Waist to height ratio and the Ashwell® shape chart could predict the health risks of obesity in adults and children in all ethnic groups

Determinants of central obesity in children and adolescents and associated complications in South Africa: a systematic review

Background

Central obesity in children is a global health concern associated with cardiovascular risk factors. In 2019 the World Obesity Federation predicted that in 2025, 206 million children and adolescents aged 5 to 19 will be obese, and the number is estimated to reach 254 million by 2030. There is limited literature on the factors that are associated with the development of central obesity in children. We report a systematic review, aimed to describe the current literature on determinants of central obesity and its associated health outcomes in children and adolescents in the South African population.

Methods

We searched for peer-reviewed studies in Google Scholar, PubMed, and Science Direct search engines, and about seven studies were included. This systematic review has been registered with the International Prospective Register of Systematic Reviews (PROSPERO) (Registration number: CRD42023457012). This systematic review was conducted and reported according to an updated version of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. The quality of the included studies was assessed by following guidelines from the Newcastle-Ottawa Scale (NOS). The method considered three main domains: selection, comparability, and outcome across different study designs.

Results

The prevalence of central obesity in children and adolescents by waist-to-height ratio (WHtR) ranged from 2.0 to 41.0%; waist-to-hip [WHR ranged from 10 to 25%; waist circumference (WC) ranged from 9 to 35%]. Central obesity was associated with age, physical inactivity, gender socio, and demographic profiles of the household. Central obesity in children was associated with cardiovascular diseases and mental health issues.

Conclusion

Central obesity in children and adolescents was determined by gender, pubertal development, and age of the parents, households with high socioeconomic status, dietary practices, and overweight/obesity. Given the high prevalence of central obesity in children which can ultimately result in cardiometabolic diseases, cardiovascular risk factors, and mental health issues. This highlights the need for systems, jointly initiated by healthcare providers, policymakers, and the general society aimed at reducing the burden of central obesity such as introducing children and adolescents to health-promoting lifestyles.

Nutrition and Health in Arab Adolescents (NaHAR): Study protocol for the determination of ethnic-specific body fat and anthropometric cut-offs to identify metabolic syndrome

The prevalence of adolescent obesity in the Middle-East is considered among the highest in the world. Obesity in adolescents is associated with several cardiometabolic abnormalities, the constellation of which is referred to as the metabolic syndrome (MetS). This multi-country cross-sectional study aims to determine the optimal cut-off values for body fat (BF); body mass index (BMI) z-score; waist circumference (WC) percentile, and mid-upper arm circumference (MUAC) for the prediction of MetS among adolescents from Kingdom of Saudi-Arabia (KSA), Kuwait, Jordan, Lebanon and Syria. A secondary objective is to examine the validity of Bioelectrical Impendence Vector Analysis (BIVA) in estimating BF against the deuterium dilution technique (DDL). In each country, a sample of 210 adolescents will be recruited. Data collection will include demographics, socioeconomic, lifestyle and dietary data using a multi-component questionnaire; anthropometric measurements will be obtained and body composition will be assessed using the DDL and BIVA; blood pressure and biochemical assessment will be performed for the identification of the MetS. Receiver operating characteristic analyses will be undertaken to determine optimal cut-off values of BMI, WC, MUAC and BF in identifying those with MetS. Odds ratios (OR) and their respective 95% confidence interval (CI) for the association of the anthropometric measurements with MetS will be computed based on multiple logistic regression analysis models. The Bland and Altman approach will be adopted to compare BIVA against the reference DDL method for the determination of body composition parameters. This study responds to the need for ethnic-specific anthropometric cut-offs for the identification of excess adiposity and associated cardiometabolic risks in the adolescent population. The adoption of the generated cut-offs may assist policy makers, public health professionals and clinical practitioners in providing ethnic-specific preventive and curative strategies tailored to adolescents in the region.

Comparative Evaluation of Waist-to-Height Ratio and BMI in Predicting Adverse Cardiovascular Outcome in People With Diabetes: A Systematic Review

Central obesity is strongly associated with cardiovascular risk in people with diabetes. BMI does not reflect a regional fat distribution. The other anthropometric indices, which are markers of central obesity, like waist circumference and waist-hip ratio, are subject to age, sex, and ethnic variations. An index like waist-to-height ratio (WHtR), which considers central obesity, outperforms BMI in predicting cardiometabolic risk. With a single cut-off of 0.5, irrespective of age, sex, and ethnic variations, WHtR has a wide application in screening obesity in population settings. Previous systematic analyses were conducted in the general population, assessing cardiometabolic risk. The current study is the first systematic analysis to compare the applicability of WHtR and BMI in predicting both cardiovascular risk and adverse cardiovascular outcomes in people with diabetes. It includes prospective cohort studies, cross-sectional studies, and randomized control trials to generate evidence. The summary scores indicate that WHtR is probably a better indicator than BMI to assess cardiovascular risk in people with diabetes. A future meta-analysis will pave the way for more robust evidence.

Are cardiovascular health measures heritable across three generations of families in Soweto, South Africa? A cross-sectional analysis using the random family method

OBJECTIVES

Cardiovascular disease is increasing in many low and middle-income countries, including those in Africa. To inform strategies for the prevention of cardiovascular disease in South Africa, we sought to determine the broad heritability of phenotypic markers of cardiovascular risk across three generations.

DESIGN

A cross-sectional study conducted in a longitudinal family cohort.

SETTING

Research unit within a tertiary hospital in a historically disadvantaged, large urban township of South Africa.

PARTICIPANTS

195 individuals from 65 biological families with all three generations including third-generation children aged 4-10 years were recruited from the longest running intergenerational cohort study in Africa, the Birth to Twenty Plus cohort. All adults (grandparents and parents) were female while children were male or female.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was heritability of blood pressure (BP; brachial and central pressures). Secondary outcomes were heritability of arterial stiffness (pulse wave velocity), carotid intima media thickness (cIMT) and left ventricular mass indexed to body surface area (LVMI).

RESULTS

While no significant intergenerational relationships of BP or arterial stiffness were found, there were significant relationships in LVMI across all three generations (p<0.04), and in cIMT between grandparents and parents (p=0.0166). Heritability, the proportion of phenotypic trait variation attributable to genetics, was estimated from three common statistical methods and ranged from 23% to 44% for cIMT and from 21% to 39% for LVMI.

CONCLUSIONS

Structural indicators of vascular health, which are strong markers of future clinical cardiovascular outcomes, transmit between generations within African families. Identification of these markers in parents may be useful to trigger assessments of preventable risk factors for cardiovascular disease in offspring.

Evaluating future risk of NAFLD in adolescents: a prediction and decision curve analysis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the commonest liver condition in the western world and is directly linked to obesity and the metabolic syndrome. Elevated body mass index is regarded as a major risk factor of NAFL (steatosis) and NAFLD fibrosis. Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), we sought to investigate whether other variables from adolescence could improve prediction of future NAFL and NAFLD fibrosis risk at 24 years, above BMI and sex.

METHODS

Aged 24 years, 4018 ALSPAC participants had transient elastography (TE) and controlled attenuation parameter (CAP) measurement using Echosens 502 Touch. 513 participants with harmful alcohol consumption were excluded. Logistic regression models examined which variables measured at 17 years were predictive of NAFL and NAFLD fibrosis in young adults. Predictors included sex, BMI, central adiposity, lipid profile, blood pressure, liver function tests, homeostatic model assessment for insulin resistance (HOMA-IR), and ultrasound defined NAFL at 17 years (when examining fibrosis outcomes). A model including all these variables was termed "routine clinical measures". Models were compared using area under the receiver operator curve (AUROC) and Bayesian Information Criterion (BIC), analysis, which penalises model complexity. Models were tested in all participants and those with overweight or obese standardised BMIs (BMI SDS) centiles at the 17-year time point. A decision curve analysis (DCA) was performed to evaluate the clinical utility of models in overweight and obese adolescents predicting NAFLD fibrosis at a threshold probability of 0.1.

RESULTS

The "routine clinical measures" model had the highest AUROC for predicting NAFL in all adolescent participants (AUROC 0.79 [SD 0.00]) and those with an overweight/obese BMI SDS centile (AUROC 0.77 [SD 0.01]). According to BIC analysis, insulin resistance was the best predictor of NAFL in all adolescents, whilst central adiposity was the best predictor in those with an overweight/obese BMI SDS centile. The "routine clinical measures" model also had the highest AUROC for predicting NAFLD fibrosis in all adolescent participants (AUROC 0.78 [SD 0.02]) and participants with an overweight/obese BMI SDS centile (AUROC 0.84 [SD 0.03]). However, following BIC analysis, BMI was the best predictor of NAFLD fibrosis in all adolescents including those with an overweight/obese BMI SDS centile. A decision curve analysis examining overweight/obese adolescent participants showed the model that had the greatest net benefit for increased NAFLD fibrosis detection, above a treat all overweight and obese adolescents' assumption, was the "routine clinical measures" model. However, the net benefit was marginal (0.0054 [0.0034-0.0075]).

CONCLUSION

In adolescents, routine clinical measures were not superior to central adiposity and BMI at predicting NAFL and NAFLD fibrosis respectively in young adulthood. Additional routine clinical measurements do provide incremental benefit in detecting true positive fibrosis cases, but the benefit is small. Thus, to reduce morbidity and mortality associated with NASH cirrhosis in adults, the ultimate end point of NAFLD, the focus must be on obesity management at a population level.

Waist circumference, waist-to-height ratio and BMI percentiles in children aged 5 to 19 years in India: A population-based study

OBJECTIVE

Nationally representative percentiles for waist circumference (WC), waist-to-height-ratio (WHtR), and body mass index (BMI) are not available for children and adolescents in India.

METHODS

Using LMS method, age- and gender-specific reference growth charts were constructed for WC (n = 68,261), WHtR (n = 68,261), and BMI (n = 67,741) from children/adolescents aged 5-19 years who participated in a nationally representative survey. General obesity, indicating overall obesity, was defined as age-sex-specific BMI z-scores ≥ 95th percentile. Central obesity was defined in three ways: WC ≥ 90th percentile, WHtR ≥ 0.5, and both WC ≥ 90th percentile and WHtR ≥ 0.5.

FINDINGS

WC and BMI percentiles for boys and girls are lower than those previously reported from India and several other countries. The BMI percentiles are lower than the WHO 2007 reference population. The prevalence of general obesity using India specific BMI centiles was 2.9% (95% CI: 2.6-3.2). The prevalence of central obesity was 6.1% (95% CI: 5.7-6.6) using WC ≥ 90th percentile, 5.3% (95% CI: 5.0-5.7) using WHtR ≥ 0.5, and 3.6% using both criteria. Three-fourth of children with general obesity also had central obesity based on WC ≥ 90th.

CONCLUSIONS

Indian children are thinner than Caucasian and other Asian children, and the global WHO reference population. Using India specific reference, the prevalence of central obesity is higher than general obesity with a significant overlap between the two.

Elevated blood pressure and its relationship with bodyweight and anthropometric measurements among 8-11-year-old Indonesian school children

Objective: Increased prevalence of elevated blood pressure in children and adolescents was associated with increased body weight and measures. Also, prevalence of elevated blood pressure varies between countries. This study is to investigate the prevalence of elevated blood pressure in Indonesian children and its relationship with bodyweight and anthropometric measures. Methods: This cross-sectional study involved 1010 elementary students aged 8 - 12 years (479 girls, 531 boys). The anthropometric measures and blood pressure were assessed. Elevated blood pressure (EBP) was determined if at the 90^th percentile or above for gender, age, and height. Independent t-test, Chi-square, Pearson correlation, and multivariate logistic regression were applied. Significance was determined at p<0.05. Results: Overall prevalence of EBP was 28.8% (35.9% in girls, 22.4% in boys). BMI, waist circumference (WC), waist to height ratio (WHtR), and abdominal skinfold had significant correlation with EBP. Elevated BP was higher in overweight and obesity than in normoweight (60.5% vs 39.5%, p=0.00). In girls, the OR of EBP for overweight and obesity were 2.33 (95% CI 1.40-3.87, p=0.03) and 3.44 (95% CI 1.98-5.99, p=0.00) whereas in boys were 4.26 (95% CI 2.20-8.28, p=0.00) and 8.82 (95% CI 5.10-15.38, p=0.00). Conclusions: Prevalence of EBP in Indonesian school children aged 8 - 11 years was higher and more prevalent in overweight/ obesity and in girls. Anthropometric measures were correlated with EBP.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Is waist circumference more strongly associated with metabolic risk factors than waist-to-height ratio in Asians?

OBJECTIVES

Differential distribution of fats can vary among ethnic groups and thus have varying effects on metabolic risk. Measuring metabolic risk of individuals using simple anthropometric measurements is essential to replace current invasive methods of obtaining blood samples. Waist-to-height ratio (WHtR) has been advocated as the best simple anthropometric measurement, but, because of the high visceral fat of Asians, there has been speculation as to the possibility of using only waist circumference (WC) to measure metabolic risk. The aim of this study was to compare the performance of WC and WHtR in terms of their association with measures of obesity and metabolic risk factors (e.g., homeostasis model assessment for insulin resistance, low-density lipoprotein, triacylglycerol, and ratio of triacylglycerol to high-density lipoprotein) and to obtain an optimal cutoff value for one anthropometric measurement.

METHODS

The study was performed on healthy Asian Chinese (N = 527) men (n = 209) and women (n = 318) who participated in a cross-sectional study conducted at the Clinical Nutrition Research Centre located in Singapore. Association of WC and WHtR with metabolic risk factors was obtained using Spearman's rank correlation coefficient. Optimal cutoff value was obtained using receiver operating characteristic curve.

RESULTS

WC and WHtR performed equally well in both sexes in terms of their strength of association between metabolic risk factors. Receiver operating characteristic curve analysis showed that 73.5 cm (in women) and 82.5 cm (in men) were the optimal WC cutoff values to identify insulin resistance.

CONCLUSION

It is suggested that WC is a simpler anthropometric measurement that has strong association with an individual's metabolic risk level.

Waist-to-height ratio and its associations with body mass index in a sample of Tuscan children in primary school

BACKGROUND

Visceral obesity in children increases the risk of developing cardiovascular diseases. To evaluate overweight children, in addition to Body Mass Index (BMI), waist-to-height ratio (WHtR) can be used to predict cardiometabolic risk. The goal of this study is to describe WHtR in a sample of Tuscan children.

METHODS

A sample of children living in the province of Pistoia, Tuscany, was measured for the following anthropometric parameters: weight, height, and waist circumference. BMI and WHtR were calculated. For the latter indicator, a threshold of 0.5 was considered as a cardiovascular risk predictor. The subjects were classified into underweight, normal weight, overweight, and obese using Cole's cut-offs.

RESULTS

The number of children enrolled were 1575 (821 males; 754 females), aged 6-11 years. Of them, 64.3% were normal weight, 4.9% underweight, 22.3% overweight, and 8.5% obese. Moreover, 12.8% had a WHtR ≥0.5 (85.7% males; 88.7% females). The average WHtR value was 0.45 ± 0.045, and was significantly different as per gender (F = 0.45 vs. M = 0.46). WHtR was significantly correlated with BMI (r = 0.766).

CONCLUSION

The average WHtR value was in line with previous studies conducted among children of similar age groups. Large-scale perspective studies are needed to validate the Italian WHtR cut-offs for children.

Beyond Body Mass Index: Using Anthropometric Measures and Body Composition Indicators to Assess Odds of an Endometriosis Diagnosis

BACKGROUND

Body mass index (BMI) and endometriosis have been inversely associated. To address gaps in this research, we examined associations among body composition, endometriosis, and physical activity.

MATERIALS AND METHODS

Women from 14 clinical sites in the Salt Lake City, Utah and San Francisco, California areas and scheduled for laparoscopy/laparotomy were recruited during 2007-2009. Participants (N = 473) underwent standardized anthropometric assessments to estimate body composition before surgery. Using a cross-sectional design, odds of an endometriosis diagnosis (adjusted odds ratio [aOR]; 95% confidence interval [CI]) were calculated for anthropometric and body composition measures (weight in kg; height in cm; mid upper arm, waist, hip, and chest circumferences in cm; subscapular, suprailiac, and triceps skinfold thicknesses in mm; arm muscle and fat areas in cm²; centripetal fat, chest-to-waist, chest-to-hip, waist-to-hip, and waist-to-height ratios; arm fat index; and BMI in kg/m²). Physical activity (metabolic equivalent of task-minutes/week) and sedentariness (average minutes sitting on a weekday) were assessed using the International Physical Activity Questionnaire-Short Form. Measures were modeled continuously and in quartiles based on sample estimates. Adjusted models were controlled for age (years, continuous), site (Utah/California), smoking history (never, former, or current smoker), and income (below, within 180%, and above of the poverty line). Findings were standardized by dividing variables by their respective standard deviations. We used adjusted models to examine whether odds of an endometriosis diagnosis were moderated by physical activity or sedentariness.

RESULTS

Inverse relationships were observed between endometriosis and standardized: weight (aOR = 0.71, 95% CI 0.57-0.88); subscapular skinfold thickness (aOR = 0.79, 95% CI 0.65-0.98); waist and hip circumferences (aOR = 0.79, 95% CI 0.64-0.98 and aOR = 0.76, 95% CI 0.61-0.94, respectively); total upper arm and upper arm muscle areas (aOR = 0.76, 95% CI 0.61-0.94 and aOR = 0.74, 95% CI 0.59-0.93, respectively); and BMI (aOR = 0.75, 95% CI 0.60-0.93), despite similar heights. Women in the highest versus lowest quartile had lower adjusted odds of an endometriosis diagnosis for: weight; mid-upper arm, hip, and waist circumferences; total upper arm and upper arm muscle areas; BMI; and centripetal fat ratio. There was no evidence of a main effect or moderation of physical activity or sedentariness.

CONCLUSION

In a surgical cohort, endometriosis was inversely associated with anthropometric measures and body composition indicators.

Prediction of whole-body fat percentage and visceral adipose tissue mass from five anthropometric variables

Background

The conventional measurement of obesity utilises the body mass index (BMI) criterion. Although there are benefits to this method, there is concern that not all individuals at risk of obesity-associated medical conditions are being identified. Whole-body fat percentage (%FM), and specifically visceral adipose tissue (VAT) mass, are correlated with and potentially implicated in disease trajectories, but are not fully accounted for through BMI evaluation. The aims of this study were (a) to compare five anthropometric predictors of %FM and VAT mass, and (b) to explore new cut-points for the best of these predictors to improve the characterisation of obesity.

Methods

BMI, waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR) and waist/height^0.5 (WHT.5R) were measured and calculated for 81 adults (40 women, 41 men; mean (SD) age: 38.4 (17.5) years; 94% Caucasian). Total body dual energy X-ray absorptiometry with Corescan (GE Lunar iDXA, Encore version 15.0) was also performed to quantify %FM and VAT mass. Linear regression analysis, stratified by sex, was applied to predict both %FM and VAT mass for each anthropometric variable. Within each sex, we used information theoretic methods (Akaike Information Criterion; AIC) to compare models. For the best anthropometric predictor, we derived tentative cut-points for classifying individuals as obese (>25% FM for men or >35% FM for women, or > highest tertile for VAT mass).

Results

The best predictor of both %FM and VAT mass in men and women was WHtR. Derived cut-points for predicting whole body obesity were 0.53 in men and 0.54 in women. The cut-point for predicting visceral obesity was 0.59 in both sexes.

Conclusions

In the absence of more objective measures of central obesity and adiposity, WHtR is a suitable proxy measure in both women and men. The proposed DXA-%FM and VAT mass cut-offs require validation in larger studies, but offer potential for improvement of obesity characterisation and the identification of individuals who would most benefit from therapeutic intervention.

Waist-to-height ratio as a measure of abdominal obesity in southern Chinese and European children and adolescents

BACKGROUND

Waist-to-height ratio (WHtR), with a 0.5 threshold (WHtR0.5), is regarded as a simple age- and gender-independent criterion of abdominal obesity (AO) and a better predictor than the 90th percentile of waist circumference (WCP90).

OBJECTIVE

An analysis of gender and ethnic differences of WHtR and other AO indices between children and adolescents from southern China (HK: Hong-Kong, China) and Europe (LD: Łódź, Poland).

SUBJECTS

Two large cross-sectional surveys of children and adolescents aged 7-19 years, one from LD (13 172) and one from HK (14 566).

METHODS

The percentile and standardized values of WHtR and other parameters (WC, body mass index (BMI)) were assessed using the LMS method. The WHtR values corresponding to WCP90 and to the BMI definition of global obesity (BMIP95) were evaluated with the polynomial regression model. The compliance of the AO prevalence data, obtained with two criteria (WCP90 vs WHtR0.5) was analyzed using Cohen's kappa index (κC).

RESULTS

The WHtR data of Polish subjects were generally higher than those of their HK peers, and the ethic differences increased with age. The WHtR values of HK boys showed a stronger relationship with BMI z-score. WHtR corresponding to WCP90 assumed values <0.5. An application of Cohen's kappa coefficient (κC) to Polish subjects showed either 'substantial' (κC>0.6) or 'almost perfect' (κC>0.8) agreement in the AO prevalence for both criteria (WCP90 and WHtR0.5). For these criteria, either 'fair' (κC <0.4) or 'moderate' (κC<0.6) AO consistency ratings were observed among HK girls. In HK boys, a significant difference in the prevalence of AO was observed, independent of the criterion used.

CONCLUSIONS

Our results provide further evidence of the need for developing ethnic-specific WC charts and for recommending that a WHtR cutoff of 0.5 may not be appropriate to predict cardiometabolic risk in children of different ethnic groups.

Risk of Cardiovascular Disease among Diabetic Patients in Manipur, Northeast India

Atherosclerotic cardiovascular disease is the major cause of premature mortality in patients with type 2 diabetes. The present study was conducted to assess cardiovascular risk among diabetic patients of Northeast India. The present cross-sectional study included 81 diabetic patients (39 males and 42 females) aged 36–74 years from the district Imphal of Manipur, Northeast India. Sex-specific Framingham general cardiovascular risk prediction equations were used to calculate the 10-year risk for cardiovascular disease. The probable risk factors were determined by cross-tabulation of cardiometabolic parameters with the 10-year cardiovascular risk level. Males were found to be at higher risk of developing CVD in the future as compared to females with a discernible accumulation of adverse cardiovascular risk factors among them. 38.3% patients were at high risk, 37.0% at moderate risk and 24.7% at low risk for developing CVD in the next 10 years. Systolic blood pressure, total cholesterol, triglyceride, and smoking contributed significantly to high degree of cardiovascular risk. Presence of cardiovascular risk factors among diabetic patients at diagnosis accentuates the need of intensive management of cardiovascular complications, taking into consideration the traditional dietary pattern of the population.

Pregnancy complications and calculated cardiovascular risk in urban women: do we envisage an association?

Most researches related to pregnancy complications and future cardiovascular disease, and their risk factors have been equivocal. Existence and extent of these complications, as a contributing factor to CVD risks, with underlying mechanisms of these associations, still remain uncertain. Hence, the current study tends to examine associations between "complicated pregnancies" with obesity markers known to be coherent reflections of cardiovascular health in urban women. A cross-sectional sample of 631 Punjabi Khatri (mean age: 33 ± 5.58 years) urban women was studied for associations of pregnancy diabetes mellitus, hypertensive disorders, preterm delivery, and size for GA with calculated 10-year CVD risk (based on the Framingham score). A wide range of obesity markers (BMI, waist circumference (WC), WHR, and WHtR) were measured 3-8 years postpregnancy to determine its association with complications during pregnancy. The association with the calculated 10-year CVD risk (≥10 %) based on the Framingham prediction score was 3.01 OR (2.11-3.72 CI) for pregnancy DM, 4.52 (3.68-4.93 CI) for preeclampsia/gestational hypertension, 2.16 (2.01-2.79 CI) for size at GA (SGA and LGA), 2.25 (1.91-2.85 CI) for preterm births, and 2.48 (2.08-3.98 CI) for abnormal birth weight when compared with women without pregnancy diabetes mellitus, preeclampsia/gestational hypertension, appropriate gestational age, full-term babies, and normal birth weight, respectively, in completely adjusted models. Therefore, HDP, pregnancy diabetes mellitus, and pregnancy outcomes are all associated with an increased risk of CVD 10 years later. Pregnancy may provide an opportunity to identify women at increased risk of CVD relatively early in life.

Use of the waist-height ratio to predict metabolic syndrome in obese children and adolescents

AIM

To demonstrate that the waist-height ratio (WHtR) is a simple and effective screening tool that could be used to identify obese children with the metabolic syndrome.

METHODS

Data from 109 obese boys and girls, aged 10.00-16.50 years, who were recruited as part of the Eat Smart study were analysed. Systolic (SBP) and diastolic (DBP) blood pressure, blood lipids (total cholesterol, triglycerides (TG), high- and low-density lipoproteins), insulin, glucose, height, weight and waist circumference (WC) were collected. These measurements were used to calculate WHtR, body mass index (BMI), Z-scores for BMI, WC, weight and homeostatic model assessment for insulin resistance (HOMA-IR). Correlations between anthropometric measures and blood pressure, lipids, insulin, glucose and HOMA-IR were assessed. Binary logistic regression was used to test which anthropometric measure was a significant predictor of the metabolic syndrome.

RESULTS

Among boys, WHtR was negatively correlated with glucose (P < 0.05); WHtR and BMI Z-score were positively correlated with insulin, HOMA-IR and TG (P < 0.05) and WC Z-score was significantly correlated with age. Among girls, WHtR, BMI Z-score and WC Z-score were positively correlated with insulin and HOMA-IR and negatively correlated with high-density lipoprotein-cholesterol (P < 0.05), whereas BMI Z-score was significantly correlated with SBP and DBP Z-scores. Twenty per cent of subjects were classified as having the metabolic syndrome, with WHtR, BMI Z-score and HOMA-IR being significant predictors.

CONCLUSION

The WHtR is a significant predictor of the metabolic syndrome in obese youth. The WHtR is the simplest index to calculate and interpret, making it an ideal non-invasive screening tool to use in clinical practice.

A proposed cutoff point of waist-to-height ratio for metabolic risk in African township adolescents

OBJECTIVE

A waist:height ratio (WHtR) higher than 0.5 has been proposed as a cutoff point for abdominal obesity in both sexes and at all ages. It is unknown if this cutoff point is appropriate for previously undernourished adolescents. We assessed the cutoff value of the WHtR associated with an increased metabolic risk in 178 black South African 14- to 18-y-old adolescents (69 boys, 109 girls).

METHODS

We measured weight, height, waist circumference, fasting plasma glucose and insulin levels, serum high-sensitivity C-reactive protein, and blood pressure and calculated the WHtR and homeostasis model assessment of insulin resistance (HOMA-IR). Using receiver operating characteristics curve analyses, we assessed the WHtR with the highest sensitivity and specificity to discriminate adolescents with increased fasting plasma glucose, HOMA-IR, serum high-sensitivity C-reactive protein, and blood pressure from those with "normal" values.

RESULTS

The WHtR cutoff points derived from the receiver operating characteristics curves ranged from 0.40 to 0.41, with best diagnostic value at 0.41. A WHtR of 0.40 had 80% sensitivity and 38.5% specificity to classify adolescents with fasting blood glucose level higher than 5.6 mmol/L (area under the curve [AUC] 0.57). A WHtR of 0.41 had 64% sensitivity and 58.5% specificity for a HOMA-IR higher than 3.4 (AUC 0.66), 55% sensitivity and 55.6% specificity for a high-sensitivity C-reactive protein level higher than 1 mg/L (AUC 0.57), and 64% sensitivity and 50.2% specificity for a blood pressure higher than the age-, sex-, and height-specific 90th percentiles (AUC 0.56). Adolescents with a WHtR higher than 0.41 had an odds ratio of 2.46 (95% confidence interval 0.96-6.30) for having a HOMA-IR higher than 3.4.

CONCLUSION

The WHtR cutoff to indicate metabolic risk for black South African adolescents is 0.41, which is lower than the proposed international cutoff of 0.5. The WHtR can be used for screening adolescents with components of the metabolic syndrome in intervention programs.

Utility of the waist-to-height ratio as an instrument to measure parental perception of body weight in children and its use in a population-based survey of children

OBJECTIVE

To investigate which anthropometric measure of overweight status, BMI or waist-to-height ratio (WHtR), is most closely associated with parents' perception of their child's overweight status.

DESIGN

The sensitivity and specificity of parental perception against child-specific BMI and WHtR definitions of overweight were tested.

SETTING

Primary schools in Queensland, Australia.

SUBJECTS

Boys and girls aged 9·00-11·99 years (n 1431).

RESULTS

Of the 138 boys and 202 girls who were classified as overweight according to BMI, only 27·5 % (boys) and 22·7 % (girls) were also perceived as overweight by their parents. Using WHtR, 206 boys and 333 girls were classified as overweight, of whom only 21·9 % and 13·8 %, respectively, were perceived as overweight. Perception of overweight was underestimated in approximately 15 % of boys and 21 % of girls when compared with BMI. Underestimation was higher when compared with WHtR: 25 % (boys) and 39 % (girls). Overweight prevalence was significantly lower according to perception than according to BMI or WHtR. Mother's education level was significantly associated with accurate perception of overweight status (P < 0·001).

CONCLUSIONS

The sensitivity of parental perception of child overweight was higher when BMI was used. However, emphasis needs to be placed on using WHtR as an actual measure of overweight because high central adiposity is associated with increased risk of CVD. The combined use of WHtR, body-shape images rather than word responses regarding perception and public health messages that educate parents and children about body shape and associated health risks may be the best combination in improving parents' perception of their child's overweight status.

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-to-height ratio is not a predictor of systolic blood pressure in 3-year-old children

Waist:height has been proposed as an indicator of cardiovascular risk. We investigated the association of waist:height with systolic BP (sBP) in 3 year old children. Body mass index was a significant predictor of sBP, whereas waist:height was not: suggesting waist:height is not a useful indicator of sBP in this age group.

South Yorkshire Cohort: a 'cohort trials facility' study of health and weight - protocol for the recruitment phase

Background

Growing levels of both obesity and chronic disease in the general population pose a major public health problem. In the UK, an innovative 'health and weight' cohort trials facility, the 'South Yorkshire Cohort', is being built in order to provide robust evidence to inform policy, commissioning and clinical decisions in this field. This protocol reports the design of the facility and outlines the recruitment phase methods.

Method/Design

The South Yorkshire Cohort health and weight study uses the cohort multiple randomised controlled trial design. This design recruits a large observational cohort of patients with the condition(s) of interest which then provides a facility for multiple randomised controlled trials (with large representative samples of participants, long term outcomes as standard, increased comparability between each trial conducted within the cohort and increased efficiency particularly for trials of expensive interventions) as well as ongoing information as to the natural history of the condition and treatment as usual.

This study aims to recruit 20,000 participants to the population based South Yorkshire Cohort health and weight research trials facility. Participants are recruited by invitation letters from their General Practitioners. Data is collected using postal and/or online patient self completed Health Questionnaires. NHS numbers will be used to facilitate record linkage and access to routine data. Participants are eligible if they are: aged 16 - 85 years, registered with one of 40 practices in South Yorkshire, provide consent for further contact from the researchers and to have their information used to look at the benefit of health treatments. The first wave of data is being collected during 2010/12 and further waves are planned at 2 - 5 year intervals for the planned 20 year duration of the facility.

Discussion

The South Yorkshire Cohort combines the strengths of the standard observational, longitudinal cohort study design with a population based cohort facility for multiple randomised controlled trials in a range of long term health and weight related conditions (including obesity). This infrastructure will allow the rapid and cheap identification and recruitment of patients, and facilitate the provision of robust evidence to inform the management and self-management of health and weight.

Waist circumference and waist for height percentiles in urban South Indian children aged 3-16 years

OBJECTIVES

To develop age and gender specific waist circumference references for urban Indian children aged 3 -16 years.

DESIGN

Cross-sectional study.

SETTING

Urban preschools and schools of Bangalore.

PARTICIPANTS

9060 children (5172 boys and 3888 girls) in the age group of 3-16 years.

METHODS

Weight, height, and waist circumference were measured using standard anthropometric methodology. Percentiles for waist circumference and Waist/height ratio (W/Ht) for each age and gender were constructed and smoothed using the LMS method.

RESULTS

Mean waist circumference increased with age for both girls and boys. The upper end of curve in boys continued to increase, whereas in the girls it tended to plateau at 14 years. The waist circumference of the Indian children from the present study was higher than age and sex matched European children. The proportion of children with W/Ht ratio greater than 0.5 decreased as their age increased.

CONCLUSIONS

These curves represent the first waist and waist height ratio percentiles for Indian children and could be used as reference values for urban Indian children. We suggest that for a start, the 75th percentile of waist circumference from this study be used as an action point for Indian children to identify obesity (as a tautological argument), while retaining the cut-off of 0.5 for the W/Ht ratio; however this underlines the need to derive biologically rational cut-offs that would relate to different levels of risk for adult cardiovascular disease.

Ability of different measures of adiposity to identify high metabolic risk in adolescents

Introduction. This study aimed to evaluate the screening performance of different measures of adiposity: body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) for high metabolic risk in a sample of adolescents. Methods. A cross-sectional school-based study was conducted on 517 adolescents aged 15-18, from the Azorean Islands, Portugal. We measured fasting glucose, insulin, total cholesterol (TC), HDL-cholesterol, triglycerides, and systolic blood pressure. HOMA and TC/HDL-C ratio were calculated. For each of these variables, a Z-score was computed by age and sex. A metabolic risk score (MRS) was constructed by summing the Z-scores of all individual risk factors. High risk was considered when the individual had ≥1SD of this score. Receiver-operating characteristics (ROC) were used. Results. Linear regression analyses showed that, after adjusting for age and pubertal stage, all different measures of adiposity are positively and significantly associated with MRS in both sexes, with exception of WHtR for boys. BMI, WC, and WHtR performed well in detecting high MRS, indicated by areas under the curve (AUC), with slightly greater AUC for BMI than for WC and WHtR in both sexes. Conclusion. All measures of adiposity were significantly associated with metabolic risk factors in a sample of Portuguese adolescents.

Developing waist-to-height ratio cut-offs to define overweight and obesity in children and adolescents

OBJECTIVE

The waist-to-height ratio (WHtR) assesses abdominal adiposity and has been proposed to be of greater value in predicting obesity-related cardiovascular health risks in children than BMI. The present study aims to develop WHtR cut-offs for overweight and obesity based on the 85th and 95th percentiles for the percentage body fat (%BF) in a cohort of children and adolescents.

DESIGN

Waist circumference (WC), height, triceps and subscapular skinfolds were used to calculate WHtR and %BF. Correlations between WHtR and %BF and WHtR/mid-abdominal skinfold were made. Receiver-operating characteristic (ROC) curve analysis was used to select WHtR cut-offs to define overweight and obesity. Subjects were grouped by WHtR cut-offs, and mean values for anthropometry, blood lipids and blood pressure (BP) variables were compared.

SETTING

Australian primary and secondary schools.

SUBJECTS

A total of 2773 male (M) and female (F) subjects of the 1985 Australian Health and Fitness Survey, aged 8-16 years.

RESULTS

Correlation coefficients between WHtR and %BF were M: r = 0.73, F: r = 0.60, P < 0.01 and WHtR/mid-abdominal skinfold were M: r = 0.78, F: r = 0.65, P < 0.01. WHtR of 0.46(M) and 0.45(F) best identified subjects with > or = 85th percentile for %BF and 0.48(M) and 0.47(F) identified subjects with > or = 95th percentile for %BF. When comparing the highest WHtR group to the lowest, both sexes had significantly higher means for weight, WC, %BF, TG (male subjects only), systolic BP (female subjects only) and lower means for HDL cholesterol (P < 0.05).

CONCLUSIONS

WHtR is useful in clinical and population health as it identifies children with higher %BF at greater risk of developing weight-related CVD at an earlier age.

Validating the waist-height ratio and developing centiles for use amongst children and adolescents

AIM

To assess the statistical validity of the waist-height ratio (WHtR) as an appropriate method of adjusting waist circumference (WC) for height in children and adolescents.

INTRODUCTION

Recently, WHtR has been proposed to be of greater value than body mass index (BMI), in predicting obesity-related cardiovascular co-morbidities in children. This index, however, is yet to be extensively validated within the paediatric population.

METHODS

Height and WC in centimetres, were measured in 3597 children from grades 1 (5-7 years), 5 (9-11 years) and 10 (15-17 years). Log regression analyses using WC and height were performed to determine appropriate powers (p) to raise height, to completely adjust the index for height, by sex and grade. Correlations between WHtR and height were assessed.

RESULTS

Statistically, the WHtR is only valid for use among grade 1 boys and girls (p = 1.09 [95%CI 0.95-1.23] and p = 1.07 [95%CI 0.92-1.22], respectively) and grade 10 girls p = 0.85 (95%CI 0.62-1.08). However, the error (0.25%-1.85%), associated with the use of this index, in all ages and both sexes is clinically and biologically acceptable.

CONCLUSION

The WHtR is a clinically and biologically valid index to use among Australian children and adolescents.

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.

A physical activity programme and its effects on insulin resistance and oxidative defense in obese male patients with type 2 diabetes mellitus

AIM

The aim of this study was to investigate the effects of regular aerobic execise on glycaemic control, insulin resistance, cardiovascular risk and oxidative stress-defense parameters in overweight and obese type 2 diabetic patients.

METHODS

Changes from baseline to 3 and 6 months of aerobic exercise in total of 30 type 2 diabetics were assessed for physical activity index (PAI), fasting glycaemia (FG), glycated hemoglobin (HbA(1c)), median blood glucose (MBG), insulin resistance (HOMA), triglycerides (TG), cholesterol, the Ashwell Shape Chart Health Risk, SCORE risk, body mass index (BMI), waist and hip circumference, systolic (SBP) and diastolic (DBP) blood pressure, plasma and erythrocyte malondialdehyde (MDA), glutathione, sulphydryl groups and catalase (CAT) and were compared to the results of 30 healthy control subjects.

RESULTS

At baseline, significant differences were recorded between the control and diabetes group for FG (P<0.001), HOMA (P<0.001), SBP and DBP (P<0.001), TG (P<0.01), MDA(pl) (P<0.01), CAT (P<0.01) and SCORE risk (P<0.001). Significant changes within the diabetes group were found for PAI (P<0.05), FG (P<0.001), MBG (P<0.05), HbA(1c)(P<0.05), HOMA (P<0.01), SBP and DBP (P<0.001) from baseline to 3 months, as well as for FG (P<0.01), HOMA (P<0.001), SBP and DBP (P<0.05) from 3 to 6 months. Significant (P<0.05) correlations were found for FG and PAI (R=0.432), as well as for HOMA and both HbA(1c)(R=0.412) and SCORE risk (R=-0.387) in the diabetes group.

CONCLUSION

Regular aerobic exercise has beneficial effects on glycaemic control, insulin resistance, cardiovascular risk, oxidative stress-defense parameters in overweight and obese type 2 diabetics.