Establishing international optimal cut-offs of waist-to-height ratio for predicting cardiometabolic risk in children and adolescents aged 6-18 years.

BACKGROUND: Waist-to-height ratio (WHtR) has been proposed as a simple and effective screening tool for assessing central obesity and cardiometabolic risk in both adult and pediatric populations. However, evidence suggests that the use of a uniform WHtR cut-off of 0.50 may not be universally optimal for pediatric populations globally. We aimed to determine the optimal cut-offs of WHtR in children and adolescents with increased cardiometabolic risk across different countries worldwide. METHODS: We used ten population-based cross-sectional data on 24,605 children and adolescents aged 6-18 years from Brazil, China, Greece, Iran, Italy, Korea, South Africa, Spain, the UK, and the USA for establishing optimal WHtR cut-offs. We performed an external independent test (9,619 children and adolescents aged 6-18 years who came from other six countries) to validate the optimal WHtR cut-offs based on the predicting performance for at least two or three cardiometabolic risk factors. RESULTS: Based on receiver operator characteristic curve analyses of various WHtR cut-offs to discriminate those with ≥ 2 cardiometabolic risk factors, the relatively optimal percentile cut-offs of WHtR in the normal weight subsample population in each country did not always coincide with a single fixed percentile, but varied from the 75th to 95th percentiles across the ten countries. However, these relatively optimal percentile values tended to cluster irrespective of sex, metabolic syndrome (MetS) criteria used, and WC measurement position. In general, using ≥ 2 cardiometabolic risk factors as the predictive outcome, the relatively optimal WHtR cut-off was around 0.50 in European and the US youths but was lower, around 0.46, in Asian, African, and South American youths. Secondary analyses that directly tested WHtR values ranging from 0.42 to 0.56 at 0.01 increments largely confirmed the results of the main analyses. In addition, the proposed cut-offs of 0.50 and 0.46 for two specific pediatric populations, respectively, showed a good performance in predicting ≥ 2 or ≥ 3 cardiometabolic risk factors in external independent test populations from six countries (Brazil, China, Germany, Italy, Korea, and the USA). CONCLUSIONS: The proposed international WHtR cut-offs are easy and useful to identify central obesity and cardiometabolic risk in children and adolescents globally, thus allowing international comparison across populations.

Efficacy of anthropometric measures for identifying cardiovascular disease risk in adolescents: review and meta-analysis.

INTRODUCTION: To compare the ability of Body Mass Index (BMI), waist circumference (WC) and waist to height ratio (WHtR) to estimate cardiovascular disease (CVD) risk levels in adolescents. EVIDENCE ACQUISITION: A systematic review and meta-analysis was performed after a database search for relevant literature (Cochrane, Centre for Review and Dissemination, PubMed, British Nursing Index, CINAHL, BIOSIS citation index, ChildData, metaRegister). EVIDENCE SYNTHESIS: The study included 117 records representing 96 studies with 994,595 participants were included in the systematic review, 14 of which (13 studies, N.=14,610) were eligible for the meta-analysis. The results of the meta-analysis showed that BMI was a strong indicator of systolic blood pressure, diastolic blood pressure, triglycerides, high-density lipoprotein cholesterol and insulin; but not total cholesterol, low-density lipoprotein or glucose. Few studies were eligible for inclusion in the meta-analysis considering WC or WHtR (N.≤2). The narrative synthesis found measures of central adiposity to be consistently valid indicators of the same risk factors as BMI. CONCLUSIONS: BMI was an indicator of CVD risk. WC and WHtR were efficacious for indicating the same risk factors BMI performed strongly for, though there was insufficient evidence to judge the relative strength of each measure possibly due to heterogeneity in the methods for measuring and classifying WC.

Use of Static Cutoffs of Hypertension to Determine High cIMT in Children and Adolescents: An International Collaboration Study.

BACKGROUND: Pediatric hypertension is typically defined as blood pressure ≥ sex-, age-, and height-specific 95th percentile (high) cutoffs. Given the number of strata, there are hundreds of cutoffs for defining elevated and high blood pressure that make it cumbersome to use in clinical practice. This study aimed to evaluate the utility of the static cutoffs for pediatric hypertension (120/80 mm Hg for children and 130/80 mm Hg for adolescents) in determining high carotid intimamedia thickness (cIMT) in children and adolescents. METHODS: Data were from 6 population-based cross-sectional studies in Brazil, China, Greece, Italy, Spain, and the United Kingdom. A total of 4280 children and adolescents, aged 6 to 17 years, were included. High cIMT was defined as cIMT ≥ sex-, age- and cohort-specific 90th percentile cutoffs. RESULTS: Compared with normal blood pressure, hypertension defined using the percentile-based cutoffs from 2017 American Academy of Pediatrics guideline, and the static cutoffs were associated with similar higher odds for high cIMT (percentile-based cutoffs: odds ratio [OR], 1.46, 95% confidence interval [CI], 1.15-1.86; static cutoffs: OR, 1.65, 95% CI, 1.25-2.17), after adjustment for sex, age, race/ethnicity, body mass index, high-density lipoprotein-cholesterol, triglyceride, and fasting blood glucose. The similar utility of 2 definitions in determining high cIMT was further confirmed by area under the receiver operating characteristic curve and net reclassification improvement methods (P for difference > 0.05). CONCLUSION: Static cutoffs (120/80 mm Hg for children, 130/80 mm Hg for adolescents) performed similarly compared with percentile-based cutoffs in determining high cIMT, supporting the use of static cutoffs in identifying pediatric hypertension in clinical practice.

Metabolic syndrome, clustering of cardiovascular risk factors and high carotid intima-media thickness in children and adolescents.

OBJECTIVE: The clinical utility of screening for pediatric metabolic syndrome (MetS) in children and adolescents is still controversial. We examined the performance of pediatric MetS vs. clustering of cardiovascular risk factors (which are the components of MetS) for predicting high carotid intima-media thickness (cIMT) in children and adolescents. METHODS: Participants included 2427 children and adolescents aged 6-17 years from population-based studies in three countries (Brazil, China and Italy). Pediatric MetS was defined using either the modified National Cholesterol Education Program Adult Treatment Panel III criteria or the modified International Diabetes Federation criteria. Clustering of cardiovascular risk factors was calculated as the sum of five components of MetS (i.e. central obesity, elevated blood pressure, elevated triglycerides, reduced HDL-cholesterol and elevated fasting blood glucose). High cIMT was defined as cIMT at least 95th percentile values for sex and age developed from European children. RESULTS: Presence of one, two or at least three cardiovascular risk factors (using the National Cholesterol Education Program Adult Treatment Panel III criteria), as compared with none, was associated with gradually increasing odds of high cIMT [odds ratios (95% confidence intervals): 1.60 (1.29-1.99), 2.89 (2.21-3.78) and 4.24 (2.81-6.39), respectively]. High cIMT was also associated with presence (vs. absence) of MetS (odds ratio = 2.88, 95% confidence interval = 1.95-4.26). However, clustering of cardiovascular risk factors predicted high cIMT markedly better than MetS (area under the curve of 0.66 vs. 0.54, respectively). Findings were similar using the International Diabetes Federation criteria for pediatric MetS. CONCLUSION: In children and adolescents, a graded score based on five cardiovascular risk factors (used to define MetS) predicted high cIMT markedly better than MetS. These findings do not support the clinical utility of MetS for screening youth at increased cardiovascular risk, as expressed in this study by high cIMT.

Metabolically Healthy Obesity and High Carotid Intima-Media Thickness in Children and Adolescents: International Childhood Vascular Structure Evaluation Consortium.

OBJECTIVE: It has been argued that metabolically healthy obesity (MHO) does not increase cardiovascular disease (CVD) risk. This study examines the association of MHO with carotid intima-media thickness (cIMT), a proxy of CVD risk, in children and adolescents. RESEARCH DESIGN AND METHODS: Data were available for 3,497 children and adolescents aged 6-17 years from five population-based cross-sectional studies in Brazil, China, Greece, Italy, and Spain. Weight status categories (normal, overweight, and obese) were defined using BMI cutoffs from the International Obesity Task Force. Metabolic status (defined as "healthy" [no risk factors] or "unhealthy" [one or more risk factors]) was based on four CVD risk factors: elevated blood pressure, elevated triglyceride levels, reduced HDL cholesterol, and elevated fasting glucose. High cIMT was defined as cIMT ≥90th percentile for sex, age, and study population. Logistic regression model was used to examine the association of weight and metabolic status with high cIMT, with adjustment for sex, age, race/ethnicity, and study center. RESULTS: In comparison with metabolically healthy normal weight, odds ratios (ORs) for high cIMT were 2.29 (95% CI 1.58-3.32) for metabolically healthy overweight and 3.91 (2.46-6.21) for MHO. ORs for high cIMT were 1.44 (1.03-2.02) for unhealthy normal weight, 3.49 (2.51-4.85) for unhealthy overweight, and 6.96 (5.05-9.61) for unhealthy obesity. CONCLUSIONS: Among children and adolescents, cIMT was higher for both MHO and metabolically healthy overweight compared with metabolically healthy normal weight. Our findings reinforce the need for weight control in children and adolescents irrespective of their metabolic status.

Associations between obesity, adverse behavioral patterns and cardiovascular risk factors among adolescent inhabitants of a Greek island.

BACKGROUND: Excess weight, unhealthy lifestyle habits and their sequelae have become a well-recognized public health problem in most countries. The objective of the study was to examine the relationship of adolescent overweight/obesity with behavioral habits and their association with blood pressure (BP) and lipid profile. METHODS: Anthropometric parameters, lifestyle, BP and lipid profile of 736 adolescents were evaluated cross-sectionally. The classifications of normal weight, overweight and obese were based on BMI z-scores. RESULTS: About 42.1% of adolescents were overweight/obese, 11.3% were smokers, 33.2% consumed alcohol and 34% reported low activity. Males began smoking earlier, consumed alcohol more often, exercised less and spent more screen time than females. Alcohol consumption was more prevalent among smokers and was associated with higher BP and dyslipidemia. Smokers exercised less intensely and had lower high density lipoprotein-cholesterol (HDL-C) than non-smokers. Obesity was a risk factor for higher BP and dyslipidemia. Longer screen time was associated with higher triglycerides, while intense physical activity with lower systolic BP. CONCLUSIONS: Obesity is related to an adverse lipid and BP profile during adolescence. Clustering of hazardous habits was observed, which is known to aggravate the cardiovascular risk.

Adiposity, blood pressure, and carotid intima-media thickness in greek adolescents.

OBJECTIVE: In children and adolescents with cardiovascular risk factors, the assessment of subclinical target-organ damage is of paramount importance. This study investigated factors associated with carotid intima-media thickness (cIMT) in adolescents. DESIGN AND METHODS: A cross-sectional study was performed in 448 apparently healthy adolescents recruited from schools (mean age 14 ± 2.2 years, 211 boys), which involved cIMT measurements (common carotid artery) and assessment of lipid profile, glucose, and blood pressure (BP). RESULTS: The prevalence of overweight/obesity was 28.1%/12.7% and of BP ≥95th percentile 19.6%. Left cIMT was correlated with age (r = 0.10), waist circumference (WC) (0.15), and BP (0.21/0.13, systolic/diastolic) (all P < 0.05). Right cIMT was correlated with waist to hip ratio (WHR) (0.10), whereas the mean of left and right cIMT was correlated with WC (0.12), WHR (0.12), and systolic BP (0.14) (all P < 0.05). After the age of 13 years, boys tended to have higher cIMT than girls, which was significant in the 13-15 years subgroup (P < 0.05). In stepwise multivariate analysis (independent variables: age, gender, WC, WHR, body mass index z-score, lipid parameters, glucose, BP), left cIMT was independently associated with systolic BP; right cIMT with WHR; mean left and right cIMT with WC. Adolescents with BP ≥90th percentile had higher left cIMT than those <90th percentile (0.63 ± 0.09 vs. 0.61 ± 0.09 mm respectively, P < 0.05). CONCLUSION: Central adiposity and systolic BP appear to be independently associated with increased cIMT values in apparently healthy adolescents. Left side cIMT appears to be superior to right side measurements in terms of association with cardiovascular risk factors.