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

Obesity and Left Ventricular Function in American Indian Adolescents: Strong Heart Family Study

OBJECTIVES

Obesity is a known risk factor for developing cardiovascular disease (CVD). American Indian (AI) children have the highest obesity rates of all racial/ethnic groups in the United States (US). However, cardiometabolic health among AI adolescents is understudied. The purpose of this study was to describe the cardiometabolic characteristics of AI adolescents enrolled in the Strong Heart Family Study (SHFS), a longitudinal study of CVD from 12 AI communities, and associations with the development of abnormal left ventricular mass index (LVMI) and ejection fraction (EF).

STUDY DESIGN

This study included AI youth ages 14-22 years. Primary outcome variables were depressed EF (< 55%) and abnormal LVMI at 6-year follow-up. The primary predictor variable was BMI. Covariates included sex, cholesterol levels, blood pressure, and hemoglobin A1c. Wilcoxon signed-rank test for matched pairs evaluated cardiometabolic trends over time. Stratified univariate logistic regression by obese/nonobese categories evaluated associations with depressed EF and abnormal LVMI.

RESULTS

There were 384 subjects, 58% of whom were overweight (n = 87) or obese (n = 122) at baseline. Among overweight/obese subjects, cholesterol and triglyceride levels were elevated. At 6-year follow-up, BMI increased while EF decreased among overweight/obese males, with 3.6 times the odds of having depressed EF (95% CI 1.22-10.98, p = 0.021) compared to normal-weight males. There were no significant cardiometabolic associations with LVMI.

CONCLUSIONS

This is one of the largest longitudinal evaluations of CVD in AI adolescents. Concerning trends in BMI and depressed EF among AI males suggest the importance of culturally competent interventions to promote healthy weight and reduce cardiometabolic risk.

Cardiovascular Risk Factors and Target Organ Damage in Adolescents: The SHIP AHOY Study

BACKGROUND

Development of cardiovascular disease in adults has been directly linked to an adverse metabolic phenotype. While there is evidence that development of these risk factors in childhood persists into adulthood and the development of cardiovascular disease, less is known about whether these risk factors are associated with target organ damage during adolescence.

METHODS

We collected data from 379 adolescents (mean age 15.5, 60% male) with blood pressure between the 75th and 95th percentile to determine if there is a metabolic phenotype that predicts cardiovascular changes (left ventricular mass, systolic and diastolic function, pulse wave velocity, and renal function). We determined the number of risk factors for cardiovascular disease (hypertension, dyslipidemia, obesity, and insulin resistance) present in each participant. Generalized linear models were constructed to determine if the number of cardiovascular risk factors (CVRFs) were associated with measures of target organ damage.

RESULTS

The number of CVRFs present were associated with statistically significant differences in increased left ventricular mass index, increased pulse wave velocity, decreased peak longitudinal strain, urine albumin to creatine ratio and echocardiographic parameters of diastolic dysfunction. Generalized linear models showed that dyslipidemia and insulin resistance were independently associated with markers of diastolic dysfunction (P ≤ .05) while increased blood pressure was associated with all makers of target organ damage (P ≤ .03).

CONCLUSIONS

These data suggest the of the number of CVRFs present is independently associated with early changes in markers of target organ damage during adolescence.

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.

Iron Metabolism in Obesity and Metabolic Syndrome

Obesity is an excessive adipose tissue accumulation that may have detrimental effects on health. Particularly, childhood obesity has become one of the main public health problems in the 21st century, since its prevalence has widely increased in recent years. Childhood obesity is intimately related to the development of several comorbidities such as nonalcoholic fatty liver disease, dyslipidemia, type 2 diabetes mellitus, non-congenital cardiovascular disease, chronic inflammation and anemia, among others. Within this tangled interplay between these comorbidities and associated pathological conditions, obesity has been closely linked to important perturbations in iron metabolism. Iron is the second most abundant metal on Earth, but its bioavailability is hampered by its ability to form highly insoluble oxides, with iron deficiency being the most common nutritional disorder. Although every living organism requires iron, it may also cause toxic oxygen damage by generating oxygen free radicals through the Fenton reaction. Thus, iron homeostasis and metabolism must be tightly regulated in humans at every level (i.e., absorption, storage, transport, recycling). Dysregulation of any step involved in iron metabolism may lead to iron deficiencies and, eventually, to the anemic state related to obesity. In this review article, we summarize the existent evidence on the role of the most recently described components of iron metabolism and their alterations in obesity.

The measurement of both carotid intima-media thickness and epicardial adipose tissue thickness in children with epilepsy receiving antiepileptic drug therapy

OBJECTIVE

The aim of this study was to evaluate the carotid intima-media thickness together with the thickness of the epicardial adipose tissue in patients receiving antiepileptic drug therapy and to investigate the presence of increased cardiovascular risk in these patients.

METHODS

The study included a total of 52 patients comprising 32 males and 20 females who were diagnosed as having epilepsy and who were using one or more antiepileptic drugs. The control group consisted of 34 healthy individuals comprising 16 males and 18 females. The individuals selected for the study group were requested to go to the hospital after overnight fasting. After blood sampling for serum lipid value, the carotid intima-media thickness was measured with high resolution B-mode ultrasonography and epicardial adipose tissue thickness with echocardiography in the patients and the control group subjects.

RESULTS

The carotid intima-media thickness was determined as 0.47 ± 0.05 mm in the patient group and 0.44 ± 0.04 mm in the control group (p = 0.028). The carotid intima-media thickness was measured as 0.45 ± 0.05 mm in patients with epilepsy taking monotherapy and 0.49 ± 0.04 mm in those taking polytherapy (p = 0.003). The epicardial adipose tissue thickness was determined as 3.42 ± 0.09 mm in the patient group and 1.72 ± 0.90 mm in the control group (p = 0.000). The epicardial adipose tissue thickness was measured as 3.16 ± 0.87 mm in patients with epilepsy taking monotherapy and 3.77 ± 0.83 mm in those taking polytherapy (p = 0.041).

CONCLUSIONS

It was determined that carotid intima-media thickness and epicardial adipose tissue thickness were significantly high in children with epilepsy taking long-term antiepileptic drugs. These results demonstrate that these patients could be at increased risk of the development of cardiovascular complications. There is a need for more extensive studies on this subject.

Assessment of left ventricular mass index could predict metabolic syndrome in obese children

BACKGROUND

Childhood obesity is a major risk factor for cardiovascular diseases in children and adults.

OBJECTIVES

The purpose of this study was to evaluate the serum leptin level and the cardiac changes in normotensive obese children and to study the relationship between left ventricular mass index (LVMI) and serum leptin with the parameters of metabolic syndrome (MS) in obese children.

METHODS

This study was conducted in al Jeddani Hospital and Ibn Sina College Hospital in Saudi Arabia in the period from July 2012 to December 2013, and included 82 obese children. Their mean age was 10.2 ± 2.8 years; they were divided into 25 obese children with MS and 57 obese children without MS, and 40 healthy age- and sex-matched children were also included in the study as a control group. All children were subjected to clinical assessment including standing height, body weight, body mass index (BMI), waist circumference (WC), and blood pressure measurements. All children received an echocardiographic examination (2-dimensional, M-mode, Doppler, and tissue Doppler echocardiograpy) and laboratory assessment of serum leptin level, fasting glucose, fasting insulin, the homeostatic model assessment for insulin resistance (HOMA) index, total cholesterol, triglycerides, and high- and low-density lipoprotein profile.

RESULTS

BMI, BMI standard deviation score, WC, fasting glucose, fasting insulin, HOMA index and the serum leptin level were significantly higher in obese children compared to control group (p < 0.05). The LVMI were increased in the obese compared to the control group (p < 0.001) while left ventricle systolic and diastolic functions did not differ in obese versus control group (p > 0.05). There was a significant positive correlation between both LVMI and serum leptin level in comparison to BMI, WC, fasting glucose, fasting insulin, HOMA, triglycerides, and low-density lipoprotein in all obese children, especially the MS group. However, there was a significant negative correlation between both LVMI and serum leptin level in comparison to high-density lipoprotein.

CONCLUSION

Assessment of LVMI as routine echocardiographic examinations and serum leptin level might be a feasible and reliable method for the evaluation of obesity and its related cardiovascular risks during childhood that can predict metabolic syndrome and insulin resistance.

Left ventricular mass and diastolic function in obese children and adolescents

BACKGROUND

Our aims were to assess left ventricular structure and diastolic function in obese subjects stratified according to ambulatory blood pressure status, and to investigate independent predictors of the left ventricular mass (LVM) index.

METHODS

Obese subjects aged 9-19 years referred for ambulatory blood pressure monitoring (ABPM) were evaluated in the cross-sectional study. In addition to biochemical and anthropometric measurements, subjects underwent ABPM, Doppler echocardiography, and treadmill exercise test.

RESULTS

According to ABPM results, 103 subjects with obesity (mean age 14.1 ± 2 years) were split in two groups: 49 hypertensive, and 54 without hypertension. Left ventricular hypertrophy was found in 16.3 % of hypertensive, and 5.6 % of normotensive. Variables included in stepwise regression analysis as potential determinants of LVM index were age, body mass index z score, waist circumference, peak systolic blood pressure on exercise test, 24-h heart rate, and night heart rate. Peak systolic blood pressure (adjusted R(2) = 0.051, β = 0.245, p = 0.013) remained as the independent predictor of LVM index. Diastolic function evaluated by mitral E/A ratio was decreased in both obese groups.

CONCLUSIONS

Early markers of cardiac disease including hypertrophy and diastolic dysfunction of the left ventricle are present in youths with obesity prior to the development of sustained hypertension.

Which metabolic syndrome criteria best predict non-alcoholic fatty liver disease in children?

OBJECTIVE

The aim of this study was to identify which metabolic syndrome criteria (WHO or IDF) better reflect the presence of non-alcoholic fatty liver disease (NAFLD) and to determine the prevalence of metabolic syndrome (MS) and NAFLD.

METHODS

Two hundred and seventeen obese children and adolescents, 8-15 years of age (body mass index >95 p), were included in the study. Anthropometric measurements, blood pressure measurements, an oral glucose tolerance test and lipid profile were measured. MS was diagnosed according to WHO and IDF criteria. NAFLD risk ratio was assessed according to the two MS criteria.

RESULTS

The prevalence of MS according to the IDF criteria was 43.3 %, and according to WHO criteria it was 55.2 %. NAFLD prevalence in the metabolic syndrome group according to IDF criteria was 25.5 % and this was statistically significant (p = 0.007). The prevalence of NAFLD was 20.8 % in the group with MS according to WHO criteria and this was not a statistically significant difference (p = 0.15). NAFLD hazard ratios were 7.06 (95 % CI 1.29-5.50) in the MS group according to IDF criteria and 2.02 (95 % CI 0.81-3.53) in the group with metabolic syndrome according to WHO criteria. IDF criteria were found to have a higher odds ratio.

CONCLUSION

The prevalence of MS depends on the diagnostic criteria used. IDF criteria give the best measure for the presence of NAFLD. NAFLD might be important as diagnostic criterion for MS.

Childhood obesity and autonomic dysfunction: risk for cardiac morbidity and mortality

OPINION STATEMENT

The epidemic of childhood obesity is becoming a major predictor for risk of cardiovascular diseases (CVD) and mortality during adulthood. Alterations in the morphology of the heart due to obesity could be a predictor for the dysfunction of cardiac autonomic modulation (CAM). A number of epidemiologic studies have evaluated the effect of obesity and CAM in children, finding that obesity impaired the balance of CAM toward a sympathetic overflow and reduced parasympathetic modulation, a significant predictor of CVD morbidity and mortality in adults. Lifestyle modifications, for example long-term exercise programs, have been shown to improve CAM in the obese. This review discusses the recent evidence on childhood and adolescent obesity and its impact on CAM, as well as how early lifestyle changes could help improve CAM, which may in turn reduce the burden of CVD in adults.

Epicardial adiposity in children with obesity and metabolic syndrome

OBJECTIVE

Obesity increases cardiac diseases by increasing tendency to atherosclerosis. Our aim was to define epicardial adipose tissue thickness, and its related factors in obese children.

METHODS

Total of 94 patients were divided into obesity with metabolic syndrome (MS) (n=30), obesity without MS (n=33), and control (n=31) groups. Auxological values with fasting glucose, fasting insulin, alanine transaminase, serum lipid levels, and high sensitive C-reactive protein levels were evaluated. Epicardial adipose tissue thickness, interventricular septum thickness and left ventricular mass were measured by echocardiography.

FINDINGS

Weight, body mass index, waist circumference, insulin, alanine transaminase, and high sensitive C-reactive protein values were markedly higher in obesity group when compared with controls (P<0.001). Epicardial adipose tissue thickness was 0.64±0.23 cm in obesity with MS; 0.60±0.20 cm in obesity without MS, and 0.27±0.12 cm in control group (P<0.001). Interventricular septum thickness and left ventricular mass values were markedly high in obesity without MS group (P<0.001 and P=0.002).

CONCLUSION

Our study has indicated that obesity has unfavorable effects on heart starting in the adolescence.

Detection of early diastolic alterations by tissue Doppler imaging in untreated childhood-onset essential hypertension

The aim of the study was to determine the presence of preclinical diastolic dysfunction in hypertensive children relative to normotensive children by Tissue Doppler Imaging (TDI). We prospectively enrolled children with untreated essential hypertension in absence of any other disease and a matched healthy control group with normal blood pressure (BP); both groups confirmed by clinic BP and a 24-hour ambulatory BP monitoring. Echocardiographic diastolic parameters were determined using spectral transmitral inflow Doppler, flow propagation velocity, TDI, and systolic parameters were determined via midwall shortening fraction and ejection fraction. A total of 80 multiethnic children were prospectively enrolled for the study: 46 hypertensive (median age, 13 years; 72% males) and 34 control (median age, 14 years; 65% males). The only echocardiography parameters that had a statistically significant change compared with the control children, were regional mitral Ea, Aa, and the E/Ea ratio by TDI. In comparison with controls, hypertensive children had lower Ea and Aa velocities of anterior and posterior walls and higher lateral wall E/Ea ratio. The decrease in posterior wall Ea and Aa remained significant after adjustment for gender, age, body mass index, ethnicity, and left ventricular hypertrophy on multivariate analysis. The lateral and septal wall E/Ea ratios correlated significantly with fasting serum insulin levels on similar multivariate analysis. Decreased regional TDI velocities were seen with preserved left ventricular systolic function even when other measures of diastolic dysfunction remained unchanged in untreated hypertensive children. Hypertension and serum insulin levels had strong associations with preclinical diastolic alterations in children.

Childhood obesity and cardiovascular dysfunction

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