The reliability of body mass index in the diagnosis of obesity and metabolic risk in children

Obesity Is Associated with Increased 11-Oxyandrogen Serum Concentrations during Puberty

INTRODUCTION

While the influence of various factors on classical androgen synthesis in children and adolescents and its impact on puberty has been widely investigated, there appear to be gaps and contradictory findings regarding the association of overweight and obesity with the synthesis of adrenal-derived 11-oxygenated androgen (11-OA) serum levels. With this study, we aimed to examine how overweight and obesity affect 11-OA serum levels during puberty in a large cohort of children and adolescents.

METHODS

Our cohort comprised 1,054 healthy children aged 6-19 years providing serum samples at a total of 1,734 visits. Liquid chromatography-tandem mass spectrometry was used to quantify 11-ketotestosterone (11-KT), 11-ketoandrostendione (11-KA4), 11-β-hydroxytestosterone (11-OHT), 11-β-hydroxyandrostendione (11-OHA4), testosterone, androstenedione, and DHEAS. In addition, we assessed BMI-SDSs, skinfold thicknesses, and Tanner stages. The significance level α was set to α = 0.05.

RESULTS

Increases in 11-KT, 11-KA4, 11-OHT, and 11-OHA4 levels were observed in boys and girls during puberty. 11-KT (β = 0.2, p < 0.001), 11-KA4 (β = 0.16, p < 0.001), and 11-OHA4 (β = 0.12, p = 0.003) were positively correlated with BMI in boys aged 13 years and under. 11-KT (β = 0.1, p = 0.047) was positively correlated with BMI in girls aged 11 years and under. 11-OHT was positively correlated with BMI independent of age (boys 13 years and under: β = 0.17, p < 0.001; over 13 years: β = 0.14, p = 0.001; girls 11 years and under: β = 0.17, p < 0.001; over 11 years: β = 0.18, p < 0.001).

CONCLUSION

We found increasing 11-OA serum levels throughout all Tanner stages. 11-OAs were observed to be associated with BMI and skinfold thickness, suggesting that overweight and obesity may be associated with pubertal alterations in 11-OA serum levels.

Genetics, pharmacotherapy, and dietary interventions in childhood obesity

Childhood obesity has emerged as a major global health issue, contributing to the increased prevalence of chronic conditions and adversely affecting the quality of life and future prospects of affected individuals, thereby presenting a substantial societal challenge. This complex condition, influenced by the interplay of genetic predispositions and environmental factors, is characterized by excessive energy intake due to uncontrolled appetite regulation and a Westernized diet. Managing obesity in childhood requires specific considerations compared with adulthood, given the vulnerability of the critical juvenile-adolescent period to toxicity and developmental defects. Consequently, common treatment options for adult obesity may not directly apply to younger populations. Therefore, research on childhood obesity has focused on genetic defects in regulating energy intake, alongside pharmacotherapy and dietary interventions as management approaches, with an emphasis on safety concerns. This review aims to summarize canonical knowledge and recent findings on genetic factors contributing to childhood obesity. Additionally, it assesses the efficacy and safety of existing pharmacotherapies and dietary interventions and suggests future research directions. By providing a comprehensive understanding of the complex dynamics of childhood obesity, this review aims to offer insights into more targeted and effective strategies for addressing this condition, including personalized healthcare solutions.

Percent body fat, but not body mass index, is associated with cardiometabolic risk factors in children and adolescents

Background

The epidemic of overweight and obesity has become a worldwide public health problem. Cardiometabolic diseases may originate in childhood. We investigated the association between percent body fat (PBF) measured by the bioelectrical impedance assay and cardiometabolic risk (CMR) in pediatrics.

Methods

This cross-sectional study involved 3819 subjects (6-17 years old) in Shanghai. We assessed the association between PBF and body mass index (BMI) with multiple CMR factors. We examined the risk for cardiometabolic abnormalities attributable to overweight and obesity based on age- and sex-specific PBF Z-scores and BMI Z-scores, respectively.

Results

PBF, but not BMI, was positively associated with multiple CMR factors in males and females except for total cholesterol in females (all p < 0.05). Compared with the non-overweight group based on PBF, overweight and obese subjects had increasingly higher odds ratio of dyslipidemia (2.90 (1.99-4.23), 4.59 (2.88-7.32) for males and 1.82 (1.20-2.75), 2.46 (1.47-4.11) for females) and elevated blood pressure (BP) (3.26 (2.35-4.51), 4.55 (2.92-7.09) for males and 1.59 (1.07-2.34), 3.98 (2.27-6.17) for females). Obesity females showed a higher likelihood for hyperglycemia (2.19 (1.24-3.84)) than non-overweight females. In both sexes, the predictive effect of PBF on dyslipidemia and elevated BP in adolescents was better than that in children. For hyperglycemia, the predictive effect of PBF was better in male adolescents and female children. There was no risk difference for cardiometabolic abnormalities attributable to BMI-based obesity categories.

Conclusions

PBF but not BMI was associated with CMR. Overweight and obesity categories based on PBF had an increased risk for cardiometabolic abnormalities in children and adolescents.

Metabolomic Predictors of Dysglycemia in Two U.S. Youth Cohorts

Here, we seek to identify metabolite predictors of dysglycemia in youth. In the discovery analysis among 391 youth in the Exploring Perinatal Outcomes among CHildren (EPOCH) cohort, we used reduced rank regression (RRR) to identify sex-specific metabolite predictors of impaired fasting glucose (IFG) and elevated fasting glucose (EFG: Q4 vs. Q1 fasting glucose) 6 years later and compared the predictive capacity of four models: Model 1: ethnicity, parental diabetes, in utero exposure to diabetes, and body mass index (BMI); Model 2: Model 1 covariates + baseline waist circumference, insulin, lipids, and Tanner stage; Model 3: Model 2 + baseline fasting glucose; Model 4: Model 3 + baseline metabolite concentrations. RRR identified 19 metabolite predictors of fasting glucose in boys and 14 metabolite predictors in girls. Most compounds were on lipid, amino acid, and carbohydrate metabolism pathways. In boys, no improvement in aurea under the receiver operating characteristics curve AUC occurred until the inclusion of metabolites in Model 4, which increased the AUC for prediction of IFG (7.1%) from 0.81 to 0.97 (p = 0.002). In girls, %IFG was too low for regression analysis (3.1%), but we found similar results for EFG. We replicated the results among 265 youth in the Project Viva cohort, focusing on EFG due to low %IFG, suggesting that the metabolite profiles identified herein have the potential to improve the prediction of glycemia in youth.

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.

Metabolic syndrome and cardiorespiratory fitness in children and adolescents: the role of obesity as a mediator

OBJECTIVES

To analyse the prevalence and association between metabolic syndrome (MetS), clustered cardiometabolic risk (CCMR), obesity (body mass index [BMI], fat mass [FM] and waist circumference [WC]), and cardiorespiratory fitness (CRF); and to assess whether obesity (BMI, FM, and WC) acts as a mediator between CRF and MetS or CCMR.

METHODS

This cross-sectional study included a subsample of the AFINA-te Study (n = 209; 11.51 ± 0.72 years old). BMI, FM, and WC were assessed. The Course-Navette test was used to assess CRF. MetS was calculated following the International Diabetes Federation (IDF) definitions, and assessed using WC, triglycerides (TGs), high density lipoprotein (HD), fasting glucose (FG), and systolic and diastolic blood pressures (SBP/DBP). CCMR was calculated based on the sex and age-specific z score.

RESULTS

The prevalence of overweightness, obesity, MetS, and CCMR were 17.22, 1.44, 5.74, and 18.36%, respectively. After including BMI, FM, or WC into the model, the association between CRF and MetS was no longer significant, and the association between CRF and CCMR was only significant when it was mediated by BMI (β = -0.006; p = 0.026). The rest of the analysis of the mediation did not show a direct effect, although a significant indirect effect with a significant value for the Sobel test was observed (all p < 0.001).

CONCLUSIONS

BMI, FM, and WC act as full mediators in the association between CRF and MetS; FM and WC act as full mediators in the association between CRF and CCMR; and BMI acts as a partial mediator. The use of FM or WC as obesity variables is recommended.

Social and Behavioral Factors Associated with BMI and Waist Circumference among Adolescents: The Jackson Heart KIDS Pilot Study

Background

African American children and adolescents make up a disproportionately large segment of those classified as overweight and obese. The purpose of this study was to examine social and behavioral factors associated with accelerated accumulation of weight and adiposity among this group.

Methods

The data for this cross-sectional study were drawn from the Jackson Heart KIDS Pilot Study - an offspring cohort study comprising 12- to 19-year-old descendants of Jackson Heart Study participants (N=212). Body mass index (BMI) and waist circumference were the outcomes of interest. Daily hassles, fruit and vegetable consumption, physical activity, television watching, parent/grandparent weight status and participant birth weight, age and sex were the independent variables included in the analyses.

Results

Males and females were equally represented in the study and the mean BMI and waist circumference for adolescents in the study was 25.81±7.78 kg/m² and 83.91 ± 19.81 cm, respectively. Fully adjusted linear regression models for the total sample produced results indicating that age, television viewing, weight control, and parental weight status were positively associated with BMI and waist circumference, respectively. Findings from sex-stratified models for BMI and waist circumference indicated that the significance of coefficients for age, television viewing, and parent/grandparent weight status varied by sex.

Conclusions

Knowledge is limited about how sex or gender interact with social and behavioral factors to influence African Americans' health and additional studies are needed to specify how these factors interact to accelerate weight gain and adipose tissue accumulation over the life course.

Dietary assessment methods in surveillance systems targeted to adolescents: A review of the literature

AIMS

The present paper aims to identify ongoing multinational surveillance systems (SURSYSs) assessing diet and nutrition targeted to adolescents, including European surveys involving multiple countries and similar initiatives conducted in non-European countries with developed economies, and to describe the dietary assessment methods used.

DATA SYNTHESIS

A total of 13 SURSYSs conducted in Europe, USA, Canada, Australia and New Zealand were identified. Dietary assessment methods commonly used include 24-h recalls (24H-Rs) and questionnaires or interviews. Food frequency questionnaires (FFQs) are used in combination with 24H-Rs in six SURSYSs: only FFQs are used in four SURSYSs; 24H-Rs only in one system and a 24H-R in combination with a general questionnaire/interview in one SURSYS. Eleven systems collect information also on some dietary habits and ten systems on other nutritional indicators such as anthropometric and/or biochemical measures. The FFQs used are not homogeneous and often include limited food or beverage items such as fruits and vegetables or sugar-sweetened beverages. In seven systems, foods specifically consumed by adolescents, such as fast food or snacks, are not assessed; instead, a total of seven systems collect data on supplement intake and just in very few cases on fats, legumes and/or water.

CONCLUSIONS

This study detected considerable variability across the systems identified, suggesting the need for a SURSYS targeted to adolescents that gathers as much as possible complete dietary information, with standardised methodology and regular periodicity. The detailed information provided by this review could be useful to national authorities for the choice of protocols to be applied in their own national surveys.

Impact of Body Mass Index on Perioperative Outcomes of Endoscopic Pituitary Surgery

Background Endoscopic pituitary surgery (EPS) is increasingly being used for the treatment of pituitary lesions. Obesity is a growing epidemic in our nation associated with numerous comorbidities known to impact surgical outcomes. We present a multi-institutional database study evaluating the association between body mass index (BMI) and postsurgical outcomes of EPS. Methods Patients who underwent EPS from 2005 to 2013 were identified from the American College of Surgeons National Surgical Quality Improvement Program database. Preoperative variables, comorbidities, and postoperative outcomes, such as 30-day complications, morbidity, and mortality, were analyzed. Results A total of 789 patients were analyzed, of which 382 were obese (BMI ≥ 30) (48.4%). No difference in reoperation rate ( P = .928) or unplanned readmission rates ( P = .837) was found between the obese versus nonobese group. A higher overall complication rate was observed in the obese group compared to the nonobese counterparts ( P = .005). However, when separated into surgical complications (3.7% vs 1.5%, P = .068) and medical complications (7.6% vs 3.9%, P = .027), only medical complications, specifically pneumonia, remained significantly different. EPS on obese patients was also associated with prolonged operating time (154.8 min vs 141.0 min, P = .011). Conclusions EPS may be a safe treatment option for pituitary lesions in the obese population. Although obese patients undergoing EPS are at increased risk of medical complications and prolonged operating times, this did not influence mortality, reoperation, or readmission rate.

Evaluating the predictive factors of resting energy expenditure and validating predictive equations for Chinese obese children

BACKGROUND

To study the predictive factors of resting energy expenditure (REE) and evaluate the accuracy of predicted equations with indirect calorimeter (IC) in Chinese school-age children, particularly for the obese population.

METHODS

Recruited children were from the department of child healthcare in Nanjing children's hospital during July 2014-September 2015. Anthropometric parameters and body composition were measured by bioelectrical impedance. Measured REE was assessed by IC. Predicted REE was estimated using ten published equations.

RESULTS

248 children aged 7-13 years were recruited, including 148 obese [body mass index standard deviation score (BMISDS) = 2.48 ± 0.91] and 100 non-obese (BMISDS = - 0.96 ± 1.08). The unit mass of REE (REE/kg) in obese group (29.06 ± 5.74) was lower than that in non-obese group (37.51 ± 6.56). The stepwise regression showed that age, BMISDS and fat-free mass (FFM) had a major impact on REE/kg as the regression equation: Y = 54.41 - 1.36 × X₁ - 2.25 × X₂ - 0.16 × X₃ (Y REE/kg, X₁ age, X₂ BMISDS, X₃ FFM; R = 0.633, R² = 0.401, P < 0.01). The accuracy of predicted REE in obese subjects was 62.16% by the new predictive equations.

CONCLUSIONS

The REE/kg in obese children was lower and closely correlated with age, BMISDS and FFM. It is necessary to validate the new predictive equation in a larger sample to estimate energy requirements, particularly for children with 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.