older than 15. The independent risk factors for elevated BP were determined according to BMI and WC. Although several anthropometric measurements were significant in our participants, BMI and WC were significant among all participants irrespective of age and sex.

Receiver-operating characteristics of adiposity for metabolic syndrome: the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study

OBJECTIVE

To assess the predictive values of various adiposity indices for metabolic syndrome (MetS) among adults using baseline data from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) cohort.

DESIGN

In a cross-sectional study, BMI, waist circumference (WC), body composition by dual-energy X-ray absorptiometry (DEXA) and metabolic risk factors such as TAG, HDL cholesterol, blood pressure, fasting glucose and insulin, uric acid and C-reactive protein were measured. Receiver-operating characteristic (ROC) curves and logistic regression analyses were conducted.

SETTING

Baltimore, Maryland.

SUBJECTS

White and African-American US adults (n 1981), aged 30-64 years.

RESULTS

In predicting risk of MetS using obesity-independent National Cholesterol Education Program Adult Treatment Panel III criteria, percentage total body fat mass (TtFM) assessed using DEXA measuring overall adiposity had no added value over WC. This was true among both men (area under the ROC curve (AUC) = 0.680 v. 0.733 for TtFM and WC, respectively; P < 0.05) and women (AUC = 0.581 v. 0.686). Percentage rib fat mass (RbFM) was superior to TtFM only in women for MetS (AUC = 0.701 and 0.581 for RbFM and TtFM, respectively; P < 0.05), particularly among African-American women. Elevated percentage leg fat mass (LgFM) was protective against MetS among African-American men. Among white men, BMI was inferior to WC in predicting MetS. Optimal WC cut-off points varied across ethnic-sex groups and differed from those recommended by the National Institutes of Health/North American Association for the Study of Obesity.

CONCLUSIONS

The study provides evidence that WC is among the most powerful tools to predict MetS, and that optimal cut-off points for various indices including WC may differ by sex and race.

Relationship of body mass index to percent body fat and waist circumference among schoolchildren in Japan--the influence of gender and obesity: a population-based cross-sectional study

Background

Although the correlation coefficient between body mass index (BMI) and percent body fat (%BF) or waist circumference (WC) has been reported, studies conducted among population-based schoolchildren to date have been limited in Japan, where %BF and WC are not usually measured in annual health examinations at elementary schools or junior high schools. The aim of the present study was to investigate the relationship of BMI to %BF and WC and to examine the influence of gender and obesity on these relationships among Japanese schoolchildren.

Methods

Subjects included 3,750 schoolchildren from the fourth and seventh grade in Ina-town, Saitama Prefecture, Japan between 2004 and 2008. Information about subject's age, sex, height, weight, %BF, and WC was collected from annual physical examinations. %BF was measured with a bipedal biometrical impedance analysis device. Obesity was defined by the following two criteria: the obese definition of the Centers for Disease Control and Prevention, and the definition of obesity for Japanese children. Pearson's correlation coefficients between BMI and %BF or WC were calculated separately for sex.

Results

Among fourth graders, the correlation coefficients between BMI and %BF were 0.74 for boys and 0.97 for girls, whereas those between BMI and WC were 0.94 for boys and 0.90 for girls. Similar results were observed in the analysis of seventh graders. The correlation coefficient between BMI and %BF varied by physique (obese or non-obese), with weaker correlations among the obese regardless of the definition of obesity; most correlation coefficients among obese boys were less than 0.5, whereas most correlations among obese girls were more than 0.7. On the other hand, the correlation coefficients between BMI and WC were more than 0.8 among boys and almost all coefficients were more than 0.7 among girls, regardless of physique.

Conclusions

BMI was positively correlated with %BF and WC among Japanese schoolchildren. The correlations could be influenced by obesity as well as by gender. Accordingly, it is essential to consider gender and obesity when using BMI as a surrogate for %BF and WC for epidemiological use.

Efficacy of increasing physical activity to reduce children's visceral fat: a pilot randomized controlled trial

OBJECTIVE

To examine whether differentially targeting physical activity within the context of pilot family-based pediatric weight control treatment results in differential change in abdominal fat, particularly visceral fat.

METHOD

Twenty-nine overweight children (>85(th) body mass index [BMI] percentile) and at least one participating parent were randomly assigned to one of two family-based behavioral weight management conditions that either targeted 1) primarily dietary change (STANDARD; n = 15) or 2) dietary plus physical activity change (ADDED; n = 14). Differences at post-treatment in overall child weight status (e.g., BMI), whole-body composition (measured by dual x-ray absorptiometry), and abdominal fat (measured by waist circumference and magnetic resonance imaging) were assessed using intent-to-treat analyses, as were post-treatment parent BMI and waist circumference. Child and parent physical activity and dietary behavior changes were also evaluated. Results. At post-treatment, overall child weight status, whole-body composition, and child dietary measures did not differ by condition. Children in the ADDED condition tended to have higher physical activity and lower visceral abdominal fat at post-treatment relative to children in the STANDARD condition.

CONCLUSIONS

Increasing physical activity may be important to optimize reductions in abdominal fat, especially visceral fat, among overweight children provided with family-based behavioral weight management treatment.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00359957.

Abdominal fat and metabolic risk in obese children and adolescents

The aim of this study was to investigate fat distribution, mainly abdominal fat, and its relationship with metabolic risk variables in a group of 126 children and adolescents (60 males and 66 females) aged 5.0 to 14.9. According to IOTF criteria, 46 were classified as normal weight, 28 overweight and 52 obese. Weight, height, waist (WC) and hip circumferences were measured. The body mass index (BMI) was calculated. Total body fat, trunkal and abdominal fat were also assessed by dual energy x-ray absorptiometry (DXA). Glucose, insulin, HDL-Cholesterol, triglycerides (TG), ferritine, homocystein and C-reactive protein (CRP) were measured. Obesity status was related with insulin concentrations, CRP, TG and HDL. Obese patients had higher abdominal fat and higher CRP values than overweight and normal subjects. All markers of central body adiposity were related with insulin and lipid metabolism; however, they were not related with homocystein or ferritin. A simple anthropometric measurement, like waist circumference, seems to be a good predictor of the majority of the obesity related metabolic risk variables.

Waist circumference cut-off values for the prediction of cardiovascular risk factors clustering in Chinese school-aged children: a cross-sectional study

BACKGROUND

Waist circumference has been identified as a valuable predictor of cardiovascular risk in children. The development of waist circumference percentiles and cut-offs for various ethnic groups are necessary because of differences in body composition. The purpose of this study was to develop waist circumference percentiles for Chinese children and to explore optimal waist circumference cut-off values for predicting cardiovascular risk factors clustering in this population.

METHODS

Height, weight, and waist circumference were measured in 5529 children (2830 boys and 2699 girls) aged 6-12 years randomly selected from southern and northern China. Blood pressure, fasting triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and glucose were obtained in a subsample (n = 1845). Smoothed percentile curves were produced using the LMS method. Receiver-operating characteristic analysis was used to derive the optimal age- and gender-specific waist circumference thresholds for predicting the clustering of cardiovascular risk factors.

RESULTS

Gender-specific waist circumference percentiles were constructed. The waist circumference thresholds were at the 90th and 84th percentiles for Chinese boys and girls respectively, with sensitivity and specificity ranging from 67% to 83%. The odds ratio of a clustering of cardiovascular risk factors among boys and girls with a higher value than cut-off points was 10.349 (95% confidence interval 4.466 to 23.979) and 8.084 (95% confidence interval 3.147 to 20.767) compared with their counterparts.

CONCLUSIONS

Percentile curves for waist circumference of Chinese children are provided. The cut-off point for waist circumference to predict cardiovascular risk factors clustering is at the 90th and 84th percentiles for Chinese boys and girls, respectively.

Construct validity of a continuous metabolic syndrome score in children

OBJECTIVE

The primary purpose of this study was to examine the construct validity of a continuous metabolic syndrome score (cMetS) in children. The secondary purpose was to identify a cutpoint value(s) for an adverse cMetS based on receiver operating characteristic (ROC) curve analysis.

METHODS

378 children aged 7 to 9 years were assessed for the metabolic syndrome which was determined by age-modified cutpoints. High-density-lipoprotein cholesterol, triglycerides, the homeostasis assessment model of insulin resistance, mean arterial pressure, and waist circumference were used to create a cMetS for each subject.

RESULTS

About half of the subjects did not possess any risk factors while about 5% possessed the metabolic syndrome. There was a graded relationship between the cMetS and the number of adverse risk factors. The cMetS was lowest in the group with no adverse risk factors (-1.59 +/- 1.76) and highest in those possessing the metabolic syndrome (> or =3 risk factors) (7.05 +/- 2.73). The cutoff level yielding the maximal sensitivity and specificity for predicting the presence of the metabolic syndrome was a cMetS of 3.72 (sensitivity = 100%, specificity = 93.9%, and the area of the curve = 0.978 (0.957-0.990, 95% confidence intervals).

CONCLUSION

The results demonstrate the construct validity for the cMetS in children. Since there are several drawbacks to identifying a single cut-point value for the cMetS based on this sample, we urge researchers to use the approach herein to validate and create a cMetS that is specific to their study population.

Association of the components of the metabolic syndrome with non-alcoholic fatty liver disease among normal-weight, overweight and obese children and adolescents

OBJECTIVES

This study aimed to determine the prevalence of the metabolic syndrome, abnormalities of liver enzymes and sonographic fatty liver, as well as the inter-related associations in normal weight, overweight and obese children and adolescents.

METHODS

This cross-sectional study was conducted among a sample of 1107 students (56.1% girls), aged 6-18 years in Isfahan, Iran. In addition to physical examination, fasting blood glucose, serum lipid profile and liver enzymes were determined. Liver sonography was performed among 931 participants. These variables were compared among participants with different body mass index (BMI) categories.

RESULTS

From lower to higher BMI category, alanine aminotransferase (ALT), total cholesterol, LDL-cholesterol, triglycerides and systolic blood pressure increased, and HDL-cholesterol decreased significantly. Elevated ALT, aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were documented in respectively 4.1%, 6.6% and 9.8% of normal weight group. The corresponding figure was 9.5%, 9.8% and 9.1% in overweight group, and 16.9%, 14.9% and 10.8% in obese group, respectively. In all BMI categories, ALT increased significantly by increasing the number of the components of the metabolic syndrome. Odds ratio for elevated liver enzymes and sonographic fatty liver increased significantly with higher number of the components of the metabolic syndrome and higher BMI categories before and after adjustment for age.

CONCLUSIONS

Because of the interrelationship of biochemical and sonographic indexes of fatty liver with the components of the metabolic syndrome, and with increase in their number, it is suggested to determine the clinical impact of such association in future longitudinal studies.

Body Fat Percentages by Dual-energy X-ray Absorptiometry Corresponding to Body Mass Index Cutoffs for Overweight and Obesity in Indian Children

BACKGROUND

Indians are suspected to have higher body fat percent at a given body mass index (BMI) than their western counterparts.

OBJECTIVE

To estimate percent body fat in apparently healthy Indian children and adolescents by dual-energy X-ray absorptiometry (DXA) and explore linkages of BMI with body fat percent for better health risk assessment.

METHODS

Age, weight, height of 316 boys and 250 girls (6-17 years) were recorded. Body composition was measured by dual-energy X-ray absorptiometry (DXA). High adiposity was defined as body fat percent (BF%) > McCarthy's 85th percentile of body fat reference data. Receiver operating characteristic analysis (ROC) was carried out for CDC BMI Z score for it's ability to judge excess fatness.

RESULTS

High BF% was seen in 38.5% boys and 54.0% girls (p < 0.05). Percentage of obese children as defined by the BMI cutoffs of International Obesity Task Force (IOTF) (2.1% for boys and 6.9% for girls) was lower than that using Indian (13.7% for boys and 20.9% for girls) and CDC (14.1% for boys and 20.9% for girls) cutoffs. The point closest to one on the ROC curves of CDC BMI Z-scores indicated high adiposity at BMI cutoff of 22 at the age of 17 yr in both the genders.

CONCLUSIONS

Higher body fat percentage is associated with lower BMI values in Indian children.

Food group intake and central obesity among children and adolescents in the Third National Health and Nutrition Examination Survey (NHANES III)

OBJECTIVE

To explore mean food group intakes associated with central obesity anthropometry among children and adolescents enrolled in the Third National Health and Nutrition Examination Survey (NHANES III).

DESIGN

Cross-sectional study.

SETTING

Representative sampling of the US population (1998-2002).

SUBJECTS

Subjects were 3761 children (5-11 years) and 1803 adolescents (12-16 years) with single 24 h dietary recalls and anthropometric measures of central body fat (waist circumference and sum of subscapular and suprailiac skinfold thicknesses).

RESULTS

Results were controlled for confounding by age, height, race/ethnicity, Tanner stage, television viewing and parental education. In younger children, there was no relationship between central adiposity and mean intakes of dairy, fruit, vegetables or grains, while a positive association with meat intake was found among boys. In adolescent boys and girls, central body fat measures were inversely associated with mean dairy and grain intakes. Adolescent boys in the highest quartile of central adiposity consumed less fruit and fewer vegetables; those in the lowest central adiposity quartile consumed less meat. Finally, adolescents who met the criteria for central obesity (waist circumference >or=85th percentile for age and sex) reported consuming significantly less total dairy (as well as milk and cheese separately), total grains (whole and refined) and total fruit and vegetables. There was no association with meat consumption. To test the stability of these findings, the final analysis was replicated in 2541 same-aged adolescents from NHANES 1999-2002; the results were very similar.

CONCLUSIONS

These cross-sectional analyses suggest that intakes of dairy, grains and total fruits and vegetables are inversely associated with central obesity among adolescents.

Comparison of different anthropometric indices for identifying insulin resistance in schoolchildren

OBJECTIVES

Anthropometric indices have been associated with insulin resistance in children. This study (1) determined the association between insulin resistance and anthropometric indices, including body mass index (BMI), waist circumference (WC), WC/height, weight/(sitting height)(2), and WC/sitting height, and (2) compared the abilities of these five indices to identify children with insulin resistance.

METHODS

Data were collected from six elementary schools in Argentina between April and August 2007. Anthropometric data and Tanner staging were obtained. Fasting serum concentrations of glucose, lipids, and insulin were measured.

RESULTS

Six hundred twenty-five children (318 boys) between 6 and 14 years old were examined. The mean age of the children was 9.6 +/- 2.0 years. Ninety-six (15.4%) of the children were obese, 91 (14.6%) were overweight, and 438 (70.1%) were normal weight using Centers for Disease Control and Prevention norms. Sixty percent, 23.0%, 14.0%, and 3.0% were Tanner stage I, II, III, and IV, respectively. The areas under the receiver operator characteristic curves were as follows: WC = 0.78 +/- 0.021 (95% confidence interval [CI] 0.74-0.82), BMI = 0.77 +/- 0.022 (95% CI 0.73-0.82), weight/(sitting height)(2) = 0.76 +/- 0.022 (95% CI 0.72-0.81), WC/height = 0.67 +/- 0.027 (95% CI 0.62-0.72), and WC/sitting height = 0.67 +/- 0.27 (95% CI 0.62-0.72), indicating that BMI, WC, and weight/(sitting height)(2) were acceptable predictors for insulin resistance, whereas WC/height and WC/sitting height were fair predictors as the areas under the curve were <0.7.

CONCLUSIONS

This study suggests that WC and BMI are (and remain) the best correlates for insulin resistance. In contrast, the indices of the ratio between WC and height were fair predictors for insulin resistance. Additional longitudinal studies should be done to further confirm these findings.

How well do waist circumference and body mass index reflect body composition in pre-pubertal children?

OBJECTIVE

To investigate the quantitative relationship between waist circumference (WC) and height (Ht), and subsequently the association between waist circumference index (WCI), body mass index (BMI) and body composition in pre-pubertal children.

DESIGN

Cross-sectional sample (n=227; boys=127) of pre-pubertal black children (age range 8.8-11.0 years) from the Bone Health sub-study of the Bt20 birth cohort study set in Soweto-Johannesburg, South Africa. Measures of height, weight and WC by anthropometry, total and truncal fat and lean mass by dual-energy X-ray absorptiometry were used in the analysis. Pearson's correlation coefficients were used to examine the associations between BMI, WC and body composition outcomes.

RESULTS

WC was independent of height when height was raised to a power of approximately 0.8. BMI and WCI (WC/Ht) were significantly associated with total and truncal fat and lean mass in both sexes (all P<0.001). BMI showed consistently and significantly higher correlations with body composition than WCI and this association was significantly greater for fat mass than lean mass.

CONCLUSION

BMI, rather than WCI, would be a better screening tool for total and truncal fat mass in both sexes before puberty.

Serum transaminases concentrations in obese children and adolescents

The aim of the study was to investigate the relationship between liver transaminase levels and metabolic syndrome (MS) features in obese children and adolescents. A total of 132 children and adolescents (73 males and 59 females) aged 8 - 16, participated in the study. All were studied at the department of Paediatrics, University Hospital of Zaragoza (Spain). Inclusion criteria were the existence of obesity as defined by body mass index (BMI) according to Cole cut-off values (when BMI was higher than the age and sex specific equivalent to 30 kg/m2). The definition of metabolic syndrome was according to the International Diabetes Federation criteria. Weight (kg), height (cm), waist circumference (cm), blood pressure and BMI were measured. Laboratory determinations after overnight fasting included: transaminases (ALT, AST, GGT), fasting glucose, insulin, triglycerides and HDL-C. The MS was found in 21.6% of the obese children and adolescents and the prevalence was higher in males (25.9%) than in females (15.9%). Serum transaminases (ALT, AST and GGT) mean concentrations were higher in males than in females, and decreased during pubertal development. The obese children and adolescents with the MS did not show higher transaminases concentrations when compared with those without the MS. Some MS manifestations (mainly waist circumference) showed a correlation with ALT, although all transaminases values were normal according to adult references. Liver transaminases, a surrogate marker of NAFLD, did not show an early and consistent manifestation of abnormalities in the obese children and adolescents studied. In order to define the presence of the disease, it would be necessary to obtain aminotransferase reference standards for children and adolescents, considering pubertal stage and gender.

Frequency of secondary dyslipidemia in obese children

Objective:

This paper reports the frequency, type, and degree of dyslipidemia in obese children before therapeutic intervention. The relationships between lipid values and weight status, as well as lipid values and physical fitness, of these children were also investigated.

Design and methods:

The initial examination of the Freiburg Intervention Trial for Obese Children (FITOC) measured the values of triglycerides (TG), total cholesterol (C), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) in 546 obese children aged 7–12 (body mass index [BMI] > 97th percentile), and compared these values with those of the age- and sex-specific reference group in the Lipid Research Clinics Population Studies Data Book (LRC). Four groups were selected according to the following scheme: A, Normolipidemia; B, Hyper-LDL-cholesterolemia alone; C, Hypo-HDL-C + hypertriglyceridemia; D, Combined hyperlipidemia = Hyper-LDL-C + hypertriglyceridemia. Body mass index, BMI-SDS (corrected BMI), and physical performance in watt/kg body weight were measured.

Results:

A total of 45.8% of the overweight children showed an abnormal lipid profile. Ten percent of the children had high LDL-C levels (group B), while 15% had increased LDL-C and increased TG (group D) (higher prevalence in boys). In 18.9% we found increased TG, combined with decreased HDL-C values (group C).

Conclusion:

Obese children are at risk of dyslipoproteinemia and related diseases. Children with the highest BMI-SDS and lowest physical fitness have the lowest HDL-C values and increased TG, indicating a higher risk for the metabolic syndrome.

Central adiposity and associated lifestyle factors in Cree children

Aboriginal children are prone to central adiposity (CA), a component of the metabolic syndrome. The objective of this study was to determine if lifestyle factors were associated with CA in Canadian Cree children. Children aged 9-12 years were classified as having CA if their waist circumference met or exceeded the 85th percentile of the NHANES III reference. Weight status was determined using the CDC growth reference, dietary intake using three 24 h dietary recalls, physical activity using pedometers, and fitness by completion of the 20 m shuttle run test. Of the 178 children (79% participation rate), 32.6% were normal weight, 23.6% were overweight, and 43.8% were obese. Half (52.2%) of the children had CA (97.4% of obese children, 35.7% of overweight children, and 2.2% of normal weight children). Waist circumference was negatively correlated with pedometer step counts (r = -0.187, p = 0.012) and shuttle run time (r = -0.508, p < 0.001). In children with CA, waist circumference was positively correlated with sweetened beverage intake (r = 0.250, p = 0.016). The odds ratio (adjusted for age and sex) for CA for children consuming 3 or more fruits and vegetables per day was 0.43 (95% CI 0.18 - 0.98), for meeting step recommendations for a healthy body weight was 0.45 (95% CI 0.24 - 0.84), and for relative fitness was 0.12 (95% CI 0.04 - 0.33). CA was prevalent in children who were overweight and obese. Preventive strategies might include promoting a healthy diet, physical activity, and fitness.

Waist circumference and waist-to-height ratio of Hong Kong Chinese children

BACKGROUND

Central body fat is a better predictor than overall body fat for cardiovascular (CV) risk factors in both adults and children. Waist circumference (WC) has been used as a proxy measure of central body fat. Children at high CV risk may be identified by WC measurements. Waist-to-height ratio (WHTR) has been proposed as an alternative, conveniently age-independent measure of CV risk although WHTR percentiles have not been reported. We aim to provide age- and sex-specific reference values for WC and WHTR in Hong Kong Chinese children.

METHODS

Cross sectional study in a large representative sample of 14,842 children aged 6 to 18 years in 2005/6. Sex-specific descriptive statistics for whole-year age groups and smoothed percentile curves of WC and WHTR were derived and presented.

RESULTS

WC increased with age, although less after age 14 years in girls. WHTR decreased with age (particularly up to age 14). WHTR correlated less closely than WC with BMI (r = 0.65, 0.59 cf. 0.93, 0.91, for boys and girls respectively).

CONCLUSION

Reference values and percentile curves for WC and WHRT of Chinese children and adolescents are provided. Both WC and WHTR are age dependent. Since the use of WHRT does not obviate the need for age-related reference standards, simple WC measurement is a more convenient method for central fat estimation than WHRT.