Effects of physical training and its cessation on the hemostatic system of obese children

Durability of Changes in Biomarkers of Cardiometabolic Disease: 1-Year Family-Based Intervention in Children with Obesity

Background: The sustainability of health benefits in response to lifestyle-based interventions remains unclear in children with overweight and obesity, and cardiometabolic disease (CMD). We determined the changes in novel biomarkers of CMD in a 1-year family-based intervention (FBI) program, during 6-month active monitoring phase and at 12-month follow-up. Methods: Children with an age-adjusted body mass index (BMI) percentile ≥85 (N = 130; age 8-11 years) were recruited for a 1-year (6-month monitored and 6-month unmonitored) randomized controlled FBI program. Anthropometry and selected biomarkers of CMD were measured in 87 participants, randomly allocated to intervention (INT) and education-only (EDU) groups, at baseline, immediately after a 6-month active intervention or control period, and at 12-month unmonitored follow-up. Results: Samples from 87 participants (age 10.00 ± 0.11 years and Tanner stage ≤3) with obesity (BMI%ile = 97.45 ± 0.15) were available. Overall intervention effect (between groups), was observed for total (T) and high molecular weight (HMW) adiponectin, ratio of total to HMW adiponectin, fibrinogen, and interleukin (IL)-6 (P < 0.05 for all). However, between-group beneficial changes after adjusting for baseline levels were limited to BMI percentile, T and HMW adiponectin and their ratio, IL-6, and fibrinogen (P < 0.05 for all) mainly during the 6-month period of monitored intervention. Changes in traditional risk factors such as lipids and triglycerides were inconsistent. During the 6-month follow-up period, the changes in biomarkers leveled-off, except for T and HMW adiponectin, IL-6, and fibrinogen that continued to show benefits (P < 0.05) from the 6- to 12-month follow-up. Conclusions: The FBI program beneficially altered novel biomarkers of CMD during the monitored intervention phase in school-age children with obesity, but they mostly moved back toward baseline during the unmonitored follow-up phase. The changes in novel biomarkers of CMD appear to be more sensitive compared to the traditional risk factors. The study implies the need for refinements in lifestyle-based approaches in the preservation of cardiovascular health and calls for robust biomarkers to monitor the changes. The study was registered at ClinicalTrials.gov (NCT01146314).

The Effects of Resistance Training on Blood Pressure in Preadolescents and Adolescents: A Systematic Review and Meta-Analysis

The aim was to systematically review and meta-analyze the current evidence for the effects of resistance training (RT) on blood pressure (BP) as the main outcome and body mass index (BMI) in children and adolescents. Two authors systematically searched the PubMed, SPORTDiscus, Web of Science Core Collection and EMBASE electronic databases. Inclusion criteria were: (1) children and adolescents (aged 8 to 18 years); (2) intervention studies including RT and (3) outcome measures of BP and BMI. The selected studies were analyzed using the Cochrane Risk-of-Bias Tool. Eight articles met inclusion criteria totaling 571 participants. The mean age ranged from 9.3 to 15.9 years and the mean BMI of 29.34 (7.24) kg/m²). Meta-analysis indicated that RT reduced BMI significantly (mean difference (MD): −0.43 kg/m² (95% CI: −0.82, −0.03), P = 0.03; I² = 5%) and a non-significant decrease in systolic BP (SBP) (MD: −1.09 mmHg (95% CI: −3.24, 1.07), P = 0.32; I² = 67%) and diastolic BP (DBP) (MD: −0.93 mmHg (95% CI: −2.05, 0.19), P = 0.10; I² = 37%). Limited evidence suggests that RT has no adverse effects on BP and may positively affect BP in youths. More high-quality studies are needed to clarify the association between RT and BP in light of body composition changes throughout childhood and adolescence.

Effects of physical training on anthropometrics, physical and physiological capacities in individuals with obesity: A systematic review

Increasing the amount of physical activity is an important strategy for weight loss. This systematic review summarizes recent findings on the effects of physical training on anthropometric characteristics, physical performances and physiological capacities in individuals with overweight and obesity. A systematic literature search strategy was conducted from inception until June 2019 using four electronic databases that identified 2,708 records. After screening for titles, abstracts and full texts, 116 studies were included in our final analysis. Both aerobic (e.g., endurance training) and anaerobic training (e.g., high-intensity training, resistance training) improved body composition and physical fitness indicators in adults, adolescents and children with obesity (effect size: 0.08 < d < 2.67, trivial to very large). This systematic review suggests that both low- and high-intensity training significantly reduced body weight and fat mass while increasing fat-free mass in individuals with obesity (effect size: 0.04 <d <3.2, trivial to very large). A significant increase in VO_2max also occurs in individuals with obesity in response to aerobic training or high-intensity interval training (effect size: 0.13 < d < 6.24, trivial to very large). Further studies are needed to define the optimal combination of training intensity and duration needed to produce the most efficacious results in individuals with obesity.

Tune out and turn in: the influence of television viewing and sleep on lipid profiles in children

BACKGROUND/OBJECTIVES

Physical activity is beneficial to lipid profiles; however, the association between sedentary behavior and sleep and pediatric dyslipidemia remains unclear. We aimed to investigate whether sedentary behavior or sleep predicted lipid profiles in children over a 2-year period.

SUBJECTS/METHODS

Six hundered and thirty children from the QUALITY cohort, with at least one obese parent, were assessed prospectively at ages 8-10 and 10-12 years. Measures of sedentary behavior included self-reported TV viewing and computer/video game use. Seven-day accelerometry was used to derive sedentary behavior and sleep duration. Adiposity was assessed using DEXA scans. Twenty-four-hour dietary recalls yielded estimates of carbohydrate and fat intake. Outcomes included fasting total cholesterol, triglycerides, HDL and LDL-cholesterol. Multivariable models were adjusted for adiposity and diet.

RESULTS

At both Visit 1 (median age 9.6 year) and Visit 2 (median age 11.6 year), children were of normal weight (55%), overweight (22%), or obese (22%). Every additional hour of TV viewing at Visit 1 was associated with a 7.0% triglyceride increase (95% CI: 3.5, 10.6; P < 0.01) and 2.6% HDL decrease (95% CI: -4.2, -0.9; P < 0.01) at Visit 2; findings remained significant after adjusting for adiposity and diet. Every additional hour of sleep at Visit 1 predicted a 4.8% LDL decrease (95% CI: -9.0, -0.5; P = 0.03) at Visit 2, after adjusting for fat intake; this association became nonsignificant once controlling for adiposity.

CONCLUSIONS

Longer screen time during childhood appears to deteriorate lipid profiles in early adolescence, even after accounting for other major lifestyle habits. There is preliminary evidence of a deleterious effect of shorter sleep duration, which should be considered in further studies.

Changes in leukocyte profile and C-reactive protein concentration in overweight and obese adolescents after reduction of body weight

Aim of the study

To assess the changes in the leukocyte profile and C-reactive protein (CRP) concentration in adolescents with excess fat mass after 6-12 months of dietary intervention.

Material and methods

The retrospective study included 99 overweight and obese adolescents, aged from 10.0 to 17.5 years, 82 of whom were re-hospitalized 6 to 12 months after dietary counseling. The control group consisted of 42 normal weight peers. Anthropometric measurements and laboratory tests were performed, homeostasis model assessment – insulin resistance (HOMA-IR) and triglycerides/high-density lipoprotein cholesterol (TG/HDL-C) ratio were calculated.

Results

Obese and overweight adolescents had higher white blood cells (WBC), neutrophil, monocyte counts and CRP concentration. In the backward stepwise regression analysis, body mass index standard deviation score (BMI SDS) and fasting insulin concentration were independent predictors of WBC and neutrophil counts at the baseline. At the follow-up visit in 45 (54.8%) children, who had lost weight, decreases in WBC, neutrophil and monocyte counts and CRP, fasting insulin, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) concentrations were observed. Changes in WBC and neutrophil counts were dependent on changes in HOMA-IR and TG/HDL ratio. Changes in HOMA-IR had a significant impact on changes in the monocyte count.

Conclusions

Adipose tissue promotes systemic inflammation and its intensity depends on the degree of obesity and insulin resistance. This state is reversible. Changes in HOMA-IR were independent predictors of changes in WBC, neutrophil and monocyte counts after reduction of body weight.

WITHDRAWN: Interventions for treating obesity in children

BACKGROUND

Child and adolescent obesity is increasingly prevalent, and can be associated with significant short- and long-term health consequences.

OBJECTIVES

To assess the efficacy of lifestyle, drug and surgical interventions for treating obesity in childhood.

SEARCH METHODS

We searched CENTRAL on The Cochrane Library Issue 2 2008, MEDLINE, EMBASE, CINAHL, PsycINFO, ISI Web of Science, DARE and NHS EED. Searches were undertaken from 1985 to May 2008. References were checked. No language restrictions were applied.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) of lifestyle (i.e. dietary, physical activity and/or behavioural therapy), drug and surgical interventions for treating obesity in children (mean age under 18 years) with or without the support of family members, with a minimum of six months follow up (three months for actual drug therapy). Interventions that specifically dealt with the treatment of eating disorders or type 2 diabetes, or included participants with a secondary or syndromic cause of obesity were excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data following the Cochrane Handbook. Where necessary authors were contacted for additional information.

MAIN RESULTS

We included 64 RCTs (5230 participants). Lifestyle interventions focused on physical activity and sedentary behaviour in 12 studies, diet in 6 studies, and 36 concentrated on behaviorally orientated treatment programs. Three types of drug interventions (metformin, orlistat and sibutramine) were found in 10 studies. No surgical intervention was eligible for inclusion. The studies included varied greatly in intervention design, outcome measurements and methodological quality.Meta-analyses indicated a reduction in overweight at 6 and 12 months follow up in: i) lifestyle interventions involving children; and ii) lifestyle interventions in adolescents with or without the addition of orlistat or sibutramine. A range of adverse effects was noted in drug RCTs.

AUTHORS' CONCLUSIONS

While there is limited quality data to recommend one treatment program to be favoured over another, this review shows that combined behavioural lifestyle interventions compared to standard care or self-help can produce a significant and clinically meaningful reduction in overweight in children and adolescents. In obese adolescents, consideration should be given to the use of either orlistat or sibutramine, as an adjunct to lifestyle interventions, although this approach needs to be carefully weighed up against the potential for adverse effects. Furthermore, high quality research that considers psychosocial determinants for behaviour change, strategies to improve clinician-family interaction, and cost-effective programs for primary and community care is required.

Diet, physical activity and behavioural interventions for the treatment of overweight or obese children from the age of 6 to 11 years

BACKGROUND

Child and adolescent overweight and obesity has increased globally, and can be associated with significant short- and long-term health consequences. This is an update of a Cochrane review published first in 2003, and updated previously in 2009. However, the update has now been split into six reviews addressing different childhood obesity treatments at different ages.

OBJECTIVES

To assess the effects of diet, physical activity and behavioural interventions (behaviour-changing interventions) for the treatment of overweight or obese children aged 6 to 11 years.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, LILACS as well as trial registers ClinicalTrials.gov and ICTRP Search Portal. We checked references of studies and systematic reviews. We did not apply any language restrictions. The date of the last search was July 2016 for all databases.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) of diet, physical activity, and behavioural interventions (behaviour-changing interventions) for treating overweight or obese children aged 6 to 11 years, with a minimum of six months' follow-up. We excluded interventions that specifically dealt with the treatment of eating disorders or type 2 diabetes, or included participants with a secondary or syndromic cause of obesity.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened references, extracted data, assessed risk of bias, and evaluated the quality of the evidence using the GRADE instrument. We contacted study authors for additional information. We carried out meta-analyses according to the statistical guidelines in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We included 70 RCTs with a total of 8461 participants randomised to either the intervention or control groups. The number of participants per trial ranged from 16 to 686. Fifty-five trials compared a behaviour-changing intervention with no treatment/usual care control and 15 evaluated the effectiveness of adding an additional component to a behaviour-changing intervention. Sixty-four trials were parallel RCTs, and four were cluster RCTs. Sixty-four trials were multicomponent, two were diet only and four were physical activity only interventions. Ten trials had more than two arms. The overall quality of the evidence was low or very low and 62 trials had a high risk of bias for at least one criterion. Total duration of trials ranged from six months to three years. The median age of participants was 10 years old and the median BMI z score was 2.2.Primary analyses demonstrated that behaviour-changing interventions compared to no treatment/usual care control at longest follow-up reduced BMI, BMI z score and weight. Mean difference (MD) in BMI was -0.53 kg/m2 (95% confidence interval (CI) -0.82 to -0.24); P < 0.00001; 24 trials; 2785 participants; low-quality evidence. MD in BMI z score was -0.06 units (95% CI -0.10 to -0.02); P = 0.001; 37 trials; 4019 participants; low-quality evidence and MD in weight was -1.45 kg (95% CI -1.88 to -1.02); P < 0.00001; 17 trials; 1774 participants; low-quality evidence.Thirty-one trials reported on serious adverse events, with 29 trials reporting zero occurrences RR 0.57 (95% CI 0.17 to 1.93); P = 0.37; 4/2105 participants in the behaviour-changing intervention groups compared with 7/1991 participants in the comparator groups). Few trials reported health-related quality of life or behaviour change outcomes, and none of the analyses demonstrated a substantial difference in these outcomes between intervention and control. In two trials reporting on minutes per day of TV viewing, a small reduction of 6.6 minutes per day (95% CI -12.88 to -0.31), P = 0.04; 2 trials; 55 participants) was found in favour of the intervention. No trials reported on all-cause mortality, morbidity or socioeconomic effects, and few trials reported on participant views; none of which could be meta-analysed.As the meta-analyses revealed substantial heterogeneity, we conducted subgroup analyses to examine the impact of type of comparator, type of intervention, risk of attrition bias, setting, duration of post-intervention follow-up period, parental involvement and baseline BMI z score. No subgroup effects were shown for any of the subgroups on any of the outcomes. Some data indicated that a reduction in BMI immediately post-intervention was no longer evident at follow-up at less than six months, which has to be investigated in further trials.

AUTHORS' CONCLUSIONS

Multi-component behaviour-changing interventions that incorporate diet, physical activity and behaviour change may be beneficial in achieving small, short-term reductions in BMI, BMI z score and weight in children aged 6 to 11 years. The evidence suggests a very low occurrence of adverse events. The quality of the evidence was low or very low. The heterogeneity observed across all outcomes was not explained by subgrouping. Further research is required of behaviour-changing interventions in lower income countries and in children from different ethnic groups; also on the impact of behaviour-changing interventions on health-related quality of life and comorbidities. The sustainability of reduction in BMI/BMI z score and weight is a key consideration and there is a need for longer-term follow-up and further research on the most appropriate forms of post-intervention maintenance in order to ensure intervention benefits are sustained over the longer term.

Significant associations between hemostatic/fibrinolytic systems and accumulation of cardiovascular risk factors in Japanese elementary schoolchildren

The aim of this study was to establish the reference values of hemostatic/fibrinolytic markers and investigate their relationship with physical constitution and cardiovascular risk factors in a normal schoolchildren population. This study comprised 148 healthy Japanese children aged 9-10 years (males 73; females 75). We performed laboratory tests including blood levels of leptin, high-sensitive C-reactive protein (hs-CRP), hemostatic and fibrinolytic markers [plasminogen activator inhibitor 1 (PAI-1), coagulation factor VII (FVII), coagulation factor X (FX), fibrinogen (Fbg), protein C, protein S], as well as common biochemical markers in the morning after an overnight fast. We investigated the mean, 10th, 50th and 90th percentile values of these markers. All parameters were compared between two groups, that is those with body mass index (BMI) 90th percentile or higher and BMI less than 90th percentile, and between subgroups based on the number of cardiovascular risk factors. Multiple-linear regression was used to assess associations between these hematological parameters and the components related to metabolic syndrome (MetS). Alanine aminotransferase (ALT), uric acid, leptin, hs-CRP, and all hemostatic/fibrinolytic markers (PAI-1, FVII, FX, Fbg, protein C, protein S) tested were significantly higher in the group with BMI 90th percentile or higher, and increased with accumulation of cardiovascular risk factors. Multiple-linear regression analysis showed that these values were associated with one or more components related to MetS. Reference values of hemostatic/fibrinolytic markers in Japanese schoolchildren were obtained. Many hemostatic/fibrinolytic markers showed significant association with BMI and accumulation of cardiovascular risk factors in normal Japanese schoolchildren.

Childhood obesity and cardiovascular dysfunction

Obesity-related cardiovascular disease in children is becoming more prevalent in conjunction with the rise in childhood obesity. Children with obesity are predisposed to an increased risk of cardiovascular morbidity and mortality in adulthood. Importantly, research in children with obesity over the last decade has demonstrated that children may exhibit early signs of cardiovascular dysfunction as a result of their excess adiposity, often independent of other obesity-related comorbidities such as dyslipidemia and insulin resistance. The clinical evidence is accumulating to suggest that the cardiovascular damage, once observed only in adults, is also occurring in obese children. The objective of this review is to provide a synopsis of the current research on cardiovascular abnormalities in children with obesity and highlight the importance and need for early detection and prevention programs to mitigate this potentially serious health problem.

Cardiometabolic Risk Factors in Children

Considerable evidence has accrued that cardiovascular disease (CVD) has its beginnings during childhood, with some reports of endothelial damage occurring in early adolescence. Thus, early prevention and intervention on developing cardiometabolic risk factors is important. Presently, diet and exercise are strategic parts of any CVD prevention or treatment program. Although diet is important, the effects of exercise training or regular moderate-to-vigorous intensity physical activity go beyond simply modifying the traditional risk factors. For children, the majority of studies show that regular physical activity can lower elevated blood pressure, positively influence lipid profiles, reduce inflammation, and improve vascular functioning. These changes are most evident in children who exercise and lose weight. Despite these potential benefits of physical activity, not all studies on children have found positive effects of habitual physical activity on CVD risk factors. Reasons for these differences are discussed throughout this review. The literature also suggests that habitual physical activity, although meeting guidelines, may not be sufficient for all individuals to bring about changes; thus, to be an effective modality physical activity needs to increase beyond habitual levels or be of a moderate to vigorous intensity. This review provides recent evidence (since 2008) regarding the influence of physical activity on the cardiometabolic risk factors in children.

Age and menarcheal status do not influence metabolic response to aerobic training in overweight girls

BACKGROUND

Multidisciplinary intervention is an alternative for the treatment of children and adolescent obese. However, the influence of age and menarcheal status in the pattern of metabolic response of obese girls has not been investigated. The following study examined the effects of a 12-week multidisciplinary intervention on metabolic health in overweight girls and the contribution of age and menarcheal status on the resulting changes.

METHODS

Eighty-eight overweight girls (10 - 16 years) were considered initially for this study and randomly assigned (intervention group: n = 58; control group: n = 30). Forty-six girls completed the intervention program and 16 girls completed the follow-up for the control group. The 12-week intervention included aerobic exercises (three times per week) and nutritional intervention. Anthropometrical measures (body mass, body mass index and waist circumference), menarcheal status and metabolic profiles including glucose, insulin, triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were assessed in the beginning and after of intervention. Additionally, were calculated homeostatic model assessment-insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI).

RESULTS

After 12-week, girls decreased significantly the body mass (76.6 ± 14.7 to 75.7 ± 14.6 kg) body mass index (30.1 ± 4.0 to 29.4 ± 4.0 kg/m2) and waist circumference (98.9 ± 10.9 to 96.5 ± 11.4 cm). There were differences in HDL-C (43.1 ± 8.2 to 50.3 ± 9.4 mg/dl), TG (120.9 ± 64.3 to 93.3 ± 47.9 mg/dl) and insulin (16.9 ± 7.6 to 15.6 ± 9.8 mg/dl). Relative contribution of age was significant only for within-subject variability in waist circumference.

CONCLUSIONS

The multidisciplinary based on aerobic training intervention used in this study produced substantial benefits on metabolic health indicators in overweight girls. The changes observed were not related to inter-individual variability in age and maturity status.

Trunk weighted obesity, cholesterol levels and low grade inflammation are main determinants for enhanced thrombin generation

OBJECTIVE

Endogenous thrombin generation (ETP) may be critically involved in obesity associated thromboembolism.

METHODS

Three hundred and one participants of the STyrian Juvenile OBesity (STYJOBS)/Early DEteCTion of Atherosclerosis (EDECTA) study cohort (age, 16-58years) were analysed. ETP was measured by the new CE-IVD marked Siemens-Innovance(®) ETP test on a BCS-XP analyser, and correlated to clinical findings and extended lipometry-based anthropometric data, biomarkers, and coagulation parameters.

RESULTS

In the overweight/obese study group, ETP and fibrinogen levels were significantly higher compared to controls (p<0.001). In a multiple stepwise regression including all subjects, subcutaneous adipose tissue thickness of upper back, cholesterol and ultrasensitive C-reactive protein were the best predictors for ETP.

CONCLUSION

Trunk weighted obesity together with low grade inflammation and hypercholesterolemia enhance thrombin generation.

Metabolic, inflammatory, endothelial and haemostatic markers in a group of Italian obese children and adolescents

Childhood obesity and its related comorbidities are increasingly recognised in children, predisposing them to early cardiovascular disease and metabolic syndrome. The objective of the study was to investigate markers of metabolism, inflammation and haemostasis in a group of Italian obese children and adolescents. Fifty-nine obese and 40 non-obese subjects were recruited. Fasting glucose and insulin, total cholesterol, HDL and LDL cholesterol, triglycerides, high-sensitivity C-reactive protein (hsCRP), tumour necrosis factor alpha (TNF-α), and adiponectin were measured. Hypercoagulability was assessed by measuring the circulating levels of thrombin-antithrombin complex (TAT), D: -dimer, fibrinogen, plasminogen activator inhibitor 1 (PAI-1) and von Willebrand Factor (vWF). A significant degree of insulin resistance was present in obese subjects compared with controls (p < 0.0001). The obese showed higher levels of total cholesterol, LDL cholesterol and triglycerides, and lower levels of HDL cholesterol than controls (p < 0.0001). Circulating levels of hsCRP and TNF-α were significantly higher in obese than in controls while serum adiponectin levels were significantly lower in obese than non-obese subjects (p < 0.001; p = 0.031; p < 0.0001, respectively). vWF, TAT, D-dimer, fibrinogen and PAI-1 levels were significant higher in obese subjects compared with control group (p = 0.02; p < 0.0001; p = 0.0037; p < 0.0001; p = 0.017, respectively). In conclusion, our results suggest that childhood obesity per se is associated with a proinflammatory and prothrombotic state.

Nontraditional risk factors and biomarkers for cardiovascular disease: mechanistic, research, and clinical considerations for youth: a scientific statement from the American Heart Association

The rapid increase in the prevalence and severity of obesity in children is likely to lower the age of onset and increase the incidence of cardiovascular disease worldwide. Understanding the pathophysiology and improving the clinical management of cardiovascular disease involve a knowledge of novel risk factors and biomarkers. The clinical and mechanistic roles of these novel biological factors during childhood are currently being investigated. The goals of this scientific statement are to present the existing knowledge and theoretical framework of nontraditional risk factors for cardiovascular disease as they relate to children and adolescents, to describe the relevance and weight of available experimental and clinical evidence and the therapeutic implications pertaining to nontraditional risk factors in the pediatric population, and to stimulate further research with a goal of developing valid and reliable approaches to identify and validate novel risk factors that will aid in the clinical evaluation and perhaps prediction of cardiovascular disease in the pediatric population. Although several biomarkers are promising, substantial research is required before nontraditional risk factors can be used to identify and reduce cardiovascular disease risk in children and adolescents.

Weight loss induced by 6-month lifestyle intervention improves early endothelial activation and fibrinolysis in obese adolescents

BACKGROUND

Adolescent obesity is associated with an increased risk of adult obesity and subsequent cardiovascular diseases. The present study aimed to assess the effect of weight loss after 6-month lifestyle intervention in obese adolescents on biomarkers of endothelial activation and fibrinolytic system.

METHODS

Eighty-five obese adolescents aged 10 to 16 years were assigned to a 6-month lifestyle intervention and 61 completed the programme. We examined the effect of the intervention on adhesion molecules (selectin E, soluble intercellular adhesion molecule 1 and soluble vascular adhesion molecule 1) and fibrinolytic parameters [plasminogen activator inhibitor-1 (PAI-1) and fibrinogen]. Thirty-six lean adolescents were studied only at baseline as a comparison group.

RESULTS

Compared with lean participants, obese adolescents at baseline demonstrated significantly higher levels of triglycerides, glucose, insulin, homeostasis model assessment, soluble intercellular adhesion molecule 1, PAI-1 and fibrinogen. After 6-month lifestyle intervention, those obese adolescents with decreased standard deviation score-body mass index (SDS-BMI) displayed significant decreases in insulin (19.2 ± 11.2 vs. 26.8 ± 13.2 mU/L, P≤ 0.01), homeostasis model assessment (4.24 ± 3.19 vs. 6.58 ± 4.08, P≤ 0.01), selectin E (100.2 ± 60.9 vs. 116.0 ± 69.0 ng/mL, P≤ 0.01) and PAI-1 (39.6 ± 38.0 vs. 51.8 ± 25.6 ng/mL, P≤ 0.05) with respect to the baseline levels. No changes in these parameters were observed in the obese adolescents with stable or increased SDS-BMI. The changes of triglycerides after intervention in subgroup with decreased SDS-BMI were significantly greater than those in subgroup with stable SDS-BMI.

CONCLUSIONS

The present study demonstrated increased endothelial activation and impairment of the fibrinolytic system in early life, which is in part reversible by a 6-month lifestyle intervention.

Limited Weight Loss or Simply No Weight Gain following Lifestyle-Only Intervention Tends to Redistribute Body Fat, to Decrease Lipid Concentrations, and to Improve Parameters of Insulin Sensitivity in Obese Children

Objectives. To investigate whether lifestyle-only intervention in obese children who maintain or lose a modest amount of weight redistributes parameters of body composition and reverses metabolic abnormalities. Study Design. Clinical, anthropometric, and metabolic parameters were assessed in 111 overweight or obese children (CA of 11.3 ± 2.8 years; 63 females and 48 males), during 8 months of lifestyle intervention. Patients maintained or lost weight (1-5%) (group A; n: 72) or gained weight (group B). Results. Group A patients presented with a decrease in systolic blood pressure (SBP) and diastolic blood pressure (DBP) (P < .005 and P < .05, resp.), BMI (P < .0001), z-score BMI (P < .0001), waist circumference (P < .0001), fat mass (P < .005), LDL-C (P < .05), Tg/HDL-C ratio (P < .05), fasting and postprandial insulin (P < .005), and HOMA (P < .005), while HDL-C (P < .05) and QUICKI increased (P < .005). Conversely, group B patients had an increase in BMI (P < .0001), waist circumference (P < .005), SBP (P < .005), and in QUICKI (P < .005), while fat mass (P < .05), fasting insulin (P < .05), and HOMA (P < .05) decreased. Lean mass, DBP, lipid concentrations, fasting and postprandial glucose, postprandial insulin, and ultrasensitive C-reactive protein (CRP) remained stable. Conclusions. Obese children who maintain or lose a modest amount of weight following lifestyle-only intervention tend to redistribute their body fat, decrease blood pressure and lipid levels, and to improve parameters of insulin sensitivity.

Haemostatic alterations in overweight children: associations between metabolic syndrome, thrombin generation, and fibrinogen levels

BACKGROUND

The metabolic syndrome (MetS) is associated with central obesity and leads to increased morbidity and mortality due to cardiovascular disease (CVD). Since obesity is associated with a hypercoagulable state, it has been speculated that hypercoagulation is linking MetS to CVD.

METHODS

We prospectively examined 81 overweight children and 32 normal-weight children aged 10-16 years. We analyzed blood pressure, fasting lipids, glucose, insulin, fibrinogen, and thrombin generating test determining time to peak (TTPeak), peak, time preceding the thrombin burst (lag-time), and 'endogenous' thrombin potential (ETP).

RESULTS

Overweight children demonstrated significantly higher fibrinogen levels (p<0.001), shorter lag-time (p<0.001), and TTPeak (p=0.038) compared to normal-weight children. Furthermore, ETP (p<0.001) and peak (p<0.001) were significantly higher in overweight than in normal-weight children. Fibrinogen and all parameters of the clotting test correlated significantly (p always <0.05) to body mass index (BMI) but not significantly to insulin resistance index HOMA-IR or occurrence of MetS in multiple linear backward regression analyses adjusted for age and gender.

CONCLUSIONS

The increased fibrinogen levels and the changes in the thrombin generation test points towards a haemostatic alteration in overweight children. The parameters of the clotting test were related to the degree of overweight but not to insulin resistance or occurrence of MetS questioning a direct association between MetS and the coagulation system. Longitudinal studies are needed to confirm these findings.

Interventions for treating obesity in children

BACKGROUND

Child and adolescent obesity is increasingly prevalent, and can be associated with significant short- and long-term health consequences.

OBJECTIVES

To assess the efficacy of lifestyle, drug and surgical interventions for treating obesity in childhood.

SEARCH STRATEGY

We searched CENTRAL on The Cochrane Library Issue 2 2008, MEDLINE, EMBASE, CINAHL, PsycINFO, ISI Web of Science, DARE and NHS EED. Searches were undertaken from 1985 to May 2008. References were checked. No language restrictions were applied.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) of lifestyle (i.e. dietary, physical activity and/or behavioural therapy), drug and surgical interventions for treating obesity in children (mean age under 18 years) with or without the support of family members, with a minimum of six months follow up (three months for actual drug therapy). Interventions that specifically dealt with the treatment of eating disorders or type 2 diabetes, or included participants with a secondary or syndromic cause of obesity were excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data following the Cochrane Handbook. Where necessary authors were contacted for additional information.

MAIN RESULTS

We included 64 RCTs (5230 participants). Lifestyle interventions focused on physical activity and sedentary behaviour in 12 studies, diet in 6 studies, and 36 concentrated on behaviorally orientated treatment programs. Three types of drug interventions (metformin, orlistat and sibutramine) were found in 10 studies. No surgical intervention was eligible for inclusion. The studies included varied greatly in intervention design, outcome measurements and methodological quality.Meta-analyses indicated a reduction in overweight at 6 and 12 months follow up in: i) lifestyle interventions involving children; and ii) lifestyle interventions in adolescents with or without the addition of orlistat or sibutramine. A range of adverse effects was noted in drug RCTs.

AUTHORS' CONCLUSIONS

While there is limited quality data to recommend one treatment program to be favoured over another, this review shows that combined behavioural lifestyle interventions compared to standard care or self-help can produce a significant and clinically meaningful reduction in overweight in children and adolescents. In obese adolescents, consideration should be given to the use of either orlistat or sibutramine, as an adjunct to lifestyle interventions, although this approach needs to be carefully weighed up against the potential for adverse effects. Furthermore, high quality research that considers psychosocial determinants for behaviour change, strategies to improve clinician-family interaction, and cost-effective programs for primary and community care is required.

Response of fractional synthesis rate (FSR) of fibrinogen, concentration of D-dimer and fibrinolytic balance to physical activity-based intervention in obese children

BACKGROUND

Physical activity-induced reduction in obesity-related hyperfibrinogenemia in children has been reported. The underlying mechanisms remain elusive. Further, the effect of such interventions on fibrinolysis in children is scarce.

OBJECTIVES

To investigate in obese children, before and after a physical activity-based intervention: (i) the mechanistic role of fractional synthesis rate (FSR) of fibrinogen in the reduction of hyperfibrinogenemia; and (ii) the changes in fibrinolytic factors.

METHODS

Subjects included 21 (age > 14 < 18 years; Tanner stage, IV-V) children (15 obese, BMI >95%tile for age and sex and six lean, BMI <85%tile). After baseline measurements of FSR of fibrinogen, and concentrations of fibrinogen, D-dimer, PAI-1 and t-PA in all children, studies were repeated after a 3-month randomized controlled physical activity-based lifestyle intervention in obese children only.

RESULTS

FSR of fibrinogen was higher (P = 0.002) in the obese (vs. lean) group, which was reduced (P = 0.001) after intervention. This almost completely accounted for the reduction in obesity-related hyperfibrinogenemia. High levels of D-dimer decreased (P = 0.001) after intervention, whereas fibrinolysis was not enhanced.

CONCLUSIONS

The direct reduction in the FSR of fibrinogen and the remarkable correlation between the magnitudes of reduction in fibrinogen FSR and concentration signify a mechanistic role for FSR in the regulation of physical activity-induced reversal of hyperfibrinogenemia in obese children. The congruent reductions in the FSR of fibrinogen and the concentrations of fibrinogen and D-dimer in response to intervention despite depressed fibrinolysis suggest an overall improvement in the hypercoagulable state in obese children with physical activity-based lifestyle intervention.

Ten months of exercise improves general and visceral adiposity, bone, and fitness in black girls

OBJECTIVE

The goal of this study was to evaluate the impact of a 10-month after-school physical activity (PA) program on body composition and cardiovascular (CV) fitness in young black girls.

RESEARCH METHODS AND PROCEDURES

Subjects were 8- to 12-year-olds recruited from elementary schools. Body composition was measured using anthropometrics {waist circumference and BMI, DXA [percentage body fat (%BF)] and bone mineral density (BMD)}, and magnetic resonance imaging [visceral adipose tissue (VAT)]. CV fitness was measured using a graded treadmill test. The intervention consisted of 30 minutes homework/healthy snack time and 80 minutes PA (i.e., 25 minutes skills instruction, 35 minutes aerobic PA, and 20 minutes strengthening/stretching). Analyses were adjusted for age, baseline value of the dependent variable, and sexual maturation (pediatrician observation).

RESULTS

Mean attendance was 54%. Compared with the control group, the intervention group had a relative decrease in %BF (p < 0.0001), BMI (p < 0.01), and VAT (p < 0.01) and a relative increase in BMD (p < 0.0001) and CV fitness (p < 0.05). Higher attendance was associated with greater increases in BMD (p < 0.05) and greater decreases in %BF (p < 0.01) and BMI (p < 0.05). Higher heart rate during PA was associated with greater increases in BMD (p < 0.05) and greater decreases in %BF (p < 0.005).

DISCUSSION

An after-school PA program can lead to beneficial changes in body composition and CV fitness in young black girls. It is noteworthy that the control and intervention groups differed in change in VAT but not waist circumference. This suggests that changes in central adiposity can occur in response to PA, even in young children, but that waist circumference may not be a good indicator of central adiposity.

Associations of low-grade inflammation with physical activity, fitness and fatness in prepubertal children; the European Youth Heart Study

OBJECTIVE

To examine the associations of low-grade inflammation with objectively measured physical activity, cardiovascular fitness (CVF) and fatness in prepubertal children.

DESIGN

Cross-sectional study.

SUBJECTS

One hundred and forty-two children (74 boys and 68 girls) aged 9-10 years (pubertal stage I and II) from the Swedish part of the European Youth Heart Study.

MEASUREMENTS

Total physical activity and its intensity levels (moderate, vigorous, moderate + vigorous) were measured by accelerometry. CVF was measured with a maximal ergometer bike test. Body fat was derived from the sum of five skinfold thicknesses. The measured low-grade inflammatory markers include C-reactive protein, fibrinogen, complement factors C3 and C4.

RESULTS

C-reactive protein and C3 were negatively associated with CVF (beta=-0.254 and -0.267, respectively, P<0.05) and positively associated with body fat (beta=0.439 and 0.446, respectively, P<0.001), after controlling for sex, age and pubertal development. C-reactive protein and C3 were not significantly associated with CVF once body fat was in the model. Low-grade inflammation was not associated with physical activity, but physical activity was associated with CVF.

CONCLUSIONS

The results showed that low-grade inflammatory markers were negatively associated with CVF and positively associated with body fat in prepubertal children. For most of the variables, the influence of fatness was slightly higher than the influence of CVF. The findings suggest that the potential beneficial effects of physical activity on low-grade inflammation may be explained by its association with CVF. Understanding the interplay between physical activity, CVF and fatness may be of importance to reducing cardiovascular disease risk in young people.

Aerobic exercise in adolescents with obesity: preliminary evaluation of a modular training program and the modified shuttle test

BACKGROUND

Increasing activity levels in adolescents with obesity requires the development of exercise programs that are both attractive to adolescents and easily reproducible. The aim of this study was to develop a modular aerobic training program for adolescents with severe obesity, with a focus on variety, individual targets and acquiring physical skills. We report here the effects on aerobic fitness from a pilot study. Furthermore, we examined the feasibility of the modified shuttle test (MST) as an outcome parameter for aerobic fitness in adolescents with severe obesity.

METHODS

Fifteen adolescents from an inpatient body weight management program participated in the aerobic training study (age 14.7 +/- 2.1 yrs, body mass index 37.4 +/- 3.5). The subjects trained three days per week for 12 weeks, with each session lasting 30-60 minutes. The modular training program consisted of indoor, outdoor and swimming activities. Feasibility of the MST was studied by assessing construct validity, test-retest reliability and sensitivity to change.

RESULTS

Comparing pretraining and end of training period showed large clinically relevant and significant improvements for all aerobic indices: e.g. VO2 peak 17.5%, effect size (ES) 2.4; Wmax 8%, ES 0.8. In addition, a significant improvement was found for the efficiency of the cardiovascular system as assessed by the oxygen pulse (15.8%, ES 1.6). Construct validity, test-retest reliability and sensitivity to change of the MST were very good. MST was significantly correlated with VO2 peak (r = 0.79) and Wmax (r = 0.84) but not with anthropometric measures. The MST walking distance improved significantly by 32.5%, ES 2.5. The attendance rate at the exercise sessions was excellent.

CONCLUSION

This modular, varied aerobic training program has clinically relevant effects on aerobic performance in adolescents with severe obesity. The added value of our aerobic training program for body weight management programs for adolescents with severe obesity should be studied with a randomized trial. This study further demonstrated that the MST is a reliable, sensitive and easy to administer outcome measure for aerobic fitness in adolescent body weight management trials.

The Medical College of Georgia Fitkid project: the relations between program attendance and changes in outcomes in year 1

OBJECTIVE

To investigate the relations of attendance of children in an after-school physical activity (PA) program to changes in body composition and cardiovascular fitness (CVF).

DESIGN

Eight-month after-school PA-based intervention.

SUBJECTS

In all, 278 third-grade boys and girls from nine elementary schools (age, 8.7 y (s.d. = 0.6 y), body mass index (BMI) 19.1 kg/m2 (s.d. = 4.4) and percent body fat (%BF) 26.0 (s.d. = 9.0)).

MEASUREMENTS

Body composition (from dual-energy X-ray absorptiometry), BMI (from height and weight), waist circumference (WC) and CVF (from the YMCA submaximal bench-stepping test).

RESULTS

There was a significant negative linear trend between level of attendance in the after-school program and change in %BF and fat mass; there was also a significant positive linear trend between program attendance and change in CVF. There was a marginally significant linear trend between program attendance and fat-free mass. Greater increases in bone mineral density were observed with higher program attendance. Changes in BMI and WC were not influenced by program attendance.

CONCLUSION

Understanding the dose-response effect of PA on health outcomes, particularly body composition, in children is crucial in our effort to prevent overweight and its health consequences. Since there is limited data available to base PA dose recommendations for youths, findings from this study are relevant, and suggest that greater health benefits can be obtained in young children with more frequent participation in PA.

Lifestyle-only intervention attenuates the inflammatory state associated with obesity: a randomized controlled study in adolescents

OBJECTIVES

The primary goals were to understand the relationship among the inflammatory factors, C-reactive protein (CRP), interleukin-6 (IL-6), and fibrinogen, and indices of obesity in normoglycemic, insulin-resistant adolescents and to investigate the impact of a lifestyle-only intervention on these nontraditional risk factors for cardiovascular disease (CVD).

STUDY DESIGN

Randomized controlled lifestyle-only intervention study in adolescents. Of the 21 adolescents studied, 15 obese subjects (body mass index [BMI] = 37.6 +/- 3.3 kg/m 2 ) were randomized to either a lifestyle intervention program or usual care. The lean controls were studied only at baseline. Analysis of variance (ANOVA) for repeated measures was used to study intervention effect and t test, one-way ANOVA, and discriminant function analysis for baseline comparisons.

RESULTS

The intervention group maintained weight, whereas the control group gained weight (P = .02). A redistribution of body composition and a decrease in insulin resistance were observed. Elevated circulating concentrations of CRP, fibrinogen, and IL-6 were significantly reduced (all P <or=.02) in response to intervention, but not in controls.

CONCLUSIONS

Modest lifestyle-only change in previously sedentary obese adolescents redistributes the parameters of body composition in the absence of weight loss and reverses, at least in part, the inflammatory state in association with an improvement of insulin resistance.

Exercise Training in Obese Children and Adolescents

Childhood obesity has reached epidemic proportions worldwide and is associated with increased cardiovascular mortality and morbidity in adult life. The increase in fat mass in children and adolescents has occurred concomitantly with a decline in reported time for exercise. Evidence suggests that non-physically active children are more likely to become non-physically active adults and that encouraging the development of physical activity habits in children helps establish patterns that continue into adulthood. Dietary treatment of obesity is relatively ineffective in adults and it has been suggested that prevention of obesity in childhood and adolescence should emphasise increased physical activity rather than diet because of fears relating to the adverse effects of inappropriate eating patterns. Despite this, there are very few randomised controlled studies investigating the efficacy of exercise training in obese children or adolescents and many of the extant studies have been poorly controlled and have not specifically stratified the independent effect of exercise versus dietary modification. This review focuses on the well designed controlled trials that have evaluated the effect of exercise training in obese children and adolescents on body composition, haemodynamic and metabolic variables, cardiovascular fitness, muscular strength and vascular function. These studies indicate that, although exercise training does not consistently decrease bodyweight or body mass index, it is associated with beneficial changes in fat and lean body mass, emphasising the importance of comprehensive assessment of body composition in future exercise-training studies. Exercise training improves cardiovascular fitness and muscular strength; however, it seems to have little effect on blood lipid profile or blood pressure in obese young people. Importantly, recent studies have demonstrated that exercise training improves vascular endothelial function, an important surrogate measure that may predict future atherosclerotic risk in obese children and adolescents. Given that improvement in vascular function in these training studies occurred in the absence of changes in lipid fractions, haemodynamic variables or glucose metabolism, exercise appears to have a direct beneficial effect on the vasculature, in addition to its putative benefits through risk-factor modification.

C-reactive protein in young individuals: problems and implications for Asian Indians

Recent data in adults showed that C-reactive protein (CRP) level robustly predicts future coronary heart disease (CHD) and type 2 diabetes mellitus (T2DM). Although data in children are scarce, overweight, obesity, and insulin resistance were shown to be associated with elevated CRP concentrations. Preliminary data in children also show association of CRP with endothelial dysfunction and other cardiovascular risk factors. Adult Asian Indians, highly predisposed to develop CHD and T2DM, have significantly higher CRP levels than do Europeans. Recent studies show that nearly 13% of Asian Indian children and young adults in India have subclinical inflammation, and approximately 20% have insulin resistance, portending high risk for CHD in adulthood. Possible determinants of high CRP levels in Asian Indians might be excess body fat, including high subcutaneous fat, and physical inactivity. The relationships of recurrent infections, protein deficiency, and subclinical inflammation in Asian Indians remain uninvestigated. Finally, prevention of childhood adiposity is critical to decrease future risk for development of T2DM and CHD, particularly in highly predisposed ethnic groups such as Asian Indians and South Asians.

Changes in fat mass, fat-free mass and aerobic fitness in severely obese children and adolescents following a residential treatment programme

The purpose of this study was to describe changes in fat mass (FM), fat-free mass (FFM) and aerobic fitness in severely obese children and adolescents during residential treatment in the Medical Paediatric Centre Zeepreventorium. Treatment consisted of moderate dietary restriction, physical activity and psychological support. This study was a clinical observation of 20 severely obese children and adolescents (8 boys and 12 girls, aged 15.4+/-1.8 years) who completed the 10-month residential programme. Height, weight, FM, FFM and aerobic fitness was measured four times during the intervention: at baseline, 11 weeks, 24 weeks and at 33 weeks (at the end of the programme ). The mean decrease in level of overweight was 46% (P<0.001), with a mean loss of 8.9% FM (P<0.001). Submaximal performance (PWC150) improved from 123+/-35 Watt to 152+/-37 Watt (P<0.001). Maximal performance levels increased (performance time: from 14+/-2.9 min to 15.3+/-3.5 min, peak power: from 186+/-38 Watt to 205+/-45 Watt, P<0.01) without an improvement in absolute VO(2 peak).

CONCLUSION

A moderate dietary restriction in combination with physical activity and psychological support in severely obese children and adolescents is effective in decreasing body fat and improving physical performance. Further research is needed to evaluate the longer-term effects of such a programme.

Physical fitness and C-reactive protein level in children and young adults: the Columbia University BioMarkers Study

OBJECTIVE

To examine the association of physical fitness with C-reactive protein (CRP) level in children and young adults.

METHODS

Subjects (N = 205) aged 6 to 24 years were enrolled in the Columbia University BioMarkers Study (1994-1998). Physical fitness was assessed using a non-effort-dependent treadmill testing protocol (physical work capacity at heart rate of 170 beats per minute). CRP level was measured using a high-sensitivity assay.

RESULTS

Subjects were 54% female and 65% of Hispanic origin. Mean fitness level was higher in boys than in girls, but CRP levels did not differ by gender. Fitness level was inversely correlated with CRP (r = -0.22). This relationship was significant in boys (r = -0.32) but not in girls (r = -0.15). After multivariate regression adjustment for age, race/ethnicity, body mass index, and family history of early-onset ischemic heart disease, physical fitness remained inversely associated with CRP level in boys (beta = -0.02; standard error = 0.01).

CONCLUSIONS

These findings indicate that physical fitness is inversely related to CRP level in children and that this relationship is more pronounced in boys than in girls.

Interventions for treating obesity in children

BACKGROUND

The prevalence of overweight and obesity is increasing in child populations throughout the world. Obesity in children has significant short and long term health consequences.

OBJECTIVES

To assess the effects of a range of lifestyle interventions designed to treat obesity in childhood.

SEARCH STRATEGY

We searched CCTR, MEDLINE, EMBASE, CINAHL, PsychLIT, Science Citation Index, Social Science Citation Index. Each database was searched from 1985 to July 2001. We also contacted experts in child obesity treatment.

SELECTION CRITERIA

We selected randomised controlled trials of lifestyle interventions for treating obesity in children with a minimum of six months duration. Examples of lifestyle interventions include dietary, physical activity and/or behavioural therapy interventions, with or without the support of associated family members. Interventions from any setting and delivered by any professional were considered. However, interventions that specifically dealt with the treatment of eating disorders were excluded.

DATA COLLECTION AND ANALYSIS

Two of our research team independently assessed trial quality and extracted data. Authors of the included studies were contacted for additional information where this was appropriate.

MAIN RESULTS

We included 18 randomised controlled trials with 975 participants. Many studies were run from a specialist obesity clinic within a hospital setting. Five studies (n=245 participants) investigated changes in physical activity and sedentary behaviour. Two studies (n=107 participants) compared problem-solving with usual care or behavioural therapy. Nine studies (n=399 participants) compared behavioural therapy at varying degrees of family involvement with no treatment or usual care or mastery criteria and contingent reinforcement. Two studies (n=224 participants) compared cognitive behavioural therapy with relaxation.Most of the studies included in this review were too small to have the power to detect the effects of the treatment. We did not conduct a meta-analysis since so few of the trials included the same comparisons and outcomes. Therefore, we synthesised the results in a narrative format.

REVIEWER'S CONCLUSIONS

Although 18 research studies were found, most of these were very small studies drawn from homogenous, motivated groups in hospital settings and so generalisable evidence from them is limited. In conclusion, there is a limited amount of quality data on the components of programs to treat childhood obesity that favour one program over another. Further research that considers psychosocial determinants for behaviour change, strategies to improve clinician-family interaction, and cost-effective programs for primary and community care is required. We conclude that no direct conclusions can be drawn from this review with confidence.

Hemostatic and inflammatory markers in obese youths: effects of exercise and adiposity

OBJECTIVES

To determine the relation of hemostatic markers to cardiovascular fitness and adiposity and the effect of physical training (PT) on these markers.

STUDY DESIGN

Seventy-four obese teenagers were randomly assigned to 8 months of lifestyle education (LSE), LSE plus moderate-intensity PT, or LSE plus high-intensity PT. Measures included fibrinogen, plasminogen activator inhibitor-1 (PAI-1), D-dimer, C-reactive protein (CRP), fitness, percent body fat (%BF), and visceral adiposity (VAT).

RESULTS

At baseline, fibrinogen and CRP were significantly correlated with %BF and VAT (0.27 </= r </= 0.51), and fitness (r = -0.39, r = -0.43, respectively); PAI-1 with %BF (r = 0.30) and VAT (r = 0.48); D-dimer with fitness (r = -0.24). Although PT produced significant changes in fitness and adiposity, there were no significant group differences in the hemostatic markers. Change in PAI-1 was significantly correlated with its baseline value (r = -0.47) and change in %BF (r = 0.38). Changes in D-dimer and CRP were significantly correlated with their respective baseline values (r = -0.68,r = -0.48, respectively).

CONCLUSIONS

Unfavorable levels of fitness and adiposity were associated with higher levels of hemostatic markers, putting individuals with this profile at greater risk for future cardiovascular disease. No evidence was provided that 8 months of PT had a direct influence on these markers in obese youths.

Exercise and thrombosis

Long-term moderate or strenuous physical activity is associated with a considerable reduction in cardiovascular morbidity and mortality in primary and secondary prevention. Various mechanisms, including changes in lipids, lifestyle habits, and other positive physiologic effects, have been suggested to mediate these beneficial effects. In addition, the hemostatic and fibrinolytic systems appear to play an important role. Fibrinogen has been convincingly shown to be an independent cardiovascular risk factor. Other hemostatic and fibrinolytic parameters that are predictive of coronary events include factor VII, platelet hyperreactivity, plasminogen-activator inhibitor 1 (PAI-1), and tissue-plasminogen activator. The effects of exercise on fibrinogen have been intensively studied. Several randomized controlled trials, various other intervention studies and a large number of population-based cross-sectional studies all found an inverse relationship between measures of sport activity or leisure activity and plasma fibrinogen. The magnitude of the effect reported might be associated with a sizeable reduction in major coronary events. Relatively few data are available on the effects of endurance exercise on markers of the fibrinolytic system, with inconsistent results. Acute exercise leads to a transient activation of the coagulation system, which is accompanied by an increase in the fibrinolytic capacity in healthy subjects. Patients with ischemic heart disease, who cannot increase their fibrinolytic potential, however, may be at considerable risk for acute ischemic events if they are exposed to unaccustomed strenuous physical exertion.

Effects of short-term energy restriction and physical training on haemostatic risk factors for coronary heart disease in obese children and adolescents

OBJECTIVE

To study the changes of haemostatic risk factors for coronary heart disease during a weight reduction programme in obese children and adolescents.

DESIGN

A short-term longitudinal study.

SUBJECTS

Thirty-seven obese white girls (age, 12+/-1.8 y; body mass index (BMI), 26.9+/-5.25) and 19 obese white boys (age, 11.9+/-1.7 y; BMI, 26.2+/-5.2).

MEASUREMENTS

Fibrinogen, factor VII coagulant activity, von Willebrand factor antigen, and soluble P-selectin were determined before and after a 3 week programme including energy restriction and physical activities.

RESULTS

All determined haemostatic risk factors decreased significantly during the programme. Changes in risk factors were correlated to changes in body composition. Children and adolescents with the highest initial concentrations showed the greatest decreases.

CONCLUSION

Energy restriction combined with physical activity improves the haemostatic risk profile in obese children and adolescents.

Determinants of haemostatic risk factors for coronary heart disease in obese children and adolescents

OBJECTIVE

To investigate the contribution of serum lipids, parameters of glucose metabolism, body composition and cardiovascular fitness to the variance of several haemostatic risk factors for coronary heart disease (CHD) in obese children and adolescents.

SUBJECTS AND MEASUREMENTS

Forty-two healthy, obese children and adolescents (20 male, 22 female, age 12.6 +/- 3.2y; body mass index (BMI), 30.4 +/- 5.3 kg/m2), were screened for haemostatic and metabolic risk factors for CHD. Thirty-five of the participants (18 male, age 13.5 +/- 2.9y; BMI, 29.9 +/-4.5kg/m2; 17 female, age 12.8+/-2.1 y, BMI, 31.1 +/- 5.3 kg/m2) were assessed for cardiovascular fitness by means of incremental cycle ergometer exercise.

RESULTS

After adjustment for age, fat mass correlated significantly with plasminogen activator inhibitor-1 antigen (PAI-1-Ag) in boys and girls and factor VIIc only in girls. Children with lower power output (< or = 2.77W/kg) showed significantly higher values for factor VIIc, fibrinogen and tissue-type plasminogen activator antigen (tPA-Ag). Neither body composition nor cardiovascular fitness contributed independently to the variance of the determined haemostatic risk factors, except PAI-1-Ag, which has been shown to be determined by fat mass. In multiple linear regression analysis, triglycerides and PAI-1-Ag explained significant independent proportions of the variance of tPA-Ag. Factor VIIc was explained by C-peptide, insulin and fibrinogen. Von Willebrand factor antigen (vWF-Ag) was significantly related to glucose and insulin.

CONCLUSION

The results suggest that in obese children and adolescents the haemostatic risk factors factor VIIc, vWF-Ag and tPA-Ag are mainly determinated by plasma insulin and triglyceride concentrations, but are primarily independent of body composition and cardiovascular fitness.

Infantile obesity: a situation of atherothrombotic risk?

Obesity is a major risk factor for cardiovascular disease frequently associated with hypertension, dyslipidemia, and diabetes. In recent years, alterations in the hemostatic system have been added to these dysfunctions. We analyzed some of these alterations in coagulation and fibrinolysis in obese children (6 to 9 years old) of both sexes. We studied 61 obese children (mean body mass index [BMI], 22.35 kg/m2; 95% confidence interval [CI], 21.82 to 22.87) and 70 non-obese children (mean BMI, 16.58 kg/m2; 95% CI, 16.24 to 16.93) as a control group. The obese subjects presented significantly elevated values for insulin (P < .001), tissue-plasminogen activator ([t-PA] P < .001), plasminogen activator inhibitor-1 ([PAI-1] P < .001), and fibrinogen (P < .001) with respect to the control group. We found no significant differences in the concentration of glucose and fragment 1 + 2 of prothrombin (F1 + 2). In the obese subjects, insulin, PAI-1, and F1 + 2 were positively correlated with the BMI. On the other hand, t-PA was correlated with insulin and PAI-1 but not with the BMI. Therefore, in the obese children, there was an increment of the risk factors for cardiovascular disease.