Stabilization of BMIz Score is Associated with a Decrease in Visceral Fat in Children with Obesity.

BMIz-score (BMIz) is commonly used to assess childhood obesity. Whether change in BMIz score predicts change in visceral fat remains unclear. The objective of the work was to study changes in visceral fat, cardiovascular fitness (CVF), and metabolic health over 6 months in children with stable/decreased-BMIz vs. increased-BMIz. Ninety children with obesity, referred for lifestyle intervention were studied (mean age 11±3.1 years, 50% girls, 22% Hispanic). Assessment included abdominal and total fat by dual X-ray absorptiometry (DXA), sub-maximal VO2 for CVF, anthropometrics, and fasting insulin, glucose, HDL-C, triglycerides, AST and ALT at 0 and 6 months. Sixty-three children (70%) showed a stable/decrease in BMIz over 6 months. There was no significant change in total body fat between groups (-1.3±2.9% in BMIz-stable/down vs. - 0.6 ± 2.6% BMIz-up, p=0.459); however, BMIz-stable/down group showed a decrease in visceral fat compared to the BMIz-up group (-258±650 g vs.+137±528 g, p=0.009). BMIz-stable/down group also demonstrated increased CVF (+1.2 ml/kg/min, p<0.001), not seen in the BMIz-up group. Neither group had significant changes in metabolic markers. Preventing BMIz increase in obese children predicts a significant decrease in visceral fat even if total body fat is unchanged. This is often associated with increased fitness. Thus, increasing fitness level and keeping BMI stable are strategic initial goals for obese children.

BMI z-score in obese children is a poor predictor of adiposity changes over time.

BACKGROUND: The age and sex standardized body mass index (BMIz) is a simple and widely utilized screening tool for obesity in children and adolescents. The purpose of this study was to evaluate the relationship between the BMIz trajectory versus the percent body fat (%FAT) trajectory, and if BMIz could predict significant changes in %FAT in a sample of obese children and adolescents. METHODS: In this longitudinal observational study, body composition was measured by dual energy x-ray absorptiometry (DXA) in obese children within a multidisciplinary pediatric fitness clinic at an academic medical center over a 3-year time period. Regression analyses were conducted to evaluate the association between changes in BMIz and changes in %FAT. RESULTS: Baseline assessment was obtained from 515 participants. The reduction observed in BMIz (2.20 to 2.08, p < 0.0001) correlated with the reduction in %FAT (38.5 to 35.8%, p < 0.05) in the first two years. The overall correlation between the slope in BMIz reduction versus %FAT reduction was moderate (r = 0.36, p < 0.0001) over the 3-year follow-up period. The sensitivity of BMIz changes for predicting a decrease in %FAT was acceptable (70, 95% CI: 61-78%), however the specificity was poor (42, 95% CI: 31-54%). CONCLUSIONS: These findings advance the understanding of the utility and limitations of BMIz in children and adolescents. While BMIz may be sensitive to changes in adiposity, it is a weak predictor of these changes in total body fat (%FAT) due to the poor specificity. Therefore, clinicians must exercise caution when monitoring changes in a growing child's body composition to avoid misclassifying or missing substantial change when utilizing BMIz alone.

BMI is a poor predictor of adiposity in young overweight and obese children.

BACKGROUND: The body mass index (BMI) is a simple and widely utilized screening tool for obesity in children and adults. The purpose of this investigation was to evaluate if BMI could predict total fat mass (TFM) and percent body fat (%FAT) in a sample of overweight and obese children. METHODS: In this observational study, body composition was measured by dual energy x-ray absorptiometry (DXA) in 663 male and female overweight and obese children at baseline within a multidisciplinary, pediatric fitness clinic at an academic medical center. Univariate and multivariate regression analyses were conducted to evaluate whether BMI z-score (BMIz) predicts TFM or %FAT. RESULTS: The BMIz, sex and age of subjects were identified as significant predictors for both TFM and %FAT. In subjects younger than 9 years, the BMIz was a weak to moderate predictor for both TFM (R2 = 0.03 for males and 0.26 for females) and %FAT (R2 = 0.22 for males and 0.38 for females). For subjects between 9 and 18 years, the BMIz was a strong predictor for TFM (R2 between 0.57 and 0.73) while BMIz remained only moderately predictive for %FAT (R2 between 0.22 and 0.42). CONCLUSIONS: These findings advance the understanding of the utility and limitations of BMI in children and adolescents. In youth (9-18y), BMIz is a strong predictor for TFM, but a weaker predictor of relative body fat (%FAT). In children younger than 9y, BMIz is only a weak to moderate predictor for both TFM and %FAT. This study cautions the use of BMIz as a predictor of %FAT in children younger than 9 years.

Structural equation modeling of the associations between the home environment and obesity-related cardiovascular fitness and insulin resistance among Hispanic children.

Hispanic children are disproportionally affected by obesity-related risk of metabolic disease. We used the structural equation modeling to examine the associations between specific diet and physical activity (PA) behaviors at home and Hispanic children's metabolic health. A total of 187 Hispanic children and their parents from an urban community in Wisconsin participated in the study. Exposure variables included, children's daily intake of sugar-sweetened beverages (SSB) and PA; home availability of SSB and PA areas/equipment; and parents' intake of SSB and PA, assessed through self-administered questionnaires. Outcome variables for children's metabolic health included, measured anthropometrics; cardiovascular fitness assessed using the Progressive Aerobic Cardiovascular Endurance Run (PACER); and insulin resistance determined with the homeostasis model assessment of insulin resistance (HOMAIR). We found that children's daily intake of SSB was positively associated with BMI z-score, which in turn, was positively associated with HOMAIR (P < 0.05). Specific diet behaviors at home associated with children's intake of SSB, included home availability of SSB, which mediated the association between parents' and children's intake of SSB (P < 0.05). Children's PA was positively associated with PACER z-score, which in turn, was inversely associated with HOMAIR (P < 0.05). Specific PA behaviors at home associated with children's PA, included home availability of PA areas/equipment, which mediated the association between parents' and children's PA (P < 0.05). The structural equation model indices suggested a satisfactory model fit (Chi-square, X(2) = 53.1, comparative fix index = 0.92, root-mean-squared error associated = 0.04). The findings confirm the need for interventions at the family level that promotes healthier home environments by targeting poor diet and low levels of PA in all family members.

In Nonobese Children, Fitness and BMI are Independent Predictors of Fasting Insulin.

OBJECTIVE: Although fitness and obesity have been shown to be independent predictors of cardiometabolic disease risk in obese children, this interaction is not well defined in nonobese children. The purpose of this study was to define the relationships between peak aerobic capacity, body composition, and fasting insulin levels in nonobese middle school children. STUDY DESIGN: 148 middle school children (mean age 11.0 ± 2.1 years, 49% male) underwent determination of body mass index (BMI) z-score, fasting glucose, fasting insulin, body composition by DXA scan (lean body mass and body fat percentage), and peak oxygen uptake per kg of lean body mass (VO2peak). Univariate correlations and multivariate regression analysis were used to identify independent predictors of fasting insulin using age, sex, percent body fat, body mass index z-score, and VO2peak. RESULTS: fasting insulin was significantly related to VO2peak (r =-0.37, p < .001), percent body fat (r = .27, p < .001), and BMI z-score (r = .33, p = .002). After inclusion in the multivariate model, VO2peak (p = .018) and body mass index z-score (p = .043) remained significant predictors of fasting insulin, while age (p = .39), sex (p = .49), and percent body fat (p = .72) did not. CONCLUSIONS: Among nonobese middle school children, fasting insulin is independently related to aerobic fitness after accounting for age, sex, and body composition. Public health efforts to reduce cardiometabolic disease risk among all adolescents should include exercise programs to increase cardiovascular fitness.

Long-term effects of recombinant human growth hormone therapy in children with Prader-Willi syndrome.

PURPOSE OF REVIEW: Recombinant human growth hormone (hGH) therapy in children with Prader-Willi syndrome (PWS) improves linear growth, body composition, physical strength and agility, and other metabolic parameters. These benefits must be weighed against potential adverse effects, including rare occurrences of sudden death. This review summarizes recent evidence important to a benefit-risk analysis of hGH use in children with PWS. RECENT FINDINGS: Studies consistently show that hGH improves stature, body composition, fat percentage and distribution, and other metabolic markers in children with PWS. Preliminary reports of improved cognitive development during hGH have also emerged. Scoliosis progression is influenced by growth rate, but frequency of occurrence and severity are not increased by hGH exposure. PWS genotype does not appear to affect response to hGH. Concerns about hGH-associated sudden death persist, but recent studies show either absence of change in sleep-disordered breathing or improved sleep cardiovascular function during hGH therapy. SUMMARY: Recent studies confirm and expand reported benefits of hGH therapy in children with PWS, including a possible salutary role in cognitive development. These findings support previous assertions that hGH can reduce morbidity and improve function in children with PWS, and suggest that potential risks of such treatment are favorably balanced by its benefits.

A Multidisciplinary Approach to Pediatric Obesity Shows Improvement Postintervention.

OBJECTIVE: Outpatient management of pediatric obesity can be difficult, requiring a significant time commitment from both provider and patient. Multidisciplinary clinic-based programs have shown promising effects in reducing BMI during intervention, but whether these changes are sustained over time is not well studied. The purpose of this study was to determine the post-treatment outcomes of children seen in a multidisciplinary pediatric obesity clinic (MPOC). METHODS: A retrospective chart review was performed using the MPOC database, which included all clinic patients from January 2008 to August 2016 who attended a minimum of 2 visits (n = 472). The primary outcome was the absolute change in BMI Z-score (BMIZ) from the final intervention visit compared to 1- and 2-years post-intervention. Multivariate regression analysis was performed to characterize predictors of change in BMIZ. RESULTS: MPOC patients ranged in age from 3 to 18 years. Mean BMIZ decreased significantly during intervention (-0.13 ± 1.47, P < .001) and was maintained at 1- and 2-years post-intervention. In participants ages 3 to 5, BMIZ further decreased at 1 year post intervention (-0.27 ± 0.26, P < .001). Age at time of referral was the only significant predictor of change in BMIZ. CONCLUSIONS: Outpatient, multidisciplinary intervention for pediatric obesity was effective in reducing or stabilizing BMIZ during and beyond the intervention, particularly when patients were referred at an early age. Although primary prevention is the ideal management, multidisciplinary clinic intervention can be effective in the sustained treatment of pediatric obesity.

Standardized childhood fitness percentiles derived from school-based testing.

OBJECTIVE: To develop a statewide school-based program of measuring and reporting cardiovascular fitness levels in children, and to create age- and sex-specific cardiovascular fitness percentile-based distribution curves. STUDY DESIGN: A pilot study validated cardiovascular fitness assessment with Progressive Aerobic Cardiovascular Endurance Run (PACER) testing as an accurate predictor of cardiovascular fitness measured by maximal oxygen consumption treadmill testing. Schools throughout the state were then recruited to perform PACER and body mass index (BMI) measurement and report de-identified data to a centralized database. RESULTS: Data on 20 631 individual students with a mean age 12.1 ± 2.0 years, BMI of 21.4 ± 5.1, and a cardiovascular fitness measured with PACER of 29.7 ± 18.2 laps (estimated maximal oxygen consumption of 36.5 mL/kg/min) were submitted for analysis. Standardized fitness percentiles were calculated for age and sex. CONCLUSIONS: This study demonstrates the feasibility of performing, reporting, and recording annual school-based assessments of cardiovascular fitness to develop standardized childhood fitness percentiles on the basis of age and sex. Such data can be useful in comparing populations and assessing initiatives that aim to improve childhood fitness. Because health consequences of obesity result from both adiposity and physical inactivity, supplementation of BMI measurement with tracking of cardiovascular fitness adds a valuable tool for large-scale health assessment.

Sharp Rise in New-Onset Pediatric Diabetes During the COVID-19 Pandemic.

INTRODUCTION: Recent studies report a significant impact of the COVID-19 pandemic on the incidence, severity, and management of diabetes. OBJECTIVE: To determine the incidence of new onset pediatric diabetes prepandemic versus during the pandemic and to analyze the presentation based on age, severity, HbA1c, body mass index, and COVID testing. METHODS: We conducted a retrospective review of all pediatric patients admitted with newly diagnosed type 1 and type 2 diabetes mellitus admitted to the American Family Children's Hospital (Madison, Wisconsin) from 2018 through 2021. Data included age at diagnosis, body mass index, hemoglobin A1c percent and pH at presentation, presence of autoimmune pancreatic antibodies, and COVID-19 polymerase chain reaction (PCR) results at admission in pre-COVID (January 2018-February 2020) versus during COVID (March 2020-December 2021). Statistical analysis was performed using SAS software with the incidences analyzed using univariate and multivariate Poisson regression analyses. RESULTS: During the pandemic, the incidence of both type 1 and type 2 diabetes mellitus increased significantly (69% and 225%, P < 0.001, respectively), and a higher number of patients had diabetic ketoacidosis. Type 1 diabetes patients with a body mass index greater than the 95th percentile increased from 11.1% to 16.9% (OR 0.62; 95% CI, 0.29-1.29; P = 0.19). Almost all patients were COVID-19 PCR negative at the time of diagnosis. CONCLUSIONS: A dramatic increase in number and severity of newly diagnosed pediatric diabetes cases was seen during the pandemic. The increase was not explained by factors such as changes in referral patterns or insurance coverage. Further work is needed to understand the impact of societal factors and the direct diabetogenic effect of SARS-CoV-2.

Low HDL-C is a non-fasting marker of insulin resistance in children.

OBJECTIVES: Childhood obesity and associated comorbidities, including insulin resistance, are increasing in the United States. Our objectives were to (1) determine the prevalence of insulin resistance in children seen in dyslipidemia clinic and (2) evaluate which aspects of the lipid profile correlate with insulin resistance. METHODS: Children and adolescents seen in a specialized pediatric dyslipidemia clinic without secondary diagnoses known to alter the lipid panel were included. Simultaneous fasting lipid panel, insulin, and glucose levels were available in 572 children (50.5% male). RESULTS: Mean patient age was 15.0 ± 3.6 years with the majority being over 10 years of age (92.5%). Mean BMI was 29.8 ± 8.1 kg/m2 and BMI standard deviation score was 1.80 ± 0.9. Mean HOMA-IR was 6.2 ± 5.7 with a range of 0.4-49.3, and interquartile range of 2.7-7.6. Triglyceride level had a positive correlation with HOMA-IR (p<0.001). HDL-C negatively correlated with HOMA-IR even controlling for triglyceride level by multivariate analysis (p=0.001) and HDL-C <30 mg/dL predicted IR with 41.5% PPV. CONCLUSIONS: In children and adolescents with dyslipidemia, insulin resistance is common and significantly correlates with reduced HDL-C levels. Non-fasting samples are easier to obtain in children and low HDL-C, which is minimally affected on non-fasting samples, could be an easily obtained indicator of IR. Increasing detection of insulin resistance in children with dyslipidemia may provide greater opportunities for lifestyle interventions and possible pharmacotherapy to modify cardiovascular risk.

Adolescent Girls With Overweight and Obesity Feel Physically Healthy and Highlight the Importance of Mental Health.

INTRODUCTION: Obesity in adolescence is a significant ongoing public health problem that has not improved over the past decade. OBJECTIVE: This descriptive qualitative study explores the perspective of female adolescents who are overweight or obese regarding their views on health and weight within the clinic setting. METHODS: In-depth interviews were conducted with female adolescents (age 13-19 years old; BMI ≥85th percentile) from the mid-west region of the United States (N = 28). Inductive thematic analysis using Braun & Clarke's methods was utilized. RESULTS: The findings from this study revealed that the adolescents' view of health encompasses physical, mental, and psychosocial health dimensions, and despite being overweight and obese, the participants felt healthy. Participants discussed the need to eat healthier and increase their daily physical activity, but were unable to transform this into action. Within the clinical setting, the adolescents were sensitive to weight discussions. CONCLUSION: Results from this study can increase providers' understanding of the adolescent, increase awareness of adolescent sensitivity, and assist researchers in developing age-appropriate interventions for effective treatment and prevention of childhood obesity.

Female adolescents with overweight and obesity share their perspectives on the clinical setting and weight management.

The clinical setting remains a strategic environment for early assessment, identification and treatment of adolescents with obesity. Yet, healthcare providers' (HCPs) efforts have been unsuccessful in improving physical activity, nutritional intake or body mass index in adolescents with obesity. Obesity is a chronic condition that influences how patients interact with HCPs and experience ambulatory healthcare appointments. However, it is unknown how female adolescents with obesity perceive the clinical setting, especially regarding weight management. The purpose of this study was to explore the perceptions of female adolescents with obesity regarding health and weight management in the clinical setting. Using a qualitative design, 28 English-speaking female adolescents, 13 to 19 years of age, with a body mass index ≥85th percentile for height and weight participated in individual interviews. Results demonstrate that adolescents with obesity desire to be recognized as unique individuals and to be involved in their own health conversations. The participants reported that their health care was inadequate when they received impersonal and vague advice from HCPs on weight loss. Weight-related communication was best received in a kind and empathetic manner, with a focus on improving one's health (instead of losing weight). Adolescents in this study articulated the components of healthy eating and physical exercise, yet were unable to synthesize this knowledge into specific dietary practices and daily physical activities. The insights derived from female adolescents with obesity provide guidance on how HCPs can improve their relationship and engage the adolescent in weight-based discussions. Concrete, actionable recommendations are provided for providers who work with female adolescents who are overweight or obese.

Submaximal treadmill test predicts VO2max in overweight children.

OBJECTIVE: To demonstrate the ability of a submaximal test to predict VO(2max) in overweight children. STUDY DESIGN: A total of 130 children, 11 to 14 years old, with body mass index >85 percentile for age and sex performed a submaximal walking test. VO(2max) was measured by using open circuit spirometry during a graded exercise test to volitional fatigue. An equation to predict VO(2max) was modeled by using the variables of sex, weight (kg), height (cm), heart rate (HR) after 4 minutes during the submaximal test (4minHR), HR difference (4minHR - resting HR), and submaximal treadmill speed (miles per hour [mph]) in 75% of the subjects. Validation was performed by using the remaining 25% of subjects. RESULTS: A total of 113 subjects achieved a maximal effort and was used in the statistical analysis. Development and validation groups were similar in all aspects. On validation, the mean square error was 241.06 with the predicted VO(2max) within 10% of the observed value in 67% of subjects. CONCLUSION: VO(2max) was accurately predicted in this cohort of overweight children by using a submaximal, treadmill-based testing protocol.

Environment and obesity in the National Children's Study.

OBJECTIVE: In this review we describe the approach taken by the National Children's Study (NCS), a 21-year prospective study of 100,000 American children, to understanding the role of environmental factors in the development of obesity. DATA SOURCES AND EXTRACTION: We review the literature with regard to the two core hypotheses in the NCS that relate to environmental origins of obesity and describe strategies that will be used to test each hypothesis. DATA SYNTHESIS: Although it is clear that obesity in an individual results from an imbalance between energy intake and expenditure, control of the obesity epidemic will require understanding of factors in the modern built environment and chemical exposures that may have the capacity to disrupt the link between energy intake and expenditure. The NCS is the largest prospective birth cohort study ever undertaken in the United States that is explicitly designed to seek information on the environmental causes of pediatric disease. CONCLUSIONS: Through its embrace of the life-course approach to epidemiology, the NCS will be able to study the origins of obesity from preconception through late adolescence, including factors ranging from genetic inheritance to individual behaviors to the social, built, and natural environment and chemical exposures. It will have sufficient statistical power to examine interactions among these multiple influences, including gene-environment and gene-obesity interactions. A major secondary benefit will derive from the banking of specimens for future analysis.

The influence of fitness on insulin resistance in obese children.

An increasingly pervasive environment of reduced activity and easy access to high caloric food is leading to an epidemic of poor cardiovascular fitness, obesity, insulin resistance and type 2 diabetes (T2DM) in children. Studies have shown that insulin resistance (IR) to be an independent predictor for morbidity as well as mortality. These serve as a strong stimulus for public health strategies to improve fitness in children and adolescents. Methods to assess IR, improve IR and understand complications are increasingly important in children.

Fitness level and body composition are associated with inflammation in non-obese children.

Childhood obesity and poor fitness are associated with insulin resistance (IR), risk for coronary heart disease (CHD), and type 2 diabetes mellitus. Elevated markers of inflammation (e.g., C-reactive protein [CRP]) are independent predictors of CHD. Whether higher percent body fat and poor fitness in non-obese children are associated with evidence of inflammation and IR is unclear. We evaluated 75 children with non-obese body mass index (BMI) for age (<95th percentile), ages 11-14 years for fasting insulin, glucose, adiponectin, CRP, body composition, and maximum oxygen-consumption (VO2max). CRP correlated positively with body composition (BMI z-score, p = 0.00062; percent body fat, p = 0.00007; and total body fat in grams, p = 0.00006) and negatively with VO2max, p = 0.036. Using multivariate analysis, VO2max and percent body fat were both independent predictors of CRP. Fasting insulin and insulin resistance as assessed by QUICKI did not correlate with CRP, fitness, or fatness in these non-obese children. Adiponectin showed no significant correlations, and gender did not influence correlation analyses. We conclude that in non-obese children, low fitness and higher body fat are both associated with inflammation (i.e., higher levels of CRP). This observation strengthens the importance of promoting both fitness and healthy body composition in all children.

School-based exercise improves fitness, body composition, insulin sensitivity, and markers of inflammation in non-obese children.

BACKGROUND: Poor cardiovascular fitness (CVF) is a risk factor for obesity, as well as insulin resistance (IR), inflammation, and cardiovascular disease. We have previously shown that a school-based fitness curriculum can improve CVF, as well as IR and body composition in obese children. Whether such a program improves CVF, IR, and other health indicators in non-obese children is unresolved. AIM: To determine whether a school-based fitness program improves body composition, CVF, markers of inflammation (e.g. CRP, TNF-alpha, adiponectin), and insulin sensitivity in nonobese children. STUDY DESIGN: 35 non-obese middle school children with body mass index below the 95th percentile for age were enrolled in a 'fitness-oriented' gym class. Children underwent fasting evaluation of insulin, glucose, adiponectin, CRP, TNF-alpha, body composition by dual X-ray absorptiometry (DXA), and maximal VO2 treadmill testing at baseline (prior to the school year) and again at end of the school year. MAIN OUTCOME MEASURES: Testing for CVF (maximal VO2 treadmill testing), DXA, and fasting evaluation of insulin, glucose, adiponectin, CRP and TNF-alpha. RESULTS: Children demonstrated a decrease in BMI z-score (-0.14 +/- 0.33, p = 0.02), HOMA-IR (-0.15 +/- 0.35, p = 0.016), and TNF-alpha (-2.55 +/- 1.79 pg/ml, p < 0.001), and an increase in VO2(max) (+1.58 +/- 2.34 ml/kg/min, p < 0.001), adiponectin (+7,553 +/- 11,100 ng/ml, p < 0.001), and muscle mass (+2,282 +/- 1,882.73 g, p < 0.001) after nine months of study. CONCLUSIONS: The school-based fitness oriented curriculum resulted in improved body composition and insulin sensitivity, increased CVF, and decreased inflammation in non-obese children. Combined with prior studies, these data demonstrate that school-based fitness curricula can benefit both obese and non-obese children. Partnerships with schools to promote fitness should be part of a public health approach to improving children's health.

US Centers for Disease Control and Prevention-Based Physical Activity Recommendations Do Not Improve Fitness in Real-World Settings.

BACKGROUND: The US Centers for Disease Control and Prevention (CDC) promotes school-based strategies to increase physical activity (PA). Implementation feasibility and effect of these interventions on cardiovascular fitness (CVF) is unknown. METHODS: Forty-nine low-SES schools were randomly assigned to either (1) continue routine PA programs (N = 24 schools, 2399 students) or (2) implement 4 CDC-based PA strategies (N = 25 schools, 2495 students). CVF assessed by PACER (Progressive Aerobic Cardiovascular Endurance Run) was obtained at the beginning and end of the school year. A post-study questionnaire was administered at each school to assess adherence. RESULTS: Overall, PACER z-scores were not augmented by CDC-based PA strategies. In boys, PACER z-scores increased similarly in both intervention and control schools. In girls, increased mean PACER z-score was greater in control schools (p < .01). Fifty-two percent of intervention school's staff reported inability to implement or sustain 4 CDC-based PA strategies. CONCLUSIONS: Planned implementation of school-based CDC PA strategies did not increase CVF compared to routine PA programming. Lack of efficacy in girls suggests need for sex-specific targeted strategies. These findings highlight limited efficacy of CDC-based PA recommendations alone in low-SES schools. Schools may require additional support to successfully implement recommendations and meaningfully affect health outcomes.