Effect of puberty on body composition

The Relationship of Handgrip Strength to Body Composition and Cardiopulmonary Fitness in Children and Young Adults

Objective

To investigate the relationship between handgrip strength (HGS) and sex, anthropometrics, body composition, and cardiovascular fitness has not been well studied in children, adolescents, and young adults.

Study design

A single-center retrospective review of patients <25 years old without known heart disease and referred for clinical cardiopulmonary exercise testing was performed. Each patient underwent HGS testing, bioelectrical impedance body composition analysis, and cardiopulmonary exercise testing. Relationships between variables were assessed using the Pearson correlation coefficient, linear regression, cubic spline, and multivariable analysis. Comparisons by sex were performed using the Student t test.

Results

The study included 316 patients without heart disease (age 15.1 ± 2.4 years old; 35% male). Male patients had greater peak dominant (34.4 ± 11.9 kg vs 27.8 ± 6.2 kg; P < .001) and nondominant (32.1 ± 11.1 kg vs 25.3 ± 6.0 kg; P < .001) HGS than female patients, with these differences more noticeable in the teenage years. Peak dominant HGS averaged 30.2 ± 9.3 kg and was correlated with age (r = 0.49, P < .001) and weight (r = 0.56, P < .0001); peak dominant HGS was even more strongly correlated with total body skeletal muscle mass (r = 0.80, P < .001), peak oxygen consumption (mL/min) (r = 0.69, P < .0001), and peak work rate (r = 0.70, P < .001).

Conclusions

HGS is strongly associated with total and segmental skeletal muscle mass, peak work rate, and peak oxygen consumption. Sex-based differences in handgrip strength values emerge in mid-teenage years in parallel to expected pubertal changes.

Childhood obesity: The threatening apprentice of the adiposity empire

Childhood obesity is a global health problem, with its prevalence having tripled since 1975. The increase in its prevalence has been predominantly in developing countries, but also in those with high economic status. Nowadays, there are multiple obesity definitions, however, one of the most accurate is the one which defines obesity as the accumulation of excessive body adiposity and not as an body weight excess. Nevertheless, the body mass index (BMI) is the most frequently used tool for its classification, according to the cut-off points established by the Center for Disease Control and World Health Organization tables. In children and adolescents an adiposity excess is related to the appearance of cardiovascular disease in adulthood and with many comorbidities such as metabolic syndrome, insulin resistance, type 2 diabetes, hypertension and metabolic dysfunction-associated steatotic liver disease, among others. Currently, there is still controversy about which is the ideal indicator for measuring overweight and obesity. BMI is still used as a standardized measure but may miss cases in which body composition is pathological despite a BMI within the normal-weight category. An adequate knowledge of the impact on health of dysfunctional adiposity as well as its accurate diagnosis will allow health professionals to address this condition in a more precise and comprehensive manner, and substantially improve the associated cardiometabolic risk and prognosis.

The diagnostic utility of bioelectrical impedance analysis in distinguishing precocious puberty from premature thelarche

OBJECTIVES

Clinical (assessing breast development), laboratory (FSH, LH, estradiol, and GnRH stimulation test), and radiological methods (bone age and pelvic ultrasonography) are used to distinguish central precocious puberty (CPP) from premature thelarche (PT). We examined also via bioelectrical impedance analysis (BIA).

METHODS

The fat mass (FM), fat-free mass (FFM), muscle mass (MM), bone mass (BM), total body water, and percentages (%), basal metabolic rate, phase angle (PhA), muscle-to-fat ratio (MFR), sarcopenic index, and segmental body proportions were determined via Tanita MC-780 MA model measuring device.

RESULTS

A total of 111 girls, 34 with CPP, 35 with PT, and 42 with healthy controls, were included. Although the baseline weight, height, and BMI SDS of the groups were not statistically different, the FM (%) was found to be lower (p=0.021), and the FFM (%) (p=0.021), MM (%) (p=0.015), BM (%) (p=0.022), and MFR values (p=0.017) were higher in CPP group. In CPP group, right arm FM (%) (p=0.016), left arm FM (%) (p=0.007), and trunk FM (%) (p=0.008) were lower than other groups.

CONCLUSIONS

We detected a MFR cutoff value of (2.96) with 58.8 % sensitivity and 58.4 % specificity, a cutoff value of (3.57) with 50 % sensitivity and 82 % specificity to differentiate CPP cases from others (PT and healthy controls). These rates are relatively low, but these are the first results in this field and may be guiding for studies conducted in large series.

Fit for comparison: controlling for cardiorespiratory fitness in exercise physiology studies of sex as a biological variable

More studies in exercise physiology are investigating sex as a biological variable, but the potential confounding effect of cardiorespiratory fitness is often neglected. As maximal oxygen uptake (V ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{max}}}}$ ) correlates with many physiological outcomes at rest and in response to exercise, differences inV ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{max}}}}$ between male and female participants may hinder interpretation. Here we revisit decades-old arguments that advocate for matching males and females forV ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{max}}}}$ normalized to fat-free mass (FFM) when investigating sex differences in the context of exercise. The rationale for using FFM to normalizeV ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{max}}}}$ , as opposed to total body mass, is that females, on average, have a greater proportion of body fat than males and body fat does not contribute toV ̇ O 2 ${{\dot{V}}_{{{{\mathrm{O}}}_2}}}$ . Using a multistudy dataset of males (n = 54) and females (n = 54) matched forV ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{max}}}}$ per FFM, we illustrate the different approaches toV ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{max}}}}$ normalization and the effects of poor or incorrect matching on interpretation. Modern assessments of body composition allow for segregation of bone from total FFM and regional measures of body composition; however neither approach seems to be an improvement on whole-body FFM as the normalization factor forV ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{max}}}}$ . A group-level difference of less than 5% forV ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{max}}}}$ per unit FFM is a strong starting point for comparisons between males and females, but the allowable difference depends on the extent to which cardiorespiratory fitness influences the variable of interest and other competing study design decisions. Researchers should be encouraged to normalizeV ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{max}}}}$ to FFM for exercise physiology studies investigating sex differences.

Independent effect of body fat content on inflammatory biomarkers in children and adolescents: The GENOBOX study

BACKGROUND AND AIMS

To assess the relationship between body composition indicators and inflammatory biomarkers in children and adolescents of the GENOBOX study.

METHODS AND RESULTS

Anthropometry data from 264 subjects from the subsample of Zaragoza (Spain) included: weight, height, waist circumference, body mass index and triponderal index. Body composition was determined by Dual-energy X-ray Absorptiometry (DXA), obtaining visceral adipose tissue, fat mass index and lean mass index. Age and sex specific z-scores were computed. Simple linear regression models were performed with inflammatory biomarkers (hsCRP, IL8, TNF-α, adiponectin, leptin and resistin) as dependent variables, and each of the body composition indices as independent variables. Prepubertal boys had higher IL8 and resistin values and pubertal girls had higher HOMA-IR and leptin values. hsCPR and leptin were associated with fat mass, both in prepubertals and pubertals, independently of lean mass, and regardless of how body composition was measured. All body composition indices were inversely associated with adiponectin, except for fat mass index in pubertals, but none of them were statistically significant.

CONCLUSION

A positive association between hsCRP and leptin with all body fat composition parameters, measured by standard nutritional indicators and DXA, was observed in both sexual stages.

Twenty Four-Hour Movement Behaviours Research Among Australian Children and Adolescents: A Scoping Review

BACKGROUND

Adherence to 24-h movement behaviour (24-h MB) guidelines, encompassing moderate-to-vigorous physical activity (MVPA), recreational screen time (ST) and sleep, is low among Australian children and adolescents, with poorly understood contributing factors. This review synthesised current evidence to identify areas requiring further exploration in this demographic.

METHODS

A systematic search in PubMed, Scopus, Web of Science, SportDiscus and CINAHL identified articles published from June 2016 and March 2024. Peer-reviewed articles in English focusing on healthy school-aged children and adolescents (5-17 years) addressing 24-h MB guidelines, including those using compositional data analysis (CoDA), were included.

RESULTS

Twenty-three articles met the inclusion criteria. Most were of fair quality and used cross-sectional designs and self-reported measures. Adherence to 24-h MB guidelines ranged from 2% to 22% in Australia. The included articles focused on prevalence (n = 12), correlates (n = 5), health outcomes (n = 13), academic performance (n = 4), and an intervention (n = 1). Factors negatively associated with adherence included lower socioeconomic status, transitions from primary to secondary school, and family history of diabetes. Positive outcomes associated with adherence included improved academic performance, quality of life, and physical and mental health. Important research gaps were identified, particularly regarding intervention studies and limited exploration of a causal relationship between adherence, contributing factors, and related outcomes. Compositional analyses (n = 10) suggested that reallocating time from sedentary behaviour to MVPA may improve fitness and academic performance, whereas increasing sedentary time may lower sleep efficiency.

CONCLUSIONS

A comprehensive understanding of factors associated with adherence to 24-h MB guidelines among Australian children and adolescents is lacking. More longitudinal and interventional studies using objective measures are needed to establish causality and provide a deeper understanding of adherence to 24-h MB guidelines among children and adolescents in Australia.

SO WHAT

This scoping review underscores the need for more longitudinal and intervention-based research to explore causal relationships between adherence to 24-h MB guidelines and potential benefits for health, academic performance, and quality of life in Australian children and adolescents.

Using Metabolic Testing to Personalize Behavioral Obesity Treatment

Background

There are large individual differences in weight loss and maintenance. Metabolic testing can provide phenotypical information that can be used to personalize treatment so that people remain in negative energy balance during weight loss and remain in energy balance during maintenance. Behavioral testing can assess the reinforcing value and change in the temporal window related to the personalized diet and exercise program to motivate people to maintain engagement in healthier eating and activity programs.

Objective

Provide an expository overview of how metabolic testing can be used to personalize weight control. Ideas about incorporating behavioral economic concepts are also included.

Methods

A broad overview of how resting metabolic rate, thermic effect of food and respiratory quotient can be used to improve weight control. Also discussed are behavioral economic principles that can maximize adherence to diet and activity protocols.

Results

Research suggests that measuring metabolic rate can be used to set calorie goals for weight loss and maintenance, thermic effect of food to increase energy expenditure, and respiratory quotient to guide macronutrient composition of the diet and maximize fat loss. Developing programs that foster a strong motivation to eat healthier and be active can maximize treatment success.

Conclusion

Incorporating metabolic measures can personalize behavioral weight loss programs, and the use of behavioral economic principles can increase the probability of adherence and long-term success in weight control.

Longitudinal association between social jetlag, adiposity, and body composition: Sex differences from adolescence to young adulthood

OBJECTIVE

Social jetlag (SJL) refers to the misalignment between the internal biological and social timing and has been associated with obesity and metabolic disorders. The primary aim of this study was to assess the relationship of SJL, adiposity, and body composition from adolescence to young adulthood. We propose that this association differs according to sex.

METHODS

A total of 525 adolescents who completed all the procedures in adolescence and adulthood (SJL, anthropometric, and body composition measures) were included in this longitudinal study. Changes in adiposity and body composition (BMI, waist and hip circumferences, waist:hip ratio, waist:height ratio, and fat mass and lean mass percentages) from adolescence to young adulthood were examined according to SJL in adolescence.

RESULTS

In females, SJL was associated with BMI z-score (β=0.13, p<.01), hip circumference (β=0.97, p<.05), and fat mass (β=0.38, p<.05) and lean mass (β=-0.36, p<.05) percentages in adolescence. Longitudinal analysis revealed that SJL in adolescence was related to fat mass (β=0.59, p<.05) and lean mass percentage (β=-0.57, p<.05), waist:height ratio (β=0.59, p<.05), and waist (β=0.98, p<.01) and hip (β=0.76, p<.05) circumferences in adult women. No significant results were found for males in the cross-sectional and longitudinal analyses.

CONCLUSION

Our findings suggest that SJL is associated with adverse changes in adiposity and body composition from adolescence to young adulthood in females.

Traditional pediatric massage exerted an antidepressant effect and activated IGF-1/Nrf2 pathway in CUMS-exposed adolescent rats

The activation of insulin-like growth factor-1 (IGF-1)/nuclear factor-erythroid 2 related factor 2 (Nrf2) pathway contributes to enhance anti-inflammatory M2 microglia polarization and inhibit proinflammatory M1 microglia polarization, which is essential to resist neuroinflammation and thus resist depression. The prevalence of depression is high in adolescents, who are hypersensitive to chronic stress. Traditional pediatric massage (TPM) can effectively relieve depression. In this study, we investigated the action mechanism of TPM on preventing depression-like behaviors in adolescent rats exposed to chronic unpredictable mild stress (CUMS). In this investigation, we employed several behavioral tests and detections, including western blotting, immunofluorescence staining and RT-qPCR. The findings of this study demonstrated that TPM had an effectively antidepressant effect, maintained microglia polarization homeostasis and resisted neuroinflammation in the hippocampus in CUMS-exposed adolescent rats. With the treatment of picropodophyllin, the inhibitor of IGF-1 receptor, the antidepressant effect of TPM was blocked, along with inhibited IGF-1/Nrf2 pathway which were closely related with anti-inflammatory and anti-ferroptosis actions. The results suggest that TPM enhanced the resilience of adolescent rats to CUMS and exerted an antidepressant effect partially via activating IGF-1/Nrf2 pathway.

Impact of Excess Adiposity on Cardiorespiratory Fitness in Children and Adolescents with Kawasaki Disease

(1) Background: To assess the impact of excessive body fat on cardiorespiratory fitness (CRF) and coronary artery health in children and adolescents following acute Kawasaki disease (KD-CA). (2) Methods: A retrospective study of KD-CA patients (ages 8-16) who completed cardiopulmonary exercise testing (CPET) in the last five years. Participants were classified based on body mass index (BMI) and fat mass index (FMI) into normal and excessive adiposity groups. Coronary artery (CA) Z-scores were calculated using the Lambda-Mu-Sigma method, with peak VO2 Z-scores (peak VO2 Z-score) derived from a database of Hong Kong Chinese children and adolescents. Primary outcomes included peak VO2 Z-score, Max-Z (maximum CA Z-score), anaerobic threshold metabolic equivalent (AT MET), peak MET, and pulse oxygen. Statistical analyses were conducted to evaluate differences across groups. (3) Results: A total of 112 KD-CA patients were included (mean age: 11.71 ± 2.54 years). The mean peak VO2 Z-score was -0.63 ± 0.98. Participants with normal BMI and FMI had significantly higher pulse oxygen levels compared to those with excessive BMI and FMI (both p < 0.001). Additionally, those with normal FMI showed higher AT MET, peak MET, peak VO2 Z-score (p = 0.049), and lower Max-Z (p = 0.026) than excessive FMI participants. Boys, especially those with normal adiposity, had superior AT MET, peak MET, pulse oxygen, and Max-Z compared to girls. (4) Conclusions: Excessive adiposity in KD-CA patients is associated with reduced CRF and elevated Max CA Z-score. These findings highlight the need to monitor body composition to optimize cardiovascular health in this population.

The Prospective Applications of Bioelectrical Impedance Analysis in Postpartum Women

Bioelectrical impedance analysis (BIA) has a wide range of applications. For over 25 years, it has primarily been utilized for assessing body composition. This method is non-invasive, portable, widely available, cost-effective, and user-friendly, offering the advantage of repeatability and minimal dependence on patient cooperation. BIA measures the impedance of the whole body, specifically the body's resistance to alternating current. In postpartum women, who undergo significant physiological changes following childbirth, BIA can serve as a valuable diagnostic and monitoring tool. It is commonly employed to track body weight and fat reduction, and it facilitates the differentiation of fat mass, muscle mass, and body water content. This enables the customization of nutritional plans and the development of individualized training regimens tailored to the patient's health status. Additionally, BIA aids in the assessment of hydration status, which is particularly critical during the postpartum period when women often experience fluid retention. Furthermore, optimal hydration is essential for lactation and maintaining favorable conditions for breastfeeding. BIA is also invaluable for evaluating nutritional status, micronutrient balance, and preventing both overweight and malnutrition. Moreover, BIA supports physical recovery by monitoring muscle mass, thereby assisting in the assessment of pelvic floor muscle regeneration following childbirth.

Associations between prenatal exposure to PFAS and cardiometabolic health in preadolescents

INTRODUCTION

While a number of studies have examined the effects of prenatal exposure to per- and polyfluoroalkyl substances (PFAS) on childhood obesity, the results reported have been inconsistent and few studies have integrated biological markers. The aim of this study was to investigate the associations between prenatal exposure to PFAS and cardiometabolic health parameters at age 12, taking pubertal stage into consideration.

METHOD

This study included 394 mother-child pairs enrolled in the PELAGIE mother-child cohort (France). Nine PFAS were measured in umbilical cord blood, and the children attended a clinical examination at age 12. Anthropometry, blood metabolic markers, and blood pressure were measured and used to build an internal cardiometabolic score. Linear regression and Quantile G-computation models were used to evaluate individual and mixture PFAS effects, adjusting for confounders and stratifying by sex and pubertal stage.

RESULTS

No statistically significant association was observed between prenatal exposure to PFAS and cardiometabolic score at age 12. In post-menarche girls, perfluorohexane sulfonate (PFHxS) and perfluorodecanoic acid (PFDA) were statistically significantly associated with a decrease in a number of adiposity parameters (e.g., Body mass index z-score: beta [95%CI] = -0.37 [-0.67; -0.07]), as well as a decrease in low-density lipoproteins (LDL) and leptin levels. Similar results were observed with PFAS mixture, with statistically significantly decreased tricipital skinfolds (beta [95%CI] = -1.30 [(-2.54;-0.06)]). Isolated associations, including higher systolic blood pressure, changes in cholesterol levels, and lower adiponectin levels were observed in specific subgroups.

CONCLUSION

There is no clear evidence of an association between prenatal exposure to PFAS and the cardiometabolic health at earlier stage of pubertal development. However, inverse associations between PFAS and anthropometric measures have been observed in post-menarche girls. While the literature on this topic is scarce in pre-adolescents, these results suggest the importance of considering sex and pubertal stage in these associations.

Growth and physical development of children at apparent risk of sarcopenia

BACKGROUND

The consequences of sarcopenia on growth have received little attention. We analysed the potential risk resulting from the low lean mass for age expressed through the appendicular lean body mass index (aLBMI) and the ratio aLBM/trunk fat mass (trFM).

METHODS

The sample consisted of 580 participants 10-13 yrs evaluated twice in a 12-month interval: height, trFM, total and aLBM, whole-body bone mineral density less head (WBLH BMD), tibia and radius SOS, maturity and handgrip strength were measured. All variables except maturity and BMI were standardised according to sex and age group (Z-score) using the sample as a reference. A high risk of sarcopenia was identified for Z-scores ≤ -1 on aLBMI (Group B) or aLBM/trFM (Group C), while Z-scores > -1 on both markers were considered at low risk for sarcopenia (Group A). The ANCOVA adjusted for maturity was used to compare the three groups.

RESULTS

Girls showed a more significant decrease in the total BMC/LBM ratio in Group B and a minor increase in WBLH BMD in Group C (p < 0.050); boys in Group B showed a tendency to gain less height (p = 0.053).

CONCLUSION

The high risk of sarcopenia expressed through aLBMI or aLBM/trFM Z-score ≤ -1 compromises bone mineralisation in girls.

IMPACT

The findings emphasise the necessity of implementing routine screening protocols for sarcopenia risk within clinical environments and educational institutions. Such screenings should extend beyond merely assessing body mass index to encompass broader body composition variables like lean body mass. By integrating these assessments into routine health evaluations, healthcare professionals and educators can proactively identify at-risk individuals and initiate timely interventions for suboptimal physical growth and development.

Effects of MyBFF@school, a multifaceted obesity intervention program, on anthropometry and body composition of overweight and obese primary schoolchildren

BACKGROUND

Recently, there has been an increase in the prevalence of childhood obesity in Malaysia, raising concerns about increased cardiometabolic morbidity. MyBFF@school is a multifaceted program comprising physical activity, nutritional education, and psychological empowerment introduced to combat childhood obesity in Malaysia. The efficacy of a six-month intervention on the body composition of overweight and obese primary schoolchildren was evaluated.

METHODS

This is a school-based, cluster randomized controlled trial involving selected primary schools in Kuala Lumpur, Selangor, and Negeri Sembilan. A total of 1,397 primary-school students aged 9-11 with a body mass index (BMI) z -score (corrected for age) greater than + 1 standard deviation based on the World Health Organization 2007 Growth Reference were assigned to intervention ( n = 647 ) and control ( n = 750 ) groups. BMI z-score, waist circumference (WC), percentage body fat (PBF), and skeletal muscle mass (SMM) were assessed at baseline and after three and six months of the study. Analyses of all outcomes except for the baseline characteristics were conducted according to the intention-to-treat principle.

RESULTS

After three months, there was no significant difference in the BMI z-score or PBF between the control and intervention groups, but SMM and WC were significantly higher in the intervention group versus the control group with mean difference of 0.15 kg; 95% confidence interval [CI]: 0.07-0.22, p < 0.001 and mean difference of 1.53 cm; 95% confidence interval [CI]: 1.21- 1.85, p < 0.001 for SMM and WC respectively. After six months, the intervention group demonstrated a significantly greater reduction in PBF compared to the controls (% mean difference: 0.43%, 95% CI: - 0.73 to - 0.12, p < 0.001) as well as a greater increase in SMM (mean difference: 0.28 kg, 95% CI: 0.18-0.37, p < 0.001). There was no difference in the BMI z-score or WC between the intervention and control groups at six months.

CONCLUSIONS

The multicomponent MyBFF@school intervention significantly improved body composition among obese primary schoolchildren in terms of percentage body fat and skeletal muscle mass compared to the control after six months. However, BMI z-score and waist circumference measures did not reflect the benefits of this program.

TRIAL REGISTRATION

Clinical trial number: NCT04155255, November 7, 2019 (Retrospective registered). National Medical Research Register: NMRR-13-439-16,563. Registered July 23, 2013. The intervention program was approved by the Medical Research and Ethics Committee (MREC), Ministry of Health Malaysia and the Educational Planning and Research Division (EPRD), Ministry of Education Malaysia. It was funded by the Ministry of Health Malaysia.

Traditional pediatric massage enhanced the skeletal muscle mass in OVA-exposed adolescent rats via regulating SCFAs-FFAR2-IGF-1/AKT pathway

Objective

This study aimed to investigate the potential relation between the retarded growth of skeletal muscle (SM) and dysbiosis of gut microbiota (GM) in children with asthma, and to explore the potential action mechanisms of traditional pediatric massage (TPM) from the perspective of regulating GM and short-chain fatty acids (SCFAs) production by using an adolescent rat model of asthma.

Methods

Male Sprague-Dawley rats aged 3weeks were divided randomly into the 5 groups (n=6~7) of control, ovalbumin (OVA), OVA + TPM, OVA + methylprednisolone sodium succinate (MP) and OVA + SCFAs. Pulmonary function (PF) was detected by whole body plethysmograph, including enhanced pause and minute ventilation. Airway allergic inflammation (AAI) status was assessed by concentrations of OVA-specific immunoglobulin E in plasma, interleukin (IL)-4 and IL-1β in bronchoalveolar lavage fluid via ELISA assay. SM mass was assessed by using cross-sectional areas of diaphragm muscle and gastrocnemius via hematoxylin and eosin staining. GM and SCFAs production were detected by 16S rDNA sequencing and GC-MS, respectively. The protein and gene expressions of free fatty acid receptor 2 in SM were detected by using immunohistochemical staining and qRT-PCR, respectively. qRT-PCR was used to detect other relative gene expressions that were closely related with SM mass. The activity of insulin-like growth factor-1 (IGF-1)/protein kinase B (PKB/AKT) pathway in SM was detected by western blotting test.

Results

OVA exposure caused obvious AAI and poor PF in adolescent rats. OVA-exposed adolescent rats had a retarded growth of SM mass and inhibited activity of IGF-1/AKT pathway, which was related with GM dysbiosis, reduced SCFAs production and FFAR2 expressions in SM. TPM efficiently enhanced the SM mass, along with alleviating AAI and improving PF. TPM activated IGF-1/AKT pathway in SM, which was closely related with correcting GM dysbiosis, enhanced SCFAs production and FFAR2 expressions.

Conclusion

The retarded growth of SM mass and inhibition of IGF-1/AKT pathway existed in OVA-exposed adolescent rats, which was related with GM dysbiosis, reduced SCFAs production and FFAR2 expressions in SM. TPM efficiently enhanced the SM mass, at least, partially via regulating GM, enhancing SCFAs production and activating FFAR2-IGF-1/AKT pathway.

Percent Body Fat and Weight Status of Youth Participating in Pediatric Weight Management Programs in the Pediatric Obesity Weight Evaluation Registry

Factors associated with change in percent body fat (%BF) of children in pediatric weight management (PWM) care may differ from those associated with change in weight status. Objective: To describe %BF and weight status at initial visits to 14 PWM sites, identify differences by sex, and evaluate factors associated with change over 6 months. Methods: Initial visits of 2496 males and 2821 females aged 5-18 years were evaluated. %BF was measured using bioelectrical impedance analysis. Results: Sex-specific logistic regressions [806 males (32.3%), 837 females (29.7%)] identified associations with primary outcomes: lower %BF and metabolically impactful ≥5-point drop in percent of the 95th BMI percentile (%BMIp95) over 6 months. At the initial visit, males had lower %BF and higher %BMIp95 than females. Over 6 months, males had significantly (p < 0.001) greater median drop in %BF (-1.4% vs. -0.4%) and %BMIp95 (-3.0% vs. -1.9%) and a higher frequency of decreased %BF (68.9% vs. 57.8%), but similar percentage with ≥5-point %BMIp95 drop (36.5% vs. 32.4%; p = 0.080). For males, factors significantly associated with decreased %BF (older age, ≥6 visits, lack of developmental or depression/anxiety concerns) were not related to having a ≥5-point %BMIp95 drop. For females, lack of depression/anxiety concern was significantly associated with decreased %BF but was not associated with ≥5-point %BMIp95 drop. Conclusions: There are differences by sex in initial visit %BF and %BMIp95 and in characteristics associated with changes in these measures. PWM interventions should consider evaluating body composition and sex-stratifying outcomes.

Correlations and consistency of body composition measurement indicators and BMI: a systematic review

OBJECTIVE

It is critical to accurately determine the level of obesity and health status since overweight/obesity has become a main global public health problem. This systematic review attempted to evaluate the consistency and correlation between body composition measurement indicators and body mass index (BMI) in childhood and adolescence.

METHODS

Seven electronic databases (Web of Science, PubMed, Cochrane Library, Embase, CNKI, WANFANG DATA, SinoMed) were searched to collect the literature published since 1999 with the focus on the relationship between body composition measurement indicators and BMI to measure obesity in childhood and adolescence.

RESULTS

Among the 28 articles included, 13 articles reported a moderate to very strong correlation between %BF and BMI in obesity measurement (range: 0.49-0.907), while two articles reported a strong to very strong correlation between FM and BMI (range: 0.60-0.86). Six articles reported good to excellent obesity measurement consistency between %BF and BMI (range: 0.441-0.876), one article reported WC (0.58) and WHtR (0.46) in the moderate consistency with BMI, and one article reported a relatively poor to fair consistency between FM and BMI (range: 0.167-0.409). WC, WHtR, and BMI showed the moderate consistency in pre-adolescent children. In pre-adolescence and adolescence, the measurement consistency between %BF and BMI was higher than that between FM and BMI. Gender difference existed in the consistency between %BF and BMI during adolescence.

CONCLUSION

A range of body composition indicators such as %BF, WC, WHtR, and FM could provide valuable body composition measurements, complement BMI for obesity assessment in children and adolescents, and facilitate efficient and comprehensive surveillance of childhood obesity.

REGISTRATION

PROSPERO CRD42024506932.

Nutritional Challenges in Paediatric Oncology: Screening and Managing Malnutrition and Sarcopenia

Sarcopenia and malnutrition can coexist in pediatric patients with neoplasia, worsening the patient's prognosis. The classification of primary and secondary sarcopenia may be helpful in clinical practice, as it can help with timely initiation of appropriate and tailored dietary treatments to address it. This review summarizes the current state of the art of assessing skeletal muscle function in children and adolescents with cancer and discusses the role of nutritional interventions in the management of children with cancer. It highlights the urgent need for comprehensive nutritional support and interventions to mitigate the impact of malnutritions on both treatment outcomes and patients' well-being.

Comparative effectiveness of lifestyle interventions on children's body composition management: A systematic review and network meta-analysis

PURPOSE

This study aimed to provide comparative evidence on the effectiveness of various lifestyle interventions on body composition management for preschool and school-aged children.

METHODS

PubMed (MEDLINE), Embase, CINAHL, and Web of Science were systematically searched for this network meta-analysis. Randomized controlled studies (RCTs) that included children aged 4-12 years with no physical or mental conditions; performed at least 1 type of lifestyle intervention; reported change in body mass index (BMI), BMI z-score, or body fat percentage (BFP); and were published between January 2010 and August 2023 were included.

RESULTS

The final analysis included 91 RCTs with aggregate data for 58,649 children. All interventions were categorized into single-arm approaches (physical activity, diet, and behavioral and informational support) and combined arms approaches (bicomponent and multicomponent treatment). Multicomponent treatment showed significant effectiveness on the reduction of BMI (mean deviation (MD) - 0.49, 95% confidence interval (95%CI): -0.88 to -0.12), BMI z-score (MD = -0.11, 95%CI: -0.18 to -0.04), and BFP (MD = -1.69, 95%CI: -2.97 to -0.42) compared to the usual care condition. Bicomponent treatment also significantly reduced BMI (MD = -0.28, 95%CI: -0.54 to -0.04) and BMI z-score (MD = -0.07, 95%CI: -0.12 to -0.02) compared to usual care.

CONCLUSION

Interventions targeting multiple lifestyle components achieved greater reductions in children's BMI and BFP. Among single-component approaches, physical activity engagement emerged as the most effective. These findings should guide practitioners in recommending comprehensive lifestyle modifications for children. Moreover, children with higher initial BMI and body fat levels tend to exhibit more positive responses to lifestyle interventions aimed at managing obesity.

Differences in cardiorespiratory fitness by gonadotropin-releasing hormone agonist treatment before and after testosterone in transgender adolescents

There are known sex differences in cardiorespiratory fitness (CRF). Little is known about the impact of pubertal blockade with a gonadotropin-releasing hormone agonist (GnRHa) followed by hormone therapy on CRF for transgender adolescents. We aimed to 1) determine the effect of GnRHa monotherapy on CRF and mitochondrial function and associations with metabolomic profiles and 2) evaluate changes after 1 and 12 mo of testosterone therapy among transgender adolescents. Participants assigned female at birth (n = 19, baseline age of 15.0 ± 1.0 yr) from two groups: GnRHa+ (n = 8) and GnRHa- (n = 11) were examined at baseline and 1- and 12-mo post-testosterone therapy in a longitudinal observational study to assess cardiorespiratory fitness, mitochondrial respiration, and metabolic profile. Fasted morning labs included assessment of metabolomics and peripheral blood mononuclear cell mitochondrial respiration and degree of mitochondrial coupling (respiratory control ratio, RCR). A graded cycle ergometer test was performed. Baseline differences were evaluated between groups. Changes were compared with mixed linear regression models evaluating time (baseline, 1 mo, and 12 mo), group (GnRHa treatment yes/no), and their interaction. At baseline GnRHa+ individuals had higher relative V̇o2peak (30.1 ± 4.83 vs. 25.24 ± 4.47 mL/kg/min, P = 0.042) than GnRHa- individuals. In regression models, GnRHa+ individuals had a significant increase in peak watts (P = 0.011) and total exercise time (P = 0.005) after 12 mo of testosterone (P = 0.012) but not GnRHa- individuals. GnRHa+ individuals have significantly higher RCR under carbohydrate (P = 0.0007) and lipid (P = 0.0002) conditions than GnRHa+ individuals. Pretreatment with GnRHa positively influences peak CRF and mitochondrial respiration in adolescent transgender males undergoing testosterone therapy.NEW & NOTEWORTHY This study demonstrates differences in exercise capacity and mitochondrial respiration at baseline based on whether or not individuals had feminizing puberty blocked. Individuals who had puberty blocked had greater improvements in cardiopulmonary exercise testing parameters after 12 mo of testosterone than those who went through feminizing puberty.

Accuracy of the international growth charts to diagnose obesity according to the body composition analysis in US children and adolescents

This study verified the accuracy of the international BMI references and the allometric BMI reference to diagnose obesity in children and adolescents from the USA. Data from 17 313 subjects were obtained from the National Health and Nutrition Examination Survey between the years 1999-2006 and 2011-2018. Fat Mass Index, Allometric Fat Mass Index and fat mass/fat-free mass were calculated. Receiver operating characteristic curve, AUC, sensitivity, specificity, positive likelihood ratio and negative likelihood ratio were estimated to evaluate the accuracy of the growth references for diagnosing obesity. The International Obesity Task Force, MULT BMI 17 years, MULT BMI 18 years and allometric BMI 19 years achieved the best sensitivity-specificity trade-off for boys, with sensitivities ranging from 0·92 to 0·96 and specificities of 0·94, with positive likelihood ratio of 15·51, 16·17, 13·46 and 18·01, respectively. The negative likelihood ratios were notably low, ranging from 0·04 to 0·08. In girls, the International Obesity Task Force, MULT BMI 17 years and MULT allometric BMI 17 years also demonstrated high sensitivity (0·95-0·97) and specificity (0·92), with positive likelihood ratio values of 11·54, 11·82 and 11·77, respectively and low negative likelihood ratio values (0·03-0·05). In summary, these international growth references presented satisfactory performance to diagnose obesity. However, the MULT growth reference performed better, and the MULT allometric BMI was the only indicator capable of detecting that girls have a higher proportion of fat mass than boys for the same index values. These findings suggest that the MULT growth reference may be a better tool to assess the nutritional status of children and adolescents internationally.

Higher peak height velocity in early maturing girls depends on insulin rather than fat mass or IGF-I

OBJECTIVE

Age at pubertal onset has decreased over the recent decades. Early maturing girls have longer puberty duration, and higher peak height velocity (PHV) than late maturing girls. To what extent this is generated by increased insulin-like growth factor-I (IGF-I), fat mass, or fasting insulin levels is currently unknown.

DESIGN, SETTING, PARTICIPANTS

A population-based study-part of the COPENHAGEN puberty study-longitudinal part. Eighty-one girls evaluated biannually for a median of 10 (2-15) visits for a total of 815 evaluations.

METHODS

Pubertal staging, anthropometric measures, PHV, skin fold thickness (SFT), and IGF-I and fasting insulin levels were measured.

RESULTS

Early maturing girls achieved similar final height compared to late maturing girls (166.1 vs 167.1 cm, P = .36). Early pubertal onset was associated with significantly greater PHV (8.7 vs 7.4 cm/year, P < .001) and a longer puberty duration (age at onset of breast development to age at PHV [1.8 vs 1.1 years, P < .001]) compared with late maturation. After correcting for age at pubertal onset, neither body mass index, SFT, nor IGF-I levels differed between early vs late maturing girls. By contrast, fasting insulin levels were significantly higher in early compared with late maturing girls 1.5, 2.0, and 3.0 years after pubertal onset (all P = .039).

CONCLUSION

Growth velocity was higher and more prolonged in early compared with late maturing girls and associated with higher insulin levels. Thus, the higher insulin levels may compensate for the shorter total growth period by intensifying the pubertal growth period.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01411527.

Association between endogenous sex hormones and adiposity in youth across a weight status spectrum

BACKGROUND

While endogenous sex hormones (e.g., testosterone, estradiol) are important factors regulating adipose tissue distribution, studies evaluating such relationships in youth across a wide weight status spectrum are limited.

METHODS

We performed a cross-sectional analysis of 8-21-year-old youth. Multiple linear regression models were used to evaluate associations between sex hormones and adiposity measures (android/gynoid ratio (A/G), total fat mass (FM), visceral adipose tissue (VAT), waist circumference (WC)) and total lean mass (LM), adjusting for pubertal stage and race/ethnicity, and stratified by sex and weight status.

RESULTS

Among 342 youth, the mean age was 13.0 ± 2.8 years old (52.6% female; 38.9% normal weight [NW]; 27.8% overweight/obesity [OW/OB]; 33.3% severe obesity [SO]). Testosterone was positively associated with LM among males with NW (1462 g, 95% CI: 255-2668 g) and OW/OB (3792 g, 95% CI: 1244-6340 g), with A/G and WC among males with NW (0.01, 95% CI: 0-0.2 and 10 mm, 95% CI: 4-16 mm, respectively), and negatively associated with WC among males with SO (-43 mm, -81 to -5 mm). Estradiol was positively associated with A/G, FM, and WC among males with SO, and VAT in females with NW.

CONCLUSION

Our findings showed that sex hormones were associated with adipose tissue deposition in youth across the weight spectrum.

IMPACT STATEMENT

Sex hormones (e.g., testosterone, estradiol) are associated with various adiposity measures among male and female children and adolescents across a weight status spectrum. We evaluated associations between sex hormones and various adiposity measures among 8-21-year-olds across a weight status spectrum (normal weight, overweight/class 1 obesity, class 2-3 obesity). We found that estradiol was positively associated with total fat mass, android/gynoid ratio, and waist circumference in males with class 2-3 obesity, and testosterone was positively associated with lean mass in males with normal weight and overweight/class 1 obesity. Sex hormones may influence, or may be influenced by, adiposity in youth.

Racial/Ethnic Differences in the Age-Varying Association Between Adherence to 8-5-2-1-0 Guidelines in Adolescents with High BMI

PURPOSE

To examine the association between adherence to sleep, dietary, screen time, and physical activity (PA) (8-5-2-1-0) guidelines and risk of high body mass index (BMI ≥ 85 percentile) among U.S. adolescents and to assess for racial inequities and age-varying effects in these associations.

METHODS

Data from the 2019 Youth Risk Behavior Surveillance System survey were used to conduct multivariable logistic regression models and moderation analysis by race/ethnicity and age using time-varying varying effect models (TVEM) and estimate associations of interest.

RESULTS

Of the 13,518 adolescents aged ≥ 14 years, only 0.5% met all guidelines. Adolescents adhering to sleep guidelines had a 21% reduction in their odds of having a high BMI (OR 0.79, 95% CI 0.67-0.93). Those adhering to PA guidelines had a 34% reduction in their odds of having a high BMI (OR 0.66, 95% CI 0.56-0.79), and those adhering to screen time guidelines had a 17% reduction in their odds of having a high BMI (OR 0.83, 95% CI 0.72-0.95). TVEM showed associations between adherence to sleep and screen time guidelines with high BMI fluctuate and are at specific ages. TVEM revealed substantial racial/ethnic differences in the age-varying association between adherence to 8-5-2-1-0 guidelines and high BMI throughout adolescence.

CONCLUSIONS

Associations between adherence to sleep and screen time guidelines and high BMI fluctuate with age, highlighting the need for nuanced interventions targeting 24-h movement guidelines (sleep, PA, and screen time) across adolescence, particularly given racial/ethnic disparities.

Associations of childhood BMI, general and visceral fat mass with metabolite profiles at school-age

BACKGROUND

Childhood obesity increases metabolic disease risk. Underlying mechanisms remain unknown. We examined associations of body mass index (BMI), total body fat mass, and visceral fat mass with serum metabolites at school-age, and explored whether identified metabolites improved the identification of children at risk of a metabolically unhealthy phenotype.

METHODS

We performed a cross-sectional analysis among 497 children with a mean age of 9.8 (95% range 9.1, 10.6) years, participating in a population-based cohort study. We measured BMI, total body fat mass using DXA, and visceral fat mass using MRI. Serum concentrations of amino-acids, non-esterified-fatty-acids, phospholipids, and carnitines were determined using LC-MS/MS. Children were categorized as metabolically healthy or metabolically unhealthy, according to BMI, blood pressure, lipids, glucose, and insulin levels.

RESULTS

Higher BMI and total body fat mass were associated with altered concentrations of branched-chain amino-acids, essential amino-acids, and free carnitines. Higher BMI was also associated with higher concentrations of aromatic amino-acids and alkyl-lysophosphatidylcholines (FDR-corrected p-values < 0.05). The strongest associations were present for Lyso.PC.a.C14.0 and SM.a.C32.2 (FDR-corrected p-values < 0.01). Higher visceral fat mass was only associated with higher concentrations of 6 individual metabolites, particularly Lyso.PC.a.C14.0, PC.aa.C32.1, and SM.a.C32.2. We selected 15 metabolites that improved the prediction of a metabolically unhealthy phenotype, compared to BMI only (AUC: BMI: 0.59 [95% CI 0.47,0.71], BMI + Metabolites: 0.91 [95% CI 0.85,0.97]).

CONCLUSIONS

An adverse childhood body fat profile, characterized by higher BMI and total body fat mass, is associated with metabolic alterations, particularly in amino acids, phospholipids, and carnitines. Fewer associations were present for visceral fat mass. We identified a metabolite profile that improved the identification of impaired cardiometabolic health in children, compared to BMI only.

Using B-mode ultrasound to evaluate Risser grading for the determination of skeletal maturity in adolescents

INTRODUCTION

Rapid adolescent growth is associated with an increased risk of disease and disease progression. This study assesses the reliability and validity of non-ionising B-mode ultrasound for the assessment of skeletal maturity (Risser Grade) and offers procedural guidelines for its use.

METHODS

Twenty-three female adolescents with primary-right-thoracic scoliosis (age: 13.8 (1.6) years) and twenty age-matched female control participants without scoliosis (age: 13.1 (1.8) years) were recruited. Skeletal maturity was determined from (i) a series of nine B-mode ultrasound images collected at sites equally spaced between the anterior and posterior superior iliac spines of the pelvis and (ii) clinical spine radiographs obtained as part of standard scoliosis care. Inter-rater reliability was assessed between a novice researcher and an experienced medical doctor. Concurrent-validity was assessed by comparing the location and degree of apophysis growth and fusion obtained via ultrasound with that obtained using radiograph Risser grading for scoliosis participants only.

RESULTS

The inter-rater reliability of ultrasound Risser grading was strong [ICC(2,1): 0.99, p < 0.001]. High concurrent-validity was determined, with no difference in Risser grading identified between the radiograph and ultrasound grading methods (Wilcoxon signed-rank: Z = -1.93, p = 0.053).

CONCLUSION

Ultrasound provides a reliable non-ionising alternative to the gold standard of Risser grading from radiographs to determine and monitor skeletal maturity. This study provides a detailed methodology for using ultrasound to assess skeletal maturity.

IMPLICATIONS FOR PRACTICE

Rapid adolescent growth is associated with an increased risk of disease and disease progression. Therefore, accurately determining and monitoring skeletal maturity in these adolescents is crucial. This study assesses the reliability and validity of non-ionising B-mode ultrasound for the assessment of skeletal maturity and offers procedural guidelines for its use.

A 10-week implementation of the FIT FIRST FOR ALL school-based physical activity concept effectively improves cardiorespiratory fitness and body composition in 7-16-year-old schoolchildren

Introduction

The purpose of the present study was to investigate the impact of the FIT FIRST FOR ALL school-based physical activity program on health-related physical fitness in Faroese schoolchildren. The program aimed to add three weekly sessions of organized high-intensity physical activity to the standard weekly physical education sessions for all pupils across the entire school.

Methods

A non-randomized controlled design was used to evaluate the effects of the program. Two schools participated, including one intervention school (INT; n =179) and one control school (CON; n =181), with pupils aged 7-16 years (grades 1-9). The FIT FIRST FOR ALL program consisted of three weekly 40-minute sessions of age-adjusted high-intensity physical activity over 10 weeks for the INT school, while the CON school continued their normal school program. Pre- and post-intervention assessments included cardiorespiratory fitness (Yo-Yo IR1C test), agility (Arrowhead Agility test), postural balance (Stork Stand), standing long jump performance, body composition, blood pressure, and resting heart rate.

Results

A significant time × group effect (p < 0.001) was observed for cardiorespiratory fitness, which increased by 31% [23;39] in INT (p < 0.001) and remained unaltered in CON (7% [-2;16], p = 0.13). In addition, a time × group effect (p < 0.001) was observed for agility, which improved by 2.1% [1.0;3.2] in INT (p < 0.001) and regressed by 3.3% [2.3;4.4] in CON (p < 0.001). No significant between-group effects were found for standing long jump and balance. A time × group effect (p < 0.001) was observed for changes in total muscle mass, which increased by 1.4 kg [1.2;1.5] in INT (p < 0.001) and by 0.4 kg [0.3;0.6] in CON (p < 0.05). Furthermore, a time × group effect (p < 0.001) was observed for total fat percentage, which decreased by -2.3% [-2.8;-1.9] in INT (p < 0.001) and remained unchanged in CON (-0.3% [-0.7;0.1], p = 0.16). No significant time × group effects were found for blood pressure and resting heart rate.

Discussion

The FIT FIRST FOR ALL program significantly improved cardiorespiratory fitness and agility, and it led to favorable changes in body composition in the intervention school. These findings suggest that the program is highly effective in enhancing physical fitness and health status across all investigated age groups when implemented at a school-wide level.

Insulin sensitivity, body composition and bone mineral density after testosterone treatment in transgender youth with and without prior GnRH agonist therapy

Background

1.8% of youth identify as transgender; a growing proportion are transgender male (female sex, male gender identity). Many receive gonadotropin releasing hormone agonist (GnRHa) therapy to suppress endogenous puberty and/or will start testosterone to induce secondary sex characteristics that align with gender identity.

Objectives

To determine the effects of 12 months of testosterone on cardiometabolic health among transgender youth, including insulin sensitivity, body composition, and bone mineral density and whether changes in outcomes differ based on prior GnRHa treatment.

Methods

Participants (n = 19, baseline age 15.0 ± 1.0 years) were examined prior to and 12 months after testosterone therapy in a longitudinal observational study. Fasted morning blood draw, a 2-hour 75-gram oral glucose tolerance test, body composition and bone mineral density (dual-energy X-ray absorptiometry) were assessed at baseline and 12 months. Insulin sensitivity was estimated by HOMA-IR and Matsuda index. Changes were compared with mixed linear regression models evaluating time (baseline, 12 months), group (GnRHa treatment yes/no), and their interaction.

Results

In the entire cohort, fasted insulin decreased (median [25,75 %ile]: -3 [-5, 0] mIU/L, p = 0.044) and 2-hour glucose increased (mean ± standard deviation): +18.5 ± 28.9 mg/dL, p = 0.013 from baseline after 12 months of testosterone therapy. There were no significant changes in HOMA-IR (p = 0.062) or Matsuda index (p = 0.096), nor by GnRHa status. Absolute (+6.2 [4.7, 7.5] kg, p = 0.016) and percent fat-free mass increased (+7.3 [5.4, 9.1] %, p = 0.003) and percent fat mass declined (-7.4 [-9.3, 5.3]%, p = 0.005) for the entire cohort. There were time*group interactions for absolute (p = 0.0007) and percent fat-free mass (p = 0.033). There were time*group interactions for bone mineral content (p = 0.006).

Conclusions

Twelve months of testosterone in transgender adolescents resulted in changes in body composition and bone mineral density, with baseline differences between the +/-GnRHa group and convergence after 12 months. There were no changes in insulin sensitivity over time or between groups.

Body Mass Index Distribution in Female Child, Adolescent and Adult Inpatients with Anorexia Nervosa-A Retrospective Chart Review

BACKGROUND

The variation in body mass index (BMI) of inpatients with anorexia nervosa has not been analyzed across the age span. A positive correlation between BMI and age has been reported in adolescent inpatients aged 15 years and younger that levels off at 15 to 18 years. BMIs standardized for age and sex (standard deviation scores, SDSs) were negatively correlated with age in these inpatients aged 8 to 18 years.

METHODS

The aims of the current retrospective study were threefold: first, to confirm the relationships of BMI, BMI-SDS and age in adolescent inpatients in a larger sample; second, to systematically assess the relationship of BMI, BMI-SDS, body height-SDS and age in adult inpatients at the time of referral; and third, to assess body height-SDSs and age to evaluate stunting.

RESULTS

We included 1001 girls (aged 12-17.9 years) and 1371 women (aged 18-73 years) admitted to inpatient treatment between 2014 and 2021. Mean BMI at admission was 14.95 kg/m2 (SD = 1.43; range 10.67-18.47) in adolescents and 14.63 kg/m2 (SD = 2.02; range 8.28-18.47) in adults. None of the adolescent patients but 20 adults had very low BMI values below 10 kg/m2. Adolescents showed a small but significant positive correlation between age and BMI (r = 0.12; p = 2.4 × 10-4). In adults, BMI was not correlated with age (r = -0.03; p = 0.3). BMI-SDSs was negatively correlated with age in adolescents and less so in adults (r = -0.35; p < 0.001 and r = -0.09; p = 0.001). Curve fit analyses for all patients indicated that there was a quadratic (age × age) relationship between age and BMI-SDS. Height correlated positively with BMI in adult (r = 0.1; p < 0.001) and adolescent (r = 0.09 p = 0.005) patients and we detected no evidence for stunting.

CONCLUSIONS

In conclusion, the BMI of inpatients seems to be relatively stable across the age span with mean values between 14 and 15 kg/m2. BMI values initially increase with age in younger patients, drop between ages 18 and 23 and then slowly decline with age.

Bioelectrical impedance parameters add incremental value to waist-to-hip ratio for prediction of metabolic dysfunction associated steatotic liver disease in youth with overweight and obesity

Introduction

Metabolic dysfunction-associated steatotic liver disease (MASLD) presents a growing health concern in pediatric populations due to its association with obesity and metabolic syndrome. Bioelectrical impedance analysis (BIA) offers a non-invasive and potentially effective alternative for identifying MASLD risk in youth with overweight or obesity. Therefore, this study aimed to assess the utility of BIA for screening for MASLD in the youth.

Method

This retrospective, cross-sectional study included 206 children and adolescents aged <20 years who were overweight and obese. The correlations between anthropometric measurements and BIA parameters and alanine aminotransferase (ALT) levels were assessed using Pearson's correlation analysis. Logistic regression analysis was performed to examine the associations between these parameters and ALT level elevation and MASLD score. Receiver operating characteristic (ROC) curves were generated to assess the predictive ability of the parameters for MASLD.

Results

Pearson's correlation analysis revealed that waist-to-hip ratio (WHR), percentage body fat (PBF), and BIA parameters combined with anthropometric measurements were correlated with ALT level. Logistic regression revealed that WHR, skeletal muscle mass/WHR, PBF-WHR, fat-free mass/WHR, and appendicular skeletal muscle mass/WHR were correlated with ALT level elevation after adjusting for age, sex, and puberty. WHR, PBF-WHR, and visceral fat area (VFA)-WHR were positively correlated with the MASLD score in the total population after adjusting for age, sex, and puberty. PBF-WHR and VFA-WHR were correlated with the MASLD score even in youth with a normal ALT level. The cutoff points and area under the ROC curves were 34.6 and 0.69 for PBF-WHR, respectively, and 86.6 and 0.79 for VFA-WHR, respectively.

Discussion

This study highlights the utility of combining BIA parameters and WHR in identifying the risk of MASLD in overweight and obese youth, even in those with a normal ALT level. BIA-based screening offers a less burdensome and more efficient alternative to conventional MASLD screening methods, facilitating early detection and intervention in youth at risk of MASLD.

Comparison of international height and BMI-for-age growth references and their correlation with adiposity in Brazilian schoolchildren

This study verified the diagnostic accuracy of the nutritional status classified by the international height and BMI references of the World Health Organization (WHO) (WHO/2007), International Obesity Task Force (IOTF/2012) and MULT (2023). The data pool was composed by 22 737 subjects aged five to 16 years from the Santos and Porto Alegre surveys. A correlation matrix between the z-scores of the BMI references and the skinfold measurements was calculated through the Pearson correlation coefficient (r), and the subject's nutritional status was classified according to the international growth references. The accuracy for diagnosing obesity was performed separately by sex and using the 95th percentile of the triceps and subscapular skinfold sum, while Lin's concordance coefficient, Bland-Altman method and the Cohen's Kappa coefficient (Kappa) were used to verify the concordance and reliability among the BMI references. The correlation matrix showed a high positive correlation among the BMI z-scores (r ≥ 0·99) and among the skinfold measurements (r ≥ 0·86). The prevalence of stunting was higher when applying the MULT reference (3·4 %) compared with the WHO reference (2·3 %). The Bland-Altman plots showed the lowest critical difference (CD) between the height references of WHO and MULT (CD = 0·22). Among the BMI references, the WHO obesity percentile presented lower performance than MULT for boys, presenting a lower +LR value (WHO = 6·99/MULT 18 years = 10·99; 19 years = 8·99; 20 years = 8·09) for the same -LR values (0·04). Therefore, MULT reference holds promise as a valuable tool for diagnosing childhood obesity, particularly when considering sex differences. This enhances its suitability for assessing the nutritional status of Brazilian schoolchildren.

Estrogen restores disordered lipid metabolism in visceral fat of prediabetic mice

BACKGROUND

Visceral obesity is increasingly prevalent among adolescents and young adults and is commonly recognized as a risk factor for type 2 diabetes. Estrogen [17β-estradiol (E2)] is known to offer protection against obesity via diverse me-chanisms, while its specific effects on visceral adipose tissue (VAT) remain to be fully elucidated.

AIM

To investigate the impact of E2 on the gene expression profile within VAT of a mouse model of prediabetes.

METHODS

Metabolic parameters were collected, encompassing body weight, weights of visceral and subcutaneous adipose tissues (VAT and SAT), random blood glucose levels, glucose tolerance, insulin tolerance, and overall body composition. The gene expression profiles of VAT were quantified utilizing the Whole Mouse Genome Oligo Microarray and subsequently analyzed through Agilent Feature Extraction software. Functional and pathway analyses were conducted employing Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses, respectively.

RESULTS

Feeding a high-fat diet (HFD) moderately increased the weights of both VAT and SAT, but this increase was mitigated by the protective effect of endogenous E2. Conversely, ovariectomy (OVX) led to a significant increase in VAT weight and the VAT/SAT weight ratio, and this increase was also reversed with E2 treatment. Notably, OVX diminished the expression of genes involved in lipid metabolism compared to HFD feeding alone, signaling a widespread reduction in lipid metabolic activity, which was completely counteracted by E2 administration. This study provides a comprehensive insight into E2's local and direct protective effects against visceral adiposity in VAT at the gene level.

CONCLUSION

In conclusion, the present study demonstrated that the HFD-induced over-nutritional challenge disrupted the gene expression profile of visceral fat, leading to a universally decreased lipid metabolic status in E2 deficient mice. E2 treatment effectively reversed this condition, shedding light on the mechanistic role and therapeutic potential of E2 in combating visceral obesity.

Does hypoleptinemia trigger entrapment in anorexia nervosa? Etiological and clinical considerations

Based on the recent observation that human recombinant leptin (r-Met-hu-leptin; metreleptin) may induce a profound alleviation of the complex symptomatology of patients with anorexia nervosa (AN), we examine the implications for our conceptualisation of this eating disorder. Hypoleptinemia as a core endocrine feature of AN serves as a central and peripheral trigger of tissue-specific adaptations to starvation. In this narrative review, we argue that leptin deficiency may explain many of the puzzling features of this eating disorder. Weight loss can be viewed as a two-step process, with only the second step entailing hypoleptinemia and thereby the entrapment characteristic of AN. We discuss the central and peripheral distribution of leptin receptors and consider possible functional implications of hypoleptinemia. We contrast the slow psychological recovery of patients with AN and of people who experienced starvation upon weight recovery with the rapid onset of improvements upon off-label metreleptin treatment. Characteristics of the sex and age dependent secretion of leptin may contribute to the elevated vulnerability of young females to develop AN.

Premorbid body weight predicts weight loss in both anorexia nervosa and atypical anorexia nervosa: Further support for a single underlying disorder

OBJECTIVE

For adolescents, DSM-5 differentiates anorexia nervosa (AN) and atypical AN with the 5th BMI-centile-for-age. We hypothesized that the diagnostic weight cut-off yields (i) lower weight loss in atypical AN and (ii) discrepant premorbid BMI distributions between the two disorders. Prior studies demonstrate that premorbid BMI predicts admission BMI and weight loss in patients with AN. We explore these relationships in atypical AN.

METHOD

Based on admission BMI-centile < or ≥5th, participants included 411 female adolescent inpatients with AN and 49 with atypical AN from our registry study. Regression analysis and t-tests statistically addressed our hypotheses and exploratory correlation analyses compared interrelationships between weight loss, admission BMI, and premorbid BMI in both disorders.

RESULTS

Weight loss in atypical AN was 5.6 kg lower than in AN upon adjustment for admission age, admission height, premorbid weight and duration of illness. Premorbid BMI-standard deviation scores differed by almost one between both disorders. Premorbid BMI and weight loss were strongly correlated in both AN and atypical AN.

DISCUSSION

Whereas the weight cut-off induces discrepancies in premorbid weight and adjusted weight loss, AN and atypical AN overall share strong weight-specific interrelationships that merit etiological consideration. Epidemiological and genetic associations between AN and low body weight may reflect a skewed premorbid BMI distribution. In combination with prior findings for similar psychological and medical characteristics in AN and atypical AN, our findings support a homogenous illness conceptualization. We propose that diagnostic subcategorization based on premorbid BMI, rather than admission BMI, may improve clinical validity.

PUBLIC SIGNIFICANCE

Because body weights of patients with AN must drop below the 5th BMI-centile per DSM-5, they will inherently require greater weight loss than their counterparts with atypical AN of the same sex, age, height and premorbid weight. Indeed, patients with atypical AN had a 5.6 kg lower weight loss after controlling for these variables. In comparison to the reference population, we found a lower and higher mean premorbid weight in patients with AN and atypical AN, respectively. Considering previous psychological and medical comparisons showing little differences between AN and atypical AN, we view a single disorder as the most parsimonious explanation. Etiological models need to particularly account for the strong relationship between weight loss and premorbid body weight.

Obesity: a gender-view

PURPOSE

There is a growing awareness of the importance of understanding gender differences in obesity. The aim of this short review was to revise the current evidence on anthropometric characteristics and nutritional and pharmacological aspects of obesity from a gender perspective.

METHODS

A literature search within PubMed was performed. Selected publications related to obesity and gender differences were reviewed.

RESULTS

The prevalence of obesity among men is higher than in women, but women have a higher percentage of body fat content compared to men, and gender appears to be an important factor in the manifestation of central (android) or peripheral (gynoid) obesity. In addition, while in most clinical trials, women are still underrepresented, in clinical registration trials of anti-obesity drugs, women are commonly up-represented and gender-specific analysis is uncommon. Considering that adipose tissue is one of the factors affecting the volume of distribution of many drugs, mainly lipophilic drugs, gender differences might be expected in the pharmacokinetics and pharmacodynamics of anti-obesity drugs. Indeed, although Liraglutide 3 mg, a long-acting glucagon-like peptide-1 receptor agonist, and naltrexone/bupropion display lipophilic properties, currently, a gender-dose adjustment for both these drugs administration is not recommended. In addition, despite that predicted responders to treatment offer substantial opportunities for efficient use, especially of expensive new therapies, such as anti-obesity drugs, data on gender differences to identify early responders to both these have not yet been investigated. Finally, bariatric surgery gender disparity reflects healthcare practices. Weight loss similar, but differing effects: women need more correction and face psychology challenges; men have worse physiology and fewer comorbidity improvements.

CONCLUSION

Gender differences exist in obesity prevalence and phenotype, body fat distribution, drug efficacy, clinical trial representation, and different secondary effects of bariatric surgery. Gender is an important variable in obesity analysis.

Adolescent intermittent ethanol (AIE) produces lasting, sex-specific changes in rat body fat independent of changes in white blood cell composition

Early initiation of alcohol use during adolescence, and adolescent binge drinking are risk factors for the development of alcohol use disorder later in life. Adolescence is a time of rapid sex-dependent neural, physiological, and behavioral changes as well as a period of heightened vulnerability to many effects of alcohol. The goal of the present studies was to determine age-related changes in blood (leukocyte populations) and body composition across adolescence and early adulthood, and to investigate whether adolescent intermittent ethanol (AIE) exposure would alter the trajectory of adolescent development on these broad physiological parameters. We observed significant ontogenetic changes in leukocyte populations that were mirrored by an age-related increase in cytokine expression among mixed populations of circulating leukocytes. Despite these developmental changes, AIE did not significantly alter overall leukocyte numbers or cytokine gene expression. However, AIE led to sex-specific changes in body fat mass and fat percentage, with AIE-exposed male rats showing significantly decreased fat levels and female rats showing significantly increased fat levels relative to controls. These changes suggest that while AIE may not alter overall leukocyte levels, more complex phenotypic changes in leukocyte populations could underlie previously reported differences in cytokine expression. Coupled with long-term shifts in adipocyte levels, this could have long-lasting effects on innate immunity and the capacity of individuals to respond to later immunological and physiological threats.

Effects of Age and Playing Position on Field-Based Physical Fitness Measures in Adolescent Female Netball Players

This cross-sectional study investigated the impact of age and playing position, controlling for maturity, on physical fitness indicators in 303 adolescent female netball players aged 12.0 to 15.9 years. Assessments included estimated maximal oxygen uptake (VO2max) via the 20 m shuttle run test, 10 m and 20 m sprints, change of direction speed (CODS) using the 505 test, and muscle power via the medicine ball chest throw (MBCT) and countermovement vertical jump (CMJ). Participants were grouped by age (12 to 15 years) and playing position (non-circle and circle players), with age at peak height velocity as a covariate for maturity. Results revealed that, at 15 years, CMJ height was greater than at 12 years and 13 years (p < 0.05, partial η2 = 0.048). MBCT distance increased across age groups (p < 0.01, partial η2 = 0.323). Age had no impact on sprints, VO2max, or CODS. Non-circle players outperformed circle players in the 10 m sprint (p = 0.042, partial η2 = 0.016) and 20 m sprints (p = 0.010, partial η2 = 0.025) and displayed higher VO2max (p < 0.001, partial η2 = 0.036). Circle players were taller (p = 0.046, partial η2 = 0.014) and heavier (p < 0.001, partial η2 = 0.040) than non-circle players. Playing positions showed no differences in CMJ and MBCT. In adolescent female netball players, only muscle power is influenced by age, while non-circle players exhibit superior aerobic fitness and speed compared to circle players. Coaches may be able to utilize the distinct age and playing position traits of adolescent netballers to inform player selection and design targeted training programs.

Exploring relevant parameters and investigating their reproducibility of task-oriented unimanual strength measurement in children with unilateral cerebral palsy

PURPOSE

To explore relevant parameters and investigate their test-retest reliability within the scope of the push button task of the Task-oriented Arm-hAnd Capacity (TAAC) measured in children with unilateral Cerebral Palsy (CP).

METHODS

118 children diagnosed with unilateral CP, aged between 6 and 18 years, participated in this study. Thetest-retest reliability of the force generated during the push button task of the TAAC was investigated using an intraclass correlation (ICC) two-way random model with absolute agreement. The ICCs were calculated across the whole age group and for two separate age subgroups (6-12 and 13-18 years).

RESULTS

Test-retest reliability of the parameters "mean peak force of all attempts", "overshoot of force", "number of successful attempts" and "time to complete four successful attempts" were moderate to good (ICC range 0.667-0.865; 0.721-0.908; 0.733-0.817, respectively).

CONCLUSIONS

The results showed moderate to good test-retest reliability for all parameters. The parameters "mean peak force" and "number of successful attempts" are the most relevant parameters, as these parameters are task-specific and the most functional for clinical practice.Implications for RehabilitationClinical relevant information about the use of task-oriented strength during the performance of daily activity has been added to strength measurements in children with Cerebral Palsy.The Task-oriented Arm-hAnd Capacity instrument is a reliable, objective and simple instrument to measure task-oriented strength during daily activity and is ready for use in a clinical setting.The Task-oriented Arm-hAnd Capacity instrument is both a capacity and performance-based test.The measurement with the push button task showed moderate to good test-retest reliability.

Eating behaviors and estimated body fat percentage among adolescents with type 1 diabetes

AIMS

Estimate associations between select eating behaviors and estimated body fat percentage (eBFP) and explore effect modification by sex among adolescents with type 1 diabetes (T1D).

METHODS

This analysis included 257 adolescents (mean age 14.9 ± 1.14 years; 49.8 % female) with baseline hemoglobin A1c (HbA1c) between 8 and 13 % (64 mmol/mol-119 mmol/mol) from a randomized trial designed to improve glycemia. Eating behaviors and eBFP were determined from surveys and validated equations respectively. Linear mixed models were used to estimate associations. Effect modification was assessed via stratified plots, stratified associations, and interaction terms.

RESULTS

Disordered eating, dietary restraint, and eBFP were significantly higher among females while external eating was higher among males. Disordered eating (β: 0.49, 95 %CI: 0.24, 0.73, p = 0.0001) and restraint (β: 1.11, 95 %CI: 0.29, 1.92, p = 0.0081) were positively associated with eBFP while external eating was not (β: -0.19, 95 %CI: -0.470, 0.096, p = 0.20). Interactions with sex were not significant (p-value range: 0.28-0.64).

CONCLUSION

Disordered eating and dietary restraint were positively associated with eBFP, highlighting the potential salience of these eating behaviors to cardiometabolic risk for both female and male adolescents. Prospective studies should investigate whether these eating behaviors predict eBFP longitudinally to inform obesity prevention strategies in T1D.

Body Mass Index Trends before and during the COVID-19 Pandemic in Primary School Students in Split-Dalmatia County, Croatia: A Retrospective Study

Within the last decade, childhood obesity has become a serious problem, especially during the COVID-19 pandemic. This research paper aimed to examine whether body mass index (BMI) was higher during the pandemic (2020-2022) than in the pre-pandemic period (2012/2013-2019) using trends related to sex, urban-rural area, and physical activity (PA). This study included data from physical examinations of an entire population of primary school children from Split-Dalmatia County (Croatia) over a period of 10 years. There were 103,804 students from the first, fifth, and eighth grades who participated in the analysis. During the pandemic, the BMI of all the students increased, except for eighth-grade girls. Generations of eighth graders have had significantly different BMIs throughout the past decade. We found that first graders were overweight and obese in urban areas, while in rural areas, this problem was experienced by upper grades. Girls were more overweight and obese in the first and eighth grades, but boys experienced this more in the fifth grade. Reduced PA influenced an increase in BMI in both sexes, especially in girls. During the pandemic, this situation became worse. This study could be useful to experts for the creation of new policies for Split-Dalmatia County and surrounding regions that are similar economically and culturally.

Adolescent obesity and ANGPTL8: correlations with high sensitivity C-reactive protein, leptin, and chemerin

Angiopoietin-like proteins (ANGPTLs) mediate many metabolic functions. We had recently reported increased plasma levels of ANGPTL8 in obese adults of Arab ethnicity. However, data on ANGPTL8 levels in adolescent obesity is lacking. Arab population is characterized by a rapid transition, due to sudden wealth seen in the post-oil era, in lifestyle, food habits and extent of physical activity. We adopted a cross-sectional study on Arab adolescents from Kuwait to examine the role of ANGPTL8 in adolescent obesity. The study cohort included 452 adolescents, aged 11-14 years, recruited from Middle Schools across Kuwait. BMI-for-age growth charts were used to categorize adolescents as normal-weight, overweight, and obese. ELISA and bead-based multiplexing assays were used to measure plasma levels of ANGPTL8 and other inflammation and obesity-related biomarkers. Data analysis showed significant differences in the plasma levels of ANGPTL8 among the three subgroups, with a significant increase in overweight and obese children compared to normal-weight children. This observation persisted even when the analysis was stratified by sex. Multinomial logistic regression analysis illustrated that adolescents with higher levels of ANGPTL8 were 7 times more likely to become obese and twice as likely to be overweight. ANGPTL8 levels were correlated with those of hsCRP, leptin and chemerin. ANGPTL8 level had a reasonable prognostic power for obesity with an AUC of 0.703 (95%-CI=0.648-0.759). These observations relating to increased ANGPTL8 levels corresponding to increased BMI-for-age z-scores indicate that ANGPTL8, along with hsCRP, leptin and chemerin, could play a role in the early stages of obesity development in children. ANGPTL8 is a potential early marker for adolescent obesity and is associated with well-known obesity and inflammatory markers.

Birth weight, skeletal maturity and dietary patterns are associated with body composition compartments differently in male and female physically active adolescents

Background: Adequate body composition is important for health and performance of physically active adolescents; however, some factors can influence body composition. Aim: The purpose of this study was to evaluate the association between body composition and birth weight, skeletal maturity and dietary patterns, in male (n = 124) and female (n = 107) physically active adolescents. Methods: Birth weight was obtained from health booklets. Dual-energy X-ray absorptiometry (DXA) was used to estimate fat mass (FM), fat-free mass (FFM), visceral adipose tissue (VAT) and abdominal adipose tissue (ASAT). Skeletal maturity was assessed by a hand and fist scanner using DXA. Food intake was assessed using a food frequency questionnaire and dietary patterns by factorial analysis. Results: Seventy one percent (male = 16%, female = 55%) of the participants were mature. Two dietary patterns (in natura/minimally processed and processed/ultra-processed) were identified. In males, FM (>15%, P = 0.043) and ASAT (>30%, P = 0.042) were higher in those with low-median compared to high-median birth weight. FFM (>24%) was higher in skeletally mature compared to those immatures (P = 0.001), and VAT (>28%) was higher in processed/ultra-processed compared to in natura/minimally processed dietary patterns (P = 0.015). In females, FFM (>9%) was higher in those with low-median compared to high-median birth weight (P = 0.019); and FFM (>16%), FM (>28%) and ASAT (>45%) were higher in skeletally mature compared to those immatures (P = 0.001). Conclusion: Our results may contribute to a better understanding of the complex association among body composition, birth weight, skeletal maturity and dietary patterns and in physically active adolescents, differently according to sex.

Phenotyping children and adolescents with obesity using behavioral, psychological, and familial data

OBJECTIVE

This prospective cohort study aimed to empirically derive phenotypes of children and adolescents with overweight and obesity.

METHODS

Latent class analyses using Mplus were carried out in the Growing Up Today Study. Information on participants' weight status, disordered eating behaviors, body image and weight concerns, depressive symptoms, and pubertal timing, as well as and maternal weight status, were included in the latent class analyses, which were stratified by sex. Mixed-effects regression was used to examine associations of the obesity phenotypes with adult weight gain, between age 20 and 35 years, independent of weight at beginning of follow-up and duration of follow-up.

RESULTS

Among the girls, four obesity phenotypes were identified: 1) "early puberty"; 2) "mothers with obesity"; 3) "high weight concerns"; and 4) "mixed." Only three phenotypes were identified among the boys: 1) "high weight concerns"; 2) "mothers with obesity"; and 3) "mixed." Participants who had overweight or obesity in childhood or adolescence gained more weight in young adulthood than their leaner peers, but the patterns of weight gain in young adulthood varied by phenotype of obesity in childhood and adolescence.

CONCLUSIONS

These results support examining risk factors for and treatment outcomes by obesity phenotypes.

Adolescence and the Microbiome: Implications for Healthy Growth and Maturation

The gut microbiota was initially thought to develop into a stable, adult-like profile during early postnatal life. The formation of the gut microbiota during early life has been shown to contribute to healthy growth and has lifelong implications for host health. Adolescence, the developmental period between childhood and adulthood, is a critical window for healthy growth and maturation. The composition of the gut microbiota in adolescents is distinct from that of children and adults, which supports the premise that the gut microbiota continues to develop during adolescence toward an adult-like profile. Research has begun to shift its focus from understanding the gut microbiome at the extremes of the life span to evaluating the importance of the gut microbiome during adolescence and its role in healthy development. This article provides an overview of adolescent development, host-microbiota interactions, and experimental models used to discern effects of gut microbiota on health and disease. Herein, the role of the gut microbiota is reviewed as it relates to adolescent: i) brain development, cognition, and behavior; ii) metabolism and adiposity; and iii) skeletal growth and bone mass accrual. Future directions are addressed, including omics investigations defining mechanisms through which the gut microbiota influences adolescent development. Furthermore, we discuss advancing noninvasive interventions targeting the adolescent gut microbiota that could be employed to support healthy growth and maturation.

Associations of Prenatal Per- and Polyfluoroalkyl Substance (PFAS) Exposures with Offspring Adiposity and Body Composition at 16-20 Years of Age: Project Viva

BACKGROUND

Findings on the associations between prenatal PFAS exposures and offspring adiposity are inconsistent. Whether such associations may extend to adolescence is especially understudied.

OBJECTIVES

We investigated associations of prenatal PFAS exposures with offspring adiposity and body composition at 16-20 years of age.

METHODS

We studied 545 mother-child pairs in the prospective prebirth cohort Project Viva (Boston, Massachusetts). We measured six PFAS (PFOA, PFOS, PFNA, PFHxS, EtFOSAA, and MeFOSAA) in maternal early pregnancy (median age = 9.6 wk , range: 5.7-19.6 wk) plasma samples. At the late adolescence visit (median age = 17.4 y, range: 15.9-20.0 y), we obtained anthropometric measures and assessed body composition using bioelectrical impedance analysis and dual-energy X-ray absorptiometry. We examined associations of individual PFAS with obesity [i.e., age- and sex-specific body mass index (BMI) ≥ 95 th percentile] and adiposity and body composition using multivariable Poisson and linear regression models, respectively. We assessed PFAS mixture effects using Bayesian kernel machine regression (BKMR) and quantile g-computation. We used fractional-polynomial models to assess BMI trajectories (at 3-20 years of age) by prenatal PFAS levels.

RESULTS

Thirteen percent (n = 73 ) of the children had obesity in late adolescence. After multivariable adjustment, higher prenatal PFAS concentrations were associated with higher obesity risk [e.g., 1.59 (95% CI: 1.19, 2.12), 1.24 (95% CI: 0.98, 1.57), and 1.49 (95% CI: 1.11, 1.99) times the obesity risk per doubling of PFOS, PFOA, and PFNA, respectively]. BKMR showed an interaction between PFOA and PFOS, where the positive association between PFOS and obesity was stronger when PFOA levels were lower. Each quartile increment of the PFAS mixture was associated with 1.52 (95% CI: 1.03, 2.25) times the obesity risk and 0.52 (95% CI: - 0.02 , 1.06) kg / m 2 higher BMI. Children with higher prenatal PFOS, EtFOSAA, and MeFOSAA concentrations had higher rates of BMI increase starting from 9-11 years of age.

DISCUSSION

Prenatal PFAS exposures may have obesogenic effects into late adolescence. https://doi.org/10.1289/EHP12597.

Physical activity, screen time and body composition in 13-year-old adolescents: The Generation R Study

BACKGROUND

Body composition between prepubertal children and adolescents varies, and it is unclear how physical activity and sedentary behaviour affect adolescent body composition.

OBJECTIVES

This study aimed to examine the associations of physical activity and screen time with overall and specific fat depots in the general adolescent population.

METHODS

In a population-based prospective cohort study, among 3258 adolescents aged 13 years, physical activity and screen time were assessed via self-report questionnaires. Body mass index, dual-energy X-ray absorptiometry-based measures (i.e. fat mass and lean body mass) and magnetic resonance imaging-based measures (i.e. abdominal subcutaneous and visceral fat mass) were obtained.

RESULTS

After adjusting for social-demographic and growth-related factors, each additional hour of daily physical activity was associated with lower fat mass, abdominal visceral fat mass and higher lean body mass (all p < 0.05). However, these associations were not observed in the longitudinal analyses. Each additional hour of daily screen time was associated with higher body mass index, fat mass, abdominal subcutaneous and visceral fat mass (all p < 0.05), which were consistent with the longitudinal analyses.

CONCLUSION

Adolescents with higher physical activity and lower screen time had lower levels of adiposity both at the general and visceral levels.

Testosterone Restores Body Composition, Bone Mass, and Bone Strength Following Early Puberty Suppression in a Mouse Model Mimicking the Clinical Strategy in Trans Boys

Transgender youth increasingly present at pediatric gender services. Some of them receive long-term puberty suppression with gonadotropin-releasing hormone analogues (GnRHa) before starting gender-affirming hormones (GAH). The impact of GnRHa use started in early puberty on bone composition and bone mass accrual is unexplored. It is furthermore unclear whether subsequent GAH fully restore GnRHa effects and whether the timing of GAH introduction matters. To answer these questions, we developed a mouse model mimicking the clinical strategy applied in trans boys. Prepubertal 4-week-old female mice were treated with GnRHa alone or with GnRHa supplemented with testosterone (T) from 6 weeks (early puberty) or 8 weeks (late puberty) onward. Outcomes were analyzed at 16 weeks and compared with untreated mice of both sexes. GnRHa markedly increased total body fat mass, decreased lean body mass, and had a modest negative impact on grip strength. Both early and late T administration shaped body composition to adult male levels, whereas grip strength was restored to female values. GnRHa-treated animals showed lower trabecular bone volume and reduced cortical bone mass and strength. These changes were reversed by T to female levels (cortical bone mass and strength) irrespective of the time of administration or even fully up to adult male control values (trabecular parameters) in case of earlier T start. The lower bone mass in GnRHa-treated mice was associated with increased bone marrow adiposity, also reversed by T. In conclusion, prolonged GnRHa use started in prepubertal female mice modifies body composition toward more fat and less lean mass and impairs bone mass acquisition and strength. Subsequent T administration counteracts GnRHa impact on these parameters, shaping body composition and trabecular parameters to male values while restoring cortical bone architecture and strength up to female but not male control levels. These findings could help guide clinical strategies in transgender care. © 2023 American Society for Bone and Mineral Research (ASBMR).

Body Composition and Physical Activity in Pediatric Intestinal Failure On and Off Parenteral Nutrition

OBJECTIVES

Data on the relationship between body composition (BC) and physical activity (PA) in children with intestinal failure (IF) are lacking. The objectives were to collect data on PA and BC in children with IF, both parenterally and enterally fed, and to assess the relationship between PA and BC.

METHODS

Cross-sectional study in children 5-18 years with IF including those receiving parenteral nutrition (PN) and those fully enterally fed. PA levels were measured using accelerometry. BC was measured by dual-energy X-ray absorptiometry. Data were compared to age- and sex-matched population norms using t tests. Regression analysis assessed the relationship between BC and PA.

RESULTS

Fifty-eight children with IF (38 males), mean (SD) age of 10.0 (3.5) years, 20 dependent on PN were included. Patients with IF had significantly fewer steps per day ( P ≤ 0.001) compared with literature controls, with a mean (SD) of 7,972 (3,008) and 11,749 (1,106), respectively. There were no significant differences between patients receiving PN and those enterally fed, but both groups were significantly less active than literature controls ( P < 0.001). Patients with IF had higher fat mass and lower fat-free mass compared to literature controls ( P = 0.008). PA had a significant effect on BC ( r2 = 0.32, P < 0.001).

CONCLUSIONS

Children with IF, those receiving PN and those fully enterally fed, are at risk of decreased PA and altered BC. PA should be part of ongoing rehabilitation and management to optimize outcomes.

Calcium plus vitamin D supplementation during pregnancy reduces postpartum fat mass in adolescents: A randomized trial

BACKGROUND

Pregnancy during adolescence may increase the risk of overweight/obesity. There is evidence that increasing calcium intake, alone or vitamin D-combined, may favor loss of weight and/or fat mass.

OBJECTIVES

We hypothesized that calcium supplementation during pregnancy reduces excessive fat accumulation during postpartum period. We aimed to investigate the effect of calcium plus vitamin D supplementation during pregnancy on body composition measurements throughout 1 year postpartum in Brazilian adolescents with habitually low calcium intake (~600 mg/day).

METHODS

Adolescents (14-19 years) were randomly assigned to receive a daily supplement (600 mg of calcium plus 200 UI of cholecalciferol, n = 30) or a placebo (n = 26) from 26 weeks of gestation until parturition. Body composition was determined at 5, 20, and 56 weeks postpartum by dual-energy x-ray absorptiometry. The effects of intervention group, time point, as well as their interaction were assessed using repeated measures mixed-effects models.

RESULTS

In the adjusted analysis, those supplemented showed lower total body mass [mean difference = -3.32 kg; confidence interval (CI) 95% -6.12 to -0.52 kg], trunk (-1.25 kg; CI 95% -2.34 to -0.15 kg), android (-0.29 kg; CI 95% -0.53 to -0.04 kg) and subcutaneous (-0.23 kg; CI 95% -0.43 to -0.03 kg) fat masses. In the supplemented group, BMI and postpartum weight retention significantly decreased from 5 to 20 weeks (-0.90 kg/m2 and -1.76 kg, respectively; p < .05). At 56 weeks, BMI was still lower (-1.22 kg/m2 ; p < .05) than 5 weeks.

CONCLUSIONS

Our findings suggest that increasing calcium intake through supplementation in combination with vitamin D contributes to a more pronounced reduction in total body mass overtime, mostly as a consequence of fat mass reductions in central body regions. This trial was registered at clinicaltrials.gov as NCT01732328.

Gene-Environment Interplay in the Development of Overweight

PURPOSE

Overweight in youth is influenced by genes and environment. Gene-environment interaction (G×E) has been demonstrated in twin studies and recent developments in genetics allow for studying G×E using individual genetic predispositions for overweight. We examine genetic influence on trajectories of overweight during adolescence and early adulthood and determine whether genetic predisposition is attenuated by higher socioeconomic status and having physically active parents.

METHODS

Latent class growth models of overweight were fitted using data from the TRacking Adolescents' Individual Lives Survey (n = 2720). A polygenic score for body mass index (BMI) was derived using summary statistics from a genome-wide association study of adult BMI (N = ∼700,000) and tested as predictor of developmental pathways of overweight. Multinomial logistic regression models were used to examine effects of interactions of genetic predisposition with socioeconomic status and parental physical activity (n = 1675).

RESULTS

A three-class model of developmental pathways of overweight fitted the data best ("non-overweight", "adolescent-onset overweight", and "persistent overweight"). The polygenic score for BMI and socioeconomic status distinguished the persistent overweight and adolescent-onset overweight trajectories from the non-overweight trajectory. Only genetic predisposition differentiated the adolescent-onset from the persistent overweight trajectory. There was no evidence for G×E.

DISCUSSION

Higher genetic predisposition increased the risk of developing overweight during adolescence and young adulthood and was associated with an earlier age at onset. We did not find that genetic predisposition was offset by higher socioeconomic status or having physically active parents. Instead, lower socioeconomic status and higher genetic predisposition acted as additive risk factors for developing overweight.