Metabolic syndrome in obese Caucasian children: prevalence using WHO-derived criteria and association with nontraditional cardiovascular risk factors

Albuminuria in children

PURPOSE OF REVIEW

Albuminuria is a marker of present and future cardiovascular and renal morbidity, and mortality, in adults. Because the roots of these diseases extend back into childhood, assessment of albuminuria has become relevant to child and adolescent clinical care.

RECENT FINDINGS

Normal levels of albumin excretion in children are well below the cut-off for microalbuminuria. In healthy children, albuminuria relates to fasting insulin, but not blood pressure, BMI, lipid levels, fasting glucose, or insulin resistance. In obese children, albuminuria relates to multiple measures of insulin resistance. In children with type 1 diabetes, hemoglobin A1c seems to be the most consistent clinical predictor of microalbuminuria although multiple mechanisms seem to be involved, including genetic polymorphisms. Children with type 2 diabetes and hypertension already exhibit microalbuminuria.

SUMMARY

When considering the population as a whole, children make ideal subjects in which to study the natural history of albuminuria given their relative lack of multiple morbidities commonly seen in adults. The unfortunate rise in 'adult' diseases in the pediatric age group makes this especially relevant. There is a need for longitudinal studies examining predictors of elevated urinary albumin levels as well as potential treatment strategies.

Serum uric acid and its association with metabolic syndrome and carotid atherosclerosis in obese children

OBJECTIVE

The association between hyperuricemia, metabolic syndrome (MS), and atherosclerotic vascular disease has been reported in adults, but very little is known about this association in children. The aims of our study were to ascertain the correlates of uric acid (UA) in a sample of obese children, and to investigate whether UA is associated with carotid intima-media thickness (IMT) independently from classical risk factors including MS.

METHODS

We analyzed carotid IMT along with serum triglycerides, total and high-density lipoprotein cholesterol, glucose, insulin, insulin resistance index (as homeostasis model assessment of insulin resistance), alanine aminotransferase, gamma-glutamyltransferase, creatinine, and UA in 120 obese children and 50 healthy control children.

RESULTS

UA concentrations were significantly higher in obese children compared with controls; moreover, they correlated with the most established cardiovascular risk factors. In the group of obese children, after adjustment for age, sex, pubertal stage, and creatinine, an independent association between UA levels and the presence of MS syndrome was observed (unstandardized coefficient, 0.044 (95% confidence intervals (CI) 0.015-0.072); P<0.01). Carotid IMT significantly increased in the fourth quartile of UA compared with that in the first, second, and third quartile (0.49 (0.46-0.53), 0.53 (0.49-0.56), and 0.55 (0.52-0.59) vs 0.61 (95% CI, 0.58-0.64); P<0.01). When multivariate analysis was performed after adjusting for age, gender, pubertal stage, creatinine, and MS (considered as a single clinical entity), or the individual components of MS simultaneously included, the association between UA and carotid IMT was significant (P<0.01).

CONCLUSIONS

In obese children and adolescents, increased UA levels are associated with carotid atherosclerosis.

Prevalence and risk factors of metabolic syndrome in Brazilian and Italian obese adolescents: a comparison study

BACKGROUND

Metabolic syndrome (MS) prevalence between different populations in obese adolescents is scanty to date.

OBJECTIVE

To compare the MS prevalence and related risk factors in Brazilian and Italian obese adolescents.

METHODS

A total of 509 adolescents (110 Brazilian, 399 Italian), aged 15-19 years. Anthropometric characteristics, triglycerides (TG), total, low-density lipoprotein (LDL)-, high-density lipoprotein (HDL)-cholesterol, fasting plasma glucose (FPG), insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and blood pressure were measured.

RESULTS

Age, body mass index (BMI) and BMI z-score were not significantly different between the two subgroups. BMI z-score, TG, FPG, HOMA-IR and systolic blood pressure (SBP) were significantly higher in boys than in girls both in Brazilian and Italian adolescents, while HDL-cholesterol levels were lower in boys than in girls. No significant differences were observed in BMI, LDL and total-cholesterol and DBP in two genders and groups. Insulin, FPG, HOMA-IR and TG were significantly higher, while LDL-cholesterol and SBP were significantly lower in Brazilian than in Italian subjects, both in males and females. HDL and total-cholesterol and diastolic blood pressure (DBP) were not significantly different between the two subgroups and genders. MS prevalence was higher in Brazilian than in Italian obese boys (34.8 vs. 23.6%, p < 0.001) and girls (15.6 vs. 12.5%, p < 0.01). The most frequently altered parameter was HOMA-IR both in subjects with MS (100% in Brazilian and 81.8% in Italian) and without MS (42.9% and 11.7%).

CONCLUSION

Metabolic syndrome represents a worldwide emerging health problem in different ethnical populations, the alterations of the risk factors related to MS (different in their prevalence between different subgroups) being strictly linked to the degree of obesity.

Adipokines and the prediction of the accumulation of cardiovascular risk factors or the presence of metabolic syndrome in elementary school children

BACKGROUND

Information is limited about how adipokines predict the accumulation of cardiovascular (CV) risk factors or the presence of metabolic syndrome (MS) in children.

METHODS AND RESULTS

The subjects were 321 children (200 boys and 121 girls; 109 normal and 212 obese) aged 6-12 years. Obesity was defined as a body mass index of >or= the 95(th) percentile for age and sex. MS was defined by using the newly established Task Force criteria. The levels of the adipokines--adiponectin, leptin, ghrelin, high sensitive C-reactive protein (CRP) and resistin--were measured. Regression analyses revealed that high leptin levels were predictive of the accumulation of CV risk factors in normal weight, obese, and entire (normal weight and obese) group of subjects. High CRP in the normal weight group and low adiponectin in the obese and the entire groups were also independently predictive of the accumulation of risk factors. A high leptin level was solely predictive of the presence of MS in obese and entire groups.

CONCLUSIONS

Leptin was the most sensitive marker for predicting the accumulation of CV risk factors and the presence of MS in elementary school children. Primary prevention is important because both leptin and adiponectin levels abruptly worsened when children obtained any 1 risk factor.

Prevalence of metabolic syndrome (MS) in children and adolescents with varying degrees of obesity

OBJECTIVE

Childhood obesity is increasingly common and is associated with health problems; in particular, obesity plays a central role in the metabolic syndrome (MS). We estimated the prevalence of MS in Caucasian children and adolescents with varying degrees of obesity.

PATIENTS AND METHODS

We studied 191 obese [body mass index (BMI) > 97th percentile] children and adolescents. Obesity was stratified on the basis of a threshold BMI z-score and subjects were classified as moderately (z-score 2-2.5) or severely obese (z-score > 2.5). Seventy-six, nonobese subjects were recruited into a comparison group. Thirty-one of them were of normal weight (BMI < 75th percentile) and 45 overweight (BMI 75th-97th percentile). Patients were classified as having MS if they met three or more of the following criteria for age and sex: BMI > 97th percentile, triglyceride levels > 95th percentile, high density lipoprotein (HDL) cholesterol level < 5th percentile, systolic or diastolic blood pressure > 95th percentile and impaired glucose tolerance (blood glucose level: 7.8-11.1 mmol/l at 2 h). Insulin resistance was calculated using the homeostasis model assessment for insulin resistance (HOMA-IR) and impaired insulin sensitivity was defined as a HOMA-IR > or = 2.5 in prepubertal patients and HOMA-IR > 4 in pubertal subjects.

RESULTS

The overall prevalence of MS was 13.9% and was present in 12.0% of moderately obese and 31.1% of severely obese subjects; no overweight or normal weight subjects met the criteria for MS. The rate of the MS increased progressively with increasing BMI categories (P < 0.001). Severely obese patients had a threefold increased risk with respect to moderately obese patients.

CONCLUSIONS

The prevalence of the MS is higher in obese as opposed to nonobese subjects and increases with severity of obesity.

Albumin excretion rate in normal adolescents: relation to insulin resistance and cardiovascular risk factors and comparisons to type 1 diabetes mellitus patients

BACKGROUND AND OBJECTIVES

Although albumin excretion rates have been related to cardiovascular morbidity and mortality in both diabetic and nondiabetic adults, little is known about the relation between albuminuria and either cardiovascular risk factors or the insulin resistance syndrome in adolescents. A normal range for albumin excretion in adolescents was established, correlations between albumin excretion and cardiovascular risk factors were evaluated, and albumin excretion in normal adolescents was compared with that in type 1 diabetes mellitus adolescents.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Albumin excretion rate was measured in 368 normal and 175 diabetic adolescents. Multiple regression analysis was used to predict the relation of age, sex, Tanner stage, body mass index, and systolic blood pressure to albumin excretion in both cohorts. In addition, correlations between albumin excretion and age, blood pressure, body mass index, lipids, and measurements of insulin resistance were performed in the normal adolescents.

RESULTS

Mean albumin excretion was significantly lower in normal adolescents (4.0 microg/min) than in type 1 diabetic adolescents (5.0 microg/min). Albumin excretion increased with age in diabetics. Albumin excretion did not significantly correlate with any measure of cardiovascular risk or insulin resistance but did significantly correlate with fasting insulin.

CONCLUSIONS

Albumin excretion rate is not related to insulin resistance or traditional cardiovascular risk factors in adolescence but is related to fasting insulin. Diabetic adolescents have increased albumin excretion compared with normal adolescents.

Body mass index status is effective in identifying metabolic syndrome components and insulin resistance in Pacific Island teenagers living in New Zealand

Although adults of Pacific ethnicity living in New Zealand have more than double the prevalence of diabetes and cardiovascular disease than the general population, little is known regarding the presence of risk factors for these disorders among young Pacific Islanders. The study aim was to examine relationships between body composition, glucose and lipid metabolism, and components of the metabolic syndrome (MS) in a community sample of Pacific Island (PI) teenagers living in Dunedin. Anthropometry, body composition (dual-energy x-ray absorptiometry), glucose and lipid metabolism, insulin resistance (homeostasis model assessment [HOMA2], McAuley index), and components of MS were assessed in 80 PI teenagers (aged 15-18 years). Results showed that 6 participants had full MS, 2 had high fasting blood glucose values (>7.0 mmol/L), 55 had high adiposity, and 21 had insulin resistance. Assessment of the components of MS by body mass index (BMI) status showed that obese participants (n = 29) had a high prevalence (86.2% had one or more component), whereas only 10.5% of those with healthy BMI status (n = 19) had any MS component. Elevated fat mass had substantial effects on fasting insulin values, HOMA2, and the McAuley index because in data adjusted for age, sex, and lean mass, a 10% greater fat mass was associated with a 4.7% increase in fasting insulin, a 5.3% rise in HOMA2, and a 2.3% decrease in the McAuley index. Our results suggest that the antecedents of cardiovascular disease and type 2 diabetes mellitus occur frequently in young Pacific Islanders having high adiposity. We conclude that community studies of PI adolescents should focus on assessing risk factors whenever BMI values are high.

Prothrombogenic factors and reduced antioxidative defense in children and adolescents with pre-metabolic and metabolic syndrome

BACKGROUND

The aim of this study was to examine prothrombogenic factors and antioxidative defense in obese children and adolescents with pre-metabolic and metabolic syndrome, and to analyze insulin secretion and resistance, early glycoregulation disorders and lipid status.

METHODS

Insulin sensitivity was determined using the homeostasis model assessment for insulin resistance (HOMA-IR), while insulin secretion was determined using the homeostasis model assessment beta (HOMA-beta). Prothrombogenic factors analyzed were plasma plasminogen activator inhibitor-1 (PAI-1) and fibrinogen. Superoxide dismutase and glutathione peroxidase were measured as markers of antioxidative defense.

RESULTS

Patients with metabolic syndrome were characterized with increased body mass index (BMI), waist circumference, and HOMA-IR and HOMA-beta levels, and all had increased blood pressure and triglyceride levels, low high-density lipoprotein cholesterol levels, increased PAI-1 levels and reduced antioxidative defense levels. Patients with pre-metabolic syndrome had higher levels of basal and mean insulinemia during an oral glucose tolerance test, higher levels of HOMA-beta and lower levels of antioxidative defense compared to patients with metabolic syndrome.

CONCLUSIONS

Negative correlations between antioxidative defense parameters and BMI, abdominal obesity, insulin secretion, systolic blood pressure and atherogenic lipid factors, as well as correlations between PAI-1 and insulin resistance and basal glycemia in the metabolic syndrome group contribute to accelerated atherosclerosis. Positive correlations between PAI-1 and waist circumference and BMI, and negative correlations between BMI and antioxidative defense in the pre-metabolic syndrome patients show that this early stage preceding the metabolic syndrome is also characterized by atherosclerotic complication risks and evident hyperinsulinism and insulin resistance.

Being overweight modifies the association between cardiovascular risk factors and microalbuminuria in adolescents

OBJECTIVE

The goal was to determine the association between cardiovascular risk factors and microalbuminuria in a nationally representative sample of adolescents and to determine whether being overweight modifies this association.

METHODS

We analyzed cross-sectional data from the National Health and Nutrition Examination Survey (1999-2004) for 2515 adolescents 12 to 19 years of age. Cardiovascular risk factors included abdominal obesity, impaired fasting glucose, diabetes mellitus, insulin resistance, high triglyceride levels, low high-density lipoprotein cholesterol levels, hypertension, smoking, and the metabolic syndrome. Microalbuminuria was defined as a urinary albumin/creatinine ratio of 30 to 299 mg/g in a random morning sample. Overweight was defined as BMI of > or = 95th percentile, according to the Centers for Disease Control and Prevention 2000 growth charts.

RESULTS

Microalbuminuria was present in 8.9% of adolescents. The prevalence of microalbuminuria was higher among nonoverweight adolescents than among overweight adolescents. The median albumin/creatinine ratio decreased with increasing BMI z scores. The association of microalbuminuria with cardiovascular risk factors differed according to BMI category. Among nonoverweight adolescents, microalbuminuria was not associated with any cardiovascular disease risk factor except for overt diabetes mellitus. Among overweight adolescents, however, microalbuminuria was associated with impaired fasting glucose, insulin resistance, hypertension, and smoking, as well as diabetes mellitus.

CONCLUSION

For the majority of adolescents, microalbuminuria is not associated with cardiovascular risk factors. Among overweight adolescents, however, microalbuminuria is associated with cardiovascular risk factors. The prognostic importance of microalbuminuria in overweight and nonoverweight adolescents with regard to future cardiovascular and renal disease needs to be defined in prospective studies conducted specifically in children.

Metabolic syndrome in youth: a cross-sectional school-based survey

AIM

To assess the prevalence of metabolic syndrome (MetS) among students attending vocational secondary school (VSE). VSE provides practice-oriented education in which young people learn a specific occupation. Previously we reported VSE to be the type of education with the highest prevalence of overweight and obesity.

METHODS

All data were collected in a cross-sectional school-based survey. Subjects were recruited from a community sample of 869 adolescents in 14 secondary schools. In this total sample all components of the metabolic syndrome were assessed in a subgroup of 506 students. MetS was defined analogous to National Cholesterol Education Program: Adult Treatment Panel III criteria, with modifications for students under 19 years of age.

RESULTS

In the subsample (n=506) 4.1% of the students had metabolic syndrome. There was a significant difference in the prevalence of metabolic syndrome among BMI categories (p<0.001). The prevalence of metabolic syndrome was higher in obese students (39.1%) than in overweight students (2.8%) and normal weight students (0.3%).

CONCLUSION

Being overweight or obese substantially increases the risk for metabolic syndrome, even in an adolescent school population.

Epidemiology of paediatric metabolic syndrome and type 2 diabetes mellitus

The epidemic in childhood obesity is a driving force behind the increase in paediatric metabolic syndrome, a collection of abnormalities that is associated in adults with increased risk for cardiovascular disease and type 2 diabetes mellitus. Although there is no clear consensus about the paediatric definition for metabolic syndrome, the prevalence of this syndrome is clearly rising. Children with metabolic syndrome are at increased risk for metabolic syndrome in adulthood. A late consequence of metabolic syndrome is type 2 diabetes, which increasingly affects adolescents. The rise in metabolic syndrome and type 2 diabetes in children is almost sure to lead to an increase in associated complications in young adulthood, including early cardiovascular disease. This epidemic will bear fruit in forthcoming decades, putting further stress on the healthcare system and probably leading to increased morbidity and a shorter lifespan for future generations.

Metabolic risk-factor clustering estimation in children: to draw a line across pediatric metabolic syndrome

BACKGROUND

The diagnostic criteria of the metabolic syndrome (MS) have been applied in studies of obese adults to estimate the metabolic risk-associated with obesity, even though no general consensus exists concerning its definition and clinical value. We reviewed the current literature on the MS, focusing on those studies that used the MS diagnostic criteria to analyze children, and we observed extreme heterogeneity for the sets of variables and cutoff values chosen.

OBJECTIVES

To discuss concerns regarding the use of the existing definition of the MS (as defined in adults) in children and adolescents, analyzing the scientific evidence needed to detect a clustering of cardiovascular risk-factors. Finally, we propose a new methodological approach for estimating metabolic risk-factor clustering in children and adolescents.

RESULTS

Major concerns were the lack of information on the background derived from a child's family and personal history; the lack of consensus on insulin levels, lipid parameters, markers of inflammation or steato-hepatitis; the lack of an additive relevant effect of the MS definition to obesity per se. We propose the adoption of 10 evidence-based items from which to quantify metabolic risk-factor clustering, collected in a multilevel Metabolic Individual Risk-factor And CLustering Estimation (MIRACLE) approach, and thus avoiding the use of the current MS term in children.

CONCLUSION

Pediatricians should consider a novel and specific approach to assessing children/adolescents and should not simply derive or adapt definitions from adults. Evaluation of insulin and lipid levels should be included only when specific references for the relation of age, gender, pubertal status and ethnic origin to health risk become available. This new approach could be useful for improving the overall quality of patient evaluation and for optimizing the use of the limited resources available facing to the obesity epidemic.

Diagnostic criteria patterns of U.S. children with Metabolic Syndrome: NHANES 1999-2002

BACKGROUND

As childhood obesity increases in the U.S., the Metabolic Syndrome (MS) can be assumed to be increasing in the pediatric population as well. To date, there is lack of information on the most prevalent risk factors of MS in children and the patterns of risk factors present in children met the criteria for MS.

METHODS

Anthropometric and medical data of children 2-18 years old of a nationally representative data set (NHANES 1999-2002) were obtained and the diagnostic criteria of Cook et al. employed to determine MS prevalence. Three samples were examined: a) Children 2-18 years old with non-missing data on at least three of the five diagnostic criteria but missing blood glucose data (n = 5,172), b) a subsample of 12-18 year olds also providing fasting glucose data but who were not overweight or obese using the International Obesity Task Force (IOTF) standards (n = 1,064), and c) 12-18 year olds with blood glucose data who were overweight or obese (n = 641).

RESULTS

Disease prevalence estimates were 2%, 0.7%, and 23% in the three populations. More than 10% of the children providing fasting blood levels had hyperglycemia. 2% of the overweight or obese 12-18 year olds with fasting blood glucose data met all five diagnostic criteria for MS. In all groups, elevated total triglycerides but low high density lipoprotein (HDL) level affected a large proportion of the population.

CONCLUSION

Results indicate a reason for concern, since the prevalence of MS risk factors in children was high. Dyslipidemia (concurrent high total triglyceride levels and low HDL levels) were prevalent in large portions of the population, even in the non-overweight. Thus, chronic disease prevention efforts in the pediatric population should not only encourage healthy body weight but also include dietary recommendations to consume diets moderately low in fat with emphasis on polyunsaturated and monounsaturated fats within recommended ratios of omega-6 and omega-3 fatty acids.

Sympathoadrenergic and metabolic factors are involved in ambulatory blood pressure rise in childhood obesity

We investigated in a young Italian obese population, the relationship between ambulatory BP (ABP) and several pathophysiological factors linking obesity to hypertension. A total of 89 obese children and adolescents underwent a 24-h ambulatory BP monitoring (ABPM) and an oral glucose tolerance test. The circulating levels of insulin, lipids, uric acid, C-reactive protein, interleukin-6, renin and aldosterone and the 24-h urinary levels of epinephrine, norepinephrine and albumin excretion rate were measured. Nine percent of subjects had daytime sustained hypertension (SH), 26% night-time hypertension and 11% a non-dipping pattern. SH subjects compared to those with sustained normotension (SN) were more obese (P<0.05), with a more frequent family history of hypertension (P<0.05), higher urinary catecholamine (P<0.05) and heart rate values (P<0.05) after adjustment for standard deviation score (SDS) of body mass index (BMI) and sex. Subjects with night-time hypertension compared to those with night-time normotension were more obese (P<0.0001), with a higher prevalence of impaired glucose tolerance (P<0.05) and metabolic syndrome (P<0.05) and higher 2-h glucose (P<0.05), uric acid (P<0.05) and triglycerides (P<0.05). In multivariate regression analysis, daytime systolic BP (SBP) remained independently correlated with urinary norepinephrine and SDS-BMI (P<0.05 for both), daytime diastolic BP (DBP) with waist circumference (P<0.05) and night-time SBP and DBP with SDS-BMI (P<0.01 for both). The risk of having systolic and diastolic hypertension increased with the increase in SDS-BMI and waist circumference, respectively. In conclusion, in our cohort of obese children and adolescents, daytime and night-time hypertension were associated with activation of the sympathoadrenal system and worst metabolic conditions, respectively.

The Prevalence of Metabolic Syndrome in Various Populations

The insulin resistance/metabolic syndrome is characterized by the variable co-existence of hyperinsulinemia, obesity, dyslipidemia (small dense low-density lipoprotein, hypertriglyceridemia, and decreased high-density lipoprotein cholesterol), and hypertension. The pathogenesis of the syndrome has multiple origins. However, obesity and sedentary lifestyle coupled with diet and still largely unknown genetic factors clearly interact to produce the syndrome. This multifactorial and complex trait of metabolic syndrome leads to increased risk of cardiovascular disease. The scope of this review is to examine the differences in prevalence of the metabolic syndrome in various groups (eg, according to age, sex, ethnicity, social status, or presence of obesity) that could help with the better understanding of the pathogenesis of this syndrome. This review also considers the impact of metabolic syndrome on cardiovascular disease.

Pediatric nonalcoholic fatty liver disease (NAFLD): a "growing" problem?

Nonalcoholic fatty liver disease (NAFLD) can affect both adults and children. With the current worldwide epidemic of pediatric obesity, pediatric NAFLD is increasingly being diagnosed. It is not exactly identical to NAFLD in adults, and these differences may be due in part to the occurrence of hepatic metabolic derangements typical of NAFLD during periods of active growth (infancy, mid-childhood and puberty). The natural history of pediatric NAFLD is not yet known; however, children with pediatric NAFLD can develop cirrhosis. Although details of disease mechanism in pediatric NAFLD remain unclear, hyperinsulinemia with insulin resistance appears to be critical. Determining the pathogenesis of pediatric NAFLD is likely to enhance our understanding of NAFLD in all age groups and may identify new treatment opportunities. Finding effective ways to prevent pediatric NAFLD is an important issue for children's health.

Sleep-disordered breathing and uric acid in overweight and obese children and adolescents

OBJECTIVE

The aim of this study was to determine whether the severity of sleep-disordered breathing (SDB) was associated with increased levels of uric acid (UA), both in serum and in urine, as a marker of tissue hypoxia, in a sample of overweight and obese subjects, irrespective of indexes of adiposity.

METHODS

Consecutive subjects underwent polysomnography, fasting blood sampling, and 24-h urine collection. Outcome parameters were serum UA, UA excretion ([24-h urinary UA x serum creatinine]/urine creatinine) and urinary UA/creatinine ratio.

RESULTS

A total of 93 subjects were included (44% boys; mean [+/- SD] age = 11.1 +/- 2.5; 73% obese). A fasting measurement of serum UA levels was available for 62 patients. The respiratory disturbance index was a significant covariate (beta = 0.09 +/- 0.03; p = 0.01) in the regression model for serum UA, controlling for sex (beta = 0.32 +/- 0.29; p = 0.3), puberty (beta = 0.87 +/- 0.34; p = 0.01), and waist circumference (beta = 0.04 +/- 0.01; p = 0.005). The percentage of total sleep time with arterial oxygen saturation < or = 89% (beta = 0.94 +/- 0.45; p = 0.04) was also significantly associated with serum UA level, controlling for sex (beta = 0.22 +/- 0.30; p = 0.5), puberty (beta = 0.83 +/- 0.35; p = 0.02), and waist circumference (beta = 0.04 +/- 0.02; p = 0.02). None of the SDB variables correlated with UA excretion or with urinary UA/creatinine ratio.

CONCLUSION

This study in overweight children and adolescents demonstrated a relationship between the severity of sleep apnea and increased levels of serum UA, independent of abdominal adiposity. In view of the known associations between UA and cardiovascular risk, this finding may contribute to the mechanisms linking SDB with cardiovascular morbidity.

Serum concentrations of uric acid and the metabolic syndrome among US children and adolescents

BACKGROUND

The association between concentrations of uric acid and the metabolic syndrome in children and adolescents remains incompletely understood. The objective of this study was to examine how these 2 were associated in a nationally representative sample of US children and adolescents.

METHODS AND RESULTS

We performed a cross-sectional analysis of 1370 males and females aged 12 to 17 years using data from the National Health and Nutrition Examination Survey 1999-2002. The prevalence of the metabolic syndrome was < 1% among participants in the lowest quartile of serum concentration of uric acid, 3.7% in the second quartile, 10.3% in the third quartile, and 21.1% in the highest quartile. Compared with the lowest 2 quartiles of uric acid together (< or = 291.5 micromol/L), the odds ratios were 5.80 (95% confidence interval, 3.22 to 10.46) for those in the third quartile (> 291.5 to < or = 339 micromol/L or > 4.9 to < or = 5.7 mg/dL) and 14.79 (95% confidence interval, 7.78 to 28.11) for those in the top quartile (> 339 micromol/L) after adjustment for age, sex, race or ethnicity, and concentrations of C-reactive protein. Starting with the lowest quartile of concentration of uric acid, mean concentrations of serum insulin were 66.2, 66.7, 79.9, and 90.9 pmol/L for ascending quartiles, respectively (P for trend <0.001).

CONCLUSIONS

Among US children and adolescents, serum concentrations of uric acid are strongly associated with the prevalence of the metabolic syndrome and several of its components.

Update on the metabolic syndrome in children

PURPOSE OF REVIEW

Provides an update on the metabolic syndrome in childhood.

RECENT FINDINGS

The metabolic syndrome is increasingly recognized among children. It is nearly exclusively encountered in overweight and obese individuals and is associated with atherosclerosis. Development and clustering of cardiovascular risk factors is influenced by many characteristics including heritable traits, prenatal and infantile influences, diet, physical activity, and socioeconomic status.

SUMMARY

Epidemiological data have become mature in this area. Efforts to design and implement systems to prevent and treat the metabolic syndrome are required.

A Cascade of Events – Obesity, Metabolic Syndrome, and Type 2 Diabetes Mellitus in Youth

Increased rates of obesity among youth in the last several decades also have led to the emergence of several health problems. Insulin resistance and metabolic syndrome are direct outcomes of increasing obesity rates, which, in turn, lead to the emergence of type 2 diabetes mellitus in youth. Nurses are well positioned to intervene with individual youth and populations at risk to interrupt the cascade of events that lead from obesity to severe health problems.

Factor analysis of risk variables associated with metabolic syndrome in Asian Indian adolescents

The purpose of the present cross-sectional study was to identify components of risk variables associated with metabolic syndrome in Asian Indian adolescents. The sample included 400 adolescents (boys = 200; mean age, 15.0 +/- 4.5 years; girls = 200; mean age, 14.4 +/- 3.8 years) from Calcutta, India. The following variables were considered: body mass index, waist circumference, sum of four skinfolds, subscapular/triceps ratio, total cholesterol, triglycerides, blood glucose, and systolic, diastolic, and mean arterial pressure. Principal component factor analysis revealed four uncorrelated factors for adolescent boys that cumulatively explained 76.3% of the observed variance of metabolic syndrome. Four factors with overlap between factors 1 and 2 were observed for adolescent girls that cumulatively explained 74.3% of the total variation of metabolic syndrome. The four factors identified were central body fat distribution (factor 1), centralized subcutaneous fat (factor 2), lipids-blood glucose (factor 3), and blood pressure (factor 4). Furthermore, the first two factors, i.e., central body fat distribution and centralized subcutaneous fat, cumulatively explained more than 46% (46.5% for boys; 46.4% for girls) of the observed variation of metabolic syndrome. Since more than one factor was identified for metabolic syndrome, more than one physiological mechanism could account for the clustering of risk variables of metabolic syndrome in Asian Indian adolescents. Factor analysis of Asian Indian adults also revealed four uncorrelated factors, similar to the present factors, therefore warranting intervention as early as adolescence.

Metabolic syndrome in youth: current issues and challenges

The current paper reviews the important issues and challenges facing children and adolescents with the metabolic syndrome (MetS). Studies suggest that the MetS and its risk components may be on the rise in children along with rising rates of obesity; however, further study remains warranted. The topics reviewed encompass the definition of the syndrome, its prevalence, clustering and tracking of metabolic risk factors, the role of physical activity and diet in the development of the MetS, criticisms and utility of the MetS definition, and special considerations needed in the pediatric population. Physical activity and diet may play important roles in the MetS; however, research with precise measurements of activity, diet, and metabolic outcomes is needed. The paper concludes by emphasizing that regardless of one’s position in the ongoing debate about the MetS, the long-term risks attributable to each individual risk component are real. The abnormality of one component should automatically prompt the screening of other components. Among children and adolescents, lifestyle modification should always serve as the frontline strategy. Prevention during childhood is key to the largest possible impact on adult health at the population level.

Assessment of metabolic profile in a clinical setting

PURPOSE OF REVIEW

The metabolic syndrome, a clustering of abnormalities such as hyperglycemia, insulin resistance, hypertension, dyslipidemia, and central obesity, is a principal risk factor for cardiovascular disease, the leading cause of morbidity and mortality in the Western world. There are several definitions of the metabolic syndrome, all aiming at including as many persons at risk as possible. The assessment and, hence, the identification of such persons in a clinical setting is of utmost importance.

RECENT FINDINGS

Clinicians should document the presence of central obesity, assessed by waist circumference measurement or determination of body composition using dual X-ray absorptiometry or measurement of visceral fat using computed tomography or magnetic resonance imaging. The presence of dyslipidemia, insulin resistance, and arterial hypertension constitutes the full profile of the metabolic syndrome. Nevertheless, elevated uric acid levels or presence of nonalcoholic fatty liver, or the diagnosis of the polycystic ovary syndrome in women of reproductive age, all are reflected in high risk of later occurrence of the full metabolic syndrome and atherosclerotic cardiovascular disease.

SUMMARY

Although no unified definition for the metabolic syndrome exists, it is important to identify persons at risk, in order to reduce the resultant high morbidity and mortality rates.

Adiponectin is a candidate marker of metabolic syndrome in obese children and adolescents

The aim of this study was to compare the use of several biomarkers to identify obese children and adolescents with increased metabolic risk. One hundred sixty-two Caucasian obese children and adolescents (41% males, 9-18 years old) referred to the Istituto Auxologico Italiano between 2003 and 2004 underwent an oral glucose tolerance test. Circulating levels of adiponectin (AD), plasminogen activator inhibitor 1 (PAI-1), interleukin 18 (IL-18), C-reactive protein (CRP), fibrinogen, uric acid, lipids and insulin were measured. Twenty five percent of obese children had the MS defined using World Health Organization-derived child specific criteria. MS subjects had significantly lower AD (p<0.01) and higher log-PAI-1 (p<0.001), uric acid (p<0.0001), and IL-18 (p<0.001). Subjects with AD levels </=median value had a significantly increased risk of having the MS (p<0.0001), as did subjects with uric acid and PAI-1 levels greater than the median. There was no increased risk with elevated IL-18, CRP, or fibrinogen. Hypoadiponectinemia was independently associated with the MS risk (p<0.0001). In conclusion in obese children and adolescents AD is the best predictor of MS and thus of higher cardiovascular disease risk.