The impact of perceived school climate on exercise behavior engagement among obese adolescents: a dual mediation effect test of exercise benefits and perseverance qualities.

Introduction: This study explores the relationship between perceived school climate and exercise behavior among obese adolescents, as well as the multiple mediating effects of perseverance qualities and exercise benefits. Methods: A survey was conducted on 586 obese adolescents in Beijing, with an age range of 13-18 years old and an average age of 15.40 ± 1.824, among who 337 were male, 249 were female, 303 were high school students and 238 were middle school students. A standard scale was used to evaluate perceived school climate, exercise benefits, perseverance qualities, and exercise behaviors. The data was analyzed by independent samples t-test, bivariate correlation analysis, descriptive statistical analysis, and structural equation model (SEM). Results: (1) Perceived school climate among obese adolescents positively predicted exercise behavior (Z = 2.870, p < 0.01), perseverance qualities (Z = 3.107, p < 0.01) and exercise benefits (Z = 4.290, p < 0.001); perseverance qualities positively predicted exercise behavior in obese adolescents (Z = 4.431, p < 0.001); exercise benefits positively predicted the obese adolescents' exercise behavior (Z = 4.267, p < 0.001). (2) Perseverance qualities (Z = 2.282, 95% CI [0.032, 0.191], [0.028, 0.179]) and exercise benefits (Z = 2.518, 95% CI [0.060, 0.287], [0.053, 0.271]) play a mediating role in the obese adolescents' perceived school climate and exercise behavior, respectively. These two factors have parallel multiple mediating effects between obese adolescents' perceived school climate and exercise behavior, with mediating effects accounting for 16 and 25%, respectively. The mediating effect of exercise benefits is greater than that of perseverance qualities. (3) There is no difference in the specific indirect effects of perseverance qualities and exercise benefits (Z = -0.800, 95% CI [- 0.198, 0.064], [-0.190, 0.068]). Conclusion: Obese adolescents' perception of school climate can effectively enhance their motivation to participate in exercise behavior and indirectly influence exercise behavior through exercise benefits and perseverance qualities, cultivate good physical exercise behavior among obese adolescents, and effectively prevent and intervene in the occurrence of obesity.

Time course efficiency of MICE and HIIE on inhibitory control and HRV in adolescents with obesity and different cardiorespiratory fitness.

Background: Adolescent obesity is associated with impaired inhibitory control. Acute exercise can improve executive function. However, due to the influence of exercise intensity, cognitive test timing, and cardiorespiratory fitness (CF) level, the most effective exercise program remains controversial. Methods: The current study investigated the time-course effects of moderate-intensity continuous exercise (MICE) and high-intensity interval exercise (HIIE) on inhibitory control (Stroop) and task-related heart rate variability (HRV) in adolescents with different CF. A mixed experimental design of 2 CF levels (high CF, HCF; low CF, LCF) × 3 exercise methods (MICE, HIIE, CON) × 3 test timing (pre, post-0, post-20) was adopted. Heart rate variability (HRV) and Stroop task tests were conducted before exercise (pre), immediately after exercise (post-0), and 20 min after exercise (post-20). Results: Individuals with HCF exhibited a positive decrease in Stroop response time immediately and 20 min after MICE and HIIE, compared to pretest response times (RT). Conversely, individuals with LCF showed a slight increase in Stroop task (RT) only immediately after HIIE. All individuals had a slight increase in ACC after MICE and HIIE compared to before exercise. In addition, compared with the control group, the time-domain index (the square root of the mean squared differences of successive NN intervals, RMSSD) of HRV was significantly decreased, the frequency-domain index (the absolute power of the Low-Frequency band/the absolute power of the High-Frequency band ratio, LF/HF) was significantly increased after MICE and HIIE, and the effect of HIIE on RMSSD and LF/HF was significantly greater than that of MICE. Conclusion: The current study found that the acute effects of MICE and HIIE on inhibitory control in obese adolescents were influenced by the interaction of cognitive test timing and cardiorespiratory fitness. Individuals with high cardiorespiratory fitness performed better on the Stroop task than individuals with low cardiorespiratory fitness. The inhibitory control of HIIE in high-cardiorespiratory obese adolescents produced positive effects similar to those in MICE but more lasting, suggesting that HIIE is more beneficial for high-cardiorespiratory obese adolescents. MICE promoted inhibitory control in obese adolescents with low cardiorespiratory fitness, but HIIE impaired inhibitory control in obese adolescents with low cardiorespiratory fitness immediately after exercise, suggesting that low cardiopulmonary fitness obese adolescents may be suitable for MICE rather than HIIE exercise intervention. The shift from balanced HRV to sympathetic dominance after acute exercise reflects increased arousal levels and may be one of the underlying mechanisms by which acute exercise brings benefits to executive function.

Association between cardiorespiratory fitness level and insulin resistance in adolescents with various obesity categories.

BACKGROUND: An association between cardiorespiratory fitness (CRF) and insulin resistance in obese adolescents, especially in those with various obesity categories, has not been systematically studied. There is a lack of knowledge about the effects of CRF on insulin resistance in severely obese adolescents, despite their continuous rise. AIM: To investigate the association between CRF and insulin resistance in obese adolescents, with special emphasis on severely obese adolescents. METHODS: We performed a prospective, cross-sectional study that included 200 pubertal adolescents, 10 years to 18 years of age, who were referred to a tertiary care center due to obesity. According to body mass index (BMI), adolescents were classified as mildly obese (BMI 100% to 120% of the 95th percentile for age and sex) or severely obese (BMI ≥ 120% of the 95th percentile for age and sex or ≥ 35 kg/m2, whichever was lower). Participant body composition was assessed by bioelectrical impedance analysis. A homeostatic model assessment of insulin resistance (HOMA-IR) was calculated. Maximal oxygen uptake (VO2max) was determined from submaximal treadmill exercise test. CRF was expressed as VO2max scaled by total body weight (TBW) (mL/min/kg TBW) or by fat free mass (FFM) (mL/min/kg FFM), and then categorized as poor, intermediate, or good, according to VO2max terciles. Data were analyzed by statistical software package SPSS (IBM SPSS Statistics for Windows, Version 24.0). P < 0.05 was considered statistically significant. RESULTS: A weak negative correlation between CRF and HOMA-IR was found [Spearman's rank correlation coefficient (rs) = -0.28, P < 0.01 for CRFTBW; (rs) = -0.21, P < 0.01 for CRFFFM]. One-way analysis of variance (ANOVA) revealed a significant main effect of CRF on HOMA-IR [F(2200) = 6.840, P = 0.001 for CRFTBW; F(2200) = 3.883, P = 0.022 for CRFFFM]. Subsequent analyses showed that obese adolescents with poor CRF had higher HOMA-IR than obese adolescents with good CRF (P = 0.001 for CRFTBW; P = 0.018 for CRFFFM). Two-way ANOVA with Bonferroni correction confirmed significant effect of interaction of CRF level and obesity category on HOMA-IR [F(2200) = 3.292, P = 0.039 for CRFTBW]. Severely obese adolescents had higher HOMA-IR than those who were mildly obese, with either good or poor CRF. However, HOMA-IR did not differ between severely obese adolescents with good and mildly obese adolescents with poor CRF. CONCLUSION: CRF is an important determinant of insulin resistance in obese adolescents, regardless of obesity category. Therefore, CRF assessment should be a part of diagnostic procedure, and its improvement should be a therapeutic goal.

Value of 1-Hour Plasma Glucose During an Oral Glucose Tolerance Test in a Multiethnic Cohort of Obese Children and Adolescents.

One hour plasma glucose (1-hr PG) concentration during an oral glucose tolerance test (OGTT) is steadily emerging as an independent predictor of type 2 diabetes (T2D). Methods: We applied the current cut off thresholds reported in the pediatric literature for the 1-hr PG, 132.5 (7.4 mmol/l) and 155 mg/dL (8.6 mmol/l) during an OGTT, to report abnormal glucose tolerance (AGT) using ROC curve analyses. We determined the empirical optimal cut point for 1-hr PG for our multi ethnic cohort using the Youden Index. Results: About 1-hour and 2-hours plasma glucose showed the highest predictive potential based on Areas under the curve (AUC) values of 0.91 [CI: 0.85, 0.97] and 1 [CI: 1, 1], respectively. Further comparison of the ROC curves of the 1-hour and 2-hour PG measurements as predictors of an abnormal OGTT showed that their associated AUCs differed significantly (X2(1) = 9.25, P < .05). Using 132.5 mg/dL as the cutoff point for plasma glucose at 1-hour yielded a ROC curve with an AUC of 0.796, a sensitivity of 88%, and a specificity of 71.2%. Alternatively, the cutoff point of 155 mg/dL resulted in a ROC AUC of 0.852, a sensitivity of 80%, and a specificity of 90.4%. Conclusion: Our cross-sectional study affirms that the 1-hr PG can identify obese children and adolescents at increased risk for prediabetes and/or T2D with almost the same accuracy as a 2-hr PG. In our multi-ethnic cohort, a 1-hr PG ⩾ 155 mg/dL (8.6 mmol/l) serves as an optimal cut-point, using the estimation of the Youden index with AUC of 0.86 and sensitivity of 80%.We support the petition to consider the 1-hr PG as integral during an OGTT, as this adds value to the interpretation of the OGTT beyond the fasting and 2-hr PG.

Nomogram model for the risk of insulin resistance in obese children and adolescents based on anthropomorphology and lipid derived indicators.

OBJECTIVE: This study aims to screen for measures and lipid-derived indicators associated with insulin resistance (IR) in obese children and adolescents and develop a nomogram model for predicting the risk of insulin resistance. METHODS: A total of 404 eligible obese children and adolescents aged 10-17 years were recruited for this study from a summer camp between 2019 and 2021. The risk factors were screened using the least absolute shrinkage and selection operator (LASSO)-logistic regression model, and a nomogram model was developed. The diagnostic value of the model was evaluated by plotting the receiver operator characteristic curve and calculating the area under the curve. Internal validation was performed using the Bootstrap method, with 1000 self-samples to evaluate the model stability. The clinical applicability of the model was assessed by plotting the clinical decision curve. RESULTS: On the basis of the LASSO regression analysis results, three lipid-related derivatives, TG/HDL-c, TC/HDL-c, and LDL-c/HDL-c, were finally included in the IR risk prediction model. The nomogram model AUC was 0.804 (95% CI: 0.760 to 0.849). Internal validation results show a C-Index of 0.799, and the mean absolute error between the predicted and actual risks of IR was 0.015. The results of the Hosmer-Lemeshow goodness-of-fit test show a good model prediction (χ2 = 9.523, P = 0.300). CONCLUSION: Three early warning factors, TG/HDL-c, TC/HDL-c, and LDL-c/HDL-c, were screened, which can effectively predict the risk of developing IR in obese children and adolescents, and the nomogram model has an eligible diagnostic value.

Evaluation of Heart Rate Recovery in Obese Children and Adolescents With Prehypertension.

Heart rate recovery (HRR), a noninvasive assessment of autonomic nervous function, is widely studied in adults with hypertension or prehypertension. This study aimed to evaluate whether HRR was independently associated with prehypertension in obese children. A total of 326 obese children aged 7 to 16 years were divided into 2 groups: prehypertension group and normal blood pressure (BP) group (control group). Anthropometric indexes, physical activity (PA) information, biochemical parameters, and HRR were collected. Multiple logistic regression analysis showed that body mass index (BMI) (odds ratio [OR] = 1.116; P < .05), waist-to-hip ratio (WHR) (OR = 1.258; P < .05), homeostasis model assessment (HOMA-IR) (OR = 1.087; P < .01), diastolic blood pressure (DBP) (OR = 1.304; P < .01), and HRR values (OR = 0.892; P < .05) were independent risk factors of prehypertension in obese children. Our findings demonstrated decreased HRR was closely associated with prehypertension in obese children, which indicated studying the role of sympathetic/parasympathetic imbalance might be helpful to explore the underlying mechanism.

Characteristics of blood uric acid level and its correlation with metabolic indexes in obese adolescentsu / 公共卫生与预防医学

Objective To explore the characteristics of blood uric acid levels and its correlation with calcium and phosphorus levels, and glucose and lipid metabolism in obese adolescents in weight-loss training camps. Methods In this study, 357 obese adolescents aged 12-18 were selected as the research subjects, and 135 normal-weight adolescents were selected as the controls. The body shape and blood uric acid characteristics of the subjects were measured and analyzed. Further, 59 subjects were selected from the obese adolescents for blood calcium, blood phosphorus and glucose and lipid metabolism index tests to analyze the correlation between blood uric acid level and calcium, phosphorus, and glucose and lipid metabolism indicators. Results The average blood uric acid level of obese adolescents was (527.12±122.94)μmol/L, (566.58±122.51)μmol/L for boys, and (468.35±97.79)μmol/L for girls. The blood uric acid level of the obesity group was significantly higher than that of the control group (P<0.001 for boys, P<0.05 for girls), and it was higher in boys than in girls (P<0.01). Obese adolescents with high uric acid accounted for 73.39%. The HOMA-IR of obese adolescents was 5.79±3.04. The blood uric acid level was significantly correlated with blood calcium, total cholesterol, and low-density lipoprotein cholesterol (P<0.05). Gender and low-density lipoprotein cholesterol were the main influencing factors of blood uric acid (P<0.05). Conclusion Obese adolescents have high blood uric acid levels, low calcium and high phosphorus in the body, and a higher incidence of insulin resistance. There exists a positive correlation between the blood uric acid level and the body's calcium and phosphorus metabolism and glucose and lipid metabolism in obese adolescents. Clinical monitoring of lipid metabolism indicators such as low-density lipoprotein has certain reference value for the prevention and treatment of hyperuricemia.

Single Point Insulin Sensitivity Estimator for predicting type 2 diabetes mellitus in obese adolescents.

PURPOSE: The prevalence of adolescents with type 2 diabetes mellitus (T2DM) has rapidly increased in Korea over the past few decades with the increase in the number of obese adolescents. The single point insulin sensitivity estimator (SPISE) was recently introduced as a surrogate marker for insulin sensitivity to predict T2DM in adults. We aimed to determine risk factors for T2DM in obese adolescents, including SPISE. METHODS: This retrospective study included 104 adolescents diagnosed with T2DM at Korea University Hospital between January 2010 and December 2020. We compared clinical and biochemical parameters and the SPISE of normoglycemic overweight and obese individuals with those of prediabetic and diabetic adolescents to determine risk factors for T2DM. Receiver operating characteristic analysis was performed with the Youden index to determine the cutoff point of SPISE. RESULTS: Frequency of fatty liver and family history of T2DM were significantly higher and SPISE level was significantly lower in patients with T2DM than in normoglycemic overweight/obese and prediabetic adolescents (p<0.01). A family history of T2DM, fatty liver, and SPISE value below the cutoff point (4.49) were identified as significant risk factors for T2DM in multiple logistic regression analysis after controlling for age, sex, and body mass index standard deviation score (p<0.01). CONCLUSION: Family history of T2DM, fatty liver, and low SPISE (<4.49) are risk factors that can independently affect the occurrence of T2DM in obese adolescents. Among these risk factors, SPISE is a promising marker for predicting adolescent T2DM; careful monitoring of these individuals is needed to prevent progression to T2DM.

Musings in the twilight of my career.

I present a summary of my research during the last few decades of research which focused on understanding the biochemical basis for maintaining an optimum metabolism to support long-term health. I realized that adequate levels of ∼40 vitamins and minerals needed as cofactors in thousands of metabolic reactions were critical for maintaining a healthy metabolism, and thus for longevity and prevention of chronic disease. Inadequate dietary intake of vitamins and minerals accelerates the risk of aging-associated diseases, leading to insidious damage. The Triage Theory provides a mechanistic rationale for such damage: shortage of a nutrient triggers a built-in rationing mechanism that allocates the scarce nutrient to proteins needed for immediate survival (survival proteins), at the expense of those needed for long-term survival (longevity proteins). Many as-yet-unknown longevity vitamins and proteins likely remain to be discovered. The fiber and nutrient-rich CHORI-bar was developed to fill gaps in inadequate diets; it yielded broadscale metabolic improvements. The health-related damages resulting from vitamin D deficiency and the positive effects of vitamin D supplementation were connected to numerous health-related problems, including the higher level of deficiency in people of color residing at northern latitudes. In general, prevention of degenerative diseases of aging requires expertise in metabolism, nutrition, biochemistry and regulatory functions.

The Effects of Different Exercise Modalities in the Treatment of Cardiometabolic Risk Factors in Obese Adolescents with Sedentary Behavior-A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

PURPOSE: Obesity has become increasingly prevalent in adolescents due to unhealthy diet habits, sedentary behavior and a lack of physical activities. This study aims to assess the effects of different exercise modalities in the treatment of cardiometabolic risk factors (CRF) in obese adolescents with sedentary behavior. METHODS: A systematic search was conducted using databases (PubMed, Embase, Cochrane library, Web of Science, CNKI and VIP database) from the earliest available date to August 2021. Nineteen randomized controlled trials (RCTs) with 704 participants were included. The included studies were evaluated for methodological quality by the Cochrane bias risk assessment tool, and a statistical analysis was performed by the Review Manage 5.3 and Stata 15.1 software. RESULTS: The results of the meta-analysis showed that exercise could significantly improve obese adolescents' body mass index (BMI) (MD = -1.99, 95% CI: -2.81 to -1.17, p < 0.00001), low density liptein cholesterol (LDL-C) (SMD = -0.98, 95% CI: -1.58 to -0.37, p = 0.002), triglyceride (TG) (SMD = -0.93, 95% CI: -1.72 to -0.14, p = 0.02), total cholesterol (TC) (SMD = -1.00, 95% CI: -1.73 to -0.26, p = 0.008), peak oxygen uptake (VO2peak) (MD = 3.27, 95% CI: 1.52 to 5.02, p = 0.0003) and homeostatic model assessment insulin resistance (HOMA-IR) (SMD = -2.07, 95% CI: -3.3 to -0.84, p = 0.001). However, there was no statistically significant difference in high-density liptein cholesterol (HDL-C) (SMD = 0.40, 95% CI: -0.28 to 1.08, p = 0.25). CONCLUSION: Exercise can effectively improve cardiometabolic risk factors in obese adolescents with sedentary behavior. For obese adolescents who want to lose weight and improve cardiorespiratory fitness, combined aerobic and resistance training and high-intensity interval training are optimal choices. For obese adolescents with high blood lipids, aerobic training can be regarded as a primary exercise modality to reduce the high risk of cardiovascular diseases; For obese adolescents with insulin resistance, combined aerobic and resistance training can be considered to reduce the high risk of diabetes. It is hoped that more high-quality studies will further expand the meta-analysis results and demonstrate the optimal exercise frequency and treatment intensity of cardiometabolic risk factors in obese adolescents with sedentary behavior in the future.

Improved fatty acid profile reduces body fat and arterial stiffness in obese adolescents upon combinatorial intervention with exercise and dietary restriction.

OBJECTIVE: In order to examine the effect of 4-week combinatorial intervention with exercise training and dietary restriction on serum fatty acids, and to explore the correlation of intervention-induced improvement of serum fatty acid profile with the reduction of body fat and arterial stiffness. METHODS: Thirty-three obese adolescents were randomized into the intervention (n = 19) and control (n = 14) groups. The participants from the intervention group were subjected to 4-week combinatorial intervention with exercise training and dietary restriction while the participants from the control group maintained regular activities and diet habits. Anthropometry, serum fatty acids and arterial stiffness were measured before and after 4-week intervention. RESULTS: The participants upon combinatorial intervention revealed the improved body compositions and serum fatty acid profile, and reduced arterial stiffness when compared with their basal levels and the control participants (p < 0.05). Moreover, the decrease in myristic acid, stearic acid, arachidic acid, behenic acid, palmitoleic acid, and dihomo-γ-linolenic acid, was associated with the reduction in body fat. A positive correlation between arachidonic acid and left brachial ankle pulse velocity was observed, and the increase in docosahexaenoic acid was associated with the reduction of left brachial ankle pulse wave velocity and the enhancement of right ankle brachial index. CONCLUSION: The 4-week combinatorial intervention is a useful strategy to improve serum fatty acid profile along with the reduction of body fat and arterial stiffness in obese adolescents.

Investigation of quality of life in obese adolescents: the effect of psychiatric symptoms of obese adolescent and/or mother on quality of life.

OBJECTIVES: The present study assessed the obese adolescents' health-related quality of life (HRQoL) based on both adolescent-reported and maternal-reported questionnaires to clarify adolescent-related psychiatric factors, maternal psychiatric factors, and body mass index (BMI) percentile variables that independently affect the quality of life (QoL). METHODS: A total of 190 adolescents (120 females and 70 males) were included in the study. The impact of clinical and psychiatric factors on the Pediatric Quality of Life Inventory-Child Version (PedsQL-C) scores was analyzed using hierarchical linear regression methods. RESULTS: The final models showed that only the Revised Child Anxiety and Depression Scale-Child Version major depressive disorder scores negatively predicted the physical, psychosocial, and total health scores of the PedsQL-C. The psychosocial scores of the PedsQL-P were negatively predicted by the Strengths and Difficulties Questionnaire emotional, and Conners' Parent Rating Scale-Revised-Short Form (CPRS-R-S) attention-deficit/hyperactivity disorder (ADHD) index scores. The PedsQL-P total scores were negatively predicted by the CPRS-R-S ADHD index scores. CONCLUSIONS: The findings of this study indicate that the adolescents' psychiatric symptoms and BMI percentile played a significant role in the PedsQL subscale functioning of obese adolescents compared to maternal psychiatric symptoms.

Effect of vitamin D supplementation on microvascular reactivity in obese adolescents: A randomized controlled trial.

BACKGROUND AND AIM: Childhood obesity is associated with vitamin D (VD) deficiency and vascular dysfunction. Considering evidence indicates that VD may improve vascular function, this study, for the first time, assessed the effect of VD supplementation on microvascular reactivity in obese adolescents (OA). METHODS AND RESULTS: This randomized controlled trial included 26 OA, receiving fruit juice with (n = 13) or without VD (4000 IU/d; n = 13) over a 3-month lifestyle program, as well as 23 normal-weight adolescents (controls). The primary outcome was the pre-to-post-program change in microvascular reactivity determined by laser speckle contrast imaging with acetylcholine and sodium nitroprusside iontophoresis. Changes in 25 hydroxyvitamin D (25(OH)D), flow-mediated dilation (FMD), nitrate-mediated dilation (NMD), insulin resistance (HOMA-IR) and inflammatory markers (C-reactive protein [CRP]) were monitored. At inclusion, in comparison to controls, OA exhibited lower total and free 25(OH)D, impaired microvascular responses, and impaired FMD, but similar NMD. After the lifestyle program, total and free 25(OH)D increased in all OA, with a greater increase in those receiving VD supplements. HOMA-IR and CRP decreased in all OA. Neither FMD nor NMD were altered in either group. Endothelium-dependent microvascular reactivity only increased in the VD-supplemented group, reaching values comparable to that of controls. Similar results were found when analyzing only OA with a VD deficiency at baseline. CONCLUSION: VD supplementation during a lifestyle program attenuated microvascular dysfunction in OA without altering macrovascular function. REGISTRATION NUMBER FOR CLINICAL TRIAL: NCT02400151.

Metasequencing of V3-V4 Variable Regions of 16S rRNA Gene in Opportunistic Microbiota and Gut Biocenosis in Obese Adolescents.

Opportunistic microorganisms in the gut biocenosis were studied in adolescents with normal body weight and obesity (patients consulted at the Clinical Department of Research Center of Family Health and Human Reproduction Problems). The biological material was studied by standard bacteriological methods, representatives of Enterobacteriaceae family were also characterized using metagenomic sequencing of V3-V4 variable regions of 16S gene rRNA. Gut microbiota of obese adolescents was unbalanced and was characterized by low levels of bifido- and lactoflora representatives, a spectrum of E. coli associations, and high prevalence of opportunistic microorganisms and their associations. Representatives of Enterobacteriaceae family were most often found in the gut microbiota of obese adolescents.

Time to the Peak, Shape of the Curve and Combination of These Glucose Response Characteristics During Oral Glucose Tolerance Test as Indicators of Early Beta-cell Dysfunction in Obese Adolescents

Objective: Characteristics of the glucose response during oral glucose tolerance test (OGTT) may reflect differences in insulin secretion and action. The aim was to examine whether timing of the glucose peak, shape of the glucose curve and their combination could be indicators of beta-cell dysfunction in obese/severely obese adolescents with normal glucose tolerance (NGT). Methods: Data from 246 obese/severely obese adolescents who completed OGTT were reviewed. Out of 184 adolescents with NGT, 174 could be further classified into groups based on timing of the glucose peak (early/30 minutes vs late/≥60 minutes) and shape of the glucose curve (monophasic vs biphasic). Groups were compared with respect to insulin sensitivity (whole body insulin sensitivity index - WBISI), early-phase insulin secretion (insulinogenic index - IGI) and beta-cell function relative to insulin sensitivity (oral disposition index - oDI). Results: Late glucose peak (p=0.004) and monophasic glucose curve (p=0.001) were both associated with lower oDI after adjustment for age, sex, puberty stage and body mass index z-score. Among obese/severely obese adolescents with NGT, those with coexistent late glucose peak and monophasic glucose curve had lower oDI than those with early glucose peak and biphasic glucose curve (p=0.002). Moreover, a combination of late glucose peak and monophasic glucose curve was the most powerful predictor of the lowest oDI quartile [odds ratio (OR): 11.68, 95% confidence interval: 3.048-44.755, p<0.001]. Conclusion: Late timing of the glucose peak, monophasic shape of the glucose curve and, in particular, a combination of those characteristics during OGTT may indicate early beta-cell dysfunction in obese/severely obese adolescents with NGT.

Six-Week Exercise Training With Dietary Restriction Improves Central Hemodynamics Associated With Altered Gut Microbiota in Adolescents With Obesity.

Purpose: Obesity in children and in adolescents can lead to adult cardiovascular diseases, and the gut microbiota plays a crucial role in obesity pathophysiology. Exercise and diet interventions are typical approaches to improve physical condition and to alter the gut microbiota in individuals with obesity. However, whether central hemodynamic parameters including subendocardial viability ratio, the augmentation index standardized to a heart rate of 75/min (AIx75), resting heart rate, and blood pressure, correlate with gut microbiota changes associated with exercise and diet is unclear. Methods: Adolescents (n = 24, 12.88 ± 0.41 years) with obesity completed our 6-week program of endurance and strength exercises along with dietary restriction. Blood and fecal samples were collected, and physical parameters were measured before and 24 h after the last session of the intervention program. Pulse wave analysis using applanation tonometry provided the subendocardial viability ratio, a surrogate measure of microvascular myocardial perfusion, and AIx75, a measure of arterial stiffness and peripheral arteriolar resistance. Correlation analysis detected any associations of anthropometric or central hemodynamic parameters with gut microbiome composition. Results: Exercise and diet interventions significantly reduced body weight, body mass index, body fat, and waist-to-hip ratio, and lowered levels of fasting blood glucose, serum triglycerides, and high-density lipoprotein cholesterol. AIx75 and resting heart rate were also significantly reduced after the intervention without changes to systolic or diastolic blood pressure. The ratio of intestinal microbiota Firmicutes to Bacteroidetes displayed a marked increase after intervention. Interventional changes in gut microbiota members were significantly associated with anthropometric and metabolic parameters. Microbial changes were also significantly correlated with central hemodynamic parameters, including subendocardial viability ratio, AIx75, and resting heart rate. Conclusion: Exercise and diet interventions significantly improved measures of central hemodynamics, including subendocardial viability ratio, AIx75, and resting heart rate, which were correlated with altered gut microbiota in adolescents with obesity. Our findings shed light on the effects and mechanisms underlying exercise and diet interventions on obesity and suggest this approach for treating patients with both cardiovascular disease and obesity.

Is the SPARTACUS 15-15 test an accurate proxy for the assessment and tracking of maximal aerobic capacities in adolescents with obesity?

[Purpose] While there is a need for reliable field tests for the evaluation of physical fitness in pediatric obesity, the present work i) evaluates the validity of the Spartacus 15-15 test in indirectly assessing maximal aerobic capacity in adolescents with obesity and ii) evaluates its sensibility to weight loss. [Participants and Methods] Fifty-five 11-16 year-old adolescents with obesity (Tanner 3-4) were enrolled in a 12-week weight-management intervention. Maximal Aerobic fitness (VO2peak test + Spartacus test) and body composition (Dual X-ray absorptiometry) were assessed at baseline and after 12 weeks. [Results] Moderate correlations were found at baseline between VO2peak (2,231.90 ± 465.6 mL/min) and Spartacus stage (6.83 ± 1.8 stage, r=0.52; p≤0.05), speed (12.85 ± 1.8 km/h, r=0.52 ; p≤0.05) and time (20.6 ± 5.4 min; r=0.50; p≤0.05). The intervention favored significant improvements for VO2peak, Spartacus Rate of Perceived Exertion final stage, maximal speed and time. Change over time in VO2peak and Spartacus variables were not correlated. [Conclusion] The Spartacus test can be used as a proxy for VO2peak at baseline and can be used to estimate VO2peak using the proposed equation. The Spartacus 15-15 test might be a better indicator for changes in functional capacity than an indicator of VO2peak changes in youth with obesity.

Effect of a Combined Exercise and Dietary Intervention on Self-Control in Obese Adolescents.

OBJECTIVE: The aim of this study was to determine whether a combined exercise and dietary intervention improved cognitive and physical self-control and whether pre-to-post interventional changes in self-control were mediated by changes in body mass index (BMI) and maximal grip strength (MGS), in a sample of obese adolescents. METHODS: Forty-four obese adolescents were randomly assigned to a combined exercise and dietary program or to a waitlist control group; the data from 36 participants (n = 18 for each group) were analyzed. The combined exercise and dietary program was performed over 6 weeks and was supervised by qualified trainers in a closed boot camp. The exercise consisted primarily of typical aerobic training, sports, outdoor training, yoga, and resistance training. Participants were placed on moderate dietary restriction according to individual target body weight (30 kcal/kg × target weight). The primary outcomes of this study were metrics based on cognitive and physical self-control, assessed by the Stroop task and a handgrip task, respectively. Secondary outcomes included BMI and MGS. RESULTS: The combined exercise and dietary intervention significantly improved both cognitive and physical self-control. Similar positive effects were also found for reduced BMI and enhanced MGS. Correlation analyses showed that the reduced BMI and enhanced MGS were significantly closely associated with improved cognitive and physical self-control. The mediation analyses revealed that the pre-to-post intervention changes in BMI and MGS significantly mediated physical self-control, but did not mediate cognitive self-control. CONCLUSION: Our combined exercise and dietary intervention is an effective approach to improve multiple aspects of self-control, reduce BMI, and strengthen MGS among obese adolescents. These findings also suggest that reduced BMI and enhanced MGS mediate specific aspects of self-control.

Effect of omega-3 fatty acids supplementation combined with lifestyle intervention on adipokines and biomarkers of endothelial dysfunction in obese adolescents with hypertriglyceridemia.

Obesity in adolescents is considered a major public health problem; combined interventional approaches such as omega-3 supplementation with lifestyle intervention (LI) might exert synergistic effects and exceed the impact of each individual strategy. The purpose of the present study was to evaluate if the supplementation of omega-3 with LI could improve metabolic and endothelial abnormality in obese adolescents with hypertriglyceridemia. The study involved sixty-nine adolescents with normal weight and seventy obese adolescents with hypertriglyceridemia. All obese adolescents were applied to LI and randomly assigned to omega-3 supplementation or placebo group for 12 weeks. The obese adolescents with hypertriglyceridemia presented increased levels of leptin, retinol binding protein 4 (RBP4), selectin E (sE) and asymmetric dimethylarginine (ADMA) and decreased levels of adiponectin compared with control subjects. After 12-week intervention, omega-3 supplementation with LI decreased significantly in triglycerides, HOMA, leptin, RBP4, ADMA and sE. Moreover, omega-3 with LI displayed a significant reduction in triglycerides, ADMA and sE in comparison with LI alone. In subjects with omega-3 combined with LI assessed by multivariate regression model, the reduction in triglycerides was the only independent determinant of the decrease in ADMA. The reductions in triglycerides and HOMA were significantly contributed to the changes in sE. Our data indicated that omega-3 combined with LI in short duration significantly improved dyslipidemia, insulin resistance, abnormality of adipokines, endothelial dysfunction in comparison of LI alone, indicating the combined approach is an effective clinical and applicable strategy to control metabolic abnormality and decrease the risks of cardiovascular diseases in obese adolescents.

Overweight adolescents' views on physical activity - experiences of participants in an internet-based intervention: a qualitative study.

BACKGROUND: Overweight and obese adolescents are reported to be less physically active than their peers. Research-based knowledge about their views may contribute to a better understanding of key factors that may foster or undermine motivation for physical activity, and provide knowledge for the future development of interventions. This paper explores experiences of physical activity among overweight adolescents, age 13-14 years, participants in Young & Active, a web-based controlled trial intervention to increase physical activity (ClinicalTrials.gov NCT01700309). The theoretical perspective is based on Self-Determination Theory. METHODS: Two qualitative post-intervention research interviews, with a nine-month interval, were conducted with 21 adolescents, 15 girls and 6 boys to study short-term and long-term changes. The informants were recruited from a total of 84 participants from the Young & Active intervention group. Data were analyzed using qualitative content analysis. RESULTS: The participants associated physical activity with organized sports and physical education classes at school, and as a means of promoting good health and attractive bodies. A majority of the adolescents said that they experienced their health as poorer than other youths, and expressed worries about their fitness and future health. Mastering a physical activity, being together with friends and having fun promoted motivation to perform sports. Not mastering an activity, or not knowing the others made them less motivated. None of the adolescents highlighted the importance of informal active living when asked about their understanding and experiences of physical activity. Consistency was found between the first and second interviews. CONCLUSION: This study adds to limited research on overweight and obese adolescents' experiences of physical activity. The participants' views reflect opinions in society about physical activity, and its importance for health. Viewing physical activity as conducted within organized sports makes it necessary to look into how these are organized, structured and led, and what can be done to support self-esteem, autonomous motivation and participation. The ability to choose among available, affordable and desirable physical activities, together with friends, may promote participation and maintenance.