Evidence for association between insulin resistance and premature carotid atherosclerosis in childhood obesity

Vitamin B12, folate, and homocysteine levels in children and adolescents with obesity: a systematic review and meta-analysis

Background and aims

Childhood and adolescent obesity is a global public health concern. Obesity induces several metabolic disturbances. Several studies have explored the association of vitamin B12, folate, and homocysteine (Hcy) with obesity. This study aimed to synthesize the available evidence regarding the differences in serum levels of vitamin B12, Hcy, and folate among children or adolescents with and without obesity.

Methods

A random-effects meta-analysis using the Sidik-Jonkman method and corrected 95% confidence interval (CI) using the truncated Knapp-Hartung standard errors was used for all meta-analyses. Standardized mean difference (SMD) with the corresponding 95% CI was used as the only effect size. The Cochran's Q test and the I2 statistic were used to evaluate between-study heterogeneity. Publication bias was assessed using funnel plots and the Egger test.

Results

Twenty studies were included with a combined study population of 7,791 patients. There were no significant differences between children/adolescents with and without obesity with respect to serum vitamin B12 levels (SMD: -0.24; 95% CI: -0.53 to 0.06; p > 0.05, I2 = 74.93%) and folate levels (SMD: -0.12; 95% CI: -0.29 to 0.06; p > 0.05, I2 = 19.6%). However, children/adolescents with obesity had significantly higher Hcy levels compared to counterparts without obesity (SMD: 0.77; 95% CI: 0.39 to 1.14; p < 0.001, I2 = 86.4%).

Conclusion

Children and adolescents with obesity had higher Hcy levels than those without obesity. However, no significant differences were found for vitamin B12 and folate levels. Hcy may play a role in the development of obesity in this population.

Atherosclerosis Prevention in Adolescents with Obesity: The Role of Moderate-Vigorous Physical Activity

Carotid intima-media thickness (cIMT) is a subclinical marker of atherosclerotic development, which is impaired in adolescents with obesity. This study aimed to analyze the impact of physical activity (PA), cardiorespiratory fitness (CRF), body mass index (BMI), and body composition changes on the cIMT of adolescents with obesity. Longitudinal data (6 months) from adolescents aged 12-18 years, with a BMI ≥97th percentile, previously recruited for the non-randomized controlled trial PAC-MAnO (Clinicaltrials.gov-NCT02941770) were analyzed using partial correlations controlling for sex and pubertal status and multiple regressions. A total of 105 adolescents (51.4% girls, 86.7% Caucasian), 14.8 ± 1.8 years old, with a BMI z-score of 3.09 ± 0.74 were included. Total body fat mass (TBFM) (F(1,91) = 23.11, p < 0.001), moderate-vigorous PA (MVPA) (F(1,91) = 7.93, p = 0.0006), and CRF (mL/kg/min) (F(1,90) = 19.18, p < 0.001) predicted cIMT variance with an R2 of 0.24, 0.09, and 0.23, respectively. MVPA changes showed a high correlation with CRF variation (r(91) = 0.0661, p < 0.001). This study suggests that although cIMT is impaired in overweight adolescents, improvements in TBFM, MVPA, and CRF are associated with cIMT improvement. Although both energy intake and MVPA may influence TBFM, MVPA plays the most relevant role in cIMT development due to its direct association with CRF.

Maternal Phthalate and Bisphenol Urine Concentrations during Pregnancy and Early Markers of Arterial Health in Children

BACKGROUND

Fetal exposure to endocrine-disrupting chemicals such as phthalates and bisphenols might lead to fetal cardiovascular developmental adaptations and predispose individuals to cardiovascular disease in later life.

OBJECTIVES

We examined the associations of maternal urinary bisphenol and phthalate concentrations in pregnancy with offspring carotid intima-media thickness and distensibility at the age of 10 y.

METHODS

In a population-based, prospective cohort study of 935 mother-child pairs, we measured maternal urinary phthalate and bisphenol concentrations at each trimester. Later, we measured child carotid intima-media thickness and distensibility in the children at age 10 y using ultrasound.

RESULTS

Maternal urinary average or trimester-specific phthalate concentrations were not associated with child carotid intima-media thickness at age 10 y. Higher maternal average concentrations of total bisphenol, especially bisphenol A, were associated with a lower carotid intima-media thickness [differences - 0.15 standard deviation score and 95% confidence interval (CI): - 0.24 , - 0.09 and - 0.13 (95% CI: - 0.22 , - 0.04 ) per interquartile range (IQR) increase in maternal urinary total bisphenol and bisphenol A concentration]. Trimester-specific analysis showed that higher maternal third-trimester total bisphenol and bisphenol A concentrations were associated with lower child carotid intima-media thickness [differences - 0.13 (95% CI: - 0.22 , - 0.04 ) and - 0.13 (95% CI: - 0.22 , - 0.05 ) per IQR increase in maternal urinary bisphenol concentration]. Maternal urinary bisphenol or phthalate concentrations were not associated with child carotid distensibility.

DISCUSSION

In this large prospective cohort, higher maternal urinary bisphenols concentrations were associated with smaller childhood carotid intima-media thickness. Further studies are needed to replicate this association and to identify potential underlying mechanisms. https://doi.org/10.1289/EHP10293.

Insulin resistance and intestinal integrity in children with and without HIV infection in Uganda

OBJECTIVES

The risk of cardiometabolic complications in children with perinatally acquired HIV infection (PHIVs) and in perinatally HIV-exposed but uninfected children (HEUs) and its relationship to systemic inflammation and markers of gut integrity are not well established. In this current study, we assed insulin resitance in PHIV compared to HEUs and HIV unexposed uninfected children and explored potential association with intestinal damage biomarkers.

METHODS

This was a cross-sectional study in PHIVs, HEUs and HIV-unexposed, uninfected children (HUUs) aged 2-10 years enrolled in Uganda. PHIVs were on stable antiretroviral therapy (ART) with HIV viral load  < 400 HIV-1 RNA copies/mL. Insulin resistance was estimated using the homeostasis model assessment of insulin resistance (HOMA-IR). We measured markers of systemic inflammation, monocyte activation and gut integrity. Kruskal-Wallis tests were used to compare markers by HIV status; Pearson correlation and multiple linear regressions were used to assess associations of the HOMA-IR index with biomarkers of intestinal damage and translocation.

RESULTS

Overall, 172 participants were enrolled in the study (57 PHIVs, 59 HEUs and 56 HUUs). The median age was 7.8 [interquartile range (IQR) 6.39, 8.84] years, 55% were female and the median body mass index (BMI) was 15 (IQR 14.3, 15.8) kg/m² . Among PHIVs, the median CD4% was 37%, and 93% had viral load ≤ 20 copies/mL. PHIVs had higher waist:hip ratio, high-density lipoprotein (HDL) cholesterol, triglycerides and HOMA-IR index than the other groups (P ≤ 0.02). Factors correlated with insulin resistance included higher BMI and HDL cholesterol and lower soluble tumour necrosis factor receptor I (sTNFRI) (P ≤ 0.02). There was no correlation between any of the other inflammatory or gut biomarkers and HOMA-IR index (P ≥ 0.05). After adjusting for age and sTNFRI, BMI remained independently associated with the HOMA-IR index (β = 0.16; P < 0.01).

CONCLUSIONS

Despite viral suppression, Ugandan PHIVs have disturbances in glucose metabolism. Higher BMI, and not immune activation or alteration of gut integrity, was associated with insulin resistance in this population.

Ultrasonographic evaluation of the common carotid intima-media complex in healthy and overweight/obese children

BACKGROUND

Obesity is a global epidemic, including among children. It is therefore necessary to identify cardiovascular changes in overweight/obese children as early as possible. Mode B ultrasonography of the common carotids can be used to precisely evaluate in real time early changes in the thickness of the intima-media complex (IMC), which can detect onset of the atherosclerosis process.

OBJECTIVES

This study compared IMC thickness between schoolchildren with and without overweight/obesity.

METHODS

A sample of 59 children of both sexes, aged 7 to 10 years, were recruited from health centers in São Paulo, Brazil. Children were classified by z scores for body mass index (BMI) into two groups, with or without overweight/obesity. These groups were then compared in terms of IMC thickness.

RESULTS

The groups were homogenous for age and sex. The mean IMC measurement in the group with overweight/obesity was 0.49 (± 0.07) mm, whereas in the group free from overweight/obesity it was 0.41 (± 0.05) mm (p < 0.01). These differences were maintained when groups with and without overweight/obesity were compared separately by sex and for right and left sides. The coefficient for the correlation between IMC measurement and BMI z score was 0.61 (95% confidence interval = 0.42-0.75). Within the same nutritional status group, there were no differences between sexes or between right and left sides.

CONCLUSIONS

Intima-media thickness was greater among children with overweight/obesity and was directly proportional to BMI z score, denoting increased cardiovascular risk in this group.

Insulin metabolism markers are predictors of subclinical atherosclerosis among overweight and obese children and adolescents

BACKGROUND

To investigate the association between markers of insulin metabolism and carotid intima-media thickness(cIMT) among overweight and obese children and adolescents.

METHODS

A total of 378 children and adolescents aged from 6 to 13 years, with WHO body mass index Z-Scores ≥2 were enrolled in this study. We measured fasting serum insulin and glucose, conducted a homeostatic model assessment of insulin resistance(HOMA-IR), and calculated the quantitative insulin sensitivity check index(QUICKI). Carotid intima-media thickness was measured in the common carotid artery with high-resolution ultrasonography.

RESULTS

The study participants consisted of 198 boys and 180 girls with a mean(±SD) age of 9.3 ± 1.7 years, 18.3% being pre-pubertal. In boys, after controlling for confounders, a one-SD increase in fasting insulin and HOMA-IR were associated with 0.351 mm(P < 0.001) and 0.350 mm(P < 0.001) increases in cIMT, respectively. However, a one-SD increase in QUICKI was associated with a - 0.305 mm(P = 0.001) decrease in cIMT. When categorizing into tertiles, a one-SD increase in fasting insulin and HOMA-IR were associated with 87 and 81% increases in the odds of higher categories of cIMT(both P < 0.05). However, a one-SD increase in QUICKI was associated with 37% lower odds of higher categories of cIMT(P = 0.022). No significant associations were found among girls.

CONCLUSION

This study demonstrated that insulin resistance and sensitivity markers were independent predictors of cIMT in overweight and obese boys, but not in girls, highlighting the importance of chronically elevated insulin levels for predisposing these boys to alterations in their vascular structure.

Is subclinical atherosclerosis associated with visceral fat and fatty liver in adolescents with type 1 diabetes?

INTRODUCTION

There is a 3-fold higher prevalence of cardiovascular complications in patients with type 1 diabetes. The aim was to assess the relationship between subclinical atherosclerosis and visceral fat and fatty liver in diabetic adolescents.

MATERIAL AND METHODS

The study was performed on 110 adolescents with type 1 diabetes (T1D) attending the Pediatric Diabetes Clinic of the University Hospital, Ismailia, Egypt. Their mean age was 14.2 ±0.7 years with a mean duration of diabetes 6 ±0.3 years. They were divided into group 1 which consisted of 55 adolescents with T1D and normal carotid intima media thickness (cIMT) and the second group which included 55 adolescents with T1D and subclinical atherosclerosis. All adolescents were normotensive, normo-albuminuric and had no retinopathy. Visceral fat thickness was measured as the distance between the anterior wall of the aorta and the posterior surface of the rectus abdominis muscle. Hepatic steatosis was diagnosed based on enlarged liver size and evidence of diffuse hyper-echogenicity of liver relative to kidneys.

RESULTS

The mean visceral fat was significantly higher in adolescents with increased cIMT (4.8 ±1.6) than in the normal thickness group (3.9 ±1.4). Liver size was also significantly larger in the former group (13.73 ±2.26 versus 12.63 ±2.20) (p = 0.022). After adjusting for other variables, logistic regression demonstrated that glycated hemoglobin (HbA_1c) and fatty liver are independent factors affecting cIMT, OR = 1.426 (p < 0.05) and OR = 4.71 (p < 0.05).

CONCLUSIONS

In the present study, fatty liver and HbA_1c were associated with subclinical atherosclerosis in lean adolescents with T1D.

Metabolic Stress, Autophagy, and Cardiovascular Aging: from Pathophysiology to Therapeutics

Recent advances in health care have improved the management of cardiometabolic disorders, and prolonged lifespan. However, the ever-rising prevalence of metabolic stress related to obesity (insulin resistance, diabetes, hypertension, and dyslipidemia) has greatly challenged geriatric care. The ubiquitin-proteasome system and autophagy-lysosomal pathways represent two major, yet distinct cellular machineries, for degradation and removal of damaged or long-lived proteins and organelles; the function of which declines with aging. To seek new strategies for cardiovascular aging under various metabolic diseases, it is imperative to understand the precise role for metabolic stress and protein quality control, in particular autophagy, in premature cardiovascular aging. Targeting metabolic stress and autophagy may offer exciting new avenues for the management of cardiovascular aging.

Peripheral and Central Aortic Pressure, Wave-Derived Reflection Parameters, Local and Regional Arterial Stiffness and Structural Parameters in Children and Adolescents: Impact of Body Mass Index Variations

AIM

The aim was to analyze and compare the associations between body mass index (BMI) and structural and functional cardiovascular variables measured in children and adolescents.

METHODS

609 healthy subjects (mean age/range 12/4-18 years, 45% females) were studied. Subjects' BMI and the corresponding z-scores (z-BMI) were determined. Cardiovascular measurements: peripheral and aortic blood pressure (BP), aortic wave-derived parameters, common carotid, femoral and brachial artery diameters and stiffness, carotid intima-media thickness, carotid-radial and carotid-femoral pulse wave velocity (crPWV, cfPWV) and cfPWV/crPWV ratio. Cardiovascular data were standardized (z-scores) using equations (fractional polynomials) obtained from a sub-group (reference population, n = 241) non-exposed to cardiovascular risk factors (CVRFs). Simple and multiple regression models were obtained for the associations between cardiovascular z-scores and z-BMI and/or z-BMI, age, sex and CVRFs.

RESULTS

z-BMI was associated with standardized cardiovascular variables, regardless of age, sex and CVRFs. BP (peripheral rather than aortic) was the variable with the greatest variations associated with z-BMI. Systolic (SBP) and pulse pressure (PP; in that order) were the variables with the highest variations associated with z-BMI. Carotid, but not femoral or brachial stiffness showed BP-dependent variations associated with z-BMI. Arterial diameters were associated with z-BMI, without differences among arteries.

CONCLUSION

In children and adolescents, z-BMI was gradually and positively associated with haemodynamic (peripheral and central BP) and vascular parameters (structural and functional) with independence of age, sex and other CVRFs (Dyslipidemia, Hypertension, Smoke, Diabetes). There were differences in the associations depending on the arteries studied and on whether central or peripheral haemodynamic parameters were analyzed.

Carotid Intima-medial Thickness and Glucose Homeostasis in Indian Obese Children and Adolescents

OBJECTIVE

To evaluate for subclinical atherosclerosis and its risk factors in Indian obese children.

MATERIALS AND METHODS

A cross-sectional, case-control study was conducted to recruit 80 children aged 6-17 years with constitutional obesity as cases and 23 age- and gender-matched controls with normal body mass index (BMI). Anthropometric and clinical evaluation was followed by biochemical analysis and body fat estimation by dual-energy X-ray absorptiometry in cases. Similar evaluation was performed for controls except laboratory parameters. Carotid intima-media thickness (CIMT) was measured with B-mode ultrasonography in both cases and controls to evaluate subclinical atherosclerosis.

RESULTS

The mean age of cases was 12.8 ± 3 years, with mean BMI of 29.2 ± 4.8 kg/m². The mean CIMT was significantly higher in cases than controls (0.54 ± 0.13 vs. 0.42 ± 0.08; P < 0.001 across all ages). CIMT was significantly higher in participants who were hypertensive than nonhypertensive (0.6 ± 0.11 vs. 0.53 ± 0.11 mm; P = 0.04). CIMT showed a positive correlation with BMI (r = 0.23, P = 0.02), percentage body fat and fat mass index (r = 0.28 and 0.3 respectively; P < 0.001), but not with waist: hip ratio. CIMT showed significant positive correlation with blood glucose at 60 min (r = 0.22; P = 0.04), serum insulin at 60 min (r = 0.28; P = 0.01) while negative correlation with whole body insulin sensitivity (r = -0.27; P = 0.01).

CONCLUSION

CIMT correlated significantly to blood pressure, insulin sensitivity, and body fat in Indian obese children.

Risk Factors for Cardiovascular Disease in Obese Children

OBJECTIVE

To study the prevalence of cardiovascular risk factors in pediatric obesity.

METHODS

50 obese children (age 5-17y) and 50 apparently healthy non-obese children (body mass index of over 95th percentile and between 5th to 95th percentiles, respectively) using Centre for Disease Control growth charts were included. Fasting blood sugar, lipid profile, insulin, homeostasis model assessment of insulin resistance, uric acid, fibrinogen, lipoprotein (a), homocysteine, malondialdehyde, ferric reducing ability of plasma and nitric oxide were measured.

RESULTS

Insulin, insulin resistance, triglycerides, uric acid, fibrinogen, malondialdehyde, ferric reducing ability of plasma and nitric oxide were significantly higher (P <0.001) in obese children. Body mass index showed significant positive correlation with insulin r=0.519, P<0.001; insulin resistance r =0.479, P<0.001; uric acid r= 0.289, P=0.005; fibrinogen r=0.461, P<0.001; and nitric oxide r=0.235, P=0.012.

Conclusion

Pediatric obesity is associated with dyslipidemia, oxidative stress, insulin resistance and endothelial dysfunction, which are cardiovascular risk factors and components of metabolic syndrome. These children must be targeted for lifestyle and dietary modification.

Effects of Rosuvastatin Alone or in Combination with Omega-3 Fatty Acid on Adiponectin Levels and Cardiometabolic Profile

BACKGROUND

Adiponectin is an important adipocyte-related protein that has been postulated to participate in prevention of the development of metabolic syndrome. The relationship between adiponectin serum levels and risk of coronary artery disease (CAD) has been widely investigated and remains controversial. The aim of the present study was to evaluate the effects of rosuvastatin and/or omega-3 fatty acid on adiponectin serum levels in patients with insulin resistance (IR) and CAD.

PATIENTS AND METHODS

This study involved 87 patients with CADs and IR of different etiology, the patients were divided into three groups; 24 patients on treatment with rosuvastatin, 22 patients on treatment with omega-3 fatty acid, 23 patients on treatment with omega-3 fatty acid and rosuvastatin, 18 patients were not previously or currently treated with either rosuvastatin or omega-3 fatty acid, those regarded as control patients. Anthropometric measures, adiponectin serum levels, and other biochemical parameters were assessed in each treated group.

RESULTS

Rosuvastatin therapy leads to a significant elevation in adiponectin serum levels from 4.1 ± 0.99 ng/mL to 6.76 ± 1.03 ng/mL compared to control P < 0.01. Omega-3 fatty acid therapy leads to a significant elevation in adiponectin serum levels from 4.1 ± 0.99 ng/mL to 6.11 ± 1.29 ng/mL compared to control P < 0.01. Rosuvastatin plus omega-3 fatty acid therapy lead to a significant elevation in adiponectin serum levels from 4.1 ± 0.99 ng/mL to 7.99 ± 1.76 ng/mL compared to control P < 0.01.

CONCLUSIONS

Rosuvastatin and/or omega-3 fatty acid lead to significant cardiometabolic protection through an increment in adiponectin serum levels.

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.

Adiposity has no direct effect on carotid intima-media thickness in adolescents and young adults: Use of structural equation modeling to elucidate indirect & direct pathways

BACKGROUND

Carotid intima-media thickness (cIMT) is associated with CV events in adults. Thicker cIMT is found in youth with CV risk factors including obesity. Which risk factors have the most effect upon cIMT in youth and whether obesity has direct or indirect effects is not known. We used structural equation modeling to elucidate direct and indirect pathways through which obesity and other risk factors were associated with cIMT.

METHODS

We collected demographics, anthropometrics and laboratory data on 784 subjects age 10-24 years (mean 18.0 ± 3.3 years). Common, bulb and internal carotid cIMT were measured by ultrasound. Multivariable regression analysis was performed to assess independent determinants of cIMT. Analyses were repeated with structural equation modeling to determine direct and indirect effects.

RESULTS

Multivariable regression models explained 11%-22% of variation of cIMT. Age, sex and systolic blood pressure (BP) z-score were significant determinants of all cIMT segments. Body mass index (BMI) z-score, race, presence of type 2 diabetes mellitus (T2DM), hemoglobin A1c (HbA1c) and non-HDL were significant for some segments (all p = 0.05). The largest direct effect on cIMT was age (0.312) followed by BP (0.228), Blood glucose control (0.108) and non-HDL (0.134). BMI only had a significant indirect effect through blood glucose control, BP & non-HDL. High sensitivity C-reactive protein (CRP) had a small indirect effect through blood glucose control (all p = 0.05).

CONCLUSIONS

Age and BP are the major factors with direct effect on cIMT. Glucose and non-HDL were also important in this cohort with a high prevalence of T2DM. BMI only has indirect effects, through other risk factors. Traditional CV risk factors have important direct effects on cIMT in the young, but adiposity exerts its influence only through other CV risk factors.

Insulin resistance and endothelial function in children and adolescents

AIMS

Insulin resistance (IR) impairs cellular response to insulin due to a dysfunction in glucose metabolism, associated with an increased cardiovascular risk. The aim of our study was to investigate the relationship among homeostasis model assessment index (HOMA index), endothelial function and vascular morphology in order to better stratify cardiovascular risk in children and adolescents.

METHODS

A total of 150 children and adolescents (55 pre-pubertal, mean age 10.4 ± 3.1 years) were enrolled. Anthropometric [body mass index (BMI), waist circumference (WC)], laboratory [blood lipids, inflammatory markers, insulinemia, glycemia], HOMA index and ultrasound parameters [flow-mediated dilatation (FMD), common carotid intima-media thickness (cIMT) and antero-posterior diameter of infra-renal abdominal aorta (APAO)] were assessed.

RESULTS

cIMT was positively related to age (r=0.274, p<0.01), BMI (r=0.318, p<0.01), WC (r=0.315, p<0.01) and triglycerides (r=0.230, p<0.01). APAO measurements showed a linear positive correlation with age (r=0.435, p<0.01), BMI (r=0.505, p<0.01), WC (r=0.487, p<0.01), triglycerides (r=0.280, p<0.01), C-reactive protein (r=0.209, p<0.05), fasting insulin (r=0.378, p<0.01) and HOMA index (r=0.345, p<0.01). FMD was inversely related to age (r=-0.251, p<0.01), rough BMI (r=-0.318, p<0.01), WC (r=-0.340, p<0.01), fasting insulin (r=-0.281, p<0.01) and HOMA index (r=-0.282, p<0.01). Multiple regression analysis found no influence of HOMA index on APAO and cIMT. HOMA index was an independent predictor for brachial artery FMD worsening after the statistical adjustment.

CONCLUSION

HOMA index increase induced a worsening in endothelial function since childhood.

Effect of modest changes in BMI on cardiovascular disease risk markers in severely obese, minority adolescents

SUMMARY

BACKGROUND

African American and Hispanic adolescents have disproportionately higher rates of obesity compared to white adolescents. In adults, modest weight loss of five percent improves CVD risk marker levels. Less is known about the effects of modest changes in BMI on CVD risk markers in adolescents, particularly newer markers such as C reactive protein (CRP), lipoprotein (a) and homocysteine.

OBJECTIVE

To examine the effect of modest BMI change on CVD risk marker levels in a group of severely obese, African American and Hispanic adolescents.

STUDY DESIGN

A six-month longitudinal analysis.

SUBJECTS

Eighty-three African American and Hispanic adolescents were recruited (mean age ± sd: 15.1 ± 2.0 years); 50 (60%) were reevaluated at 6 ± 2 months.

RESULTS

At baseline, mean BMI was 42.3 ± 7.8 kg/m(2). BMI directly correlated with CRP (p = < 0.001); homocysteine (p = 0.02); insulin (p = 0.05); and systolic and diastolic blood pressures (both p = <0.001). BMI remained significantly associated with CRP and insulin after adjusting for age, sex and ethnicity (p = 0.001). At six-month follow up, there was a significant p for trend between the three groups of BMI change (those with a ≥5% BMI decrease, those who maintained BMI within 5% and those with ≥5% BMI increase) and CRP (p = 0.05) and insulin (p = 0.04).

CONCLUSIONS

A modest decrease in BMI is associated with improvement in CRP and insulin levels. Obese adolescents should be encouraged to continue with modest weight loss goals as they result in improvement in cardiovascular disease risk markers.

Fatty liver is a good indicator of subclinical atherosclerosis risk in obese children and adolescents regardless of liver enzyme elevation

AIM

To investigate the presence of association between nonalcoholic fatty liver disease (NAFLD) and subclinical atherosclerosis using carotid intima media thickness (c-IMT) in obese children and adolescents. Additionally, we wished to investigate the relationship between fatty liver and elevated liver enzymes.

METHODS

A total of 157 obese patients (78 boys and 79 girls, mean age: 11.3 ± 2.6 years, age range: 6-16 years) were enrolled in the study. Aminotransferase, fasting glucose and lipid levels were determined. An oral glucose tolerance test was performed. The c-IMT was measured. Infectious and metabolic causes of elevated liver enzymes were excluded. The diagnosis of NAFLD was based on ultrasound scan.

RESULTS

Obese patients with NAFLD had markedly increased carotid IMT (mean: 0.48 mm, 95% CI: 0.47-0.49) than those without NAFLD (mean: 0.45 mm 95% CI: 0.44-0.45, p < 0.001). The presence of NAFLD significantly increased c-IMT whether the patient had elevated liver enzyme or not (ANOVA, p < 0.001). In a multiple-regression model, only the presence of NAFLD was associated with increased c-IMT (β = 0.031, SE (β) = 0.008, p < 0.001).

CONCLUSION

Obese children and adolescents with NAFLD are at risk of early atherosclerotic changes. As liver function tests are not sufficient to identify patients with fatty liver, ultrasonographic evaluation of NAFLD might be considered in all obese children and adolescents.

Is Overweight a Risk of Early Atherosclerosis in Childhood?

We measured brachial artery flow-mediated dilatation (FMD) and common carotid intima-media thickness (cIMT) in overweight (n = 67) and normal weight children (n = 115, controls). Age at examination ranged from 72 to 182 months (mean 123 ± 27). Compared to controls, the overweight children had increased weight, waist and hip circumference, systolic and diastolic blood pressures (all P < .001), right and left mean cIMT (mm; 0.58 [0.42-0.68] vs 0.44 [0.3-0.64], P < .001 and 0.56 [0.32-0.70] vs 0.44 [0.3-0.60], P < .001), respectively, and decreased FMD (%; 6.25 [3.33-19.05] vs 7.69 [3.45-16], P < .001). The cIMT and FMD were closely related to the serum insulin concentrations. Age, waist circumferences, and serum triglycerides were independent predictive risk factors for increased cIMT, and fasting glucose and BMI were independent predictive variables for decreased FMD. Overweight children are also potentially at risk of early atherosclerosis as much as obese children.

Abdominal aorta intima media thickness in obese children

The aim of this study is to investigate whether abdominal aorta intima media thickness (aIMT), increases in obese children and to determine risk factors. Ninety-six children aged 5-16 (51 obese and 45 non-obese) were enrolled in this prospective and cross-sectional study. Age, gender, and relative body mass index (BMI) were recorded. Their serum lipids, thyrotropin, fasting glucose and insulin levels were analyzed. The homeostasis model assessment (HOMA-IR) score was calculated for insulin resistance. Anthropometric and biochemical data were assessed along with aIMT. Findings in obese children were compared with those of non-obese control subjects. The aIMT was significantly greater in obese children. Similar trends were observed in both prepubertal children and adolescents. In obese children, the mean aIMT (mm) was 0.021 (years of age) +0.519. In non-obese children, the mean aIMT (mm) was 0.017 (years of age) +0.381. Our data suggests a relationship between glucose metabolism and aIMT in obese children. BMI was an independent risk factor for increasing aIMT. In conclusion, when compared with non-obese controls, obese children demonstrated significantly increased aIMT. Higher BMI, insulin, HOMA-IR and increased systolic blood pressure seem to be the main factors contributing to increased aIMT and risk for developing vascular disease. Childhood obesity contributes to the development of an increased aIMT.

Relevance of increased serum cystatin C to vascular alterations in obese children

OBJECTIVE

Epidemiological studies report a positive relationship between serum cystatin C and cardiovascular outcomes in adults. Here, we tested the relevance of cystatin C as a biomarker for early vascular alterations in severely obese children.

METHODS

Two hundred nineteen obese (140 girls; age = 11.7 ± 2.7 years, BMI Z-score = 4.7 ± 1.2 SD) and 262 non-obese children (129 girls; age = 11.6 ± 0.6 years, body mass index [BMI] Z-score = 0.1 ± 1.0 SD). Serum cystatin C was measured by immunonephelometry. Intima media thickness (IMT), incremental elastic modulus, and flow-mediated and glyceryl-trinitrate-mediated dilations were determined at the common carotid artery and the brachial artery in obese children.

RESULTS

Obese children had significantly higher serum cystatin C than normal weight controls (0.86 ± 0.01 vs. 0.80 ± 0.01, P < 0.0001). In obese children, serum cystatin C correlates positively with BMI and the homeostasis model assessment index and negatively with the quantitative insulin sensitivity check index and adiponectin. A positive relationship was found between serum cystatin C and carotid IMT (r = 0.23, P = 0.0005), which remained significant in multivariate models adjusted for BMI (P = 0.01) and adiponectin with a trend towards significance (P = 0.05).

CONCLUSION

This study positions cystatin C and adiponectin as covariables associated with arterial wall thickness in obese children. Although the underlying pathophysiology linking cystatin C to early vascular disease remains to be deciphered, cystatin C may represent a novel adipose tissue-derived biomarker implicated in obesity-related comorbidities early in life.

Absence of increase in carotid artery intima-media thickness in infants of diabetic mothers

OBJECTIVE

Infants of diabetic mothers (IDM) are considered as a risk group for atherosclerosis. Increased aortic intima-media thickness has been reported in IDM. The purpose of this study was to assess carotid artery intima-media thickness (CA-IMT), left ventricular mass index (LVMI) and atherosclerotic risk factors in IDM.

METHODS

Thirty IDM and 25 healthy controls were included in the study. Of these infants, 14 were appropriate-for-gestational age (AGA) and 16 were large-for-gestational age (LGA). CA-IMT and LVMI were obtained by M-mode echocardiographic examination. The relationship between parameters of atherosclerosis and echocardiographic measurements was assessed by Pearson's correlation analysis.

RESULTS

LVMI was higher in LGA IDM when compared to AGA IDM and controls. CA-IMT was not significantly different between the groups and was also not related to atherosclerotic risk factors. Serum lipid and insulin levels were higher in LGA IDM when compared with AGA IDM and controls. There were no correlations between CA-IMT, LVMI and atherosclerotic risk factors.

CONCLUSIONS

In contrast to previous reports indicating an increase in CA-IMT in IDM, no differences were found between IDM and controls in this study. Our results indicate that macrosomic IDM are prone to hypertrophic cardiomyopathy but not to atherosclerotic changes in the blood vessels.

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.

Subclinical atherosclerosis in Latino youth: progression of carotid intima-media thickness and its relationship to cardiometabolic risk factors

OBJECTIVE

To assess carotid artery intima-media thickness (CIMT) change over 2 years in overweight Latino adolescents and examine its relationship to cardiometabolic risk.

STUDY DESIGN

Seventy-two healthy overweight male and female Latino adolescents (mean age, 14.5 ± 1.7 years; mean body mass index, 31.5 ± 6.9 kg/m(2)) were evaluated at baseline and 2 years later for CIMT by high-resolution B-mode ultrasound, the metabolic syndrome and its features, body composition by dual-energy x-ray absorptiometry and magnetic resonance imaging, glucose/insulin measures by fasting blood, and oral and intravenous glucose tolerance tests.

RESULTS

Baseline CIMT did not differ from 2-year follow-up; however, 38 participants increased CIMT (0.017 ± 0.003 mm; +2.8%) and 34 decreased or remained the same (-0.019 ± 0.002 mm; -3.1%). ANCOVA analyses showed that participants with CIMT progression had higher baseline low-density lipoprotein (LDL)-cholesterol and total cholesterol (91.3 ± 3.4 and 150.3 ± 3.9 mg/dL) compared with those with CIMT non-progression (78.1 ± 3.6 and 135.6 ± 4.2 mg/dL, P < .05), independent of sex, baseline CIMT, age, and height. In multivariate regression, LDL-cholesterol was the sole predictor of CIMT progression, but the effect was small (odds of CIMT progression increased by 3% for each 1 mg/dL higher baseline LDL-cholesterol; 95% CI, 1.004 to 1.006, P = .03).

CONCLUSIONS

These results indicate a high variability in the magnitude of CIMT change in growing overweight Latino youth and support the use of LDL-cholesterol to assess subclinical atherosclerosis risk in this population.

Increased intima-media thickness of the carotid artery in childhood: a systematic review of observational studies

Increased carotid intima-media thickness (cIMT) in adults may be caused by a childhood exposure to cardiovascular risk factors. We systematically reviewed observational studies to determine whether obesity, insulin-dependent diabetes mellitus (IDDM), dyslipidemia (DL), hypertension (HT), and chronic renal failure (CRF) are associated with increased cIMT in children and adolescent patients compared with control subjects. We performed a PubMed literature search from January 1986 to February 2010. Two reviewers separately verified the inclusion criteria of relevant studies for the objective of the review. The data extracted in the patient and control groups were sample size, age, gender, cIMT measurement methods, cIMT values, and statistical analysis results. From 348 citations, 65 cross-sectional studies (2 cited twice) with case-control design met the inclusion criteria: 26 in obesity, 14 in IDDM, 11 in DL, 8 in HT, and 8 in CRF. cIMT measurement protocols varied according to the studies, with measurements being performed on the common carotid artery in 65/67 cases and on the far wall in 57/67 cases. From the 67 studies cited, 22/26 reported a significantly increased cIMT in obese children and adolescents compared with the control group, 8/14 in IDDM patients, 10/11 in DL patients, 7/8 in HT patients, and 8/8 in CRF patients.

CONCLUSION

Despite the heterogeneity of ultrasound measurement methods, cIMT was significantly increased in 55 out of the 67 cited studies, confirming early vascular damages in pediatric populations with an increased future risk for vascular diseases.

Cardiovascular risk factors and noninvasive assessment of arterial structure and function in obese Turkish children

Obesity is associated with a number of risk factors, such as hyperlipidemia, hyperinsulinemia, hypertension, and early atherosclerosis. Evidence indicates that atherosclerosis begins in childhood and progresses over decades. In this work, we examined the relationship between cardiovascular risk factors and ultrasonographic signs of subclinical atherosclerosis in 77 obese children and adolescents compared to 40 non-obese healthy peers. Carotis intima media thickness (cIMT), carotid artery compliance (CAC), brachial artery flow-mediated dilatation (FMD), and established cardiovascular risk factors were studied. In the obese patients, cIMT was significantly increased (0.57 mm vs 0.45 mm, p < 0.001) whereas CAC (1.84% vs 3.29%, p < 0.001) and FMD (9.67 % vs 14.81%, p < 0.001) were significantly decreased. In multiple linear regression analysis, a relation was observed between cIMT, CAC, brachial FMD on one hand, and body mass index (BMI) on the other. Among the lipid anomalies, only hypertriglyceridemia was found to be positively correlated with cIMT. Additionally, we found a significant association between waist circumference (WC) and FMD. These findings indicate that obesity in children is associated with arterial wall alterations and endothelial dysfunction. In hyperlipidemic situations, only hypertriglyceridemia was found to be positively correlated with cIMT. This finding has consistently indicated TG to be a risk factor for the development of atherosclerosis. To our knowledge this is the first study to determine the relation between FMD and WC, which is used as a parameter of obesity in childhood.

Carotid Intima-media thickness in childhood and adolescent obesity relations to abdominal obesity, high triglyceride level and insulin resistance

AIM

To investigate risk factors which impact on common carotid artery intima media thickness (IMT).

METHODS

A total of 86 obese children and adolescents and 22 healthy children and adolescents with normal weight were enrolled. Moreover, 23 of 86 obese children and adolescents were diagnosed with metabolic syndrome (MetS). The clinical, biochemical data and the IMT of the common carotid artery were measured in all subjects.

RESULTS

Obese and obese with MetS subjects demonstrated a significantly (p < 0.01) thicker intima media (0.69mm, 0.66mm) as compared to the control group (0.38mm), but there was no significant difference of IMT between obese and MetS group. IMT was correlated to body weight, body mass index, waist circumference, waist to hip ratio, systolic blood pressure, diastolic blood pressure, fasting insulin, homoeostasis model assessment-insulin resistance, triglyceride, high-density lipoprotein- cholesterol, low-density lipoprotein-cholesterol, alanine aminotransferase, aspartate aminotransferase and fatty liver. Waist circumference, waist to hip ratio, triglyceride and homoeostasis model assessment-insulin resistance were independent determinants of mean IMT level.

CONCLUSION

Obesity especially abdominal obesity, high TG and insulin resistance may be the main risk predictors of increased IMT.

Importance of plasma N-terminal pro B-type natriuretic peptide, epicardial adipose tissue, and carotid intima-media thicknesses in asymptomatic obese children

This study aimed to analyze the variations of N-terminal pro B-type natriuretic peptide, epicardial adipose tissue thickness, and carotid intima-media thickness in childhood obesity. The study participants consisted of 50 obese children in the study group and 20 nonobese children referred for evaluation of murmurs who proved to have an innocent murmur and were used as control subjects. All the subjects underwent transthoracic echocardiographic examination for determination of left ventricular systolic function and mass index, myocardial tissue rates, and myocardial performance index. Epicardial adipose tissue thickness and carotid intima-media thickness also were measured during echocardiography. Serum N-terminal pro B-type natriuretic peptide levels were measured at the time of evaluation. The left ventricle mass index was 40.21 + or - 10.42 g/m(2) in the obese group and 34.44 + or - 4.51 g/m(2) in the control group (p > 0.05). The serum N-terminal pro B-type natriuretic peptide level was 109.25 + or - 48.53 pg/ml in the study group and 51.96 + or - 22.36 pg/ml and in the control group (p = 0.001). The epicardial adipose tissue thickness was 5.57 + or - 1.45 mm in the study group and 2.98 + or - 0.41 mm in the control group (p = 0.001), and the respective carotid intima-media thicknesses were 0.079 + or - 0.019 cm and 0.049 + or - 0.012 cm (p = 0.001). The left ventricular systolic and diastolic functions showed no statistically significant correlations with N-terminal pro B-type natriuretic peptide levels, carotid intima-media thickness, or epicardial adipose tissue thickness values. The results show that measurement of serum N-terminal pro B-type natriuretic peptide level, carotid intima-media thickness, and epicardial adipose tissue thickness in asymptomatic obese children is not needed.

Insulin resistance predicts mortality in nondiabetic individuals in the U.S

OBJECTIVE

Insulin resistance is a suspected causative factor in a wide variety of diseases. We aimed to determine whether insulin resistance, estimated by the homeostasis model assessment for insulin resistance (HOMA-IR), is associated with all-cause or disease-specific mortality among nondiabetic persons in the U.S.

RESEARCH DESIGN AND METHODS

We determined the association between HOMA-IR and death certificate-based mortality among 5,511 nondiabetic, adult participants of the third U.S. National Health and Nutrition Examination Survey (1988-1994) during up to 12 years of follow-up, after adjustment for potential confounders (age, sex, BMI, waist-to-hip ratio, alcohol consumption, race/ethnicity, educational attainment, smoking status, physical activity, C-reactive protein, systolic and diastolic blood pressure, plasma total and HDL cholesterol, and triglycerides).

RESULTS

HOMA-IR was significantly associated with all-cause mortality (adjusted hazard ratio 1.16 [95% CI 1.01-1.3], comparing successive quartiles of HOMA-IR in a linear model and 1.64 [1.1-2.5], comparing the top [HOMA-IR >2.8] to the bottom [HOMA-IR <or=1.4] quartile). HOMA-IR was significantly associated with all-cause mortality only in subjects with BMI <25.2 kg/m(2) (the median value) but not in subjects with BMI >or=25.2 kg/m(2). Subjects in the second, third, and fourth quartile of HOMA-IR appeared to have higher cardiovascular mortality than subjects in the lowest quartile of HOMA-IR. HOMA-IR was not associated with cancer-related mortality.

CONCLUSIONS

HOMA-IR is associated with all-cause mortality in the nondiabetic U.S. population but only among persons with normal BMI. HOMA-IR is a readily available measure that can be used in the future to predict mortality in clinical or epidemiological settings.

Early markers of cardiovascular dysfunction in young girls affected by Cushing's syndrome before and after successful cure

BACKGROUND

even after successful surgical cure, Cushing's Syndrome (CS) may induce cardiovascular (CV) diseases including hypertension, or elicit onset of CV risk factors, such as obesity.

OBJECTIVES

to evaluate some early markers of CV dysfunction in adolescent girls before and after successful surgical cure of CS; to compare after surgery data with those of a control group (C) of healthy young girls.

METHODS

23 girls affected by CS were enrolled (range: 11-17 years; mean: 14.3 +/- 1.7 years). Epicardial fat thickness (EFT), intima-media thickness (IMT), N-terminal pro B-type natriuretic peptide (NT-proBNP) were assessed; transthoracic echocardiogram coupled with Tissue Doppler imaging (TDI) was performed. RESULTS (CS before surgery vs. CS after surgery): EFT (p < 0.05). (CS after surgery vs. C): EFT (p = 0.0001); IMT (p = 0.0001); NT-proBNP (p = 0.0001). TDI: isovolumetric relaxation time (p = 0.001); isovolumetric contraction time (p = 0.001); myocardial performance index (p = 0.001). Significant correlations: NT-proBNP with IRT (r = 0.45, p = 0.026 ), ICT (r = 0.47, p = 0.028), and myocardial performance index (r = 0.51, p = 0.0032).

CONCLUSIONS

important structural and functional modifications of heart and vessels are present in young female CS despite successful surgical cure, even in paediatric age. It underlines their significantly higher cardiovascular risk. Our findings confirm that EFT, IMT, NT-proBNP and TDI diastolic parameters, not previously tested in paediatric CS, are early markers of cardiovascular dysfunction. Because of its relationship with TDI, the assessment of NT-proBNP proves to be the best marker in detecting a cardiovascular dysfunction in this specific population.

Association between adipocyte fatty acid-binding protein levels and childhood obesity in Korean children

Adipocyte fatty acid-binding protein (A-FABP) is a newly recognized adipokine that plays a role in the development of obesity and insulin resistance in adults. We investigated the association between A-FABP levels and obesity and insulin resistance in school-aged children. One hundred sixty-one 9-year-old Korean children (80 boys and 81 girls) voluntarily participated in this study at school-based health examinations. Weight, height, waist circumference, and blood pressure were measured. Fasting plasma glucose, triglycerides, high-density lipoprotein cholesterol, insulin, and A-FABP levels were measured; and insulin resistance was estimated by the homeostasis model assessment. Subjects with higher body mass index (BMI) percentiles had correspondingly higher concentrations of A-FABP in both boys and girls. Subjects within the highest quartile of A-FABP levels had correspondingly poor metabolic risk profiles (BMI, waist circumference, triglycerides, high-density lipoprotein cholesterol, fasting insulin, and homeostasis model assessment of insulin resistance) compared with those in the lowest A-FABP quartile (P < .01). Serum A-FABP concentrations were significantly correlated with BMI (r = 0.58, P < .01) and waist circumference (r = 0.51, P < .01). However, the significant correlation between serum A-FABP and insulin resistance faded after adjustment for BMI. Adipocyte fatty acid-binding protein was closely associated with obesity or abdominal obesity in children; however, the independent relationship between A-FABP and insulin resistance in children is still unclear and remains to be determined.

Vaspin and its correlation with insulin sensitivity indices in obese children

AIM

The aim of this study was to assess the vaspin and adiponectin concentrations on markers of insulin sensitivity and obesity in pubertal obese children and adolescents.

MATERIAL AND METHODS

Plasma vaspin and adiponectin level and its relationships with body mass index standard deviation score (BMI-SDS), insulin sensitivity and lipids were analyzed in 33 pubertal obese children (19 girls and 14 boys) and 36 healthy control children (18 girls and 18 boys) aged 11-16 years. Insulin resistance was evaluated by homeostasis model assessment (HOMA-IR) and fasting glucose-to-insulin ratio (FGIR). Plasma vaspin and adiponectin concentrations were determined with radioimmunoassay.

RESULTS

Mean vaspin levels were found significantly higher and inversely, adiponectin levels were found significantly lower in obese pubertal group than control subjects. Vaspin levels were positively correlated with BMI-SDS, triglycerides, fasting insulin and HOMA-IR and negatively correlated with adiponectin levels and FGIR. Adiponectin levels were positively correlated with high density lipoprotein-chloesterol, FGIR and negatively correlated with vaspin, BMI-SDS, fasting insulin and HOMA-IR.

CONCLUSION

We found higher vaspin and lower adiponectin levels in obese children and these adipokines were significantly correlated with insulin sensitivity indices in this age.

Youth with obesity and obesity-related type 2 diabetes mellitus demonstrate abnormalities in carotid structure and function

BACKGROUND

Adults with obesity or type 2 diabetes mellitus (T2DM) are at higher risk for stroke and myocardial infarction. Increased carotid intima-media thickness (cIMT) and stiffness are associated with these adverse outcomes. We compared carotid arteries in youth who were lean, were obese, or had T2DM.

METHODS AND RESULTS

Carotid ultrasound for cIMT measurement was performed, the Young elastic modulus and beta stiffness index were calculated, and anthropometric and laboratory values and blood pressure were measured in 182 lean, 136 obese, and 128 T2DM youth (aged 10 to 24 years). Mean differences were evaluated by ANOVA. Independent determinants of cIMT, Young elastic modulus, and beta stiffness index were determined with general linear models. Cardiovascular risk factors worsened from lean to obese to T2DM groups. T2DM subjects had greater cIMT than that in lean and obese subjects for the common carotid artery and bulb. For the internal carotid artery, cIMT measurements in both obese and T2DM groups were thicker than in the lean group. The carotid arteries were stiffer in obese and T2DM groups than in the lean group. Determinants of cIMT were group, group x age interaction, sex, and systolic blood pressure for the common carotid artery (r2=0.17); age, race, and systolic blood pressure for the bulb (r2=0.16); and age, race, sex, systolic blood pressure, and total cholesterol for the internal carotid artery (r2=0.21). Age, systolic blood pressure, and diastolic blood pressure were determinants of all measures of carotid stiffness, with sex adding to the Young elastic modulus (r2=0.23), and body mass index Z score, group, and group x age interaction contributing to the beta stiffness index (r2=0.31; all P<0.0001).

CONCLUSIONS

Youth with obesity and T2DM have abnormalities in carotid thickness and stiffness that are only partially explained by traditional cardiovascular risk factors. These vascular changes should alert healthcare practitioners to address cardiovascular risk factors early to prevent an increase in the incidence of stroke and myocardial infarction.

Abnormal vascular reactivity at rest and exercise in obese boys

BACKGROUND

Obese children exhibit vascular disorders at rest depending on their pubertal status, degree of obesity, and level of insulin resistance. However, data regarding their vascular function during exercise remain scarce. The aims of the present study were to evaluate vascular morphology and function at rest, and lower limb blood flow during exercise, in prepubertal boys with mild-to-moderate obesity and in lean controls.

MATERIALS AND METHODS

Twelve moderately obese prepubertal boys [Body Mass Index (BMI: 23.9+/-2.6 kg m(-2))] and thirteen controls (BMI:17.4+/-1.8 kg m(-2)), matched for age (mean age: 11.6+/-0.6 years) were recruited. We measured carotid intima-media thickness (IMT) and wall compliance and incremental elastic modulus, resting brachial flow-mediated dilation (FMD) and nitrate-dependent dilation (NDD), lower limb blood flow during local knee-extensor incremental and maximal exercise, body fat content (DEXA), blood pressure, blood lipids, insulin and glucose.

RESULTS

Compared to lean controls, obese boys had greater IMT (0.47+/-0.06 vs. 0.42+/-0.03 mm, P<0.05) but lower FMD (4.6+/-2.8 vs. 8.8+/-3.2%, P<0.01) in spite of similar maximal shear rate, without NDD differences. Lower limb blood flow (mL min(-1).100 g(-1)) increased significantly from rest to maximal exercise in both groups, although obese children reached lower values than lean counterparts whatever the exercise intensity.

CONCLUSIONS

Mild-to-moderate obesity in prepubertal boys without insulin resistance is associated with impaired endothelial function and blunted muscle perfusion response to local dynamic exercise without alteration of vascular smooth muscle reactivity.

[Critical analysis on the use of the homeostasis model assessment (HOMA) indexes in the evaluation of the insulin resistance and the pancreatic beta cells functional capacity]

Beta-cell dysfunction and insulin resistance are interrelated metabolic abnormalities in the aetiology of Type 2 Diabetes. In several countries, increases in the prevalence of obesity and diabetes have been observed in association with the presence of insulin resistance. In this context, measurement of insulin resistance and beta-cell function is useful. The HOMA indexes (Homeostasis Model Assessment) have been widely used, representing an alternative for the evaluation of these parameters, particularly as a fast, easy and cheap method. This review discusses the origin and evolution of the HOMA index, as well as details of the method, analyzing features related to its validation and the cutoff limits for its interpretation.

Association of BMI and fasting insulin with cardiovascular disease risk factors in seven-year-old Icelandic children

OBJECTIVE

. To look at overweight and common cardiovascular disease (CVD) risk factors, and associations with body mass index (BMI) and fasting insulin in seven-year-old schoolchildren in Reykjavik, Iceland.

STUDY DESIGN

Cross-sectional study of seven-year-old schoolchildren.

SETTING

Six elementary schools in Reykjavik.

SUBJECTS

All children attending second grade in these six schools were invited to participate.

MAIN OUTCOME MEASURES

Overweight, fasting serum insulin, CVD risk factors.

RESULTS

Some 14% of the participating children were classified as overweight. Overweight children had higher fasting insulin, higher fasting glucose, and higher systolic and diastolic blood pressure. Furthermore, they had significantly lower total cholesterol (TC), lower high-density lipoprotein (HDL), and lower low-density lipoprotein (LDL) but a similar TC/LDL ratio to normal-weight children. The factors that were strongly associated with BMI were serum fasting insulin, systolic blood pressure (SBP), HDL and fasting glucose, while the sum of four skinfolds, triglycerides, glucose, and LDL were highly associated with fasting insulin.

CONCLUSION

Overweight children are likelier to have unfavourable levels of common CVD risk factors included in metabolic syndrome, but surprisingly had lower LDL and TC. Skinfold thickness, higher triglyceride and glucose levels, and being female were associated with increased serum insulin.

Association of insulin resistance and inflammation with peripheral arterial disease: the National Health and Nutrition Examination Survey, 1999 to 2004

BACKGROUND

Although the role of inflammation in the pathophysiology of peripheral arterial disease (PAD) is well established, the contribution of insulin resistance (IR) to PAD is less clear. We hypothesized that IR is associated with PAD and that the presence of IR would influence the association between C-reactive protein (CRP) and PAD, an association established predominantly in healthy individuals.

METHODS AND RESULTS

We analyzed data from 3242 adults in the National Health and Nutrition Examination Survey (NHANES) 1999 to 2004 who underwent measurement of ankle brachial index, CRP, and fasting glucose and insulin, enabling calculation of homeostasis model of IR (HOMA-IR). Odds ratios (ORs) and 95% CIs were estimated by logistic regression. The mean prevalence of PAD (defined as an ankle brachial index </=0.9) was 5.5% (SE, 0.47%). HOMA-IR was independently associated with PAD (OR, 2.06; 95% CI, 1.1 to 4.0; P=0.03 for quartile 4, P for trend across quartiles=0.047) after adjustment for age, gender, race/ethnicity, hypertension, hyperlipidemia, smoking, body mass index, chronic kidney disease, and CRP. Elevated CRP (>3 mg/L) also was strongly associated with PAD (OR, 2.2; 95% CI, 1.3 to 3.6; P=0.003 versus CRP <1 mg/L). Stratifying subjects on the basis of median HOMA-IR, we found that CRP >3 mg/L was no longer significantly associated with PAD in subjects with IR (OR, 1.3; 95% CI, 0.8 to 2.1; P=0.3, P for interaction=0.08).

CONCLUSIONS

These findings demonstrate that IR is strongly and independently associated with PAD. Furthermore, IR modifies the association of inflammation with PAD. These data establish a role of IR in PAD and highlight the relative importance of inflammation in patients with and without IR.

Nonalcoholic fatty liver disease and carotid atherosclerosis in children

Nonalcoholic fatty liver disease (NAFLD) is closely associated with several metabolic syndrome features, including obesity, dyslipidemia, insulin resistance, and increased cardiovascular risk. The present study was undertaken to assess whether NAFLD in children is associated with increased carotid artery intima-media thickness (IMT), a marker of early-generalized atherosclerosis. We analyzed carotid IMT along with serum triglycerides, total, low-density lipoprotein and high-density lipoprotein cholesterol, glucose, insulin, insulin resistance index (as homeostasis model assessment of insulin resistance), aminotransferases, leptin, and adiponectin in 29 obese children with NAFLD, 33 obese children without liver involvement, and 30 control children. The diagnosis and severity of NAFLD was based on ultrasound scan, after exclusion of infectious and metabolic disorders. Obese children with NAFLD had significantly increased carotid IMT [mean 0.58 (95% confidence intervals 0.54-0.62 mm)] than obese children without liver involvement [0.49 (0.46-0.52) mm; p = 0.001] and control children [0.40 (0.36-0.43) mm; p < 0.0005]. In a stepwise multiple regression model, after adjusting for age, gender, Tanner stage, and cardiovascular risk factors, the severity of fatty liver was significantly associated with maximum IMT (b = 0.08; p < 0.0005). Our results suggest that NAFLD is strongly associated with carotid atherosclerosis even in childhood.

Carotid intima-media thickness in children and young adults with renal transplant: Internal carotid artery vs. common carotid artery

Cardiovascular diseases are the main causes of morbidity and mortality following renal transplantation. Atherosclerotic structural changes, which can be detected by high-resolution B-mode ultrasonography, begin before clinical findings. However, little is known about the extent of these abnormalities in children after renal transplantation. We aimed to determine early structural changes of large arteries in renal transplant recipients without cardiovascular disease and to evaluate the role of clinical and laboratory features on IMT of carotid arteries. IMT and hemoglobin, serum levels of creatinine, acute phase proteins, lipid profile, and homocysteine were examined in 24 asymptomatic renal transplant recipients (median age 16.5 yr; range 8-25), and 20 healthy controls (median age 16 yr; range 9-24). CCA and ICA were evaluated in patients and controls with a high-resolution B-mode ultrasonography in multiple projections to optimize detection of carotid IMT. Measurement of IMT of both CCA [0.36 mm (range 0.16-0.48) vs. 0.28 mm (range 0.21-0.35), p < 0.001] and ICA [0.27 mm (range 0.16-0.48) vs. 0.22 mm (range 0.1-0.26), p < 0.001] were significantly higher in renal recipients than in healthy controls. Among several parameters assessed, only significant correlations were found between duration of CRF, duration of dialysis prior to transplantation and ICA-IMT (p = 0.06 and p = 0.02, respectively) and between mean past serum calcium-phosphorus ion product and CCA-IMT (p = 0.002). In conclusion, our observations indicate that vascular changes begin early in the course of CRF and are directly related to time on CRF and dialysis. These changes can be detected by measuring CCA/ICA-IMT ultrasonographically. We suggest that early renal transplantation can potentially avoid long-term cardiovascular events in children with end stage kidney disease.

Dietary lipids in early development: relevance to obesity, immune and inflammatory disorders

PURPOSE OF REVIEW

Regardless of social, cultural and behavioural environments, obesity is usually caused by an energy intake above requirements, which is accommodated by the accumulation of triacylglycerols. The composition of dietary fat impacts tissue fatty acids, which are important modulators of multiple cell functions, including differentiation, lipogenesis, lipolysis and the generation of inflammatory mediators. This review focuses on the possible contribution of fatty acids to the link between obesity and inflammation in young children.

RECENT FINDINGS

Adipose tissue is a complex organ that functions to regulate fatty acid balance, clearing and releasing fatty acids, and synthesizing protein and signaling molecules that act as local and distant inflammatory mediators. Obesity, even in young children, is associated with increased circulating inflammatory mediators. As a result of changes in dietary fat compositions, infants are exposed to high n-6, saturated and trans fatty acids and low n-3 fatty acids. Saturated and trans fatty acids increase and n-3 fatty acids decrease many metabolic and inflammatory changes that accompany diet-induced triacylglycerol storage. High linoleic acid is associated with increased oxidative stress.

SUMMARY

There is a biological reason to consider that dietary fatty acids may contribute to oxidative stress and heightened inflammatory responses in young children.