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

Vascular Alterations Preceding Arterial Wall Thickening in Overweight and Obese Children

Background: Childhood obesity is linked to adverse cardiovascular outcomes in adulthood. This study aimed to assess the impact of childhood obesity on the vasculature and to investigate whether vascular alteration precedes arterial wall thickening in childhood. Methods: A total of 295 overweight (body mass index [BMI] 85th to 95th percentile, n = 30) and obese (BMI ≥ 95th percentile, n = 234) children aged 7–17 years and 31 normal-weight controls with similar age and gender were prospectively recruited. We assessed anthropometric data and laboratory findings, and measured the carotid intima–media thickness (IMT), carotid artery (CA) diameter, M-mode-derived arterial stiffness indices, and velocity vector imaging parameters, including the CA area, fractional area change, circumferential strain, and circumferential strain rate (SR). Results: The mean ± standard deviation age of the participants was 10.8 ± 2.1 years; 172 (58%) children were male. Regarding structural properties, there was no difference in the IMT between the three groups. The CA diameter was significantly increased in obese children, whereas the CA area showed a significant increase beginning in the overweight stage. Regarding functional properties, contrary to β stiffness and Young’s elastic modulus, which were not different between the three groups, the circumferential SR showed a significant decrease beginning in the overweight stage and was independently associated with BMI z-scores after adjusting for covariates. Conclusion: We have demonstrated that arterial stiffening and arterial enlargement precede arterial wall thickening, and that these vascular alterations begin at the overweight stage in middle childhood or early adolescence.

Adiposity and carotid-intima media thickness in children and adolescents: a systematic review

Background

Adiposity in childhood is associated with later cardiovascular disease (CVD), but it is unclear whether this relationship is independent of other risk factors experienced in later life, such as smoking and hypertension. Carotid-intima media thickness (cIMT) is a measure of subclinical atherosclerosis that may be used to assess CVD risk in young people. The aim of this study was to examine the relationship between adiposity and cIMT in children and adolescents.

Methods

We searched Medline, Embase, Global Health, and CINAHL Plus electronic databases (1980–2014). Population-based observational studies that reported a measure of association between objectively-measured adiposity and cIMT in childhood were included in this review.

Results

Twenty-two cross-sectional studies were included (n = 7,366 children and adolescents). Thirteen of nineteen studies conducted in adolescent populations (mean age ≥12 years, n = 5,986) reported positive associations between cIMT and adiposity measures (correlation coefficients 0.13 to 0.59). Three studies of pre-adolescent populations (n = 1,380) reported mixed evidence, two studies finding no evidence of a correlation, and one an inverse relationship between skinfolds and cIMT. Included studies did not report an adiposity threshold for subclinical atherosclerosis.

Conclusions

Based on studies conducted mostly in Western Europe and the US, adiposity does not appear to be associated with cIMT in pre-adolescents, but may be associated in adolescents. If further studies confirm these findings, a focus on cardiovascular disease prevention efforts in pre-adolescence, before arterial changes have emerged, may be justified.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-015-0478-5) contains supplementary material, which is available to authorized users.

Preclinical manifestations of organ damage associated with the metabolic syndrome and its factors in outpatient children

BACKGROUND

To evaluate whether the pediatric metabolic syndrome (MetS) or its factors are useful to detect subclinical abnormalities of cardiac, liver, and glomerular damage in an outpatient population.

METHODS

The population study included 799 children (age 10 ± 3 years, mean ± SD), 24% of whom were normalweight, 25% overweight, and 51% obese. Alanine-aminotransferase (ALT) levels, estimated glomerular filtration rate (eGFR) and HOMA-IR were analyzed in all children. Microalbuminuria (MA) and left ventricular (LV) geometry and function were evaluated in 501 and 247 children, respectively. MetS was defined using Cook's criteria.

RESULTS

MetS was diagnosed in 131 children (16%). Children with MetS+ and MetS- were similar for age, gender and Tanner stage distribution. Children with MetS+ showed higher ALT levels (31 ± 19 vs 21 ± 11 IU/L, p<0.0001), LV mass (39 ± 10 vs 34 ± 10 g/h(2.7), p<0.001) and relative wall thickness (0.37 ± 0.06 vs 0.35 ± 0.05, p<0.01) than MetS-. The two groups were similar for MA and eGFR. At multiple logistic regression analysis, children MetS+ showed a higher risk (OR, 95% Cl) adjusted for confounding factors, of high ALT levels (1.71, 1.12-2.59, p=0.012) and concentric LV hypertrophy (2.17, 1.01-4.66, p=0.047) than children MetS-. The risk of preclinical liver and cardiac damage associated with the MetS phenotype was not higher than predicted by its single components.

CONCLUSIONS

Children with MetS show a 2-fold greater risk of having high ALT levels and concentric LV hypertrophy. However, the risk of subclinical manifestations of liver and cardiac damage can be predicted equally well by the single components of the syndrome.

Left ventricular mass index in children with white coat hypertension

OBJECTIVES

To determine whether children with white coat hypertension (WCH) have evidence of target-organ damage by comparing the left ventricular mass index (LVMI) of subjects with WCH with that of matched normotensive and hypertensive controls.

STUDY DESIGN

Each subject in the WCH group was matched by body mass index (BMI; +/- 10%), age (+/- 1 year), and sex to a normotensive control and a hypertensive control. Echocardiograms were reviewed to determine the LVMI for each subject. These triple matches were analyzed using repeated-measures analysis of variance to detect differences in LVMI among the 3 groups.

RESULTS

A total of 27 matched triplets were established. The groups were comparable for sex, age, and BMI. Mean LVMI was 29.2 g/m(2.7) for the normotensive group, 32.3 g/m(2.7) for the WCH group, and 35.1 g/m(2.7) for the sustained hypertensive group (normotensive vs WCH, P = .028; WCH vs sustained hypertension, P = .07). Left ventricular hypertrophy was not present in any subject in the normotensive or WCH groups, but was found in 26% of the sustained hypertensive subjects (P < .001).

CONCLUSIONS

After controlling closely for BMI, the LVMI in the subjects with WCH was between that of the normotensives and sustained hypertensives, suggesting that WCH may be associated with hypertensive end-organ effects.

Metabolic syndrome and dyslipidemia in youth

Obesity is a well-known risk factor for metabolic syndrome. Although the cause or causes of metabolic syndrome are debated, insulin resistance, dyslipidemia, and hypertension are increasingly recognized in children and adolescents, especially those who are overweight or obese. Although adoption of a healthy lifestyle early in life offers the best long-term solution, many children and adolescents are currently at risk for future cardiovascular disease. Although long-term outcome data are lacking, the dyslipidemic triad commonly seen in youth with metabolic syndrome (elevated triglycerides, low high-density lipoprotein, and small dense low-density lipoprotein) is likely to significantly contribute to future vascular disease. Surrogate markers (carotid intima-media thickness and flow-mediated vasodilatation) for the precursors of cardiovascular disease are increased in obese youth, consistent with early vascular damage. In this work, we review the features of metabolic syndrome in children and adolescents, including age- and gender-specific norms for lipid values. Diagnostic criteria and modifications of screening guidelines unique to youth are discussed. Although recommendations for lifestyle modification are suggested for all, many youth at high risk of future cardiovascular risk may need more aggressive medical interventions to improve insulin sensitivity, achieve a less atherogenic lipid profile, and lower blood pressure.