Improvement of early vascular changes and cardiovascular risk factors in obese children after a six-month exercise program

Gender differences in vascular function and insulin sensitivity in young adults

To examine influence of insulin resistance and other clinical risk factors for the MetS (metabolic syndrome) on vascular structure and function in young adults. This cross-sectional study was conducted in a cohort of young adults (mean age 22 years) and their siblings participating in a longitudinal study of cardiovascular risk (n=370). Insulin sensitivity was determined by euglycaemic insulin clamp. EDD (endothelium-dependent dilation) was determined by flow-mediated dilation using high-resolution ultrasound imaging of the brachial artery. EID (endothelium-independent dilation) was determined by NTG (nitroglycerine)-mediated dilation. The diameter and cIMT (intima-media thickness) of the carotid artery were also measured. There was no significant difference between males and females for age or body mass index. However, males had significantly higher glucose and triacylglycerol (triglyceride) levels, while the females had significantly higher HDL-C (high-density lipoprotein-cholesterol) and insulin sensitivity (13.00 ± 0.33 compared with 10.71 ± 0.31 mg·kg-1 of lean body mass·min-1, P<0.0001). Although peak EDD was significantly lower (6.28 ± 0.26 compared with 8.50 ± 0.28%, P<0.0001) in males than females, this difference was largely explained by adjustment for brachial artery diameter (P=0.15). Peak EID also was significantly lower in males than females (20.26 ± 0.44 compared with 28.64 ± 0.47%, P<0.0001), a difference that remained significantly lower after adjustment for brachial artery diameter. Males had a significantly greater cIMT compared with females (females 0.420 ± 0.004 compared with males 0.444 ± 0.004 mm, P=0.01), but when adjusted for carotid diameter, there was no significant difference (P=0.163). Although there were gender differences in vascular function and structure in the young adult population examined in this study, many of the differences were eliminated simply by adjusting for artery diameter. However, the lower EID observed in males could not be explained by artery diameter. Future studies need to continue to examine influence of gender on EID and other measures of vascular function.

The Impact of Exercise Training on Conduit Artery Wall Thickness and Remodeling in Chronic Heart Failure Patients

Exercise training is an important adjunct to medical therapy in chronic heart failure, but the extent to which exercise impacts on conduit artery remodeling is unknown. The aim of this study was to evaluate the impact of aerobic and resistance exercise training modalities on arterial remodeling in patients with chronic heart failure. We randomized 36 untrained subjects with chronic heart failure to resistance training (58.8±3.5 years), aerobic training (61.3±2.8 years), or an untrained control group (64.4±2.4 years). Peak oxygen consumption during cycle ergometry increased after 12 weeks in both the resistance and aerobic training ( P <0.001) groups, but not in controls, whereas leg strength only increased after resistance training ( P <0.05). Brachial artery wall thickness decreased in the resistance training group (475±10 versus 443±13 μm; P <0.01), whereas no changes were apparent in the aerobic or control groups. Brachial diameter increased by ≈6% and ≈5% in the aerobic training and resistance training groups ( P <0.01), with no change evident in the control group. The wall:lumen ratio consequently declined in the resistance training group at 12 weeks (0.121±0.004 versus 0.107±0.004; P <0.01) and increased in the control group (0.111±0.006 versus 0.121±0.009; P <0.05). No wall:lumen change was evident in the aerobic training group. Our findings suggest that exercise has a systemic impact on remodeling of conduit arteries in humans and that resistance exercise training may be advantageous in subjects with chronic heart failure in this regard.

Multiwave associations between depressive symptoms and endothelial function in adolescent and young adult females

OBJECTIVE

Depression has been linked to endothelial dysfunction, and some research suggests that past depressive episodes are associated with a lasting, negative impact on the endothelium. However, investigations in this area have been predominantly cross-sectional, raising questions about the direction of these associations. Using a multiwave design, we sought to extend previous research in this area by examining whether depressive symptoms have a lasting negative influence on endothelial function.

METHODS

A total of 135 adolescent and young adult females with no known or suspected major health problems were followed for 2½ years. Endothelial function was assessed at three time points throughout the study. The Beck Depression Inventory was administered, and information about health practices was collected every 6 months.

RESULTS

Self-reported depressive symptoms covaried with endothelial functioning on a within-person basis (β = -0.23, p < .05). As a participant's depression symptoms rose beyond her typical level, her endothelial function declined commensurately. This association persisted after controlling for health practices and adiposity. There was no evidence that depressive symptoms predicted endothelial function at later time points or interacted with time to predict the trajectories of endothelial function over the follow-up period.

CONCLUSIONS

Depressive symptoms were concurrently associated with endothelial function in this cohort of healthy adolescent girls and young women. On visits when participants endorsed depressive symptoms that were higher than their mean level of depression, they tended to have worse endothelial function. We did not observe a lasting negative effect of depression on endothelial function.

Long-term follow-up of cardiovascular risk factors after exercise training in obese children

OBJECTIVE

We previously demonstrated beneficial effects of physical activity on cardiovascular disease (CVD) risk factors, body mass index (BMI) and fat mass in pre-pubescent obese children. The aim of this study was to determine whether these changes were maintained 2 years later.

METHODS

Two years after the Randomised Controlled Trial, we performed a follow-up study with 20 of 38 subjects (11.4 ± 1.8 years). Outcomes included blood pressure (BP) by ambulatory monitoring; arterial function and structure using high-resolution ultrasound, BMI, body composition by dual-energy x-ray absorptiometry (DXA), physical activity using accelerometer, and biological markers.

RESULTS

During the 2-year follow-up period, mean 24-hour diastolic BP z-score significantly decreased (1.4 ± 1.2 vs. 0.3 ± 1.4, p = 0.04), while systolic BP z-score was slightly reduced (2.4 ± 1.5 vs. 1.4 ± 1.7, p = 0.067). Blood pressure changes were greater in children who diminished their BMI z-score compared with the ones who did not. Systolic hypertension rates dropped from 50 to 28% and diastolic hypertension from 42 to 6%. In addition, arterial intima-media thickness (0.51 ± 0.03 vs. 0.51 ± 0.06, p = 0.79), BMI z-score (2.9 ± 0.8 vs. 2.9 ± 1.1 kg.cm(-2), p = 0.27), body fat (41.9 ± 6.9 vs. 42.8 ± 6.7%; p = 0.39) and physical activity count (703 ± 209 vs. 574 ± 244 cpm, p = 0.30) were stable.

CONCLUSION

To our knowledge, this is the first study reporting that beneficial effects on adiposity and CVD risk factors of a physical activity centred intervention are sustained 2 years after the cessation of training in obese children. Subjects stabilized BMI z-score and maintained physical activity with further improvement of BP and stabilization of arterial wall remodelling. We conclude that it is important to encourage physical activity in this population. Effects of Aerobic Exercise Training on Arterial Function and Insulin Resistance Syndrome in Obese Children: A Randomised Controlled Trial: NCT00801645.

Physical activity as the main therapeutic tool for metabolic syndrome in childhood

Physical activity (PA) and diet directly influence obesity and metabolic syndrome (MS) as important determinants of body composition. Understanding how PA relates to MS in youth is of great importance, and could offer a common strategy for clinical and public health approaches to control this condition. The underlying disorder of MS is a condition of insulin resistance, and a strong relationship between PA level and insulin sensitivity is clearly ascertained. The type, duration, frequency and intensity of PA affect fuel metabolism, in particular carbohydrate and lipid oxidation. The possible modulation of metabolism because of increased fat oxidation by PA is the basis for both prevention and restoration of insulin resistance and MS in obese children. In daily clinical practice, diet followed by pharmacologic treatment are usually the approaches taken, whereas PA is often considered just a suggestion. Although diet and PA have different effects on body composition, with both contributing to fat loss, only PA increases muscle mass and thus has a direct effect on metabolic function, expressed by changes in cardiovascular risk factors. Therefore, it is important to remember their complementary but different targets in daily clinical practice, such as body weight control for diet and metabolic health for PA. In this review, we have summarized the literature on the relationship between PA and MS in pediatrics. Then, we have analyzed the possibility of using PA for MS treatment, as an alternative to drugs, by discussing the results of intervention studies, reasons for low compliance to PA, related benefits, adherence difficulties and costs. Finally, we have tried to suggest recommendations for a multiple-step PA strategy in children and adolescents at risk for MS, by considering PA as the 'key' player in treatment.

Improvement in HOMA-IR is an independent predictor of reduced carotid intima-media thickness in obese adolescents participating in an interdisciplinary weight-loss program

The aim of this study was to verify whether a 1-year interdisciplinary weight-loss program improved common carotid artery intima-media thickness (IMT) and whether insulin resistance and/or inflammation (as measured by the markers plasminogen activator inhibitor type-1 and adiponectin) might underlie obesity in adolescents. A group of 29 post-pubescent obese adolescents were submitted to an interdisciplinary intervention over the course of 1 year. Common carotid artery IMT was determined ultrasonographically. Body composition, blood pressure (BP), glycemia, insulinemia, homeostasis model assessment of insulin resistance (HOMA-IR), lipid profile and adipokine concentrations were analyzed before and after the intervention. The interdisciplinary weight-loss program promoted a significant improvement in body composition, insulin concentration, HOMA-IR, lipid profile, BP and inflammatory state, in addition to significantly decreasing the common carotid artery IMT. Furthermore, this study demonstrated that the difference between baseline and final values of HOMA-IR (ΔHOMA-IR) was negatively correlated with concomitant changes in the adiponectin concentration (Δadiponectin; r=-0.42; P=0.02) and positively correlated with changes in common carotid artery IMT (Δcarotid IMT; r=0.41; P=0.03). Multiple regression analysis adjusted by age, cardiovascular risk factors and inflammatory markers showed that ΔHOMA-IR was an independent predictor of significant changes in common carotid artery IMT. This investigation demonstrated that an interdisciplinary weight-loss program promoted a reduction of the common carotid artery IMT in obese Brazilian adolescents, and the improvement of HOMA-IR was an independent predictor of carotid IMT changes in this population.

Heritability of arterial function, fitness, and physical activity in youth: a study of monozygotic and dizygotic twins

OBJECTIVES

To examine the role of heredity in determining flow-mediated dilation in young people by comparing conduit artery endothelial function in monozygotic and dizygotic twins. We also determined relationships between physical activity and fitness in each twin subset.

STUDY DESIGN

Flow-mediated dilation was assessed with high-resolution ultrasonography of the brachial artery in 22 twin pairs (11 monozygotic pairs 13.3 ± 1.6 years, 11 dizygotic pairs 13.6 ± 1.6 years). Fitness was assessed as peak oxygen uptake during an incremental treadmill test. Physical activity was measured with accelerometry. Twin versus twin intraclass correlations were performed for both groups.

RESULTS

Flow-mediated dilation was significantly correlated in monozygotic twins only (r = 0.60, P = .02). Heritability of flow-mediated dilation was estimated at 0.44. Total PA time (monozygotic r = 0.77, dizygotic r = 0.60, P < .05) and light physical activity time (monozygotic r = 0.67, dizygotic r = 0.63, P < .05) correlated significantly in both groups. The peak oxygen uptake (r = 0.84, P < .01) was correlated only in monozygotic twins.

CONCLUSION

Genetic factors appear to be responsible for a modest portion of the flow-mediated dilation response, suggesting that flow-mediated dilation can be influenced by environmental factors.

Effect of regular physical activity on carotid intima-media thickness. Results from a 6-year prospective study in the early stage of hypertension

AIM

To study the effect of leisure-time physical activity on the progression of carotid intima-media thickness (IMT) in the early stage of hypertension.

METHODS

We studied 47 sedentary and 40 physically active young pre-hypertensive or stage 1 hypertensive subjects. IMT was assessed in the common carotid artery, carotid bulb and internal carotid artery at baseline and after 6.5 years.

RESULTS

Cumulative maximum IMT of the three carotid segments (M-MAX, 0.13 ± 0.08 vs 0.10 ± 0.07 mm, p = 0.006) and cumulative mean IMT (m-IMT, 0.11 ± 0.07 vs 0.09 ± 0.06 mm, p = 0.01), adjusted for confounders, increased to a greater degree in the sedentary than the active subjects. Differences in known risk factors explained a large proportion of the observed association. Inclusion of baseline cholesterol in the regression model attenuated the strength of the association for both M-MAX (p = 0.04) and m-IMT (p = 0.049). When also baseline blood pressure, heart rate, and body mass index were taken into account the association with physical activity status remained significant for maximum IMT of internal carotid artery (p = 0.034) and was of borderline significance for M-MAX (p = 0.066).

CONCLUSIONS

Physical activity can delay the progression of carotid IMT in hypertension. This effect is mediated in substantial part by the better risk factor profile in active subjects.

Assessment of atherosclerosis: the role of flow-mediated dilatation

Evidence suggests that endothelial dysfunction is on the causal pathway for both atherogenesis and destabilization of established plaques. In this review, the role of flow-mediated dilatation (FMD) as a non-invasive method to assess endothelial function is discussed. Technical modifications and development of analysis software have significantly improved the variability of the method. Following a strict standardized protocol enables reproducible measurements to be achieved and export of the technique from specialized laboratories to population studies and multicentre settings. Endothelial function assessed by FMD has been shown to be affected by cardiovascular risk factors, to be related to structural arterial disease and to cardiovascular outcome, validating its use for studying the pathophysiology of arterial disease. Numerous studies have also demonstrated that it is responsive to physiological and pharmacological interventions. Flow-mediated dilatation provides unique opportunities in drug development programmes to assess an early rapidly responsive signal of risk or benefit, complementing endpoints of structural arterial disease and cardiovascular outcomes that take much longer and are more expensive.

Vascular function in children with repaired tetralogy of Fallot

We compared the endothelial function and vascular wall characteristics of 11 children with tetralogy of Fallot (TOF) (age 13 +/- 3 years) with the characteristics of 17 age-matched peers (12 +/- 2 years). Echocardiographic Doppler measurements were performed under standardized conditions to assess (1) the carotid and femoral artery diameter and intima-media thickness, (2) brachial artery endothelial function using flow-mediated dilation, and (3) central and peripheral compliance using pulsewave velocity. In addition, the physical activity level was assessed using a validated questionnaire. We found that the physical activity level of the children with TOF was lower than that of the controls, but the difference did not reach statistical significance (4.5 vs 5.9 h/wk, p = 0.087). A significantly larger femoral artery intima-media thickness was observed in those with TOF, and the carotid and brachial artery diameter and intima-media thickness were comparable between groups. The children with TOF demonstrated a significantly lower brachial artery flow-mediated dilation than that of the controls. The central and peripheral compliance did not differ between the 2 groups. In conclusion, children with TOF demonstrated an impaired brachial artery endothelial function and increased intima-media thickness of the femoral artery compared to their healthy peers. In conclusion, our findings have, therefore, indicated that children with TOF, already at a young age, have changes in vascular function and structure.

Arterial prehabilitation: can exercise induce changes in artery size and function that decrease complications of catheterization?

Coronary angiography and angioplasty are common invasive procedures in cardiovascular medicine, which involve placement of a sheath inside peripheral conduit arteries. Sheath placement and catheterization can be associated with arterial thrombosis, spasm and occlusion. In this paper we review the literature pertaining to the possible benefits of arterial 'prehabilitation'--the concept that interventions aimed at enhancing arterial function and size (i.e. remodelling) should be undertaken prior to cardiac catheterization or artery harvest during bypass graft surgery. The incidence of artery spasm, occlusion and damage is lower in larger arteries with preserved endothelial function. We conclude that the beneficial effects of exercise training on both artery size and function, which are particularly evident in individuals who possess cardiovascular diseases or risk factors, infer that exercise training may reduce complication rates following catheterization and enhance the success of arteries harvested as bypass grafts. Future research efforts should focus directly on examination of the 'prehabilitation' hypothesis and the efficacy of different interventions aimed at reducing clinical complications of common interventional procedures.

Is exercise a therapeutic tool for improvement of cardiovascular risk factors in adolescents with type 1 diabetes mellitus? A randomised controlled trial

BACKGROUND

Type 1 diabetes mellitus (T1DM) is associated with a high risk for early atherosclerotic complications especially risk of coronary heart disease.

OBJECTIVE

To evaluate the impact of six months exercise prgram on glycemic control, plasma lipids values, blood pressure, severity and frequency of hypoglycemia, anthropometric measurements and insulin dose in a sample of adolescents with T1DM.

RESEARCH DESIGN AND METHODS

A total of 196 type 1 diabetic patients participated in the study. They were classified into three groups: Group (A) did not join the exercise program(n = 48), group (B) attended the exercise sessions once/week (n = 75), group (C) attended the exercise sessions three times/week (n = 73). Studied parameters were evaluated before and six months after exercise programe.

RESULTS

Exercise improved glycemic control by reducing HbA1c values in exercise groups (P = 0.03, P = 0.01 respectively) and no change in those who were not physically active (P = 0.2). Higher levels of HbA1c were associated with higher levels of cholesterol, LDL-c, and triglycerides (P = 0.000 each). In both groups, B and C, frequent exercise improved dyslipidemia and reduced insulin requirements significantly (P = 0.00 both), as well as a reduction in BMI (P = 0.05, P = 0.00 respectively) and waist circumference(P = 0.02, P = 0.00 respectively). The frequency of hypoglycemic attacks were not statistically different between the control group and both intervention groups (4.7 +/- 3.56 and 4.82 +/- 4.23, P = 0.888 respectively). Reduction of blood pressure was statistically insignificant apart from the diastolic blood presure in group C (P = 0.04).

CONCLUSION

Exercise is an indispensable component in the medical treatment of patients with T1DM as it improves glycemic control and decreases cardiovascular risk factors among them.

Increased carotid IMT in overweight and obese women affected by Hashimoto's thyroiditis: an adiposity and autoimmune linkage?

BACKGROUND

Hashimoto's thyroiditis is the most important cause of hypothyroidism. It is a systemic disease that can even affect the cardiovascular system, by accelerating the atherosclerotic process. Aim of this study was to examine whether autoimmune thyroiditis has an effect on the intima-media thickness of the common carotid artery (IMT-CCT), independently of the thyroid function and well-known cardiovascular risk factors. Hashimoto's thyroiditis is a systemic disease. The aim is to examine whether autoimmune thyroiditis and adiposity can effect carotid IMT independently of thyroid hormones and cardiovascular risk factors.

METHODS

A total of 104 obese women (BMI > or = 25.0 kg/m-2), with FT3 and FT4 serum levels in the normal range and TSH levels < 4.5 microU/ml, were investigated. None of these patients was taking any kind of drug influencing thyroid function. Measurements were made of the IMT-CCT, BMI, waist circumference, blood pressure levels, as well as fasting TSH, FT3, FT4, anti-thyroid antibodies, insulin, fasting glycemia, triglycerides, total and HDL-cholesterol serum concentrations.

RESULTS

Of the 104 women, 30 (28.8%) were affected by autoimmune thyroiditis. Significantly higher values of IMT-CCT (p < 0.05), TSH (p < 0.05), and triglycerides (p < 0.05) were obtained, and significantly lower values of FT4 (p < 0.05), in patients with Hashimoto's thyroiditis as compared to those with a normal thyroid function. When examining the whole group together, at multiple regression analysis Hashimoto's thyroiditis maintained a positive association with the IMT (p < 0.001), independently of age, hypertension, BMI, and the fasting serum levels of TSH, FT3, FT4, insulin, fasting glycemia, triglycerides, total and HDL-cholesterol levels.

CONCLUSIONS

The present study shows that Hashimoto's thyroiditis is associated to an increased IMT only in overweight and obese, independently of the thyroid function, BMI and cardiovascular risk factors. These results suggest that Hashimoto's thyroiditis is a marker of evolution of the atherosclerosis if combined to adiposity.

Fetal growth restriction results in remodeled and less efficient hearts in children

BACKGROUND

Fetal growth restriction (FGR) affects 5% to 10% of newborns and is associated with increased cardiovascular mortality in adulthood. The most commonly accepted hypothesis is that fetal metabolic programming leads secondarily to diseases associated with cardiovascular disease, such as obesity, diabetes mellitus, and hypertension. Our main objective was to evaluate the alternative hypothesis that FGR induces primary cardiac changes that persist into childhood.

METHODS AND RESULTS

Within a cohort of fetuses with growth restriction identified in fetal life and followed up into childhood, we randomly selected 80 subjects with FGR and compared them with 120 normally grown fetuses, matched for gender, birth date, and gestational age at birth. Cardiovascular assessment was performed in childhood (mean age of 5 years). Compared with control subjects, children with FGR had a different cardiac shape, with increased transversal diameters and more globular cardiac ventricles. Although left ejection fraction was similar among the study groups, stroke volume was reduced significantly, which was compensated for by an increased heart rate to maintain output in severe FGR. This was associated with subclinical longitudinal systolic dysfunction (decreased myocardial peak velocities) and diastolic changes (increased E/E' ratio and E deceleration time). Children with FGR also had higher blood pressure and increased intima-media thickness. For all parameters evaluated, there was a linear increase with the severity of growth restriction.

CONCLUSIONS

These findings suggest that FGR induces primary cardiac and vascular changes that could explain the increased predisposition to cardiovascular disease in adult life. If these results are confirmed, the impact of strategies with beneficial effects on cardiac remodeling should be explored in children with FGR.

Systematic review of the health benefits of physical activity and fitness in school-aged children and youth

Background

The purpose was to: 1) perform a systematic review of studies examining the relation between physical activity, fitness, and health in school-aged children and youth, and 2) make recommendations based on the findings.

Methods

The systematic review was limited to 7 health indicators: high blood cholesterol, high blood pressure, the metabolic syndrome, obesity, low bone density, depression, and injuries. Literature searches were conducted using predefined keywords in 6 key databases. A total of 11,088 potential papers were identified. The abstracts and full-text articles of potentially relevant papers were screened to determine eligibility. Data was abstracted for 113 outcomes from the 86 eligible papers. The evidence was graded for each health outcome using established criteria based on the quantity and quality of studies and strength of effect. The volume, intensity, and type of physical activity were considered.

Results

Physical activity was associated with numerous health benefits. The dose-response relations observed in observational studies indicate that the more physical activity, the greater the health benefit. Results from experimental studies indicate that even modest amounts of physical activity can have health benefits in high-risk youngsters (e.g., obese). To achieve substantive health benefits, the physical activity should be of at least a moderate intensity. Vigorous intensity activities may provide even greater benefit. Aerobic-based activities had the greatest health benefit, other than for bone health, in which case high-impact weight bearing activities were required.

Conclusion

The following recommendations were made: 1) Children and youth 5-17 years of age should accumulate an average of at least 60 minutes per day and up to several hours of at least moderate intensity physical activity. Some of the health benefits can be achieved through an average of 30 minutes per day. [Level 2, Grade A]. 2) More vigorous intensity activities should be incorporated or added when possible, including activities that strengthen muscle and bone [Level 3, Grade B]. 3) Aerobic activities should make up the majority of the physical activity. Muscle and bone strengthening activities should be incorporated on at least 3 days of the week [Level 2, Grade A].

Lifetime cardiovascular risk of childhood obesity

An increase in the incidence and an earlier onset of coronary artery disease is expected because of the increased prevalence of childhood obesity. Comorbidities of obesity, such as dyslipidemia, insulin resistance syndrome, hypertension, associated nutritional deficiencies, and a sedentary lifestyle or associated lifestyle factors such as tobacco smoke exposure, are likely to account for this increase because these are all independent risk factors for accelerated atherosclerosis. Because clinical atherosclerotic cardiovascular disease does not manifest in obese children, assessment of the subclinical markers of atherosclerosis may help in the evaluation of the progression of atherosclerosis, in further stratification of risk, and in monitoring the effects of intervention. Furthermore, because multiple risk factors with poorly understood interplay might be present in obese children, assessment of the vasculature directly, and perhaps the assignment of a "vascular age," may be a useful method to quantify the "end organ" effect of exposure to these various risks. Obese children may show favorable changes in their behaviors that result in an improvement in clinically measurable risk factors with various clinic-based and behavior modification therapies, but the vascular benefits of such interventions need to be studied further. Broad social, cultural, legislative, and policy changes that support healthy lifestyles within families and communities need to be implemented to decrease the prevalence of childhood obesity and its cardiovascular consequences in communities. The effect of risk factor modification on the vasculature will continue to be a resource for the direction of evidence-based therapy in obese children.

The Role of Endothelial Dysfunction on Development and Progression of Atherosclerosis and Methods to Assess Vascular Function and Structure

The endothelium was originally thought to be just a semipermeable barrier between the vessel wall and the bloodstream, but today we now realize that it is actually a highly active autocrine, paracrine, and endocrine organ. Researchers have also begun to realize that the endothelium plays a key role in the development of atherosclerosis as well as other diseases. This increased recognition has resulted in considerable effort by both researchers and clinicians to develop accurate and reliable methods to measure and track changes in both vascular structure and function. In addition, research interest has focused on various cardiovascular risk factors (eg, age, gender, obesity, physical inactivity) and the effect they have on vascular structure and function. In this review, the authors discuss different research and clinical methods to assess vascular structure and function as well as the effect of various cardiovascular risk factors on the endothelium and the vascular system. They also discuss the ability to modify vascular structure and function through various lifestyle modifications such as weight loss and exercise.

Early echocardiography abnormalities in obese children and adolescent and reversibility of these abnormalities after significant weight reduction

BACKGROUND

Obesity is becoming an epidemic threat for the individual and society. The increasing prevalence of overweight children and adolescents is likely to have a great impact on the future cardiovascular health of these subjects. Obesity is a strong risk factor for cardiovascular morbidity and mortality. Cardiac abnormalities of obese children and adolescents include the echocardiographically revealed early and preclinical LV or septal hypertrophy, and left or right ventricular dysfunction. Most of these abnormalities, which are usually more pronounced in patients with morbid obesity, can be partially reversed after weight reduction.

AIM OF THE STUDY

Evaluate early echocardiography changes in obese children and whether these cardiac abnormalities reverse with significant weight reduction in children and adolescents or not.

METHODS

We started this study by 50 obese children and adolescents and 30 non obese controls matched for age and sex. BMI was calculated. Complete echocardiographic study was performed on each patient and control subject. Hematological and biochemical variables were determined in the obese subjects from fasting blood samples and included glucose, total cholesterol, triglycerides (TG), HDL cholesterol and LDL cholesterol. All our patients' strict dietetic regime with exercises for 6 months. After 6 months full examination, including all measurements and echocardiography and laboratory investigations were done again.

RESULTS

Obese children has abnormalities of left ventricle structure and function (consisting of increased left ventricular wall dimensions and mass and alteration of diastolic function) that can be detected by echocardiography. Furthermore, (parameters of lipid metabolism) were found to be independent predictors of adverse LV remodeling and of diastolic dysfunction. As well as this study provides evidence that abnormalities of left ventricular wall dimension and mass in obese children and adolescents can improve with significant weight reduction.

CONCLUSION

This study has demonstrated that young, obese children and adolescents have early significant changes in left ventricular wall dimensions and early diastolic filling compared with non obese and this changes are reversible with weight reduction.

Impact of inactivity and exercise on the vasculature in humans

The effects of inactivity and exercise training on established and novel cardiovascular risk factors are relatively modest and do not account for the impact of inactivity and exercise on vascular risk. We examine evidence that inactivity and exercise have direct effects on both vasculature function and structure in humans. Physical deconditioning is associated with enhanced vasoconstrictor tone and has profound and rapid effects on arterial remodelling in both large and smaller arteries. Evidence for an effect of deconditioning on vasodilator function is less consistent. Studies of the impact of exercise training suggest that both functional and structural remodelling adaptations occur and that the magnitude and time-course of these changes depends upon training duration and intensity and the vessel beds involved. Inactivity and exercise have direct "vascular deconditioning and conditioning" effects which likely modify cardiovascular risk.

Randomized controlled trial of the MEND program: a family-based community intervention for childhood obesity

The aim of this study was to evaluate the effectiveness of the Mind, Exercise, Nutrition, Do it (MEND) Program, a multicomponent community-based childhood obesity intervention (www.mendcentral.org). One hundred and sixteen obese children (BMI >or= 98 th percentile, UK 1990 reference data) were randomly assigned to intervention or waiting list control (6-month delayed intervention). Parents and children attended eighteen 2-h group educational and physical activity sessions held twice weekly in sports centers and schools, followed by a 12-week free family swimming pass. Waist circumference, BMI, body composition, physical activity level, sedentary activities, cardiovascular fitness, and self-esteem were assessed at baseline and at 6 months. Children were followed up 12 months from baseline (0 and 6 months postintervention for the control and intervention group, respectively). Participants in the intervention group had a reduced waist circumference z-score (-0.37; P < 0.0001) and BMI z-score (-0.24; P < 0.0001) at 6 months when compared to the controls. Significant between-group differences were also observed in cardiovascular fitness, physical activity, sedentary behaviors, and self-esteem. Mean attendance for the MEND Program was 86%. At 12 months, children in the intervention group had reduced their waist and BMI z-scores by 0.47 (P < 0.0001) and 0.23 (P < 0.0001), respectively, and benefits in cardiovascular fitness, physical activity levels, and self-esteem were sustained. High-attendance rates suggest that families found this intensive community-based intervention acceptable. Further larger controlled trials are currently underway to confirm the promising findings of this initial trial.

Effectiveness of weight management interventions in children: a targeted systematic review for the USPSTF

CONTEXT

Targeted systematic review to support the updated US Preventive Services Task Force (USPSTF) recommendation on screening for obesity in children and adolescents.

OBJECTIVES

To examine the benefits and harms of behavioral and pharmacologic weight-management interventions for overweight and obese children and adolescents.

METHODS

Our data sources were Ovid Medline, PsycINFO, the Education Resources Information Center, the Database of Abstracts of Reviews of Effects, the Cochrane databases, reference lists of other reviews and trials, and expert recommendations. After 2 investigators reviewed 2786 abstracts and 369 articles against inclusion/exclusion criteria, we included 15 fair- to good-quality trials in which the effects of treatment on weight, weight-related comorbidities, and harms were evaluated. Studies were quality rated by 2 investigators using established criteria. Investigators abstracted data into standard evidence tables.

RESULTS

In the available research, obese (or overweight) children and adolescents aged 4 to 18 years were enrolled, and no studies targeted those younger than 4 years. Comprehensive behavioral interventions of medium-to-high intensity were the most effective behavioral approach with 1.9 to 3.3 kg/m(2) difference favoring intervention groups at 12 months. More limited evidence suggests that these improvements can be maintained over the 12 months after the end of treatments and that there are few harms with behavioral interventions. Two medications combined with behavioral interventions resulted in small (0.85 kg/m(2) for orlistat) or moderate (2.6 kg/m(2) for sibutramine) BMI reduction in obese adolescents on active medication; however, no studies followed weight changes after medication use ended. Potential adverse effects were greater than for behavioral interventions alone and varied in severity. Only 1 medication (orlistat) has been approved by the US Food and Drug Administration for prescription use in those aged > or =12 years.

CONCLUSIONS

Over the past several years, research into weight management in obese children and adolescents has improved in quality and quantity. Despite important gaps, available research supports at least short-term benefits of comprehensive medium- to high-intensity behavioral interventions in obese children and adolescents.

Arterial structure and function after recovery from the metabolic syndrome: the cardiovascular risk in Young Finns Study

BACKGROUND

The reversibility of ultrasonographic vascular changes associated with the metabolic syndrome (MetS) recovery is unknown. We examined whether spontaneous recovery from MetS (according to the International Diabetes Federation definition) has a favorable effect on vascular properties and evaluated the associations between lifestyle factors and MetS recovery.

METHODS AND RESULTS

We measured carotid artery intima-media thickness, distensibility, and brachial flow-mediated dilatation by ultrasound in 1673 subjects of the Young Finns Study cohort (age, 31.5+/-5.0 years in 2001) who participated in follow-up studies in 2001 and 2007. At baseline, no differences in intima-media thickness, carotid artery distensibility, or flow-mediated dilatation were observed between the recovery group (baseline-only MetS) and those with incident (only at follow-up) or persistent (both at baseline and follow-up) MetS. After 6 years, the recovery group had smaller intima-media thickness (mean+/-SEM, 0.62+/-0.01 versus 0.68+/-0.01 mm; P=0.0009) and higher carotid artery distensibility (1.98+/-0.07%/mm Hg versus 1.56+/-0.04%/mm Hg; P=0.001) compared with the persistent group and higher flow-mediated dilatation compared with the control group (9.91+/-0.51% versus 8.57+/-0.12%; P=0.03). The recovery group had reduced intima-media thickness progression compared with the persistent group (0.036+/-0.005 versus 0.079+/-0.010 mm; P=0.001) and reduced carotid artery distensibility change compared with the incident group (-0.12+/-0.05%/mm Hg versus -0.38+/-0.10%/mm Hg; P=0.03) over the 6-year follow-up. Differences in carotid artery distensibility levels were attenuated (P=0.11) after the inclusion of weight change in the models. MetS recovery was paralleled with significant reductions in waist circumference that independently correlated with increased physical activity and increased attention paid to health habits during the follow-up.

CONCLUSIONS

Recovery from the MetS was associated with positive effects on vascular properties during a 6-year follow-up period of young adults.

Prevenção primária de doenças cardiovasculares na obesidade infantojuvenil: efeito anti-inflamatório do exercício físico

A pandemia da obesidade juvenil e do sedentarismo está relacionada com o maior risco de doenças cardiovasculares no futuro. Ambas com fisiopatologia inflamatória, essas condições têm atraído significativa atenção científica. O início dos eventos que agridem o endotélio vascular pode ocorrer na infância, porém, sinais clínicos da aterosclerose geralmente só aparecem na fase adulta. O tecido adiposo é hoje reconhecido por seu papel ativo, induzindo a produção de citocinas pró e anti-inflamatórias, como o fator de necrose tumoral-alfa, as interleucinas 1, 6 e 10, a proteína C-reativa e outras. Há várias evidências de que os níveis sanguíneos dessas citocinas se encontram mais altos em indivíduos com excesso de peso, inclusive crianças e adolescentes. A prevenção precoce, desde a infância, apresenta-se como a melhor maneira de evitar os danos da obesidade na fase adulta, enquanto o potencial da prática regular de exercícios físicos tem se mostrado surpreendente. Sua ação anti-inflamatória se manifesta através de menores concentrações séricas de interleucina 6, de proteína C-reativa e leptina, além de aumentos na adiponectina. Observa-se escassez de estudos randomizados e controlados avaliando as relações entre obesidade, inflamação e exercícios para a população jovem. Com resultados às vezes controversos, a maioria das conclusões é procedentede estudos com adultos. O objetivo desta revisão é avaliar o papel anti-inflamatório, e assim cardioprotetor, da atividade física regular na obesidade infantojuvenil.

Vascular health in children and adolescents: effects of obesity and diabetes

The foundations for cardiovascular disease in adults are laid in childhood and accelerated by the presence of comorbid conditions, such as obesity, diabetes, hypertension, and dyslipidemia. Early detection of vascular dysfunction is an important clinical objective to identify those at risk for subsequent cardiovascular morbidity and events, and to initiate behavioral and medical interventions to reduce risk. Typically, cardiovascular screening is recommended for young adults, especially in people with a family history of cardiovascular conditions. Children and adolescents were once considered to be at low risk, but with the growing health concerns related to sedentary lifestyle, poor diet and obesity, cardiovascular screening may be needed earlier so that interventions to improve cardiovascular health can be initiated. This review describes comorbid conditions that increase cardiovascular risk in youth, namely obesity and diabetes, and describes noninvasive methods to objectively detect vascular disease and quantify vascular function and structure through measurements of endothelial function, arterial compliance, and intima-media thickness. Additionally, current strategies directed toward prevention of vascular disease in these populations, including exercise, dietary interventions and pharmacological therapy are described.

Effect of habitual aerobic exercise on body weight and arterial function in overweight and obese men

The effect of habitual exercise on vascular function, including central arterial distensibility and endothelial function, in obese subjects has not yet been clarified. We investigated whether aerobic exercise training affects central arterial distensibility and endothelial function in middle-age overweight and obese men. A total of 21 overweight and obese men (age 50 +/- 2 years, body mass index 30 +/- 1 kg/m(2)) completed a 12-week aerobic exercise intervention. Aerobic exercise training significantly reduced their body weight and resulted in a significant decrease in body mass index. After the weight-reduction exercise program, carotid arterial compliance (determined by simultaneous B-mode ultrasonography and arterial applanation tonometry on the common carotid artery) significantly increased; and the beta-stiffness index, an index of arterial compliance adjusted for distending pressure, significantly decreased. The concentrations of plasma endothelin-1, a potent vasoconstrictor peptide produced by vascular endothelial cells, significantly decreased and plasma nitric oxide (measured as the stable end product [nitrite/nitrate]), a potent vasodilator produced by vascular endothelial cells, significantly increased after the weight-reduction exercise program. In conclusion, weight reduction by aerobic exercise training in overweight and obese men increased the central arterial distensibility. This increase might contribute to the improvement in endothelial function, as assessed by a decrease in endothelin-1 and an increase in nitric oxide, after exercise training-induced weight loss.

HDL-Cholesterol, Blood Pressure, and Asymmetric Dimethylarginine Are Significantly Associated With Arterial Wall Thickness in Children

Objective— Atherosclerosis is found at autopsy in the arteries of adolescents and young adults. Arterial wall thickening may be assessed in vivo by ultrasound measurement of the carotid intima media thickness (CIMT), a marker of subclinical atherosclerosis. As the determinants of arterial wall thickness in childhood are unknown, we assessed the influence of cardiovascular risk factors on CIMT in 8-year-old children.

Methods and Results— A community-based sample of 405 children (age 8.0±0.1 years, 49% girls) had anthropometry, family history, blood pressure (BP), and CIMT measured. A blood sample was collected for HDL and non-HDL cholesterol, apolipoproteins A1 and B, high-sensitivity C-reactive protein, bilirubin, and asymmetric dimethylarginine (ADMA, an endogenous nitric oxide inhibitor). CIMT was significantly associated with systolic BP ( r =0.17, P <0.001), diastolic BP ( r =0.10, P =0.04), HDL ( r =−0.13, P =0.02), and ADMA ( r =0.18, P =0.001). CIMT was significantly higher in children with premature parental CHD (0.63±0.07 versus 0.59±0.06 mm, P =0.03). On multivariate analysis, HDL (β coefficient=−0.02, P =0.04), ADMA (β coefficient=0.05, P <0.001), and systolic BP (β coefficient=0.001, P =0.003) were significantly and independently associated with CIMT.

Conclusions— Lower HDL-cholesterol, higher levels of ADMA, and systolic BP are significantly associated with greater arterial wall thickness in early childhood.

Modestly overweight women have vascular endothelial dysfunction

BACKGROUND

Vascular endothelial dysfunction occurs early in the atherosclerotic process and is predictive of cardiovascular prognosis. However, the association between specific cardiovascular risk factors and endothelial dysfunction in women has not been well characterized. This study examined the relationship between endothelial dysfunction and cardiovascular risk factors (body mass index [BMI] >or= 25 kg/m(2), current smoking, age, diabetes, hypertension, hypercholesterolemia, and family history of early coronary heart disease) in a population of women that included those already being treated for risk factors.

METHODS

Endothelial function was assessed by brachial artery ultrasound flow-mediated vasodilation (FMD) in 185 consecutive women without a history of coronary heart disease. Women with hypertension, diabetes, or hyperlipidemia were allowed to continue on their usual therapy.

RESULTS

There was an inverse linear association between age and FMD. Subjects who were active smokers had lower FMD compared with nonsmokers, and subjects with BMI >or= 25 kg/m(2) had lower FMD than subjects with BMI < 25 kg/m(2). FMD in overweight women (BMI >or= 25 and < 30 kg/m(2)) was similar to that of obese women (BMI >or= 30 kg/m(2)). Multivariate analysis demonstrated that body mass index, current smoking, and age were independent predictors of endothelial dysfunction in this population.

CONCLUSION

Modestly elevated BMI, smoking, and age predict endothelial dysfunction in women, even in the presence of treatment for other atherosclerotic risk factors. These findings demonstrate the importance of modest elevation in BMI as a risk factor for impaired vascular health in women, and underscore the need for focusing further attention on lifestyle modification as a component of cardiovascular disease prevention.

Intima-media thickness measurements in children with cardiovascular risk factors

Measuring intima-media thickness (IMT) is now a standard diagnostic procedure in assessing cardiovascular risk and hypertensive target-organ damage (TOD) in adults. There is also an increasing number of pediatric publications evaluating IMT in children from high-risk groups, such as those with arterial hypertension, diabetes, chronic kidney disease, obesity, dyslipidemia, and homocystinurias. It has been shown that carotid IMT is strongly related with other markers of TOD in children with arterial hypertension and with metabolic cardiovascular risk factors. In children with coarctation of the aorta, carotid IMT correlated both with blood pressure and even with mild residual aortic gradient. On the other hand, studies in children with high cardiovascular risk have shown that normalization of blood pressure and metabolic abnormalities led to regression of arterial changes and decrease of IMT. Although not yet accepted as standard pediatric procedure, IMT measurement is emerging as a promising method of assessing TOD and cardiovascular risk and monitoring treatment efficacy. From a practical point of view, clinical utility of IMT measurements seems to be similar to use of echocardiography in assessing left ventricular mass. However, IMT measurements in children and adolescents should be standardized to avoid bias caused by the use of different measurement methods.

The use of surrogate vascular markers in youth at risk for premature cardiovascular disease

Premature cardiovascular disease (CVD) begins in youth--a crucial period when modification of the disease may have the greatest impact. Failure to diagnose preclinical CVD at this stage misses a major opportunity to prevent the long-term consequences of this disease. An array of surrogate vascular markers (SVMs) are now available that can determine the extent of preclinical vascular injury in the pediatric population. These SVMs include flow-mediated vasodilatation, carotid intima media thickness, arterial stiffness, and biomarkers including high sensitivity C-reactive protein, cell adhesion molecules and methylarginines. We believe that the use of these SVMs will help to develop a better understanding of early pathological vascular changes in youth, facilitate earlier diagnosis of preclinical atherosclerosis and provide an objective measure of the vascular effects of any therapeutic intervention aimed at risk factor modification. Ultimately, our future health will depend on carefully balancing the benefits of early diagnosis and treatment in high-risk youth with the long-term risk of CVD. The application of SVMs in the pediatric population will help us achieve this balance.

Objectively measured physical activity and its association with adiponectin and other novel metabolic markers: a longitudinal study in children (EarlyBird 38)

OBJECTIVE

Recent evidence suggests that, in children, traditional markers of metabolic disturbance are related only weakly to physical activity. We therefore sought to establish the corresponding relationships with newer metabolic markers.

RESEARCH DESIGN AND METHODS

This was a nonintervention longitudinal study of 213 healthy children recruited from 54 schools in Plymouth, U.K. MTI accelerometers were used to make objective 7-day recordings of physical activity at ages 5 +/- 0.3 (mean +/- SD), 6, 7, and 8 years. Overall physical activity was taken as the average of the four annual time points. The metabolic markers at 8 years were adiponectin, leptin, high-sensitivity C-reactive protein (hsCRP), and insulin resistance (homeostasis model assessment). Potential confounders included percent body fat measured by dual-energy X-ray absorptiometry and diet measured by food frequency questionnaire.

RESULTS

Whereas physical activity did not correlate with insulin resistance (r = -0.01), leptin (r = +0.04), or hsCRP (r = +0.01) independently of percent body fat, it did correlate with adiponectin, but inversely (r = -0.18, P = 0.02). This unexpected inverse relationship was strongest among the less active children (physical activity < median: r = -0.30, P = 0.01) but negligible in the more active children (physical activity > median: r = +0.04, P = 0.76). Adiponectin was significantly higher (0.52 SD, P < 0.01) in the least active tertile compared with the other two tertiles. Insulin resistance, however, did not differ across the physical activity tertiles (P = 0.62).

CONCLUSIONS

Adiponectin levels in children are highest among those who are least active, but their insulin resistance is no different. Adiponectin has a known insulin-sensitizing effect, and our findings are consistent with a selective effect at low levels of physical activity.

Retinal vessel response to flicker light in children and adolescents with type 1 diabetes mellitus and overweight or obesity

It was the goal of the trial to assess cardiovascular risk factors in children and adolescents with type 1 diabetes mellitus or overweight/obesity. All children and adolescents (n=77 [n=45 patients with diabetes mellitus, n=32 patients with overweight/obesity]) admitted to our hospital during the period from 01/07 to 31/08/2006 were included in the trial. Socio-demographic and laboratory data (age, sex, diabetes duration, BMI, BMI-SDS, HbA1c, fasting blood glucose, oGTT in patients with overweight/obesity, lipids, CRP, TSH, creatinine, and microalbuminuria) were assessed. The diameter of a retinal arterial and a venous segment was measured continuously on-line with a Dynamic Vessel Analyzer, carotid intima-media thickness (IMT) was measured, and 24-h-blood pressure monitoring was applied.

RESULTS

Flicker light stimulation induces a comparable arterial dilatation in patients with type 1 diabetes and overweight/obesity. Univariate ANOVA in patients with type 1 diabetes shows an influence of diastolic blood pressure on arterial dilatation. Other factors such as BMI, age, diabetes duration, smoking, sex, HbA1c and insulin dose/kg had no effect.

CONCLUSIONS

In children and adolescents with diabetes or overweight/obesity retinal vascular alterations seem to be more sensitive and already present before the occurrence of classic cardiovascular markers.

Effects of aerobic exercise on non-high-density lipoprotein cholesterol in children and adolescents: a meta-analysis of randomized controlled trials

The authors used the meta-analytic approach to examine the effects of aerobic exercise on non-high-density lipoprotein cholesterol (non-HDL-C) in children and adolescents. Thirteen non-HDL-C outcomes in 404 males and females (221 exercise, 183 control) were available for pooling. Random-effects modeling yielded a nonstatistically significant exercise minus control group reduction of 0.61% in non-HDL-C (X +/- SEM, -0.7 +/- 2.4 mg/dL, 95% confidence interval [CI], -5.4 to 5.0 mg/dL). A statistically significant decrease of 7% was found for percent body fat (X +/- SEM, -2.1 +/- 0.5%, 95% CI, -3.0 to -1.2%) as well as an 8% increase in aerobic capacity (X +/- SEM, 3.4 +/- 1.0 mL/kg/min, 95% CI, 1.4-5.3 mL/kg/min), both secondary outcomes of the study. It was concluded that aerobic exercise does not reduce non-HDL-C but does improve percent body fat and aerobic capacity in children and adolescents. However, a need exists for additional studies on this topic.

Both aerobic endurance and strength training programmes improve cardiovascular health in obese adults

Regular exercise training is recognized as a powerful tool to improve work capacity, endothelial function and the cardiovascular risk profile in obesity, but it is unknown which of high-intensity aerobic exercise, moderate-intensity aerobic exercise or strength training is the optimal mode of exercise. In the present study, a total of 40 subjects were randomized to high-intensity interval aerobic training, continuous moderate-intensity aerobic training or maximal strength training programmes for 12 weeks, three times/week. The high-intensity group performed aerobic interval walking/running at 85-95% of maximal heart rate, whereas the moderate-intensity group exercised continuously at 60-70% of maximal heart rate; protocols were isocaloric. The strength training group performed 'high-intensity' leg press, abdominal and back strength training. Maximal oxygen uptake and endothelial function improved in all groups; the greatest improvement was observed after high-intensity training, and an equal improvement was observed after moderate-intensity aerobic training and strength training. High-intensity aerobic training and strength training were associated with increased PGC-1alpha (peroxisome-proliferator-activated receptor gamma co-activator 1alpha) levels and improved Ca(2+) transport in the skeletal muscle, whereas only strength training improved antioxidant status. Both strength training and moderate-intensity aerobic training decreased oxidized LDL (low-density lipoprotein) levels. Only aerobic training decreased body weight and diastolic blood pressure. In conclusion, high-intensity aerobic interval training was better than moderate-intensity aerobic training in improving aerobic work capacity and endothelial function. An important contribution towards improved aerobic work capacity, endothelial function and cardiovascular health originates from strength training, which may serve as a substitute when whole-body aerobic exercise is contra-indicated or difficult to perform.

An integrated view of insulin resistance and endothelial dysfunction

Endothelial dysfunction and insulin resistance are frequently comorbid states. Vasodilator actions of insulin are mediated by phosphatidylinositol 3-kinase (PI3K)-dependent signaling pathways that stimulate production of nitric oxide from vascular endothelium. This helps to couple metabolic and hemodynamic homeostasis under healthy conditions. In pathologic states, shared causal factors, including glucotoxicity, lipotoxicity, and inflammation selectively impair PI3K-dependent insulin signaling pathways that contribute to reciprocal relationships between insulin resistance and endothelial dysfunction. This article discusses the implications of pathway-selective insulin resistance in vascular endothelium, interactions between endothelial dysfunction and insulin resistance, and therapeutic interventions that may simultaneously improve both metabolic and cardiovascular physiology in insulin-resistant conditions.

The effects of body mass index on cerebral blood flow velocity

OBJECTIVE

Obesity is a risk factor for cerebrovascular disease. We aimed to determine the effects of high body mass index (BMI) on cerebral blood flow regulation in patients with type-2 diabetes mellitus, hypertension, and stroke.

METHODS

We analyzed data from 90 controls, 30 diabetics, 45 hypertensives, and 32 ischemic stroke patients who underwent transcranial Doppler for evaluation of blood flow velocities (BFV) in the middle cerebral arteries (MCA) and cerebrovascular resistance (CVR) during supine rest and head-up tilt. This study was a cross-sectional analysis. We used a structural equation multiple indicators modeling to determine the effects of BMI and other background variables (age, sex, race, smoking, alcohol use, and systolic blood pressure) on cerebral BFV.

RESULTS

Higher BMI (P = 0.02) and age (P = 0.004) were associated with lower mean BFV during baseline, independent of diagnosis of diabetes mellitus, hypertension or stroke, and after adjusting for all background variables and vessel diameters. Men, especially those with stroke, had a lower mean BFV than women (P = 0.01). CVR increased with BMI (P = 0.001) at baseline and during head-up tilt (P = 0.02), and was elevated in obese subjects (P = 0.004) compared to normal weight subjects across all groups.

INTERPRETATION

High BMI is associated with a reduction in cerebral BFV and increased CVR. These findings indicate that obesity can adversely affect cerebral blood flow and resistance in the cerebrovascular bed, independent of diagnosis of type-2 diabetes, hypertension or stroke. Obesity may contribute to cerebromicrovascular disease, and affect clinical functional outcomes of the older population.

Subclinical atherosclerosis after heart and heart-lung transplantation in childhood

Children after heart transplantation are considered as at-risk patients for extracardiac atherosclerotic complications. Noninvasive ultrasound measurement of the common carotid artery (IMT) provides valid information about the endothelial structure of the vascular system. Twenty-two patients (17 male, mean age 12.4 +/- 4.5 yr) after heart and (5.7 +/- 4.5 yr) heart-lung transplantation were enrolled. The mean IMT was measured and compared with a control group (18 children, 10 male, mean age 11.8 +/- 1.8 yr) and to normative data. Transplanted children had a higher IMT than controls (0.453 +/- 0.003 vs. 0.424 +/- 0.002 mm, p < 0.001). IMT-SDS was increased as well (1.6 +/- 0.1 vs. 0.8 +/- 0, p < 0.001). Transplanted children had a higher LDL/HDL-ratio (2.2 +/- 0.2 vs. 1.2 +/- 0.1, p < 0.001). Time after transplantation, age at the time of transplantation, or medical therapy did not influence the findings. We found evidence for subclinical atherosclerosis in children after heart and heart-lung transplantation. Even if single atherosclerotic risk factors could not be identified, transplanted children seem to be at risk for atherosclerosis. Our findings support the recently published statement of the AHA-Expert panel: after heart transplantation atherosclerotic complications may occur with increased incidence. We propose the IMT-measurement in these patients as an easy method to assess the vascular status and to guide preventive measures.

Intima-media thickness of carotid artery and susceptibility to atherosclerosis in obese children with nonalcoholic fatty liver disease

OBJECTIVE

To test, via prospective case-control study, whether measurements of carotid artery intima-media thickness (cIMT) reflect the susceptibility to atherosclerosis in obese children with nonalcoholic fatty liver disease.

PATIENTS AND METHODS

In all, 80 obese asymptomatic normotensive adolescents (body mass index [BMI], 29.12 +/- 5.13; 8.5-17.5 years) and 30 age- and sex-matched nonobese healthy children (BMI 18.55 +/- 2.24). Children were analysed in 4 groups: Controls formed group 1, 26 children with obesity without hepatosteatosis formed group 2, 32 children with grade 1 hepatosteatosis formed group 3, and 22 children with grade 2 or 3 hepatosteatosis formed group 4. The key parameters were BMI, liver function tests, lipid profiles, glucose, hepatic ultrasonography, and IMT of common carotid artery (CCA), left carotid bulbus (CB), and left internal carotid artery (ICA).

RESULTS

Comparisons of IMT measurements of left CCA, left CB, and left ICA between controls and obesity group revealed statistically significant differences (each segment P < 0.0001). There was an increase in the mean of IMT of each segment with the increase in hepatosteatosis grade (each segment P < 0.0001). The relation between the mean of IMT of left CCA, left CB, and left ICA with BMI (P = 0.001, r = 0.318), alanine aminotransferase (P = 0.007, r = 0.256), and hepatosteatosis (P < 0.0001, r = 0.470) was significant. Multiple regression analysis between left CCA, left CB, and left ICA, and age, sex, relative weight, alanine aminotransferase, total cholesterol, obesity, and hepatosteatosis grade was significant for only hepatosteatosis grade.

CONCLUSIONS

The cIMT is significantly higher, increasing susceptibility to atherosclerosis, in obese children with hepatosteatosis than in healthy children or obese children without hepatosteatosis.

Arterial function in youth: window into cardiovascular risk

Noninvasive measures of arterial function, such as intima-media thickness (IMT), endothelial function, and arterial stiffness are associated with and are prognostic of cardiovascular events in adults. Postmortem evidence, however, has established that the atherosclerotic process starts in childhood. Furthermore, cardiovascular morbidities in childhood disrupt arterial health and may lead to adverse outcomes in adulthood. Thus it is important to examine the developmental changes in IMT, endothelial function, and arterial stiffness in healthy youth in contrast to the arterial health profile of youth with cardiovascular morbidities and to examine the effect of lifestyle interventions. In healthy youth, IMT may increase slightly, arterial stiffness increases, but there is no change in endothelial function from 5 to 20 years of age. In youth with cardiovascular risk factors there are larger increases in IMT and arterial stiffness, and reductions in endothelial function compared with healthy youth. The reduced arterial function in youth with cardiovascular risk factors may be related to the atherosclerotic process. Exercise and physical activity appear to exert a protective effect on arterial function, and exercise training can improve arterial function in children with cardiovascular risk factors. Furthermore, although diet alone can improve arterial function in children, the combination of exercise and diet appears to be more effective than either intervention alone. Future studies need to focus on the mechanism by which exercise and diet improve arterial function, the most effective types of diet and exercise, and if intervening in childhood leads to favorable outcomes in adulthood.