Body Composition In Adolescents Research Articles

Randomized Controlled Study of Factors Influencing Body Composition and Exercise Quality of Male Adolescents Aged 13–15 Years Based onCross-Lagged Models: Obesity Level, Salivary Testosterone, and Exercise Combined with Caloric Restriction Intervention

Background: Obesity is a worldwide health problem with many disadvantages for children and adolescents, especially for the sexual development of boys. Exercise and caloric restriction are effective in improving obesity; however, the factors influencing these improvements should be studied in detail. We conducted a randomized controlled study of factors affecting changes in body composition and physical capacity in males aged 13–15 years. Methods: Subjects were divided into three groups based on body fat percentage (BFP), and randomly divided into control and intervention groups. The experimental conditions of this study were based on an exercise camp with a 12-week closed training period. The intervention group received a combination of aerobic exercise, resistance exercise, and caloric restriction. All subjects were uniformly housed and had a standard time for diet and rest, whereas the control group performed their coursework during the exercise intervention time and had no dietary restrictions. The subjects were tested for body composition and physical capacity before and after the intervention. Results: The effect of exercise training and energy-restricted diets on fat loss and physical capacity was limited to relatively lower extremity explosive strength and cardiorespiratory endurance, with a significant effect on body composition. Fat mass reduction was influenced by obesity with a high level of individual variability, with higher levels of obesity resulting in greater reductions in fat mass. The reduction in BFP was not affected by the level of obesity, and there was a mild causal relationship with salivary testosterone (ST) in the intervention group but not in the control group. ST was predictive of future BFP in exercisers; individuals with high ST had a greater reduction in BFP under conditions of prolonged exercise and caloric restriction. Conclusions: More obese male adolescents can obtain greater fat mass reduction with the intervention, but fat-free mass and exercise quality are minimally affected by the level of obesity. Adolescent males with higher ST ground tend to gain improvements in body composition, and ST can be predictive of future BFP but needs to be in the context of an exercise intervention.

Nutrition and Epidemiologic Transition on Body Composition and Dietary Pattern of Indigenous Children and Adolescents in Peninsular Malaysia

Malaysia has been undergoing rapid nutrition and drastic epidemiologic transition over the past two decades. This has resulted in the evolution of synergistic existence between undernutrition, overnutrition and hidden hunger. The indigenous population of Malaysia known as Orang Asli continues to experience hunger pandemic in spite of industrialisation and economic growth. The objective of this study was to appraise the impact of nutrition and epidemiologic transition among indigenous children and adolescents. A cross-sectional study was carried among Semai Orang Asli children and adolescents (6-18 years) in Perak. Population Proportion to Size (PPS) was adopted to the sample size samples (N=747) representative of all districts in Perak. Demographic and socio-economic profile was collected using a pre-tested questionnaire, anthropometric measurements were recorded using World Health Organization standard protocols and 24- hour recall method was used to appraise the dietary pattern. Physical signs and symptoms for nutritional deficiencies were done with the help of trained public health nurses. The results were analyzed using SPSS22.0 software to establish possible associations. The findings showed that the incidence of underweight (2%) and malnutrition has declined significantly, with the emerging trends of overweight (19%) and obesity (0.7%) among school children and adolescents. Protein and Energy Malnutrition, Vitamin A, iron and iodine deficiencies, and dental fluorosis were commonly present among the study population. Poor inclusion of fruits and vegetables, legumes, and dairy foods leads to poor dietary diversity among these children. Nutrition and the epidemiologic transition has had a profound impact even on the indigenous population which warrants immediate attention and intervention. Bangladesh J. Nutr. Vol. 34, December 2020, P: 41-53

Effect of Arginine Supplementation and High Intensity Training on Appetite Hormones and Body Composition of Obese Boys

Background: There is little information about the effects of high intensity aerobic exercise training (HIT) and L-arginine supplementation on appetite-regulating hormones among obese male adolescents. We aimed to determine the effect of eight weeks of HIT and L-arginine supplementation on appetite-regulating hormones and body composition indices in obese adolescent boys. Methods: Twenty obese adolescents were randomly divided into two groups of HIT and placebo (P-HIT, n=10) and HIT with supplementation of L-arginine (A-HIT, n=10). The HIT protocol was treadmill running with ventilation threshold (VT) intensity and training sessions were isoenergetic and energy consumption were set to 350 kcal per session for each participant, which were evaluated indirectly by calorimetry. The A-HIT group received 3 g of L-arginine per day for 8 weeks. Before the interventions and 48 hours after the last exercise session, anthropometric indices and levels of appetite-regulating hormones were measured. Results: There was no significant changes between the groups with respect to leptin, agouti, and PYY3-36 peptide levels. There were significant changes in weight reduction between the groups (P≤0.05). However, body max index (BMI) and percent body fat (PBF) changes were not significant in between groups (P≥0.05). Conclusion: Our findings suggest that co-supplementation of L-arginine with HIT training had no further effects on appetite regulatory hormones and body composition of obese male adolescents.

Associations between Avocado Consumption and Diet Quality, Dietary Intake, Measures of Obesity and Body Composition in Adolescents: The Teen Food and Development Study.

Avocado is a nutrient-rich food that has been shown to benefit the health and diet quality of adults. In this paper, we examined if habitual intake of avocado among adolescents is associated with their diet quality, food and nutrient intake, and measures of obesity and body composition. Participants aged 12–18 years old (n = 534) from selected public and Adventist middle-high schools reported their dietary intake in a web-based food frequency questionnaire (FFQ); anthropometrics were measured during school visits. Diet quality (DQI-I) and avocado intake were calculated from the FFQ; BMI z-scores (BMIz), waist-to-height ratio (WHtR), and fat mass (FM), fat-free mass (FFM), and %body fat (%BF) were determined from the anthropometric data. Compared to non-consumers, avocado consumers had significantly higher covariate-adjusted mean scores on total DQI-I (68.3 vs. 64.6) and energy-adjusted mean scores on variety (18.8 vs. 18.0) and adequacy (36.4 vs. 33.4). Avocado consumption was significantly associated with DQI-I components adequacy (β [SE] = 0.11 [0.03]) and moderation (β [SE] = 0.06 [0.03]) but not with BMIz, WHtR, FM, FFM, and %BF. Mean intakes of fruits, vegetables, and plant protein foods, total and vegetable proteins, dietary fiber, retinol, vitamin C, calcium, magnesium, iron, and potassium were significantly higher for avocado consumers; saturated and trans fats intakes were significantly higher for non-consumers. In our adolescent population, avocado consumption was associated with higher diet quality and intake of plant-based foods and shortfall nutrients, but not with measures of obesity and body composition. Studies are needed to determine the optimal amount of avocado that would confer health benefits during adolescence.

The Impact of Nutritional and Lifestyle Changes on Body Weight, Body Composition and Cardiometabolic Risk Factors in Children and Adolescents during the Pandemic of COVID-19: A Systematic Review.

The coronavirus (COVID-19) pandemic and the measures taken by most countries to curb virus transmission, such as social distancing, distance learning, population, home confinement and disruption of all organized activities, has affected children and adolescents worldwide. The aim of this review was to assess the role of diet and lifestyle changes due to COVID-19 measures on body weight/composition and cardiometabolic risk factors in children and adolescents. An electronic search was conducted in PUBMED, COCHRANE, Google Scholar and SCOPUS databases up to 31 October 2021. 15 eligible studies were identified. According to the studies included in the analysis, COVID-19 measures seem to have had a negative impact on the diets and lifestyles of children and adolescents, with a consequent increase in body weight and central fat accumulation. On the other hand, the parental presence and control resulted in better glycaemic control in children with diabetes mellitus (DM) Type 1, but the effect of the pandemic in the glycaemic control of children with DM2 2 is controversial. Finally, diet and lifestyle changes had a differential impact on children’s hypertension prevalence. These findings point to the need for public policy measures to prevent obesity and its complications, to and improve diet and lifestyle during the continuing and yet unresolved COVID-19 epidemic.

Association between Body Composition and Bone Mineral Density in Children and Adolescents: A Systematic Review and Meta-Analysis.

Background: Bone mass acquisition during growth is a major determinant of the risk of developing osteoporosis later in life. Body composition is an anthropometric determinant of bone mineral density (BMD) and significantly influences its development during childhood and adolescence. Objective: This study aimed to systematically examine the association between body composition and bone mineral density in children and adolescents. Methods: Observational studies addressing this association were identified from PubMed (MEDLINE), Embase, Scopus and the Cochrane Library (up to January 2021). The study populations consisted of healthy children and adolescents. The DerSimonian and Laird method was used to compute pooled estimates of effect size and the respective 95% confidence intervals for upper limbs, femoral neck (FN), lumbar spine (LS) and total body, respectively. Subgroup analyses were further performed based on age, sex and ethnicity. Results: Thirty-one published studies were eligible for inclusion in this systematic review and meta-analysis, including three longitudinal studies. The combined population from all the studies amounted to 21,393 (11,205 males and 10,188 females). The pooled estimates of the correlation coefficients for lean mass (LM) and BMD ranged from 0.53 to 0.74 (p < 0.050), and the pooled regression coefficients ranged from 0.23 to 0.79 for FN, LS and total body (p < 0.050). For fat mass (FM), the pooled correlation coefficients ranged from 0.10 to 0.50 (p < 0.050) and the pooled regression coefficient was only significant for FN BMD with a weak strength (pooled β = 0.07, p < 0.050). The pooled regression coefficients for body fat percentage (BF%) were between −0.54 and −0.04 (p < 0.050). The subgroup analysis revealed a stronger association in Asians than in Caucasians for LM and in males compared to females for BF% (p < 0.050). Conclusions: This systematic review and meta-analysis supports a positive association between LM and BMD. BF% appears to have a deleterious effect on bone acquisition in children and adolescents.

Effects of COVID-19 Lockdown on Weight, Body Composition, and Behavior of Children, Adolescents, and Young Adults with Prader-Willi Syndrome.

To reduce transmission of the coronavirus disease 2019 (COVID-19), many countries implemented lockdowns, causing the closure of childcare services. This study was designed to evaluate the impact of the COVID-19 lockdown in March–April 2020 on children, adolescents, and young adults with Prader–Willi syndrome (PWS) living in Germany. We recruited 180 participants with a genetically confirmed PWS. All families completed a questionnaire, and participants underwent a post-lockdown assessment; the last examination before the lockdown was determined as the pre-lockdown assessment. We used bivariate analyses to compare pre- and post-lockdown outcomes. Weight standard deviation scores (SDSPWS) and body mass index (BMI)-SDSPWS remained stable or even decreased in some age groups. A statistically significant gain in lean body mass (LBM) was found in all groups <18 years of age. We observed an increase in IGF-I and IGFBP-3 concentrations without a significant change in growth hormone (GH) dosage. Most families (95.4%) reported set mealtimes and implementation of structured activities (72.2%) during the lockdown period. We therefore suggest that the favorable development of weight/BMI and LBM was caused by an interplay of a suspected enhanced GH administration and continuous parental commitment. However, more intense behavioral problems were observed in 45.7%, which persisted post-lockdown in 33.7%.

Association of Mode of Obstetric Delivery With Child and Adolescent Body Composition

Although the literature on the association between birth by cesarean delivery and children's anthropometry has continued to increase, only a few studies have examined the association of cesarean delivery with measures of body composition assessed using dual-energy x-ray absorptiometry (DXA), which allows the differentiation of fat and lean mass overall and in specific regions of the body. To investigate whether differences exist in DXA-measured body composition between children and adolescents born by cesarean delivery and those born by vaginal delivery. This prospective cohort study included singleton children of mothers enrolled between April 1999 and July 2002 in Project Viva, a longitudinal prebirth cohort of mother-child pairs in Massachusetts. The children had at least 1 DXA scan at a follow-up visit during middle childhood (2007-2010) and/or early adolescence (2013-2016). Data analysis was performed from October 16, 2020, to May 9, 2021. Mode of delivery (cesarean vs vaginal). Total lean mass index, total and truncal fat mass indexes, visceral adipose tissue (VAT), subcutaneous abdominal adipose tissue, and total abdominal adipose tissue (TAAT) were estimated using DXA. Multivariable linear regression models were used to estimate the association between mode of delivery and DXA-derived outcomes with adjustment for confounders. Stabilized inverse probability weights were used to control for potential selection bias owing to loss to follow-up. A total of 975 mother-child pairs were included in the study. The mean (SD) maternal age at study entry was 32.0 (5.5) years, and the mean (SD) self-reported prepregnancy body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) was 25.0 (5.4). Of the children included in the study, 491 (50%) were female; 212 (22%) were born by cesarean delivery and 763 (78%) by vaginal delivery. Body composition in middle childhood as measured by DXA did not differ by mode of delivery. In early adolescence, participants born by cesarean delivery had a significantly greater total lean mass index (β, 0.4; 95% CI, 0.0-0.7), total fat mass index (β, 0.6; 95% CI, 0.1-1.1), truncal fat mass index (β, 0.3; 95% CI, 0.0-0.5), VAT area (β, 4.7; 95% CI, 0.9-8.6), and TAAT area (β, 23.8; 95% CI, 0.8-46.8) in a model adjusted for child sex and age at the time of DXA measurements; maternal age, educational level, race and ethnicity, total gestational weight gain, and smoking status during pregnancy; birth-weight-per-gestational-age z score; and paternal BMI. Associations between mode of delivery and measures of adiposity were found for cesarean deliveries performed in the absence of labor (total fat mass index: β, 1.3; 95% CI, 0.3-2.3; truncal fat mass index: β, 0.6; 95% CI, 0.1-1.0; VAT area: β, 10.7; 95% CI, 3.1-18.3; TAAT area: β, 47.3; 95% CI, 2.3-92.2). There were no associations after adjustment for maternal self-reported prepregnancy BMI (total lean mass index: β, 0.2; 95% CI, -0.1 to 0.6; total fat mass index: β, 0.4; 95% CI, -0.1 to 0.9; truncal fat mass index: β, 0.2; 95% CI, -0.1 to 0.4; VAT area: β, 3.0; 95% CI, -0.6 to 6.7; TAAT area: β, 13.6; 95% CI, -8.2 to 35.3). In this cohort study, adolescents born by cesarean delivery had significantly higher measures of lean mass, fat mass, and central adiposity compared with those born by vaginal delivery, but associations did not remain after adjustment for the mothers' self-reported prepregnancy BMI. The findings suggest that the association between birth by cesarean delivery and adolescent adiposity may partly be explained by maternal self-reported prepregnancy BMI.

Using bioelectrical impedance analysis in children and adolescents: Pressing issues.

Single- and multifrequency bioelectrical impedance analysis (BIA) has gained popularity as a tool to assess body composition and health status of children and adolescents, but many questions and misconceptions remain. This review addresses pressing issues researchers and health care providers may encounter when using BIA in the young population. The importance of choosing population-specific and device-specific equations to estimate body composition as well as the use of BIA in longitudinal analyses are discussed. When specific equations are not available, raw bioimpedance values (i.e., resistance, reactance, and impedance) can be used to compute bioimpedance parameters, such as phase angle, impedance ratio, and bioelectrical impedance vector analysis. As interpreting these parameters is challenging, suggestions are provided on the use of reference data, cut-off points, and adjustment factors. Furthermore, unsolved technical and analytical issues are listed. Based on existing issues and potential for future development, a greater interaction between industry and academic researchers to improve the validity of BIA measurements among children and adolescents across their developmental stages is encouraged.

Relationship Between Muscle Strength, Body Composition and Bone Mineral Density in Adolescents

Adolescence is an important period for the acquisition of bone mass, which can be enhanced by several factors. This study aimed examine the relationships of handgrip strength, free-fat mass, and fat mass with bone mineral density in adolescents. 118 adolescents (60 girls), aged 10 to 14 years, participated in the study. Information on sex, age, handgrip strength, free-fat mass, fat mass and bone mineral density were collected. Multiple linear regression analyses were conducted to examine possible relationships between bone mineral density and handgrip strength, free-fat mass and fat mass. There was a relation between handgrip strength and free-fat mass with bone mineral density in both sexes. Fat mass was correlated with bone mineral density only in girls (r= 0.314, p< 0.014). The final models, adjusted for sexual maturation, included free-fat mass (girls - β= 0.419, p< 0.001; boys - β= 0.455; p< 0.001) and handgrip strength (girls - β= 0.358, p< 0.05; boys - β= 0.325; p< 0.05) and these variables together explained 51.8% and 62.9% of the variation of bone mineral density, in girls and boys, respectively. Handgrip strength and free-fat mass were positively associated with bone mineral density. A sex-specific difference indicated that higher levels of free-fat mass are of paramount importance for both sexes.

A sex-related mediating effect of uric acid in the association between body composition and blood pressure in children and adolescents.

The increase in blood pressure (BP) during somatic growth might have direct determinants but also mediating factors. We investigated whether uric acid (UA) and other metabolic factors would mediate the association between body composition components and BP. A cross-sectional study was conducted in 928 children and adolescents (aged 6-18years), in which body composition and blood biochemistry were evaluated. Structural equation modeling was performed to test the direct and indirect pathways between systolic blood pressure (SBP) and body composition parameters. Muscle mass (MM) showed a strong direct effect on BP, regardless of sex. In girls, a mediating pathway through UA was not significant, but the association between fat mass (FM) and MM with SBP was mediated by the cluster of metabolic factors. In boys, both MM and FM were associated with SBP through a mediating pathway via UA, but not via the cluster of metabolic factors. The association between body composition and BP in children and adolescents has a complex design and also has a sex-specific mediating component. The increase in the UA levels may affect BP levels early in boys. Also, metabolic changes elicited by FM contribute to the increase in BP at an early age in girls. Novelty: MM showed a strong direct effect on BP, regardless of sex. In girls, the association between FM and MM with SBP was mediated by the cluster of metabolic factors. In boys, both MM and FM were associated with SBP through a mediating pathway via UA.

Energy cost of walking and body composition changes during a 9-month multidisciplinary weight reduction program and 4-month follow-up in adolescents with obesity.

The purpose of the present study was to investigate changes in the energy cost of locomotion during walking (Cw) related to changes in body mass (BM, kg) and body composition in adolescents with obesity. Twenty-six (12 boys and 14 girls) obese adolescents (mean: body mass index, 33.6± 3.7kg·m-2; 42.7± 4.5% fat mass (FM)) followed a 9-month multidisciplinary inpatient weight-reduction program consisting of lifestyle education, moderate energy restriction, and regular physical activity in a specialised institution. At baseline (M0), the end of the 9-month program (M9), and after the 4-month follow-up (M13), oxygen consumption and carbon dioxide production of the standardised activity program were assessed by whole-body indirect calorimetry over 24hours, and body composition was assessed by dual-energy X-ray absorptiometry. At M9, adolescents showed an 18% reduction in BM (p< 0.001) and 40% in total FM, while fat-free mass (kg) remained stable in boys but decreased by ∼6% in girls (p= 0.001). Similarly, the mean Cw decreased by 20% (p< 0.001). At M13, BM, FM, and Cw were slightly higher compared with at M9. In conclusion, moderate energy restriction and regular moderate physical activities improved walking economy, improved exercise tolerance, and induced beneficial changes in the body composition of adolescents with obesity. Novelty: Reduction of FM in the trunk region, and consequently reducing the work carried out by respiratory muscles, contributes to reducing Cw in adolescents with obesity. A lower walking cost can be effective in improving exercise tolerance and quality of life in obese adolescents.

Morphology of the prefrontal cortex predicts body composition in early adolescence: cognitive mediators and environmental moderators in the ABCD Study.

Morphological features of the lateral prefrontal cortex (PFC) in late childhood and early adolescence may provide important clues as to the developmental etiology of clinical conditions such as obesity. Body composition measurements and structural brain imaging were performed on 11 226 youth at baseline (age 9 or 10 years) and follow-up (age 11 or 12 years). Baseline morphological features of the lateral PFC were examined as predictors of body composition. Findings revealed reliable associations between middle frontal gyrus volume, thickness and surface area and multiple indices of body composition. These findings were consistent across both time points and remained significant after covariate adjustment. Cortical thicknesses of the inferior frontal gyrus and lateral orbitofrontal cortex were also reliable predictors. Morphology effects on body composition were mediated by performance on a non-verbal reasoning task. Modest but reliable moderation effects were observed with respect to environmental self-regulatory demand after controlling for sex, race/ethnicity, income and methodological variables. Overall findings suggest that PFC morphology is a reliable predictor of body composition in early adolescence, as mediated through select cognitive functions and partially moderated by environmental characteristics.

Effects of Continuous Yoga on Body Composition in Obese Adolescents.

Overweight/obesity is a pressing international health concern, and conventional treatments demonstrate poor long-term efficacy. Several studies have shown that yoga can control risk factors for cardiovascular disease, obesity, and psychosocial stress. The present study aimed to assess the effect of continuous yoga (asanas, pranayama, and Surya Namaskar yoga) on body composition in overweight participants. Forty adolescents with obesity were enrolled in this study. The study was conceived as a prospective, single-center, single-blinded randomized controlled trial. The participants were divided into 2 groups: the intervention group (n = 20), which undertook a continuous yoga practice, and the control group (n = 20). Body composition, including body weight (BW), body mass index (BMI), body fat mass (BFM), and muscle mass, was evaluated using tetrapolar bioelectrical impedance (BIA). Our results showed that the mean BMI and BFM of the yoga intervention group were significantly decreased at week 8 and week 12. The muscle mass of the yoga group continued to improve at a rate of 0.515 per week, which was statistically significant. In conclusion, a continuous yoga practice had a tendency to decrease BMI and BFM and increase muscle mass. These findings demonstrate intervention effectiveness similar to that observed in other clinical research and indicate that continuous yoga practice may be used as an alternative therapy for obesity prevention and health promotion in adolescents with obesity.

Gestational and early childhood phthalate exposures and adolescent body composition: The HOME Study

BACKGROUND AND AIM: Early life phthalate exposures may cause metabolic disruption. However, results from human studies are inconsistent and few have examined body composition during adolescence. We investigated associations of urinary phthalate metabolite concentrations during gestation and childhood with body composition at age 12 years to identify periods of heightened susceptibility. METHODS: We used data from 206 mother-child pairs in a prospective pregnancy and birth cohort enrolled in Cincinnati, OH from 2003-2006. We measured nine phthalate metabolites in spot urine samples collected twice from mothers during pregnancy and up to six times from children at 1, 2, 3, 4, 5 and 8 years. At age 12 years, we assessed whole body fat and lean mass, android, gynoid, and visceral fat mass with dual x-ray absorptiometry, and calculated android to gynoid %fat ratio and age- and sex-standardized fat and lean mass index Z-scores. Using a multiple informant model, we estimated the covariate-adjusted associations between urinary phthalate metabolite concentrations at each time period and adiposity Z-scores at age 12 years. We assessed effect measure modification by child sex using stratified models. RESULTS:Associations of urinary mono-n-butyl, mono-isobutyl, and mono-benzyl phthalate concentrations with 12-year body composition outcomes differed by time period, with stronger associations for exposures during gestation and later childhood. For example, each 10-fold increase in urinary mono-benzyl phthalate concentrations during gestation at ages 5 and 8 years was associated with a -0.34 (95%CI: -0.72,0.05), -0.44 (95%CI: -0.83,-0.05), and -0.35 (95%CI:-0.71,0.00) Z-score difference in whole body lean mass at age 12 years, respectively, but not for exposure in in early childhood. Slightly weaker but similar patterns of association were found with other body composition measures; associations did not differ by child sex. CONCLUSIONS:Exposure to certain phthalates during gestation and late childhood may be associated with adolescent body composition, particularly lean mass. KEYWORDS: Children’s environmental health, Endocrine disrupting chemicals, Obesity and metabolic disorders, Phthalates

Evaluation of Body Composition in Adolescents with Avoidant Restrictive Food Intake Disorder

Evaluation of Body Composition in Adolescents with Avoidant Restrictive Food Intake Disorder

Effects of a multiprofessional approach on anthropometric variables, body composition and food profile of overweight or obese adolescents

Introduction: To investigate the effects of a multiprofessional approach on anthropometric parameters and body composition and the level of food processing in adolescents. Methods: Twelve overweight/obese male adolescents between 13-17 years old participated in a series of 12-week multiprofessional interventioms led by physical education, nutrition and psychology professionals. The participants were assessed before the intervention as well as at 6 and 12 weeks into it. Anthropometric assessments were performed, including body weight, stature and body mass index; body composition, with fat mass (FM), body fat (%BF), skeletal muscle mass (SMM) and resting metabolic rate (RMR) and by filling in a three-day food record, in order to calculate the ingested foods, by the level of processing of the food: fresh, minimally processed, processed and ultra-processed. Results: No differences were observed for the anthropometric parameters performed at different stages (p&gt;0.05). Reductions for FM and %BF and increases in SMM and RMR (p&lt;0.05) were identified, all after 12-week of the intervention. There was an increase in the consumption of natural foods/g, and an increase in the caloric consumption of processed foods/kcal, after 12-week of interventions (p&lt;0.05). Conclusion: The model resulted in decreases in FM and %BF, an increase in SMM, RMR, natural foods/g and processed foods/kcal.

The effect and safety of high-intensity interval training in the treatment of adolescent obesity: a meta-analysis.

It's necessary to conduct meta-analysis to quantitatively evaluate the effect and safety of high-intensity interval training (HIIT) on obese adolescents, to provide a basis for the management of obesity in adolescents. Randomized controlled trials (RCTs) on the role of HIIT in the obese adolescents were searched from PubMed databases and so on up to Jan 15, 2021. Two researchers independently performed literature screening, literature quality evaluation and data extraction according to the inclusion and exclusion criteria. Revman 5.3 Software and Stata 12.2 Software were used for data analysis. A total of 11 RCTs with 488 obese adolescents were included. Meta-analysis indicated that HIIT can effectively reduce the body weight (MD =-1.73 kg, 95% CI: -3.25 to -0.21, P=0.02), BMI (MD =-1.42 kg/m2, 95% CI: -1.97 to -0.87, P<0.001), body fat percentage (MD =-1.70%, 95% CI: -2.94 to -0.45, P=0.007) and waist circumference (MD =-1.80 cm, 95% CI: -3.5 to -0.10, P=0.04). The "high-intensity short-interval" HIIT program can significantly reduce waist circumference (MD =-2.31 cm, 95% CI: -4.20 to -0.42, P=0.022), the "high-intensity long-interval" HIIT program is more beneficial to reduce the BMI (MD =-1.44 kg/m2, 95% CI: -2.03 to -0.84, P=0.001) and body fat percentage (MD =-0.56, 95% CI: -1.08 to -0.05, P=0.009). HIIT can effectively improve the body composition of obese adolescents and produce an effective fat-reducing effect, which should be promoted for the clinical treatment of adolescent obesity.

Area-level and family-level socioeconomic position and body composition trajectories: longitudinal analysis of the UK Millennium Cohort Study

SummaryBackgroundInequalities in the trajectories of body composition in childhood and adolescence have been infrequently studied. Despite the importance of environmental factors in obesity development, little research has looked at area-level socioeconomic position, independent of family socioeconomic position. We aimed to assess how inequalities in body composition develop with age.MethodsThe Millennium Cohort Study is a longitudinal study of 19 243 families who had a child born between 2000 and 2002 in the UK. Multilevel growth curve models were applied to examine change in fat mass index (FMI), fat free mass index (FFMI; using the Benn index), and fat mass to fat free mass ratio (FM:FFM), measured using Bioelectrical Impedance Analysis, from ages 7 years to 17 years by the Index of Multiple Deprivation (IMD) and household income at baseline.FindingsInequalities in FMI and FM:FFM ratio are evident at age 7 years and widen with age. At age 17 years, adolescents in the most disadvantaged IMD group had FMI 0·57 kg/mB (B=Benn parameter; 95% CI 0·43 to 0·70) higher and FM:FFM ratio 0·037 (95% CI 0·026 to 0·047) higher compared with the most advantaged group. Disadvantaged socioeconomic position is associated with higher FFMI but is reversed in adolescence after adjustment for FMI. Inequalities were greater in girls at age 7 years (mean FMI 0·22 kg/mB; 95% CI 0·13 to 0·32) compared with boys of the same age (0·05 kg/mB; –0·04 to 0·15, p=0·3), but widen fastest in boys, especially for FMI, in which there was over an 11 times increase in the inequality from age 7 years of 0·05kg/mB (95% CI –0·04 to 0·15) to 0·62 kg/mB at 17 years (0·42 to 0·82). Inequalities for the IMD were similar to income, and persisted at age 17 years independent of family socioeconomic position.InterpretationChildhood and adolescence is an important period to address inequalities in body composition, as they emerge and widen. Policies should consider FFM as well as FM, and inequalities in the environment.FundingMedical Research Council, Economic and Social Research Council.

Effects of Eight-Week High-Intensity Interval Training on Aerobic Performance, Lipid Profile, and Hematological Indices in Overweight Adolescents

Background: Research on the effects of interval training on lipid profile and hematological indices is limited. Objectives: Therefore, the purpose of this study was to determine the effects of eight weeks of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on aerobic performance, body composition, lipid profile, and hematological indices in overweight adolescents. Methods: Thirty overweight boys (13 - 16 years) participated in this study and were randomly divided into three groups, including the control (n = 10), HIIT (n = 10), and MICT (n = 10) groups. HIIT training (4 × 4-minute) was performed with an intensity of 95 - 85% of maximum heart rate, and MICT training (35-minute) was performed with an intensity of 70 - 60% of maximum heart rate, three sessions per week for eight weeks. Beep test and ELISA technique were used to measure aerobic performance, lipid profile, and hematological indices, respectively. The two-way repeated-measures ANOVA was used to determine the differences with a confidence interval of 95% (α = 0.05). Results: The results showed that except for the variables of glucose, triglyceride (TG), and low-density lipoprotein (LDL), all other variables in the HIIT group had a significant change compared to the pre-test (P &lt; 0.05). Also, the results showed that there was a significant difference between the HIIT and control groups in fat percentage, VO2Max, high-density lipoprotein (HDL), iron, and hemoglobin value (P &lt; 0.05). Conclusions: The results suggest that HIIT training can be as effective as continuous strategy training to reduce the risk factors associated with cardiovascular disease in overweight adolescents.