Association of fasting blood sugar level, insulin level, and obesity with left ventricular mass in healthy children and adolescents: The Bogalusa Heart Study

A three-dimensional atlas of child's cardiac anatomy and the unique morphological alterations associated with obesity

AIMS

Statistical shape models (SSMs) of cardiac anatomy provide a new approach for analysis of cardiac anatomy. In adults, specific cardiac morphologies associate with cardiovascular risk factors and early disease stages. However, the relationships between morphology and risk factors in children remain unknown. We propose an SSM of the paediatric left ventricle to describe its morphological variability, examine its relationship with biometric parameters and identify adverse anatomical remodelling associated with obesity.

METHODS AND RESULTS

This cohort includes 2631 children (age 10.2 ± 0.6 years), mostly Western European (68.3%) with a balanced sex distribution (51.3% girls) from Generation R study. Cardiac magnetic resonance short-axis cine scans were segmented. Three-dimensional left ventricular (LV) meshes are automatically fitted to the segmentations to reconstruct the anatomies. We analyse the relationships between the LV anatomical features and participants' body surface area (BSA), age, and sex, and search for features uniquely related to obesity based on body mass index (BMI). In the SSM, 19 modes described over 90% of the population's LV shape variability. Main modes of variation were related to cardiac size, sphericity, and apical tilting. BSA, age, and sex were mostly correlated with modes describing LV size and sphericity. The modes correlated uniquely with BMI suggested that obese children present with septo-lateral tilting (R2 = 4.0%), compression in the antero-posterior direction (R2 = 3.3%), and decreased eccentricity (R2 = 2.0%).

CONCLUSIONS

We describe the variability of the paediatric heart morphology and identify anatomical features related to childhood obesity that could aid in risk stratification. Web service is released to provide access to the new shape parameters.

Insulin resistance surrogates and left ventricular hypertrophy in normotensive obese children

BACKGROUND

The relationship between different surrogates of insulin resistance and left ventricular geometry in obese children is still unclear.

OBJECTIVE

We sought to explore the relationship between commonly used measures of insulin sensitivity/resistance (homeostatic model assessment index, serum uric acid, and triglycerides to high-density lipoprotein cholesterol ratio) and left ventricular geometry in normotensive obese children.

METHODS

In this cross-sectional study, 32 normotensive obese children were examined. Transthoracic echocardiography was used to measure left ventricular mass index and relative wall thickness. Homeostasis model assessment index, serum uric acid level, and a ratio of triglycerides to high-density lipoprotein cholesterol were used as markers of the insulin resistance. Simple and partial correlation analyses (to control for the effects of body mass index) were conducted to explore relationship between studied variables and left ventricular mass index or relative wall thickness as outcome variables.

RESULTS

We found positive correlations between homeostasis model assessment index and relative wall thickness (r = 0.47, p = 0.03) which remained significant after controlling for the effect of body mass index, z-score (r = 0.48, p = 0.03). The cutoff level of homeostasis model assessment index with the optimum sensitivity (Sn) and specificity (Sp) derived from the receiver operating characteristic (ROC) curves for predicting concentric remodelling was ≥5.51 with Sn = 83.33 and Sp = 68.75.

CONCLUSION

There is a positive relationship between homeostasis model assessment index and relative wall thickness of obese normotensive children which may help to distinguish at risk obese normotensive children for the development of concentric left ventricular remodelling.

Cardiovascular Health Promotion in Children: Challenges and Opportunities for 2020 and Beyond: A Scientific Statement From the American Heart Association

This document provides a pediatric-focused companion to "Defining and Setting National Goals for Cardiovascular Health Promotion and Disease Reduction: The American Heart Association's Strategic Impact Goal Through 2020 and Beyond," focused on cardiovascular health promotion and disease reduction in adults and children. The principles detailed in the document reflect the American Heart Association's new dynamic and proactive goal to promote cardiovascular health throughout the life course. The primary focus is on adult cardiovascular health and disease prevention, but critical to achievement of this goal is maintenance of ideal cardiovascular health from birth through childhood to young adulthood and beyond. Emphasis is placed on the fundamental principles and metrics that define cardiovascular health in children for the clinical or research setting, and a balanced and critical appraisal of the strengths and weaknesses of the cardiovascular health construct in children and adolescents is provided. Specifically, this document discusses 2 important factors: the promotion of ideal cardiovascular health in all children and the improvement of cardiovascular health metric scores in children currently classified as having poor or intermediate cardiovascular health. Other topics include the current status of cardiovascular health in US children, opportunities for the refinement of health metrics, improvement of health metric scores, and possibilities for promoting ideal cardiovascular health. Importantly, concerns about the suitability of using single thresholds to identify elevated cardiovascular risk throughout the childhood years and the limits of our current knowledge are noted, and suggestions for future directions and research are provided.

Review: Obesity and cardiometabolic syndrome in children

The cardiometabolic syndrome is highly prevalent among overweight youth. The risk of developing the cardiometabolic syndrome is likely triggered or exacerbated by concurrent obesity, unhealthy lifestyle/eating habits, and hormonal changes (puberty). Current screening recommendations include measurement of blood pressure, fasting insulin and glucose, and total cholesterol. However, limiting assessments to these measures underestimates cardiometabolic risk in overweight youth, particularly minorities. Early identification of cardiometabolic risk in its incipient stages may justify early and more aggressive intervention to prevent progression and complications. This review provides rationale for additional assessments to determine cardiometabolic risk in overweight youth and recommends treatment options.

Review: The metabolic syndrome as an endocrine disease: is there an effective pharmacotherapeutic strategy optimally targeting the pathogenesis?

The metabolic syndrome (MetS) represents a combination of cardiovascular risk determinants such as obesity, insulin resistance and lipid abnormalities such as hypertriglyceridemia, increased free fatty acids, low high-density-cholesterol and hypertension. As a multiple component condition it imparts a doubling of relative risk for atherosclerotic cardiovascular disease (ASCVD). It is currently controversial which component of the syndrome carries what weight. There is even a considerable debate whether the risk for ASCVD is greater in patients diagnosed with MetS than that by the individual risk factors. At present, no unifying pathogenetic mechanism can explain the metabolic syndrome and there is no unique treatment for it. This review summarizes and critically reviews the currently available clinical and scientific evidence for the concept that the MetS is causally an endocrine disease and discusses pharmacotherapeutic strategies targeting the pathogenesis rather than single symptoms of the cluster.

Developmental Origins of Common Disease: Epigenetic Contributions to Obesity

The perinatal period is a window of susceptibility for later life disease. Recent epigenetic findings are beginning to increase our understanding of the molecular mechanisms that may contribute to the programming of obesity. This review summarizes recent evidence that supports the role of epigenetically mediated early life programming in the later onset of obesity. Establishing such links between environmental exposures and modifiable molecular changes ultimately holds promise to inform interventional efforts toward alleviating the environmentally mediated onset of obesity.

Childhood Obesity: Causes, Consequences, and Management

One-third of North American children are overweight or obese. Pathologic obesity accounts for only a small percentage of these cases. The vast majority are the result of a complex interaction of genetic and hormonal, nutritional, physical activity, and physical and social environmental factors. Obesity increases the risk for various cardiometabolic, pulmonary, and psychosocial complications for children, which often continues into adulthood. Multidisciplinary care, focusing on family-centered behavior change, is an evidence-based, essential part of the treatment, along with pharmacologic and surgical options for more complex cases. Prevention and early intervention strategies are key to reversing the obesity epidemic.

Alterations in left ventricular, left atrial, and right ventricular structure and function to cardiovascular risk factors in adolescents with type 2 diabetes participating in the TODAY clinical trial

Data on cardiovascular disease (CVD) risk in adolescents with type 2 diabetes (T2D) are limited. Echocardiography was performed in the last year of the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) clinical trial (median 4½ yr from diagnosis of T2D, average age 18 yr), including MMode and 2D measurements of left ventricular (LV) and left atrial (LA) dimensions, LV tissue Doppler imaging (TDI), and tricuspid annular plane systolic excursion (TAPSE). Relationships between cardiac structure and function with demographic characteristics and baseline and change-from-baseline in CVD risk factors were examined in 455 participants. Mean LV mass (LVM) was high/normal and 16.2% had adverse LV geometry (8.1% concentric geometry, 4.5% LV hypertrophy, and 3.6% both). Determinants of higher LVM were male gender, black race, baseline and increasing body mass index (BMI), baseline and increasing systolic blood pressure (SBP), use of blood pressure (BP) medications, maintenance of glycemic control, and smoking; heart rate (HR) was inversely related. LV shortening fraction was high/normal and related to increasing BMI and higher baseline SBP. LV relative wall thickness was related to race-ethnicity, change in BMI, baseline glycated hemoglobin (HbA1c), and baseline and change in SBP. Mean LA internal dimension was high/normal and gender, baseline and increasing BMI, increasing SBP, and HR (inverse) were related. LV TDI was positively related to obesity (higher with adverse geometry). TAPSE was normal and related to higher baseline BMI and lower HR. There was no effect of T2D treatment on cardiac target organ injury. Adolescents with T2D have adverse measures of cardiac structure and function positively related to BMI and BP.

Impact of adiposity on cardiac structure in adult life: the Childhood Determinants of Adult Health (CDAH) study

BACKGROUND

We have examined the association between adiposity and cardiac structure in adulthood, using a life course approach that takes account of the contribution of adiposity in both childhood and adulthood.

METHODS

The Childhood Determinants of Adult Health study (CDAH) is a follow-up study of 8,498 children who participated in the 1985 Australian Schools Health and Fitness Survey (ASHFS). The CDAH follow-up study included 2,410 participants who attended a clinic examination. Of these, 181 underwent cardiac imaging and provided complete data. The measures were taken once when the children were aged 9 to 15 years, and once in adult life, aged 26 to 36 years.

RESULTS

There was a positive association between adult left ventricular mass (LVM) and childhood body mass index (BMI) in males (regression coefficient (β) 0.41; 95% confidence interval (CI): 0.14 to 0.67; p = 0.003), and females (β = 0.53; 95% CI: 0.34 to 0.72; p < 0.001), and with change in BMI from childhood to adulthood (males: β = 0.27; 95% CI: 0.04 to 0.51; p < 0.001, females: β = 0.39; 95% CI: 0.20 to 0.58; p < 0.001), after adjustment for confounding factors (age, fitness, triglyceride levels and total cholesterol in adulthood). After further adjustment for known potential mediating factors (systolic BP and fasting plasma glucose in adulthood) the relationship of LVM with childhood BMI (males: β = 0.45; 95% CI: 0.19 to 0.71; p = 0.001, females: β = 0.49; 95% CI: 0.29 to 0.68; p < 0.001) and change in BMI (males: β = 0.26; 95% CI: 0.04 to 0.49; p = 0.02, females: β = 0.40; 95% CI: 0.20 to 0.59; p < 0.001) did not change markedly.

CONCLUSIONS

Adiposity and increased adiposity from childhood to adulthood appear to have a detrimental effect on cardiac structure.

Left ventricular hypertrophy and insulin resistance in adults from an urban community in The Gambia: cross-sectional study

Objective

To determine the association between left ventricular hypertrophy and insulin resistance in Gambians.

Design

Cross-sectional study.

Setting

Outpatient clinics of Royal Victoria Teaching Hospital and Medical Research Council Laboratories in Banjul.

Participants

Three hundred and sixteen consecutive patients were enrolled from outpatient clinics. The data of 275 participants (89 males) were included in the analysis with a mean (± standard deviation) age of 53.7 (±11.9) years.

Interventions

A questionnaire was filled and anthropometric measurements were taken. 2-D guided M-mode echocardiography, standard 12-1ead electrocardiogram, fasting insulin and the oral glucose tolerance test were performed.

Main Outcome Measures

The Penn formula was used to determine the left ventricular mass index, 125 g/m² in males and 110 g/m² in females as the cut-off for left ventricular hypertrophy. Using the fasting insulin and fasting glucose levels, the insulin resistance was estimated by the homeostatic model assessment formula. Logistic regression analysis was used to determine the association between left ventricular hypertrophy and insulin resistance.

Results

The mean Penn left ventricular mass index was 119.5 (±54.3) and the prevalence of Penn left ventricular mass index left ventricular hypertrophy was 41%. The mean fasting glucose was 5.6 (±2.5) mmol/l, fasting insulin was 6.39 (±5.49) μU/ml and insulin resistance was 1.58 (±1.45). There was no association between Penn left ventricular mass index left ventricular hypertrophy and log of insulin resistance in univariate (OR = 0.98, 95% CI = 0.80 – 1.19, p = 0.819) and multivariate logistic regression (OR = 0.93, 95% CI = 0.76–1.15, p = 0.516) analysis.

Conclusion

No association was found in this study between left ventricular hypertrophy and insulin resistance in Gambians and this does not support the suggestion that insulin is an independent determinant of left ventricular hypertrophy in hypertensives.

Associations of cardiac structure with obesity, blood pressure, inflammation, and insulin resistance in African-American adolescents

To determine if obesity, blood pressure (BP), markers of inflammation, and insulin resistance are associated with cardiac structure in African-American adolescents, a cross-sectional study was performed on a cohort oversampled for high BP and obesity. Measurements included the following: anthropometrics, BP, homeostasis model assessment (HOMA) to assess insulin resistance, high-sensitivity C-reactive protein, and plasma adipokines (adiponectin, interleukin-6, plasminogen activator inhibitor-1). Echocardiogram measurements were left-ventricular mass index (LVMI) (g/m(2.7)), LV relative wall thickness (LVRWT), left-atrial diameter index [LADI (mm/m)], and LV diastolic time intervals. LADI (r (2) = 0.25) was associated with body mass index (BMI) systolic BP (SBP) and female sex. LVMI (r (2) = 0.35) variation was associated with BMI SBP, heart rate, age, and male sex. LVRWT (r (2) = 0.05) was associated with HOMA. Tissue diastolic intervals were not associated with any risk factor. Inflammatory markers and adipokines were associated with BMI but were not independently associated with any echocardiographic measures. In African-American adolescents, BMI and SBP, but not inflammatory markers or adipokines, are important correlates of LA size and LVM.

Association of cardiac changes with serum adiponectin and resistin levels in obese and overweight children

OBJECTIVES

To investigate serum adiponectin and resistin levels in childhood obesity and their relationship with cardiac changes and insulin resistance.

METHODS

Seventy-one obese and 24 overweight children and 40 healthy children and adolescents were selected for the study. Height and weight measurements, BMI values and BMI SD score values were obtained for each individual. After blood pressure measurement, left ventricular wall thickness, left ventricular mass, stroke volume, cardiac output, systolic and diastolic functions of the left ventricle were measured using an M-mode, two dimensional color-coded echocardiography device. Blood samples of the individuals were obtained for fasting blood sugar, total blood cholesterol, triglyceride, low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, insulin, C-peptide, adiponectin and resistin values.

RESULTS

Cholesterol and LDL values, homeostasis model assessment of insulin resistance, fasting insulin and fasting C-peptide values of the obese and overweight groups were higher (P<0.01). Adiponectin level (P<0.001) and resistin level (P<0.05) of the obese and overweight groups were lower than those of the control group (P<0.05). Echocardiographic evaluation showed diastolic dysfunction in addition to increased left ventricular wall thickness and left ventricle mass values in the obese and overweight children. We also detected a significant positive correlation among left ventricular mass, interventricular septum systolic diameter and resistin in obese children. Among the factors, resistin level was determined as an independent predictor of left ventricular mass in obese children.

CONCLUSION

In this study, even in asymptomatic obese and overweight children, cardiac structural and functional changes, such as increased left ventricular mass and diastolic dysfunction, were demonstrated. Although decreased adiponectin level was not related to cardiac changes, it was shown that decreased serum resistin levels in the obese cases lead to left ventricle hypertrophy.

Cardiac function and lipid distribution in rats fed a high-fat diet: in vivo magnetic resonance imaging and spectroscopy

Obesity is a major risk factor in the development of cardiovascular disease, type 2 diabetes, and its pathophysiological precondition insulin resistance. Very little is known about the metabolic changes that occur in the myocardium and consequent changes in cardiac function that are associated with high-fat accumulation. Therefore, cardiac function and metabolism were evaluated in control rats and those fed a high-fat diet, using magnetic resonance imaging, magnetic resonance spectroscopy, mRNA analysis, histology, and plasma biochemistry. Analysis of blood plasma from rats fed the high-fat diet showed that they were insulin resistant (P < 0.001). Our high-fat diet model had higher heart weight (P = 0.005) and also increasing trend in septal wall thickness (P = 0.07) compared with control diet rats. Our results from biochemistry, magnetic resonance imaging, and mRNA analysis confirmed that rats on the high-fat diet had moderate diabetes along with mild cardiac hypertrophy. The magnetic resonance spectroscopy results showed the extramyocellular lipid signal only in the spectra from high-fat diet rats, which was absent in the control diet rats. The intramyocellular lipids in high-fat diet rats was higher (8.7%) compared with rats on the control diet (6.1%). This was confirmed by electron microscope and light microscopy studies. Our results indicate that lipid accumulation in the myocardium might be an early indication of the cardiovascular pathophysiology associated with type 2 diabetes.

The relationship between metabolic syndrome and left ventricular mass index in obese children

OBJECTIVE

To investigate the relationships between metabolic syndrome (MS), other metabolic features and left ventricular mass index (LVMI) in a population of obese children and adolescents with MS.

METHODS

Two hundred and eight obese children and adolescents (119 females and 89 males, mean age: 11.9±2.7 years) and control subjects (24 females and 26 males, mean age: 11.4±2.9 years) were enrolled in the study. The insulin sensitivity index and LVMI were determined. The International Diabetes Federation criteria were used to diagnose MS.

RESULTS

The obese patients were divided into MS group (n=55) and non-MS (n=153) group. The values of LVMI in the MS group were significantly higher than those in the non-MS group (p=0.014). The present LVMI cut-off point of 33 g/m² for the diagnosis of MS yielded a sensitivity of 97% and a specificity of 98%. LVMI was found to be positively correlated in univariate analysis with height, weight, body mass index (BMI) SDS, fasting insulin level, homeostasis model assessment of insulin resistance (HOMA-IR) and fasting glucose to insulin ratio (FGIR) and negatively correlated with quantitative insulin sensitivity check index (QUICK-I).

CONCLUSIONS

We suggest that our optimal LVMI cut-off value for identifying MS may be considered as a sensitive index in screening obese children and adolescents for pediatric MS. Assessment of LVMI in obese children and adolescents may be used as a tool in predicting the presence of MS and its associated cardiovascular risks.

Wrist circumference is a clinical marker of insulin resistance in overweight and obese children and adolescents

BACKGROUND

Excess fat is one of the main determinants of insulin resistance, representing the metabolic basis for developing future cardiovascular disease. The aim of the current study was to find an easy-to-detect clinical marker of insulin resistance which can be used to identify young subjects at increased risk of cardiovascular disease.

METHODS AND RESULTS

Four-hundred and seventy-seven overweight/obese children and adolescents (mean age 10.31±2.80 years) were consecutively enrolled. Standard deviation score body mass index, fasting biochemical parameters, and homeostasis model assessment of insulin resistance were evaluated. Statistical differences were investigated using multiple linear regression analysis. Manual measure of wrist circumference was evaluated in all children and adolescents. Fifty-one subjects, randomly selected, underwent nuclear magnetic resonance imaging of the wrist to evaluate transversal wrist area at the Lister tubercle level. A statistically significant association was found between manual measure of wrist circumference and insulin levels or homeostasis model assessment of insulin resistance (β=0.34 and 0.35, respectively; P<10(-5) for both comparisons). These associations were more significant than those between SD score body mass index and insulin levels or homeostasis model assessment of insulin resistance (β=0.12 and 0.10, respectively; P≤0.02 for both comparisons). Nuclear magnetic resonance imaging acquisition clarified that the association between wrist circumference and insulin levels or homeostasis model assessment of insulin resistance reflected the association with bone tissue-related areas (P≤0.01 for both) but not with the adipose tissue ones (P>0.05), explaining 20% and 17% of the variances of the 2 parameters.

CONCLUSIONS

Our findings suggest a close relationship among wrist circumference, its bone component, and insulin resistance in overweight/obese children and adolescents, opening new perspectives in the prediction of cardiovascular disease.

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.

Waist circumference leads to prolonged microvascular reactive hyperemia response in young overweight/obese women

OBJECTIVES

Previous data in our laboratory have shown microvascular dysfunction in normoglycaemic subjects with metabolic syndrome (MS). In a step further, we have investigated which clinical parameters related or not to MS would elicit microvascular dysfunction and the need of diagnosing MS for the establishment of microcirculatory impairment in overweight/obese women.

METHODS

Nineteen lean [23.6±3.1years, body mass index (BMI) 21.9±1.8kg/m(2)] and 59 overweight/obese [24.6±3.7years; BMI 34.4±5.9kg/m(2)] sedentary non-smoking women, divided in overweight/obese without (MS negative, n=36) and obese with MS (MS positive, n=23) were evaluated. Blood biochemistry, HOMA-IR index and anthropometric variables were determined. Morphological (capillary diameters) and functional [functional capillary density, red blood cell velocity (RBCV) at baseline and peak and time (TRBCV(max)) to reach it during post-occlusive reactive hyperemia after 1min ischemia] microcirculatory variables were examined by nailfold videocapillaroscopy.

RESULTS

Compared to controls, overweight/obese MS negative and obese MS positive presented longer TRBCV(max); the presence of two MS components was sufficient to prolong it and the MS diagnosis did not add any significant impairment to the microcirculation. Among clinical parameters investigated, a direct relationship between TRBCV(max) and waist circumference and insulin concentrations was found.

CONCLUSION

Our results have shown that microvascular dysfunction is independent of metabolic syndrome diagnosis and could be predicted by the waist circumference on young overweight/obese women, reinforcing the relationship between obesity-related microvascular/metabolic disturbances.

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.

[Obesity in schoolchildren from Merida, Venezuela: association with cardiovascular risk factors]

OBJECTIVE

To investigate the prevalence of obesity and associated cardiovascular risk factors in schoolchildren in our city, given the influence of these factors on the development of atherosclerosis.

METHODS

We studied a representative sample of second grade students composed of 370 children aged 7.82+/-0.62 years (47.8% girls and 52.2% boys); 52.4% were from public schools and 47.6% were from private schools. Surveys were performed and anthropometric measurements, blood pressure (BP) values and glucose and lipid profiles in capillary blood were determined.

RESULTS

A total of 9.7% (36 schoolchildren) were obese and 13.8% were overweight. There were no differences according to sex or school system. Abdominal obesity was observed in 69.4% (p<0.0001), normal-high BP (90-97th percentile) in 27.8% (p<0.0001), dyslipidemia in 66.7% (p<0.05) and metabolic syndrome in 38.9% (p<0.0001) of the obese children compared with 1.3%, 5.1%, 48.9% and 0.4% of the children with normal weight, respectively. No association was found between fasting hyperglycemia and obesity. There were no cases of hypertension or diabetes mellitus. The risk (odds ratio) for normal-high BP, dyslipidemia, abdominal obesity and metabolic syndrome was 6.3, 2.2, 60.9, and 70.2 times higher in obese children than in non-obese children, respectively. A positive and significant correlation was found between waist circumference and body mass index with BP and the atherogenic indexes triglycerides/high-density lipoprotein cholesterol (HDL-C), total cholesterol/HDL-C and low-density lipoprotein cholesterol/HDL-C (p=0.0001).

CONCLUSIONS

Compared with cities in other countries, the city of Mérida, Venezuela, has an intermediate prevalence of overweight and obesity in schoolchildren. The high frequency of cardiovascular risk factors in the obese and its positive correlation with adiposity highlights the need to implement population-based strategies for its prevention in childhood.

Determinants of left ventricular mass and presence of metabolic risk factors in normotensive individuals

BACKGROUND

Insulin resistance and obesity are recognized as left ventricular (LV) mass determinants independent of blood pressure (BP). Prevalence of LV hypertrophy (LVH) and the relationship between LV mass to body composition and metabolic variables were evaluated in normotensive individuals as participants of a population-based study.

METHODS

LV mass was measured using the second harmonic image by M-mode 2D guided echocardiography in 326 normotensive subjects (mean 47+/-9.4 years). Fasting serum lipids and glucose, BP, body composition and waist circumference (WC) were recorded during a clinic visit.

RESULTS

Applying a normalization criterion not related to body weight (g/height raised to the power 2.7) and the cut-off points of 47.7 (men) and 46.6 g/m(2.7) (women), LVH was found in 7.9% of the sample. Univariate analysis showed LV mass (g/m(2.7)) related to age, body mass index (BMI), WC, fat and lean body mass, systolic and diastolic BP, and metabolic variables (cholesterol, HDL-c, triglycerides and glucose). In multivariate analysis only BMI and age-adjusted systolic BP remained as independent predictors of LV mass, explaining 31% and 5% of its variability. Removing BMI from the model, WC, age-adjusted systolic BP and lean mass remained independent predictors, explaining 25.0%, 4.0% and 1.5% of LV mass variability, respectively. After sex stratification, LV mass predictors were WC (8%) and systolic BP (5%) in men and WC (36%) and systolic BP (3%) in women.

CONCLUSION

BMI in general and particularly increased abdominal adiposity (WC as surrogate) seems to account for most of LV mass increase in normotensive individuals, mainly in women.

Cardiac markers of pre-clinical disease in adolescents with the metabolic syndrome: the strong heart study

OBJECTIVES

Our aim was to evaluate the impact of metabolic syndrome (MetS) on cardiac phenotype in adolescents.

BACKGROUND

A high prevalence of MetS has been reported in adolescents.

METHODS

Four hundred forty-six nondiabetic American Indian adolescents (age 14 to 20 years, 238 girls) underwent clinical evaluation, laboratory testing, and Doppler echocardiography. Age- and gender-specific partition values were used to define obesity and hypertension. Metabolic syndrome was defined according to Adult Treatment Panel III criteria, modified for adolescents. Left ventricular (LV) hypertrophy and left atrial (LA) dilation were identified using age- and gender-specific partition values.

RESULTS

One hundred eleven participants met criteria for MetS. They had a similar age and gender distribution as non-MetS participants. Analysis of covariance, controlling for relevant confounders, demonstrated that participants with MetS had higher LV, LA, and aortic root diameters, higher LV relative wall thickness, and greater LV mass index. Accordingly, MetS participants showed higher prevalences of LV hypertrophy (43.2% vs. 11.7%) and LA dilation (63.1% vs. 21.9%, both p < 0.001) compared with non-MetS participants. In addition, MetS was associated with a reduction in midwall shortening, lower transmitral mitral early to atrial peak velocity ratio, and mildly prolonged mitral early deceleration time (all p < 0.05). In multiple regression analysis, independently of demographics, obesity, blood pressure, and single metabolic components of MetS, clustered MetS was associated with a 2.6-fold higher likelihood of LV hypertrophy and a 2.3-fold higher likelihood of LA dilation (both p < or = 0.02).

CONCLUSIONS

In a population sample of adolescents, MetS is associated with higher prevalences of LV hypertrophy and LA dilation and with reduced LV systolic and diastolic function, independently of individual MetS components.

The triglyceride/HDL-cholesterol ratio as a marker of cardiovascular risk in obese children; association with traditional and emergent risk factors

OBJECTIVES

To determine the presence of traditional and emergent cardiovascular risk factors and to evaluate the triglyceride/high-density lipoprotein cholesterol (Tg/HDL-C) ratio as a marker for cardiovascular disease and metabolic syndrome (MS) in obese children.

MATERIAL AND METHODS

Sixty-seven prepubertal children of both sexes, between the ages of 6 and 12 yr, 20 normal-weight children, 18 overweight, and 29 obese subjects, were studied. Anthropometric measures, blood pressure, body mass index (BMI), and fat mass (FM), were measured. Plasma glucose, serum insulin, lipid profile, C-reactive protein (CRP), and leptin concentrations were quantified. Glucose and insulin concentrations 2 h post-glucose load were determined. The Tg/HDL-C ratio, homeostasis model assessment index (HOMA), and quantitative insulin sensitivity check index (QUICKI) were calculated.

RESULTS

Systolic, diastolic, and mean blood pressures (MBP), low-density lipoprotein cholesterol (LDL-C), Tg/HDL-C, total cholesterol/HDL-C, LDL-C/HDL-C ratios, basal and 2 h postload insulin, CRP, and leptin were significantly higher and the QUICKI index were lower in the obese group. MBP, Tg/HDL-C ratio, HOMA, CRP, and leptin levels showed a positive and significant correlation and QUICKI a negative correlation with abdominal circumference, BMI, and FM. The Tg/HDL-C ratio correlated positively with MBP. The frequency of MS in the obese group was 69%. While Tg/HDL-C ratio, CRP, and leptin were higher and the values of QUICKI were lower in subjects with MS, it was the Tg/HDL-C ratio and the BMI that significantly explained the MS.

CONCLUSIONS

Obesity increases the cardiovascular risk in childhood. The Tg/HDL-C ratio could be a useful index in identifying children at risk for dyslipidemia, hypertension, and MS.

Early cardiac abnormalities in obese children: importance of obesity per se versus associated cardiovascular risk factors

We investigated whether obese children and adolescents have early echocardiographic signs of subclinical cardiac dysfunction and evaluated the respective influence of obesity per se versus parameters of carbohydrate and lipid metabolism that are frequently abnormal in obese subjects. The role of tissue Doppler imaging as a screening tool for these abnormalities was explored. Blood pressure and echocardiographic parameters, including tissue Doppler measurements of the septal mitral annulus were evaluated in 49 obese children and adolescents and 45 age and sex matched controls. The respective influence of obesity versus parameters of carbohydrate and lipid metabolism was examined with linear regression analysis. Obese subjects showed significantly larger left ventricular wall dimensions (posterior wall, septum, and left ventricular mass index) and signs of early diastolic filling abnormalities on conventional and tissue Doppler echocardiography compared with nonobese subjects. Multiple regression analysis showed that mainly BMI-SD scores and/or body surface area explained significant proportions of the variance of the early cardiac abnormalities. In conclusion, young, obese children and adolescents have significant changes in left ventricular wall dimensions and early diastolic filling compared with nonobese subjects. Obesity per se and not the parameters of carbohydrate and lipid metabolism predicted the early cardiac abnormalities.

Effect of diet and physical exercise treatment on insulin resistance syndrome of schoolchildren

BACKGROUND

Insulin resistance syndrome (IRS) of schoolchildren may contribute to cardiovascular diseases (CVD) of young adults. The investigation of different steps, baseline screening parameters and treatment of IRS may help the prevention.

METHODS

Schoolchildren (53 boys and 61 girls age 5-17 years) because of adverse family history of CVD, hypertension, and obesity were investigated. Patients were divided into 3 groups according to baseline plasma glucose level (PGL) 120 and 180 min. after glucose consumption (GC): (1) PGL < or = 5.5 mmol/L 180 min. after GC, (2) PGL > or = 5.5 mmol/L 180 min. but < or = 7.8 mmol/L 120 min. after GC (3) PGL > or = 7.8 mmol/L 120 min. after GC. Body mass index (BMI), blood pressure (BP) and parameters of glucose and lipid metabolism were measured at baseline and after two year's lifestyle modification.

RESULTS

No significant difference was found in the prevalence of cardiovascular risk factors (CRF) between groups 2 and 3. Fasting PGL > 5.5 mmol/L was found in 1, 2, and 6 cases; HOMA index > 4.4 in 7 (24%), 21 (37%), and 9 (35%) subjects; OGIS index < 400 in 3(10%), 29(51%) and 11 (42%) schoolchildren of groups 1, 2, 3, respectively. Lifestyle modification significantly improved BMI, systolic BP, serum triglyceride and HDL-cholesterol levels and insulin sensitivity.

CONCLUSIONS

PGL measured 180 minutes after GC may define an important subgroup of pre-diabetic children. The similar prevalance of CRF in both praediabetic groups underlines the importance of this subgroup. Lifestyle modification for two years improves CRF in this population.

Anthropometric reference values in an Afro-Caribbean adolescent population

Childhood and adolescent obesity is increasingly becoming a major public health issue in the Caribbean. In this study, we analyze patterns of growth in a population of Afro-Caribbean adolescents 12-18 years old and to compare these with those established for US adolescents. A cross-section of adolescent schoolchildren had weight and height measured using standardized procedures. In addition, percentage body fat (% BF) was measured using a foot-to-foot bioelectric impedance body fat analyzer (Tanita model 531). Selected age- and gender- specific percentiles of BMI, %BF, weight and height were derived and smoothed by cubic splines. These were compared with similar percentiles from US adolescent growth data. A total of 3,707 adolescents (1,585 males; 2,122 females) participated in the study. The age-specific correlation between BMI and %BF ranged from 0.75 to 0.87 in males and 0.79 to 0.87 in females. Females had significantly higher %BF than males in each age category. Overall, Tobagonian females were heavier and had higher BMI than their US counterparts especially levels above the median percentiles. Tobagonian males had similar height, weight, and BMI to their US counterparts over the range of percentiles. Overall, the pattern of growth in this group of adolescents suggests that they are growing at rates that are comparable to those seen in a more well-nourished population.

Noninvasive assessment of target organ injury in children with the metabolic syndrome

The prevalence of overweight has increased sharply since the 1980s, with morbid obesity rising at an even higher rate. Comorbidities related to adiposity now consume almost 10% of all US health care dollars. Unfortunately, overweight children already demonstrate elevations in cardiovascular risk factors. These children are extremely likely to remain obese in adulthood and are likely to progress to diabetes and heart and kidney diseases. It is not surprising, therefore, that the diagnosis of the metabolic syndrome is being made with increasing frequency in American adolescents. The authors show that noninvasive methods are now available to measure target organ damage related to obesity and the metabolic syndrome in children. They explore the data linking the cardiovascular risk factors that cluster as the metabolic syndrome to early subclinical atherosclerotic change such as left ventricular hypertrophy, carotid intima-media thickness, vascular function abnormalities, and microalbuminuria. Evidence for the benefits of treatment and guidelines for the assessment for target organ damage in children are provided.

Obesity—A Critical Issue in Preventive Cardiology: The Bogalusa Heart Study

Obesity has become a major public health problem in the United States, with a marked upward trend occurring over the past three decades. It plays a critical role in the development of cardiovascular risk factors that mediate the evolution of asymptomatic cardiovascular disease. Longitudinal observations of children, adolescents, and young adults enrolled in the Bogalusa Heart Study show that obesity persists over time and is linked to the clustering of components of metabolic syndrome including hyperinsulinemia/insulin resistance, dyslipidemia, and hypertension, thereby creating a long-term burden of cardiovascular risk beginning in childhood. This burden is associated with subclinical and adverse structural and functional changes of the cardiovascular system in youth. Ultimately, these changes can result in morbidity from disease, as exemplified in the Framingham Heart Study. Obesity is governed by the interplay of both genetic and environmental factors. Unlike genetic factors, lifestyle behaviors are amenable to modification. Since obesity is so widespread and underlying cardiovascular disease is so prevalent, health education beginning in childhood is suggested as an approach to prevention.

Cardiovascular complications of obesity in adolescents

Obesity is an increasingly important worldwide health problem, representing the major risk factor for coronary heart disease. The increase in the prevalence of obesity, particularly among younger age groups, is likely to have long-term implications for cardiovascular disease (CVD) in the years to come, especially at a young age. Obesity plays a central role in the insulin resistance (IR) syndrome and increases the risk of atherosclerotic CVD. The present review will examine the relationships among cardiovascular risk (CVR) factors during the childhood-adolescence-adulthood transition. In fact, the relation between obesity, in particular visceral obesity and CVD, appears to develop at a relatively young age. The foremost physical consequence of obesity is atherosclerotic CVD, and an intriguing example of obesity-related cardiovascular complications affecting young women is the polycystic ovary syndrome (PCOS).

Obesity and obstructive sleep apnea in children

The prevalence and severity of obesity in children and adolescent is dramatically increasing worldwide with a corresponding increase in the prevalence of obesity-associated morbidities particularly those involving OSAS and metabolic and cardiovascular sequelae. Obstructive sleep apnea and obesity hypoventilation syndrome are important and serious consequences of obesity, and may in fact mediate components of the association between obesity and metabolic and cardiovascular morbidities, most likely via potentiation of inflammatory cascades. It is anticipated that the increased prevalence of obesity in children and adolescents in our society will be accompanied by a steady increase in the incidence of OSAS. In this review, we will examine our current understanding of sleep-disordered breathing and associated morbidities in obese children, and summarize the range of therapeutic modalities currently available for this high-risk population.

The association of left ventricular mass with blood pressure, cigarette smoking and alcohol consumption; data from the LARGE Heart study

BACKGROUND

Left ventricular mass is a risk factor for cardiovascular morbidity and mortality. Although factors associated with elevated left ventricular mass have been sought and studied extensively in elderly and in diseased subjects, few studies have examined the young and healthy. The aim of this study was to examine the possible influence of lifestyle on left ventricular mass in a large group of young men.

METHODS

Left ventricular mass was assessed using cardiovascular magnetic resonance in 541 healthy Caucasian male army recruits. Anthropometric, lifestyle and blood pressure data were collected.

RESULTS

Mean unadjusted left ventricular mass and left ventricular mass indexed to body surface area were 163.8+/-24.9 g and 86.6+/-10.2 g m(-2) respectively. In univariate analysis, age, height, weight, alcohol consumption, systolic blood pressure, diastolic blood pressure and indices of physical activity were positively associated with unadjusted left ventricular mass (all P<0.02). By contrast, smoking was associated with lower mean left ventricular mass; never smoked 167.5+/-25.8 g vs ex-smokers 159.1+/-25.2 g vs current smokers 161.0+/-23.1 g (P=0.007). Multivariate analysis revealed weight, systolic blood pressure, smoking status and indices of physical activity to be independent predictors of left ventricular mass.

CONCLUSIONS

Our data confirm an association of age, body weight, height, physical activity, diastolic and systolic blood pressure with left ventricular mass. In addition, unexpectedly, we have found smoking is associated with lower left ventricular mass in a large sample of young healthy men. Although the latter association may result from confounding effects, such an interesting observation deserves further investigation.

Relation of increase in adiposity to increase in left ventricular mass from childhood to young adulthood

This study evaluated the influence of adiposity on the progression of left ventricular (LV) mass from childhood to adulthood and the relation of LV mass to insulin resistance in young adulthood. One hundred thirty-two healthy children recruited into a longitudinal study at a mean age of 13 years and reevaluated at 27 years, at which time insulin resistance studies were also performed, were studied. Echocardiographic assessment of LV mass was made and indexed for height. Body mass index (BMI) at 13 years was highly correlated with BMI at 27 years, as was LV mass index at 13 and 27 years. The cross-sectional correlation of LV mass index and BMI at 13 years (r = 0.38, p < 0.0001) had strengthened considerably by 27 years (r = 0.55, p < 0.0001). A BMI increase > or = 5.5 kg/m2 from 13 to 27 years was associated with a significantly greater increase in the LV mass index (p < 0.0001) than a BMI change < 5.5 kg/m2, and this relation was similar in children who were thin and heavy at baseline. In young adulthood, the relation of LV mass index to lean mass was weaker than that of LV mass index to fat mass. The association of LV mass with insulin resistance was dependent on adiposity. In conclusion, adiposity and LV mass are related in childhood, and this association tracks and becomes stronger in young adulthood. Moreover, the increase in LV mass from childhood to young adulthood is related to the degree of increase in BMI, independent of BMI at 13 years, suggesting that an excessive increase in LV mass could be limited by controlling gain in body fat during adolescence.

The influence of lifestyle on cardiovascular risk factors. Analysis using a neural network

The cardiovascular pathologies are the most common causes of death in the elderly patient. To single out the main risk factors in order to effectively prevent the onset of the disease, the authors experimented a special computerized tool, the neural network, that works out a mathematical relation that can obtain certain data (defined as output) as a function of other data (defined as input). Data were processed from a sample of 276 subjects of both sexes aged 26-69 years old. The output data were: high/low cholesterolemia, HDL cholesterol, triglyceridemia with respect to an established cut-off; the input data were: sex, age, build, weight, married/single, number of children, number of cigarettes smoked/day, amount of wine and number of cups of coffee. We conclude that: (i) a relationship exists, deduced from a neural network, between a set of input variables and a dichotomous output variable; (ii) this relationship can be expressed as a mathematical function; (iii) a neural network, having learned the data on a sufficiently large population, can provide valid predictive data for a single individual with a high probability (up to 93.33%) that the response it gives is correct. In this study, such a result is found for two of the three cardiovascular risk indicators considered (cholesterol and triglycerides); (iv) the repetition of the neural network analysis of the cases in question after a "pruning" operation provided a somewhat less good performance; (v) a statistical analysis conducted on those same cases has confirmed the existence of a strong relationship between the input and the output variables. Therefore the neural network is a valid instrument for providing predictive in a single subject on cardiovascular pathology risks.

Overweight in children: definitions, measurements, confounding factors, and health consequences

The epidemic of childhood overweight continues to grow at staggering rates, increasing nearly four-fold between 1963 and 2000. Children that are overweight are more apt to be overweight adults and are more likely to suffer adverse health consequences associated with excess weight. Nurses have a unique presence in the healthcare environment to assess children for overweight, provide parent/child nutritional education, and conduct obesity-related research. This article provides an overview of the current body of literature surrounding the definition and measurement of overweight and the morbidity association with childhood overweight.

Insulin resistance syndrome in children : pathophysiology and potential management strategies

The simultaneous presence of various cardiovascular risk factors in the same individual is not rare, even in the pediatric age group. The clustering of risk factors can be termed insulin resistance syndrome (IRS) because of the putative central role of tissue insulin insensitivity in the background of the inter-related metabolic disturbances. Fasting hyperinsulinemia, impaired glucose tolerance, dyslipidemia, and hypertension are considered to represent the basic abnormalities of IRS. The most prevalent related disturbances are increased plasma levels of plasminogen activator inhibitor-1, fibrinogen, uric acid, homocysteine, and C-reactive protein, as well as visceral adiposity, microalbuminuria, disturbed essential fatty acid metabolism, low availability of lipid-soluble antioxidant vitamins, and enhanced expression of tumor necrosis factor-alpha in adipose tissues. Certain genetic abnormalities have been associated with IRS, but explain only a small part of the variability in insulin resistance. The exact prevalence of IRS in children remains to be defined; it was found to be 9% in one survey among children with obesity seeking medical attention. Modification of lifestyle, i.e. reduction of energy intake and enhancement of physical activity, are unquestionable prerequisites for long-term success in the management of IRS. In at least two randomized controlled studies, metformin proved to be clinically effective in increasing insulin sensitivity in hyperinsulinemic, nondiabetic adolescents. Thiazolidinediones have been successfully tested for the treatment of insulin resistance in adults, but not in children as yet. Prevention of the development of IRS in children is obviously of great significance for the health status of the community. However, the efficacy of various preventive approaches should be investigated further in carefully designed controlled trials.

Influence of systolic blood pressure and body mass index on left ventricular structure in healthy African-American and white young adults: the CARDIA study

OBJECTIVES

In the Coronary Artery Risk Development in Young Adults (CARDIA) Study comprised of a generally healthy, biracial cohort of 28- to 40-year-old adults, we sought to characterize the distribution of left ventricular (LV) mass and LV geometry and the relationship of systolic blood pressure (SBP), body mass index (BMI), and fasting insulin to LV mass and geometry.

BACKGROUND

Left ventricular mass is a risk factor for cardiovascular morbidity and mortality.

METHODS

Two-dimensionally guided M-mode echocardiograms were used to calculate LV mass index (g/height(2.7)) and geometry.

RESULTS

Black men had highest LV mass index followed by white men, black women, and white women. Blacks had higher LV wall thickness/diameter ratios than whites. Left ventricular hypertrophy was present in 2% of the cohort. Going from highest to lowest quartile for LV mass index and LV wall thickness/diameter ratio, SBP and BMI were highest in those with the highest LV mass index and LV wall thickness/diameter ratio. Increasing BMI and SBP over a 10-year interval was also strongly related to LV structure in most race/gender groups.

CONCLUSIONS

In a generally healthy young adult cohort, LV structure as defined by LV mass and geometry is associated with SBP and BMI at levels generally considered normal.

Insulin resistance syndrome and left ventricular mass in healthy young people

BACKGROUND

Findings of atherosclerotic plaques in adolescents, in the context of current epidemics of obesity and type 2 diabetes in youth, demand investigation into early cardiovascular risk development. Left ventricular hypertrophy has been linked to hypertension, obesity, and insulin resistance.

METHODS

Insulin resistance syndrome characteristics (fasting glucose and insulin; systolic blood pressure; waist girth) were measured in 70 normotensive, normoglycemic young people (60% male, 62% black; included 13 twin pairs; age mean +/- SD, 19 +/- 2.6 years). Left ventricular mass indexed by height (2.7) (LVMI) was obtained via ultrasound. Twin pairs were clustered to satisfy the assumption for independent observations.

RESULTS

LVMI was regressed on insulin after controlling for race, gender, and systolic blood pressure. Insulin was a significant (P = 0.02) independent predictor of LVMI (R(2)change = 0.09, P < 0.01). Waist girth accounted for an additional 4% variance of LVMI (P = 0.05). A one-factor model comprising waist (factor loading = 0.83), insulin (0.59), glucose (0.42), and LVMI (0.46) showed good fit [chi2(2) = 0.41, P = 0.81; root-mean-square error of approximation = 0.0].

CONCLUSIONS

A subclinical metabolic syndrome is detectable early in life, before abnormal fasting glucose or high blood pressure appear. Evidence of excessive load on the heart is associated with the metabolic syndrome even after accounting for the effects of race, gender, and blood pressure. Cardiac structure seems as closely associated with this syndrome as fasting glucose level. Based on this evidence, we propose that increased left ventricular mass is a part of insulin resistance syndrome and adds to the need for preventive public health measures to improve health behaviors and cardiovascular risk status in US youth.

Associations of insulin levels with left ventricular structure and function in American Indians: the strong heart study

We evaluated the association of insulin and echocardiographic left ventricular (LV) measurements in 1,388 (45% men) nondiabetic American Indian participants in the Strong Heart Study (SHS). Significant (all P < 0.05) relations were found in men and women between log(10) fasting insulin and LV mass (r = 0.24 and 0.26), left atrial diameter (r = 0.25 and 0.28), posterior wall thickness (r = 0.20 and 0.26), septal thickness (r = 0.19 and 0.24), LV diameter (r = 0.17 and 0.16), and cardiac output (r = 0.20 and 0.24) and in women relative wall thickness (r = 0.11) and peripheral resistance (r = -0.17). In regression analyses, adjusting for BMI, age, height, and systolic pressure, fasting insulin was independently correlated with cardiac output in men and relative wall thickness and septal thickness in women (all P < 0.05). The 97th percentiles of fasting insulin (25 microU/ml for men, and 23 microU/ml for women) in 163 apparently normal (BMI <26; blood pressure <140/90; and absence of diabetes, valvular disease, LV wall motion abnormality, or antihypertensive treatment) SHS participants were used to separate normal from elevated fasting insulin levels. Adjusting for age, BMI, and height, men with elevated insulin levels had larger LV diameters (5.41 vs. 5.16 cm; P = 0.05), higher cardiac output (5.5 vs. 4.9 l/min; P < 0.001), and lower peripheral resistance (1,487 vs. 1,666; P = 0.01), paralleling results of regression analyses. Positive relations between insulin and heart size in nondiabetic adults are largely due to associations with body size; after adjustments for covariates, fasting insulin levels are related to greater LV size and cardiac output in men and more concentric LV geometry in women.

Stiffness of the abdominal aorta in obese children

Obesity is pathogenically related to clinical and subclinical disorders that contribute to the development of atherosclerotic plaques and their complications leading to onset of cardiovascular events. Arterial stiffness may be an indicator of early vascular changes signaling the development of vascular disease. The purpose of this study was to assess the stiffness of the abdominal aorta using transthoracic echocardiography in normotensive obese and hypertensive obese pediatric patients and a control group. The study group consisted of 25 healthy children (M/F: 13/12) as a control group (Group I), 25 normotensive obese children (M/F: 13/12) (Group II) and 25 hypertensive obese children (M/F: 14/11) (Group III). The mean ages were 12.1 +/- 1.8, 11.9 +/- 1.5 and 12.4 +/- 1.4 years, respectively. Aortic strain (S), pressure strain elastic modulus (Ep) and normalized Ep (Ep*) measurements were significantly different in the hypertensive obese group, and cholesterol levels and body mass index were higher in this group. These findings may be important in determining the relationship between obesity and cardiovascular risk factors at pediatric age.

Emergence of obesity and cardiovascular risk for coronary artery disease: the Bogalusa Heart Study

The underlying determinants of cardiovascular risk are governed by both genetic and lifestyle factors. One of the major adverse outcomes of unhealthy lifestyles is obesity, the genesis of which begins in childhood. Obesity, an important risk factor for atherosclerotic cardiovascular disease, type 2 diabetes, and hypertension, persists (tracks) strongly from adolescent years to adulthood. Secular trends toward increased obesity in the past 25 years have occurred in children and adults alike. Of interest, baseline adiposity precedes hyperinsulinemia in all age groups, independently of race, sex, and baseline insulin levels. Adiposity is an independent predictor of the risk of developing the cluster of risk variables of the metabolic syndrome X, beginning in childhood. Exposure to a multiple risk factor burden over time enhances the development of coronary atherosclerosis and hypertensive cardiovascular disease. In fact, autopsy studies in youths have shown that the extent of fibrotic atherosclerotic plaques in coronary arteries, measured antemortem, increases markedly with the presence of syndrome X risk variables. Further, in overweight children, insulin levels are associated with left ventricular mass. In young people, overnutrition, coupled with physical inactivity, leads to weight gain. Since obesity, unhealthy dietary habits, and a sedentary lifestyle are interrelated and modifiable, prevention and intervention must begin in early life. (c)2001 CHF, Inc.

Childhood and adolescent obesity. Prevalence and significance

The prevalence of children and adolescents with body mass index (BMI) of greater than 95th percentile has doubled in the last 2 decades (present prevalence is 10.9%) and there is a 50% increase in the prevalence of those with a BMI greater than 85th percentile (present prevalence is 22.0%) in the US. There are substantial risks for morbidity in obese children even before they reach adulthood. Further, if obesity in childhood persists into the adult years, the morbidity and mortality is greater than if the obesity developed in the adult. Screening using appropriate historical and physical data will reveal those children most in need of modification of weight gain.

Insulin resistance and cardiovascular risk in the pediatric patient

The insulin resistance syndrome, a cluster of potent risk factors for atherosclerotic cardiovascular disease and type 2 diabetes in adults, is composed of hyerinsulinemia, obesity, hypertension and hyperlipidemia. In addition, left ventricular hypertrophy and its precursor increased left ventricular mass, is known to be a powerful predictor of adverse cardiovascular events, both as an independent risk factor and by association with the insulin resistance syndrome. Obesity appears to have a major role in the relations between the components of the insulin resistance syndrome, and their association with increased heart mass. Of significant impact in the adult population, atherosclerotic cardiovascular disease and death are rarely seen in the young, but the pathologic processes and risk factors associated with its development have been shown to begin during childhood. Recent studies revealed the presence of components of the insulin resistance syndrome also in children and adolescents, however, their associations are not well understood. A direct link between obesity and insulin resistance has also been reported in the young, as has the link between insulin resistance and abnormal lipid profile. There is an increasing amount of data to show that being overweight during childhood and adolescence is significantly associated with insulin resistance, abnormal lipids and elevated blood pressure in young adulthood. Weight loss in these situations results in a decrease in insulin concentration and an increase in insulin sensitivity toward normalcy. Moreover, it has been determined that increased left ventricular mass is present in childhood, and is related to other risk factors, namely obesity and insulin resistance. Based on current knowledge, it is reasonable to suggest that weight control, and lifestyle modification, could alter the incidence of the syndrome of insulin resistance, and improve the risk profiles for cardiovascular disease as children make the transition toward adolescence and young adulthood.