Where is the beef? Waist circumference is more highly correlated with BMI and total body fat than with abdominal visceral fat in children

Malnutrition Patterns in Children with Chronic Kidney Disease

Malnutrition is frequent in children with chronic kidney disease (CKD). Apart from undernutrition and protein energy wasting (PEW), overnutrition prevalence is rising, resulting in fat mass accumulation. Sedentary behavior and unbalanced diet are the most important causal factors. Both underweight and obesity are linked to adverse outcomes regarding renal function, cardiometabolic risk and mortality rate. Muscle wasting is the cornerstone finding of PEW, preceding fat loss and may lead to fatigue, musculoskeletal decline and frailty. In addition, clinical data emphasize the growing occurrence of muscle mass and strength deficits in patients with fat mass accumulation, attributed to CKD-related wasting processes, reduced physical activity and possibly to obesity-induced inflammatory diseases, leading to sarcopenic obesity. Moreover, children with CKD are susceptible to abdominal obesity, resulting from high body fat distribution into the visceral abdomen compartment. Both sarcopenic and abdominal obesity are associated with increased cardiometabolic risk. This review analyzes the pathogenetic mechanisms, current trends and outcomes of malnutrition patterns in pediatric CKD. Moreover, it underlines the importance of body composition assessment for the nutritional evaluation and summarizes the advantages and limitations of the currently available techniques. Furthermore, it highlights the benefits of growth hormone therapy and physical activity on malnutrition management.

Reference Curves of Selected Circumferential Parameters for Czech Children Aged 6 to 11 Years

(1) Background/objective: the globally discussed current issue is the increasing body weight of the population. This trend is observed in all age categories. Pediatricians and anthropologists use BMI percentile curves to determine the optimal body weight of children, based on which the child is categorized in the category of underweight, normal weight, overweight, or obese. Medical or anthropological examinations also use some methods to determine the amount of body fat. In addition to evaluating amounts of body fat, it is important to assess its distribution. The distribution of fat in the body, especially in terms of disproportionate distribution, is a risk factor for health complications, especially in terms of metabolic and health risk. Part of monitoring children’s growth is also measuring and evaluating circumferential parameters, such as abdominal circumference, gluteal circumference, and waist circumference. This study aimed to define age- and gender-specific reference curves for waist circumference (WC), abdominal circumference (AbC), and gluteal circumference (GC) in Czech children. (2) Methods: data on children’s circumferential parameters were collected via anthropometric measurements. The research sample consisted of 2093 children aged 6–11 years (boys, n = 1008; girls, n = 1085). Only children with parental informed consent were included. The statistical analysis was performed separately by age and gender using SPSS v. 22. Anthropometric data were summarized by mean and standard deviation. The percentile curves of WC, AbC, and GC were calculated (P3, P10, P25, P50, P75, P90, P97) in R 3.4.2 software (R Foundation for Statistical Computing, Vienna, Austria) using the gamlss package. (3) Results and conclusions: the study developed age- and gender-specific percentile curves of WC, AbC, and GC for Czech children aged 6–11 years. All parameters increased with age in both boys and girls. Generally, the boys had higher WC and AbC than did girls, but girls had higher GC than did boys. Female and male median WC percentiles (M) increased from the age of 6. Both girls’ and boys’ median percentiles showed a continuous increase. We found similar trends in the median GC and AbC percentile curves. All percentile curves showed similar trends in both sexes, but the 90th and 97th WC percentiles in boys were exceptions: from the age of 10, they exceeded the values of girls, reaching their peak at the age of 11 followed by a decrease in the case of the 97th percentile and a plateau in the case of the 90th percentile. This study serves as a reference to enrich the methods of evaluation of somatic and medical status in Czech children. Up–to–date percentile curves would be a practical addition to the BMI percentiles for the screening and evaluation of overweight and obese conditions and the related risks of abdominal obesity in the pediatric population.

Genetics of Obesity: What We Have Learned Over Decades of Research

There is a genetic component to human obesity that accounts for 40% to 50% of the variability in body weight status but that is lower among normal weight individuals (about 30%) and substantially higher in the subpopulation of individuals with obesity and severe obesity (about 60%-80%). The appreciation that heritability varies across classes of BMI represents an important advance. After controlling for BMI, ectopic fat and fat distribution traits are characterized by heritability levels ranging from 30% to 55%. Defects in at least 15 genes are the cause of monogenic obesity cases, resulting mostly from deficiencies in the leptin-melanocortin signaling pathway. Approximately two-thirds of the BMI heritability can be imputed to common DNA variants, whereas low-frequency and rare variants explain the remaining fraction. Diminishing allele effect size is observed as the number of obesity-associated variants expands, with most BMI-increasing or -decreasing alleles contributing only a few grams or less to body weight. Obesity-promoting alleles exert minimal effects in normal weight individuals but have larger effects in individuals with a proneness to obesity, suggesting a higher penetrance; however, it is not known whether these larger effect sizes precede obesity or are caused by an obese state. The obesity genetic risk is conditioned by thousands of DNA variants that make genetically based obesity prevention and treatment a major challenge.

Relative handgrip strength, nutritional status and abdominal obesity in Chilean adolescents

Handgrip strength (HGS) is a well-established indicator of muscle strength and can help to identify risk of sarcopenic obesity in children. This study explores the relationship between adiposity and muscular strength in healthy Chilean adolescents. Adolescents (n = 491) aged 10–17 were selected from five schools in Santiago, Chile. HGS was determined by dynamometry. Anthropometry (weight, height, waist and mid arm circumference), physical activity and socioeconomic status were also measured. Relative HGS (RHGS) was calculated by dividing maximum HGS of the dominant hand by body-mass index (BMI) and low RHGS was categorized as <25^th percentile by sex. Logistic regression was used to determine the relationship between two markers of adiposity (abdominal obesity category by waist circumference and nutritional status measured by BMI category) and low RHGS, adjusting for possible confounding variables. Participants were on average 13.6y (2.4), 32.8% were overweight or obese and 37.5% were at risk of or had abdominal obesity. RHGS was 1.25 kg/kg/m² overall, with a significant difference by sex (1.51 for boys versus 1.14 for girls). In adjusted analyses, boys and girls with risk of abdominal obesity, had 3.3 (1.6–6.6) and 4.1 (1.8–9.3) increased odds of low RHGS, respectively, compared to boys and girls with normal waist circumference. Those with abdominal obesity compared to normal WC, had 8.5 (3.4–21.4) and 6.5 (2.0–21.3) increased odds of low RHGS for boys and girls, respectively. We observed similar associations for BMI category. In our sample of healthy adolescents, higher adiposity related to greater odds of low muscle strength measured by dynamometry. Considering the demographic shift from a young to an aging population in many countries, along with the increasing prevalence of obesity beginning in childhood, understanding how adiposity relates to low muscle strength is of growing importance.

Weight Loss Intervention Impact on the Physical Fitness Test Scores of Air Force Service Members

INTRODUCTION

Overweight and obesity are a major public health concern in the United States, including among active duty military personnel. Approximately 51% of active duty personnel are classified as overweight and 15% are classified as obese. This may impact military readiness. The current study aimed to determine if a weight loss intervention impacted fitness test scores among Air Force personnel.

MATERIALS AND METHODS

From 2014 to 2016, 204 Air Force members with overweight/obesity were randomized into either a Self-paced or counselor-initiated arm in a weight loss program. Study procedures were approved by the Institutional Review Board of the 59th Medical Wing in San Antonio and were acknowledged by the Institutional Review Board at the University of Tennessee Health Science Center. Fitness test scores from before, during, and after the intervention were used to determine if the intervention resulted in improvements in overall fitness test ratings and scores on individual components of the test.

RESULTS

Participants who lost at least 5% of their weight had better fitness ratings during the intervention compared to individuals who did not lose 5%. However, in the overall sample, fitness ratings worsened from preintervention to during the intervention, and from during to postintervention. Participants with overweight had better aerobic scores pre- and postintervention as well as better abdominal circumference scores and better fitness test ratings preintervention, during the intervention and postintervention compared to participants with obesity.

CONCLUSIONS

Behavioral weight management interventions that achieve 5% weight loss may help improve military fitness test ratings.

Metabolic Risk Factors Associated with Visceral and Subcutaneous Adipose Tissue in a Sex-Specific Manner in Seven-Year-Olds

OBJECTIVE

This study aimed to investigate how visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) volumes were associated with metabolic risk factors in 7-year-old children.

METHODS

A total of 81 children (52% girls) from a Swedish birth cohort were studied. At 6 years of age, anthropometric data, fasting insulin, glucose, cholesterol, and blood pressure were collected on 53 children with normal weight and 28 children with overweight or obesity, and insulin resistance was estimated. At 7 years of age, magnetic resonance imaging quantified VAT and SAT. Sex and regression analyses were conducted.

RESULTS

SAT was more strongly associated with metabolic risk factors than VAT. The associations between VAT and metabolic risk factors were stronger in girls (P < 0.05). When VAT was adjusted for birth weight and maternal BMI and education, it accounted for 51% of insulin variance (β = 11.72; P = 0.001) but only in girls. The key finding of this study was that adjusted SAT accounted for 63% of the fasting insulin variance in girls (β = 2.76; P < 0.001). Waist circumference was the best anthropometric marker for insulin resistance.

CONCLUSIONS

Insulin resistance was associated with abdominal adipose tissue and its associated metabolic risk factors in children as young as 7 years old.

Utility of anthropometric indicators to screen for clustered cardiometabolic risk factors in children and adolescents

Background Anthropometric indicators are associated with cardiometabolic risk factors (CMRF), but there is no consensus as to which indicator is the most suitable to screen for clustered CMRF. This study aimed to evaluate the utility of five anthropometric indicators to screen for clustered CMRF in children and adolescents. Methods A cross-sectional study was conducted in 1139 schoolchildren aged 6-17 years from Northeastern Brazil. Body weight, height, waist circumference (WC) and subscapular (SSF) and triceps skinfold thickness (TSF) were measured. Body mass index (BMI) and waist-to-height ratio (WHtR) were calculated. The following CMRF were evaluated: elevated total cholesterol, low high-density lipoprotein-cholesterol (HDL-C), elevated low-density lipoprotein-cholesterol (LDL-C), high triglyceride concentration, hyperglycemia and high blood pressure. The participants were categorized into no CMRF, 1 CMRF, 2 CMRF and ≥3 CMRF. Receiver operating characteristic (ROC) curves were constructed to assess the accuracy of the anthropometric indicators in predicting CMRF for age group and sex. Results Poor associations were observed between the anthropometric indicators and 1 CMRF (accuracy of 0.49-0.64). The indicators showed moderate associations with 2 CMRF (accuracy of 0.57-0.75) and ≥3 CMRF (accuracy of 0.59-0.79). In general, TSF exhibited the worst performance in predicting CMRF, followed by WHtR. The highest accuracies were observed for BMI, WC and SSF, with no significant difference between these indicators. Conclusions The routine use of BMI, WC and SSF as epidemiological screening tools for clustered CMRF in childhood and adolescence should be encouraged.

Movement behaviors and cardiometabolic risk in schoolchildren

Growing evidence has accumulated in recent years showing that movement behaviors have important implications for health in children, especially for cardiovascular health, whose risk factors could track from childhood to adulthood. However, these findings are mixed and inconsistent in children. The aim of this study was to examine the relationship between different movement behaviors (sedentary behavior, physical activity and sleep duration) and cardiometabolic risk in schoolchildren. The study shows cross-sectional results of baseline measurement from 146 Spanish schoolchildren, aged 8-to-11 years old, participating in the MOVI-2 study. Movement behaviors were determined using accelerometry combined with self-reported sleep time. Cardiometabolic risk was assessed using a validated metabolic syndrome index. Logistic regression analysis showed that higher levels of vigorous physical activity (OR = 0.110, p = 0.004) and sleeping more than 9 hours (OR = 0.269, p = 0.015) could be protective factors against metabolic syndrome risk in children. ANCOVA analysis showed associations between vigorous physical activity and waist circumference (p < 0.001), and sleep time with insulin resistance (p = 0.017) and lipid profile (p = 0.035). No association was observed between light and moderate physical activity, sedentary behavior and metabolic syndrome (index and components). No statistically significant differences were found for blood pressure and any of the movement behaviors. Our data suggest that both the amount of vigorous physical activity accumulated and sleep duration are independently associated with higher cardiometabolic risk in children.

Estimation of visceral fat in 9- to 13-year-old girls using dual-energy X-ray absorptiometry (DXA) and anthropometry

OBJECTIVES

Accumulation of visceral fat (VF) in children increases the risk of cardiovascular disease and type 2 diabetes, and measurement of VF in children using computed tomography and magnetic resonance imaging (MRI) is expensive. Dual-energy X-ray absorptiometry (DXA) may provide a low-cost alternative. This study aims to determine if DXA VF estimates can accurately estimate VF in young girls, determine if adding anthropometry would improve the estimate and determine if other DXA fat measures, with and without anthropometry, could be used to estimate VF in young girls.

METHODS

Visceral fat was measured at lumbar intervertebral sites (L1-L2, L2-L3, L3-L4 and L4-L5) using 3.0T MRI on 32 young girls (mean age 11.3 ± 1.3 years). VF was estimated using the GE CoreScan application. Measurement of DXA android and total body fat was performed. Weight, height and waist circumference (WC) measurements were also obtained.

RESULTS

Waist circumference and body mass index were both strongly correlated with MRI, although WC was the best anthropometric covariate. Per cent fat (%fat) variables had the strongest correlation and did best in regression models. DXA %VF (GE CoreScan) and DXA android %fat and total body %fat accounted for 65% to 74% of the variation in MRI VF.

CONCLUSION

Waist circumference predicted MRI VF almost as well as DXA estimates in this population, and a combination of WC and DXA fat improves the predictability of VF. DXA VF estimate was improved by the addition of WC; however, DXA android %fat with WC was better at predicting MRI VF.

Longer-term outcomes in offspring of GDM mothers treated with metformin versus insulin

Insulin has traditionally been the gold standard pharmacological treatment for gestational diabetes mellitus (GDM). Insulin requires multiple injections a day, can cause frequent hypoglycaemia, requires careful handling, and is generally more expensive compared to oral agents. Metformin has been increasingly popular in recent years. Based on the short-term data available, metformin appears to be safe and effective for the treatment of GDM but existing studies have all stressed the lack of longer-term offspring data. This article will analyse the evidence available on the longer-term outcomes in the offspring of women with GDM treated with metformin versus insulin. Pubmed, EMBASE, CENTRAL, and CNKI were searched for follow-up studies of randomised controlled trials that compared metformin with insulin for the treatment of GDM. Existing follow-up studies did not find any significant increase in the risk of adverse effects in terms of growth and development in the offspring of GDM mothers managed with metformin versus insulin.

Waist circumference percentile curves as a screening tool to predict cardiovascular risk factors and metabolic syndrome risk in Brazilian children

The goals of this study were to develop reference values for waist circumference (WC) in Brazilian children between 6-10 years old and to evaluate the WC performance in predicting cardiovascular risk factors and metabolic syndrome (MetS) in children. This is a population-based epidemiological cross-sectional study, in which 1,397 children participated, with a 6-10 years old probability sampling and from public and private schools in the city of Uberaba, Minas Gerais State, Brazil. WC was measured at the waist narrowest point (WC1) and at the umbilicus level (WC2). Blood samples and blood pressure were collected to determine the MetS diagnosis. There was a significant effect of age (p = 0.001), anatomical point (WC1 vs. WC2, p = 0.001) and sex-anatomical point interaction (p = 0.016) for WC. Smoothed sex- and age-specific 5th, 10th, 25th, 50th, 75th, 90th and 95th percentile curves of WC1 and WC2 were designed by the LMS method. WC was accurate to predict MetS, for all ages [area under the ROC curve (AUC) > 0.79 and p < 0.05], regardless of sex. This study presented percentile curves for WC at two anatomical points in a representative sample of Brazilian children. Furthermore, WC was shown to be a strong predictor of cardiovascular risk factors and MetS in children.

Anthropometric Indices Based on Waist Circumference as Measures of Adiposity in Children

OBJECTIVE

The aim of this study was to compare the accuracy of body fat patterns and single measures in assessing body fat and to clarify the use of indices based on waist circumference as measures of adiposity in children.

METHODS

This study included 2,531 7-year-old children from the Generation XXI birth cohort (Porto, Portugal). Anthropometrics were obtained by trained personnel and whole-body dual-energy x-ray absorptiometry (DXA) scans were performed.

RESULTS

Principal component analysis identified two body fat patterns. Pattern 1 (BMI, fat mass index from tetra-polar bioelectric impedance, and waist-to-height ratio) showed strong correlations with DXA fat mass index (r = 0.85; P < 0.001), and pattern 2 (waist-to-hip, waist-to-thigh, and waist-to-weight ratios) showed moderate correlations with DXA central fat (r = 0.35; P < 0.001). Compared with single measures, body fat patterns showed similar correlations with DXA-derived measures.

CONCLUSIONS

Compared with single anthropometric indices, body fat patterns seem to add little value for estimating body fat in children. Waist-to-height ratio seems to be a proxy for total fat, while waist-to-hip, waist-to-thigh, and waist-to-weight ratios seem to be proxies for central fat. Further studies should address the predictive ability of waist-to-weight ratio to identify children at risk of developing cardiometabolic disease, as this was the first time describing its potential usefulness.

Prenatal Development and Adolescent Obesity: Two Distinct Pathways to Diabetes in Adulthood

OBJECTIVE

Higher body-mass index (BMI) and lower birth weight (BW) are associated with elevated risk of diabetes in adulthood, but the extent to which they compose two distinct pathways is unclear.

METHODS

We used data from the National Longitudinal Study of Adolescent to Adult Health, a cohort of adolescents (1994-1995) followed for 14 years over four waves into adulthood (n = 13,413). Sex-stratified path analysis was used to examine pathways from BW [kg; linear (BW) and quadratic (BW2)] to latent trajectories in BMI from adolescence to adulthood to prevalent diabetes or prediabetes (pre/diabetes) in adulthood, adjusting for sociodemographic characteristics.

RESULTS

Two pathways from BW to pre/diabetes were characterized: one from higher BW to elevated BMI and pre/diabetes and a second from lower BW, independent of BMI. In the BMI-independent pathway, greater BW was associated with marginally lower odds of pre/diabetes in women, but not men. Girls born at lower and higher BW exhibited elevated BMI in adolescence [coeff (95% CI): BW: -2.1 (-4.1, -0.05); BW2: 0.43 (0.09, 0.76)]; higher BW predicted marginally faster BMI gain and higher adolescent BMI and faster BMI gain were associated with pre/diabetes [coeff (95% CI): BMI intercept: 0.09 (0.06, 0.11); BMI slope: 0.11 (0.07, 0.15)]. In boys, BW was weakly associated with BMI intercept and slope; BMI slope, but not BMI intercept, was positively associated with pre/diabetes [coeff (95% CI): 0.29 (0.19, 0.39)].

CONCLUSIONS

Findings suggest that in girls, slowing BMI gain is critical for diabetes prevention, yet it may not address distinct pathology stemming from early life.

Pediatric severe asthma: a case series report and perspectives on anti-IgE treatment

Background

The primary goal of asthma management is to achieve disease control for reducing the risk of future exacerbations and progressive loss of lung function. Asthma not responding to treatment may result in significant morbidity. In many children with uncontrolled symptoms, the diagnosis of asthma may be wrong or adherence to treatment may be poor. It is then crucial to distinguish these cases from the truly “severe therapy-resistant” asthmatics by a proper filtering process. Herein we report on four cases diagnosed as difficult asthma, detail the workup that resulted in the ultimate diagnosis, and provide the process that led to the prescription of omalizumab.

Case presentation

All children had been initially referred because of asthma not responding to long-term treatment with high-dose inhaled steroids, long-acting β₂-agonists and leukotriene receptor antagonists. Definitive diagnosis was severe asthma. Three out four patients were treated with omalizumab, which improved asthma control and patients’ quality of life. We reviewed the current literature on the diagnostic approach to the disease and on the comorbidities associated with difficult asthma and presented the perspectives on omalizumab treatment in children and adolescents. Based on the evidence from the literature review, we also proposed an algorithm for the diagnosis of pediatric difficult-to-treat and severe asthma.

Conclusions

The management of asthma is becoming much more patient-specific, as more and more is learned about the biology behind the development and progression of asthma. The addition of omalizumab, the first targeted biological treatment approved for asthma, has led to renewed optimism in the management of children and adolescents with atopic severe asthma.

Associations of adiposity measurements with thyroid nodules in Chinese children living in iodine-sufficient areas: an observational study

OBJECTIVES

Obesity has been found to be associated with an elevated risk of thyroid nodule(s), mainly in adults; however, evidence for this association in children was limited. The objective of this study was to investigate the association of adiposity and thyroid nodule(s) in children living in iodine-sufficiency areas.

SETTING AND PARTICIPANTS

We conducted a cross-sectional study of 1403 Chinese children living in the East Coast of China in 2014.

OUTCOME MEASURES

Anthropometric measures including height, weight and waist and hip circumferences were taken, and body mass index (BMI), body surface area (BSA) and waist-hip ratio (WHR) were then calculated. Thyroid ultrasonography was performed to assess thyroid volume and nodules.

RESULTS

Based on BMI, 255 (18.17%) children were overweight and 174 (12.40%) were obese. Thyroid nodule(s) was detected in 18.46% of all participants and showed little age and sex variations. As compared with normal-weight children, obese children experienced significantly higher risks for solitary (OR 2.07 (95% CI 1.16 to 3.71)) and multiple (OR 1.67 (95% CI 1.03 to 2.70)) thyroid nodules. Similar associations with thyroid nodule(s) were observed with adiposity measured by waist circumference and BSA, but not WHR. There were no notable differences in the associations between children consuming iodised and non-iodised salt.

CONCLUSIONS

These findings provide further evidence that childhood obesity is associated with the risk for thyroid nodule(s).

Convergence between biological, behavioural and genetic determinants of obesity

Multiple biological, behavioural and genetic determinants or correlates of obesity have been identified to date. Genome-wide association studies (GWAS) have contributed to the identification of more than 100 obesity-associated genetic variants, but their roles in causal processes leading to obesity remain largely unknown. Most variants are likely to have tissue-specific regulatory roles through joint contributions to biological pathways and networks, through changes in gene expression that influence quantitative traits, or through the regulation of the epigenome. The recent availability of large-scale functional genomics resources provides an opportunity to re-examine obesity GWAS data to begin elucidating the function of genetic variants. Interrogation of knockout mouse phenotype resources provides a further avenue to test for evidence of convergence between genetic variation and biological or behavioural determinants of obesity.

Changes in pediatric waist circumference percentiles despite reported pediatric weight stabilization in the United States

BACKGROUND

Obesity is a global health concern but the United States has reported a leveling in obesity rates in the pediatric population.

OBJECTIVE

To provide updated waist circumference (WC) percentile values, identify differences across time and discuss differences within the context of reported weight stabilization in a nationally representative sample of American children.

METHODS

Percentiles for WC in self-identified African Americans (AA), European Americans (EA) and Mexican Americans (MA) were obtained from 2009-2014 National Health and Nutrition Examination Survey data (NHANES2014). Descriptive trends across time in 10th, 25th, 50th, 75th and 90th percentile WC distributions were identified by comparing NHANES2012 with previously reported NHANESIII (1988-1994).

RESULTS

WC increased in a monotonic fashion in AA, EA and MA boys and girls. When compared with NHANESIII data, a clear left shift of percentile categories was observed such that values that used to be in the 90th percentile are now in the 85th percentile. Differences in WC were observed in EA and MA boys during a reported period of weight stabilization.

CONCLUSION AND RELEVANCE

WC has changed in the US pediatric population across time, even during times of reported weight stabilization, particularly among children of diverse racial/ethnic backgrounds.

Subtraction of subcutaneous fat to improve the prediction of visceral adiposity: exploring a new anthropometric track in overweight and obese youth

BACKGROUND

The efficiency of traditional anthropometric measurements such as body mass index (BMI) or waist circumference (Waist C) used to replace biomedical imaging for assessing visceral adipose tissue (VAT) is still highly controversial in youth.

HYPOTHESIS AND OBJECTIVES

We evaluated the most accurate model predicting VAT in overweight/obese youth, using various anthropometric measurements and their correlation with different body fat compartments, especially by testing, for the first time in youth, the hypothesis that subtracting the anthropometric measurement the most highly correlated with subcutaneous abdominal adipose tissue (SAAT) and less correlated possible with VAT from an anthropometric abdominal measurement highly correlated with visceral and total abdominal adipose tissue (TAAT), predicts VAT with higher accuracy.

SUBJECTS AND METHODS

VAT and SAAT data resulted from magnetic resonance imaging (MRI) analysis performed on 181 boys and girls (7-17 y) from Diabetes & Endocrinology Care Paediatrics Clinic in Luxembourg. Height, weight, abdominal diameters, waist, hip, and thigh circumferences were measured with a view to developing the anthropometric VAT predictive algorithms.

RESULTS

In girls, subtracting proximal thigh circumference (Proximal Thigh C), the most closely correlated anthropometric measurement with SAAT, from Waist C, the most closely correlated anthropometric measurement with VAT was instrumental in improving VAT prediction, in comparison with the most accurate single VAT anthropometric surrogate. [Formula: see text] Residual analysis showed a negligible estimation error (5 cm² ). In boys, Waist C was the best VAT predictor.

CONCLUSIONS

Subtraction of abdominal subcutaneous fat is important to predict VAT in overweight/obese girls.

Central overweight and obesity in Polish schoolchildren aged 7-18 years: secular changes of waist circumference between 1966 and 2012

We investigated secular trends of body mass index (BMI) and waist circumference (WC) in Polish schoolchildren examined through a period of almost 50 years. Data on height, weight and WC came from four cross-sectional surveys conducted in Poland between 1966 and 2012, covering 34,005 boys and 34,008 girls. Raw data of BMI and WC were standardized for age classes. Statistical analyses included the Kruskal-Willis test and Pearson Chi-square test. BMI and WC increased during the studied period; however, the growth was higher for WC (increase by 0.56 and 0.44 SD scores for BMI and 1.05 and 0.77 SD scores for WC in boys and girls, respectively). In boys, secular changes in BMI and WC were similar across childhood, early and late adolescence, while in girls they differed, indicating change in the type of adipose tissue distribution to a more central one in late adolescent girls.

CONCLUSION

During 46 years, there was a tendency to a greater increase of the fraction of individuals with central obesity than the overall one. Since abdominal fat deposit is more connected with higher health risks than subcutaneous fat pattern, probably the number of metabolic complications in Polish children and adolescents will intensify in the future. What is Known: • BMI has significant limitations related to fat distribution, while WC is a measure of central adiposity. • Greater central fat deposition increases the risk of many diseases; therefore, WC may serve as a diagnostic measure for detecting central obesity in children at risk. What is New: • In girls, changes in BMI and WC indicate change in adipose tissue distribution to a more central one in late adolescence girls. • Both general and abdominal obesity in Polish children increased significantly from 1966 to 2012, with the tendency to a greater increase of the fraction of individuals with central obesity than the overall one, implying the number of metabolic complications in Polish children and adolescents may intensify in the future.

Physical Activity and Pediatric Obesity: A Quantile Regression Analysis

PURPOSE

We aimed to determine whether moderate to vigorous physical activity (MVPA) and sedentary behavior (SB) were independently associated with body mass index (BMI) and waist circumference (WC) in children and adolescents.

METHODS

Data from the International Children's Accelerometry Database were used to address our objectives (N = 11,115; 6-18 yr; 51% female). We calculated age- and gender-specific BMI and WC z-scores and used accelerometry to estimate MVPA and total SB. Self-reported television viewing was used as a measure of leisure time SB. Quantile regression was used to analyze the data.

RESULTS

MVPA and total SB were associated with lower and higher BMI and WC z-scores, respectively. These associations were strongest at the higher percentiles of the z-score distributions. After including MVPA and total SB in the same model, the MVPA associations remained, but the SB associations were no longer present. For example, each additional hour per day of MVPA was not associated with BMI z-score at the 10th percentile (b = -0.02, P = 0.170) but was associated with lower BMI z-score at the 50th (b = -0.19, P < 0.001) and 90th percentiles (b = -0.41, P < 0.001). More television viewing was associated with higher BMI and WC, and the associations were strongest at the higher percentiles of the z-score distributions, with adjustment for MVPA and total SB.

CONCLUSIONS

Our observation of stronger associations at the higher percentiles indicates that increasing MVPA and decreasing television viewing at the population-level could shift the upper tails of the BMI and WC frequency distributions to lower values, thereby lowering the number of children and adolescents classified as obese.

Physical Activity, TV Watching Time, Sleeping, and Risk of Obesity and Hyperglycemia in the Offspring of Mothers with Gestational Diabetes Mellitus

We investigated the association of physical activity, TV watching time, sleeping time with the risks of obesity and hyperglycemia among 1263 offspring aged 1-5 years of mothers with gestational diabetes (GDM) in a cross-sectional study. Logistic regression models were used to obtain the odd ratios (ORs) (95% confidence intervals [CI]) of childhood obesity and hyperglycemia associated with different levels of indoor activity, outdoor activity, TV watching, and sleeping time. The multivariable-adjusted ORs of obesity based on different levels of TV watching time (0, <1.0, and ≥1.0 hour/day) were 1.00, 1.21 (95% CI 0.72-2.05), and 2.20 (95% CI 1.33-3.63) (P_trend = 0.003), respectively. The multivariable-adjusted ORs of hyperglycemia based on different levels of indoor activity (<5.0, 5.0-6.9, and ≥7.0 hours/day) were 1.00, 0.74 (95% CI 0.45-1.21), and 0.49 (95% CI 0.28-0.84) (P_trend = 0.034), respectively. The multivariable-adjusted ORs of hyperglycemia associated with different levels of sleeping time (<11.0, 11.0-11.9, and ≥12.0 hours/day) were 1.00, 0.67 (95% CI 0.42-1.05), and 0.39 (95% CI 0.23-0.67) (P_trend = 0.003), respectively. The present study indicated a positive association of TV watching with the risk of obesity, and an inverse association of either indoor activity or sleeping time with the risk of hyperglycemia among offspring born to GDM mothers in Tianjin, China.

Utility of body mass index, waist circumference and waist-to-height ratio as screening tools for hyperglycemia in young people

OBJECTIVES

To evaluate the ability of BMI, WC and WHtR to discriminate hyperglycemia in young people, and to determine whether there is an increase in the accuracy with the addition of WC and/or WHtR to BMI.

SUBJECTS AND METHODS

A cross-sectional study was conducted on 1,139 schoolchildren aged 6 to 17 years from Northeastern Brazil. Body weight, height, WC and fasting glucose levels were measured, and the BMI and WHtR were calculated. The presence of hyperglycemia was defined as a fasting glucose level ≥ 100 mg/dL.

RESULTS

The prevalence of hyperglycemia was 6.6%. Strong correlations were observed between the anthropometric indicators studied (BMI vs. WC = 0.87; BMI vs. WHtR = 0.87; WC vs. WHtR = 0.90). Hyperglycemia was more likely to be present in young people with excess weight (PR = 1.70), high WC (PR = 1.85), and high WHtR (PR = 1.91). The accuracies to discriminate hyperglycemia were significant, but low, for the individual (BMI = 0.56; WC = 0.53; WHtR = 0.55) and combined indicators (BMI + WC = 0.55; BMI + WHtR = 0.55).

CONCLUSION

Our findings do not support the use of BMI, WC or WHtR as screening tools for hyperglycemia in children and adolescents.

The role of prenatal exposures on body fat patterns at 7 years: Intrauterine programming or birthweight effects?

BACKGROUND AND AIMS

It remains unknown whether the effects of prenatal exposures on child's adiposity reflect entirely intrauterine programming. We aimed to assess the effects of maternal gestational weight gain, diabetes and smoking on the child's body fat patterns, disentangling the direct (through intrauterine programming) and indirect (through birthweight) effects.

METHODS AND RESULTS

We included 4747 singleton 7-year-old children from the Generation XXI birth cohort (Porto, Portugal). At birth, maternal and newborn's characteristics were obtained. Anthropometrics were measured at age 7 years and body fat patterns were identified by principal component analysis. Path analysis was used to quantify direct, indirect and total effects of gestational weight gain, diabetes and smoking on body fat patterns. Pattern 1 was characterized by strong factor loadings with body mass index, fat mass index and waist-to-height ratio (fat quantity) and pattern 2 with waist-to-hip ratio, waist-to-thigh ratio, and waist-to-weight ratio (fat distribution). The positive total effect of maternal gestational weight gain and diabetes on the child's fat quantity was mainly through a direct pathway, responsible for 91.7% and 83.7% of total effects, respectively (β = 0.022; 95% Confidence Interval (CI): 0.017, 0.027; β = 0.041; 95% CI: -0.011, 0.093). No effects on fat distribution were found. Maternal prenatal smoking had a positive direct effect on patterns 1 and 2, explaining 94.9% and 76.1% of total effects, respectively.

CONCLUSION

The effects of maternal gestational weight gain, diabetes and smoking on a child's fat quantity seem to be mainly through intrauterine programming. Maternal smoking also showed a positive direct effect on child's fat distribution.

Overcoming birth weight: can physical activity mitigate birth weight-related differences in adiposity?

BACKGROUND

Individuals born at low or high birth weight (BW) have elevated adiposity. The extent to which physical activity can mitigate this risk is unknown.

OBJECTIVES

The aim of this study was to determine if associations between BW and adiposity vary by self-reported moderate-to-vigorous physical activity (MVPA) among adolescents.

METHODS

We used data on adolescents in the National Health and Nutrition Examination Survey (1999-2006; 12-15 years; n = 4064). Using gender-stratified linear regression, we modelled body mass index (BMI) and waist circumference (WC) z-scores as a function of low, normal and high BW, MVPA (weekly Metabolic Equivalent of Task hours) and MVPA*BW cross-product terms, adjusting for sociodemographics, diet and, in WC models, BMI.

RESULTS

Among girls with low MVPA, those born with high BW had greater BMI than normal BW; this difference diminished with greater MVPA (coefficient [95% confidence interval]: low MVPA: 0.72 [0.29, 1.14]; high MVPA: -0.04 [-0.48, 0.39]; P for interaction = 0.05). Among boys, MVPA did not modify the associations between BW and BMI. WC was unrelated to BW, regardless of MVPA.

CONCLUSIONS

Findings suggest that effects of high BW in total adiposity can be more easily modified with MVPA in adolescent girls than in boys.

A Comparison between BMI, Waist Circumference, and Waist-To-Height Ratio for Identifying Cardio-Metabolic Risk in Children and Adolescents

Background

There is controversial evidence on the associations between anthropometric measures with clustering of cardiovascular disease risk factors in pediatric ages. We aimed to examine the associations between body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) with clustered cardiometabolic risk factors and to determine whether these anthropometric variables can be used to discriminate individuals with increased cardiometabolic risk (increased clustered triglycerides, HDL-cholesterol, systolic and diastolic blood pressure, and HOMA-IR).

Methods

The study sample of 4255 (2191 girls and 2064 boys) participants (8–17 years) was derived from pooled cross-sectional data comprising five studies. Outcomes included a continuous cardiometabolic risk factor z-score [corresponding to the sum of z-scores for triglycerides, HDL-cholesterol, systolic and diastolic blood pressure (mean arterial pressure), and HOMA-IR] and children with ≥1.0 SD in this score were defined as being at risk for clustering cardiometabolic risk factors.. Exposure variables were BMI, WC, WHtR. Statistics included mixed-effect regression and ROC analysis.

Results

All anthropometric variables were associated with clustered risk and the magnitudes of associations were similar for BMI, WC, and WHtR. Models including anthropometric variables were similar in discriminating children and adolescents at increased risk with areas under the ROC curve between 0.70 and 0.74. The sensitivity (boys: 80.5–86.4%; girls: 76.6–82.3%) was markedly higher than specificity (boys: 51.85–59.4%; girls: 60.8%).

Conclusions

The magnitude of associations for BMI, WC, and WHtR are similar in relation to clustered cardiometabolic risk factors, and perform better at higher levels of BMI. However, the precision of these anthropometric variables to classify increased risk is low.

Association between body mass index and body fat in 9-11-year-old children from countries spanning a range of human development

The purpose was to assess associations between body mass index (BMI) and body fat in a multinational sample of 9-11-year-old children. The sample included 7265 children from countries ranging in human development. Total body fat (TBF) and percentage body fat (PBF) were measured with a Tanita SC-240 scale and BMI z-scores (BMIz) and percentiles were computed using reference data from the World Health Organization and the U.S. Centers for Disease Control and Prevention, respectively. Mean PBF at BMIz values of -1, 0 and +1 were estimated using multilevel models. Correlations between BMI and TBF were >0.90 in all countries, and correlations between BMI and PBF ranged from 0.76 to 0.96. Boys from India had higher PBF than boys from several other countries at all levels of BMIz. Kenyan girls had lower levels of PBF than girls from several other countries at all levels of BMIz. Boys and girls from Colombia had higher values of PBF at BMIz=-1, whereas Colombian boys at BMIz 0 and +1 also had higher values of PBF than boys in other countries. Our results show a consistently high correlation between BMI and adiposity in children from countries representing a wide range of human development.

Are the Recent Secular Increases in Waist Circumference among Children and Adolescents Independent of Changes in BMI?

Background

Several studies have shown that the waist circumference of children and adolescents has increased over the last 25 years. However, given the strong correlation between waist circumference and BMI, it is uncertain if the secular trends in waist circumference are independent of those in BMI.

Methods

We analyzed data from 6- to 19-year-olds who participated in the 1988–1994 through 2011–2012 cycles of the National Health and Nutrition Examination Survey to assess whether the trends in waist circumference were independent of changes in BMI, race-ethnicity and age.

Results

Mean, unadjusted levels of waist circumference increased by 3.7 cm (boys) and 6.0 cm (girls) from 1988–94 through 2011–12, while mean BMI levels increased by 1.1 kg/m² (boys) and 1.6 kg/m² (girls). Overall, the proportional changes in mean levels of both waist circumference and BMI were fairly similar among boys (5.3%, waist vs. 5.6%, BMI) and girls (8.7%, waist vs. 7.7%, BMI). As assessed by the area under the curve, adjustment for BMI reduced the secular increases in waist circumference by about 75% (boys) and 50% (girls) beyond that attributable to age and race-ethnicity. There was also a race-ethnicity interaction (p < 0.001). Adjustment for BMI reduced the secular trend in waist circumference among non-Hispanic (NH) black children (boys and girls) to a greater extent (about 90%) than among other children.

Conclusions

Our results indicate that among children in the U.S., about 75% (boys) and 50% (girls) of the secular increases in waist circumference since 1988–94 can be accounted for by changes in BMI. The reasons for the larger independent effects among girls and among NH blacks are uncertain.