Metabolic syndrome in youth: chimera or useful concept?

The predictive value of combined insulin resistance and β-cell secretion in Yemeni school-aged children for type 2 diabetes mellitus

The present study aimed to determine the predictive power of the diabetic markers and metabolic syndrome factors in School-aged children for developing Type 2 DM. In this cross-sectional study, 1288 students aged 12-13 were recruited from public schools in the capital city of Sana'a. Anthropometric measurements and blood pressure were recorded and body mass index (BMI) was calculated. Fasting venous blood (5 ml) was collected for biochemical analysis including FBG, HbA1c, insulin, and lipid profile. Insulin resistance (HOMA-IR) and β-cell function (HOMA-β) were calculated. Our results showed that neither insulin, HOMA-IR nor HOMA-β individually were good predictors for Type 2 DM as assessed by the ROC curve with AUC < 0.75. However, the ROC curve of combined HOMA-IR and HOMA-β (Model 1) gave a superior AUC of 0.998 (p = 2.7 × 10-9) and predicted 140 (10.9%) children to develop Type 2 DM. This model picked up all impaired fasting glucose (IFG), 74% of metabolic glucose, and 71% of metabolic syndrome (MetS) groups. On the other hand, the ROC curve for metabolic syndrome (Model 2) gave an AUC of 0.751 (p = 0.003) and predicted a higher number of 416 (32.3%) children to develop prediabetes and Type 2 DM. This model picked up 75% of IFG, 71% of MetS, 82% of those having two factors of MetS, and 72% of obesity groups. Moreover, the 53 children common between the two models include 75% of IFG and 43% of MetS groups. Therefore, the combined HOMA-IR and HOMA-β model in children proved to be a good predictor for Type 2 DM development, whereas the MetS model predicts the development of prediabetes and Type 2 DM.

Metabolic risk factors in prepubertal and pubertal patients with overweight and obesity

OBJECTIVES

Metabolic syndrome (MetS) is a cluster of conditions linked to obesity that increases cardiovascular risk. We evaluated the frequency of clinical abnormalities associated with overweight and obesity in childhood, to determine whether a diagnosis of MetS is appropriate in this population.

METHODS

Cross-sectional study with 116 pubertal and prepubertal children with a mean age (SD) of 10.9 (2.5) years, with overweight and obesity. We defined MetS using the International Diabetes Federation criteria, regardless of the age.

RESULTS

45 patients met the criteria, 20 had at least one metabolic abnormality in addition to a high waist circumference (WC), and seven with WC below percentile 90th, had at least one metabolic abnormality. The prepubertal had higher zBMI [3.1 (2.6-3.8) vs. 2.8 (2.4-3.3); p=0.037], less lean body mass (kg) [27.13 (7.3) vs. 34.13 (9.8); p=0.005] and a similar frequency of non-alcoholic fatty liver disease (NAFLD) compared to the pubertal [44.7 vs. 35.9; p=0.323]. Prepubertal with NAFLD had higher zBMI, lower HDL levels, higher TG/HDL ratios and higher fat percentages; while pubertal with NAFLD had higher WC/height, aspartate aminotransferase and oxaloacetic transaminase.

CONCLUSIONS

The diagnosis of MetS in childhood is not fundamental. Individualized management, focusing on the earliest age groups, in which we identified a more severe degree of obesity, should be done. We also recommend screening for NAFLD in all ages, due to the high prevalence observed.

The role of adipocytokines in the development of non-alcoholic fatty liver disease in children and adolescents

Over the past 20 years, the proportion of overweight and obese children and adolescents has increased significantly in most countries. Obesity represents a major cardiometabolic risk and is closely associated with comorbidities such as hypertension, hyperlipidemia, hyperinsulinemia, type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD). There is a lot of uncertainty regarding the diagnosis of metabolic syndrome in children, mainly due to the various and conflicting definitions that have been proposed. The prevalence of metabolic syndrome varied significantly in children (from 6 to 39%) depending on the applied definition criteria. According to these definitions, only 2% of children met all the criteria for metabolic syndrome. Over the past decade, studies have shown that, in parallel with the increase in the prevalence of obesity in the pediatric population, NAFLD has become the most common form of liver disease in childhood. In NAFLD, inflammatory cytokines/adipokines and other factors lead to steatohepatitis and/or fibrosis. Recently, several adipocytokines and inflammatory cytokines have been identified with significant positive (leptin, chemerin, vaspin, TNF-α, IL-6 and IL-8) or negative (adiponectin) associations with metabolic risk factors. Some of them can be considered as pathophysiological factors linking obesity and its complications such as insulin resistance and NAFLD. However, data on other adipocytokines and their role in metabolism remain controversial and partially unknown, especially with regard to their role in childhood (resistin, NAMPT, FGF-21, A-FABP, RBP4, lipocalin-2, omentin-1, hsCRP). Adipocytokines are a novel and powerful tool not only for the diagnosis and stratification of NAFLD and the metabolic syndrome, but also as a potential therapeutic target. Adipocytokine therapy requires further study in all patients with metabolic syndrome and NAFLD, especially in children and adolescents.

Metabolic Syndrome and Prediabetes Among Yemeni School-Aged Children

PURPOSE

In view of the high rate of obesity and physical inactivity as well as the rising incidence of Type 2 DM among children in the neighboring Gulf countries and Middle East region; the aim of this study was, therefore, to determine the prevalence of metabolic syndrome (MetS) and prediabetes in Yemeni school-aged children.

PATIENTS AND METHODS

In this study, 1402 school children aged 12-13 years old (grade 7) were recruited from public schools in the capital Sana'a during the period April-May 2013. Anthropometric measurements and BP were recorded and BMI was calculated. Fasting venous blood (5 mL) was collected for biochemical analysis including FBG, HbA1c, insulin and lipids profile. Insulin resistance (HOMA-IR) and β-cell function (HOMA-β) were calculated.

RESULTS

The prevalence of prediabetes (as defined by impaired fasting glucose) and MetS (as classified by the IDF 2007) were 0.86% and 0.5%, respectively. Our results also showed 5.21% and 20.26% of the children to have two or one factor(s) of the MetS criteria fulfilled, respectively, with low HDL-c (17%) being the most prevalent MetS component, followed by metabolic glucose (8%), raised TG (5.3%), DBP (1.4%), and high WC (0.5%). Moreover, the prevalence of overweight and obesity was 4.2% and 2.8%, respectively; and about 1.2% of children had abnormal high insulin levels. Children with impaired fasting glucose (IFG) had increased HOMA-IR (p = 0.016) and SBP (p = 0.042) and decreased HDL-c (p = 0.034) and HOMA-β (p < 0.001); whereas obese children had increased WC (p < 0.001) and TG (p = 0.049).

CONCLUSION

The main finding of this study is that Yemeni children are at potential risk of obesity, metabolic syndrome and prediabetes despite their low prevalences. These results highlight the need for early identification and close monitoring of children at risk of later Type 2 DM as an important primary care strategy that can effectively prevent or delay the onset of such condition.

Prevention of Obesity and Metabolic Syndrome in Children

In recent decades, the prevalence of overweight and obesity has become increasingly common such that it is now the major nutritional problem worldwide. Obesity occurs when dietary energy intake exceeds energy expenditure and has arisen in many societies due to an increasingly "obesogenic" environment in which physical activity has declined and yet children continue to be exposed to unhealthy, energy-dense diets. Additional risks for the development of obesity also include psychological issues and genetic factors. Obesity has many adverse health consequences including development of insulin resistance, Type 2 diabetes, and the metabolic syndrome. There are also important genetic influences on the likelihood of developing insulin resistance. Given the limited success of therapeutic interventions to treat obesity and the metabolic syndrome, there has been an increased interest in preventative strategies. These are likely to be most successful when targeting the young and will require a combination of approaches which will need inter-disciplinary collaborations across health and local government to target families, schools, and local environments to facilitate behavior changes which influence young people's eating behaviors and habitual levels of physical activity.

Novel Insights in the Metabolic Syndrome in Childhood and Adolescence

Metabolic syndrome (MetS) is recognized as an escalating major health risk in adults as well as in children and adolescents. Its prevalence ranges from 6 to 39% depending on the applied definition criteria. To date, there is no consensus on a MetS definition for children and adolescents. However, most authors agree on essential components such as glucose intolerance, central obesity, hypertension, and dyslipidemia; each representing a risk for cardiovascular disease. Recently, associations between MetS and non-alcoholic fatty liver disease, hyperuricemia, and sleep disturbances have emerged. Biomarkers like adipocytokines are a subject of current research as they are implicated in the pathogenesis of the MetS. Epigenetics and gestational programming, especially the role of microRNA, comprise a novel, rapidly developing and promising research focus on the topic of MetS. MicroRNAs are increasingly valued for potential roles in the diagnosis, stratification, and therapeutics of MetS. Early detection of risk factors, screening for metabolic disturbances, and the identification of new therapies are major aims to reduce morbidity and mortality related to MetS. Dietary modification and physical activity are currently the only adopted treatment approaches. Pharmacological therapies and bariatric surgery are still contradictory and, therefore, are only recommended in selected high-risk cases.

Associations between metabolic syndrome components and markers of inflammation in Welsh school children

We investigated the multivariate dimensionality and strength of the relationship between metabolic syndrome (MetS) and inflammation in children. Caucasian school children (N = 229; 12-14 years) from Wales were tested on several health indicators including measures of body composition, inflammation, fasting glucose regulation, blood pressure, and lipids. The multivariate association between MetS and inflammation was investigated via canonical correlation analysis. Data were corrected for non-normality by log transformation, and sex-specific z-scores computed for variables where there was a significant sex difference. Structure r's were interpreted to determine the dimensions of MetS and inflammation responsible for significant canonical variates. The overall multivariate association between MetS and inflammation was significant (Wilks' Lambda = 0.54, p < 0.001). The relationship was explained primarily by the waist circumference dimension of MetS (CC = 0.87) and inflammatory markers of fibrinogen (CC = 0.52) and C-reactive protein (CC = 0.50). The pattern of results was similar regardless of whether variables were adjusted for sex differences.

CONCLUSION

Central adiposity is the strongest predictor of the inflammatory aspect of cardiovascular disease risk in Caucasian adolescents. Future research into MetS and cardiometabolic risk should consider multivariate statistical approaches, in order to identify the separate contributions of each dimension in interrelationships and to identify which dimensions are influenced by preventive interventions. What is Known: • Metabolic syndrome (MetS) is associated with increased risk of cardiovascular disease (CVD) and type 2 diabetes. Markers of inflammation are also potential predictors of later development of CVD and type 2 diabetes. • The contribution of individual markers in interrelationships between MetS and inflammation is unknown. What is New: • We uniquely demonstrate that within a multivariate model, waist circumference is the primary link between MetS variables and markers of inflammation in children. • Waist circumference may therefore be a useful population-level screening tool to identify future risk of CVD.

[Prevalence of metabolic syndrome in pubertal stages of female students]

Objective To analyze the prevalence of metabolic syndrome (MS) in pubertal stages of female students. Methods Cross-sectional study of 449 school children between eight and 18 years, stratified by pubertal stage, body mass index (BMI) and body fat percentage (BF %). The MS was classified according to the International Diabetes Federation. The analysis by frequency distribution, confidence intervals (95 %), Chi-square and odds ratio for associations was performed. Results The prevalence of MS was 3.3 % (CI:2 %-5 %) and 2.5 % (CI: 0.1 - 5 %) in pubertal and 7.9% (CI:3.2 % - 12.6 %) in the post-pubescent, with a significant association of this group with MS (X² = 5.2 [p <0.02]). The odds ratio shows that post-pubescent girls (3.3 [CI: 1.2 to 5]) and obese girls (2.1 [CI: 2 - 2.2]) are more likely to have MS, indicating significant linear association between BMI and the outcome (X²=29.4 [p<0.001]). Pubescent children under 10 years of age with MS had higher %G. The prevalent components were altered waist circumference (27.2 % [CI23 %-31 %]) and low HDL cholesterol (39.6 % [CI 35 % - 44 %]), as well as prevalence of systemic hypertension in post-pubertal girls. Conclusions MS begins in the pubertal stage, with prevalence in the post-pubertal stage. Excess fat is a trigger in children under 10 years of age. Prevention strategies are needed for the population of children and adolescents.

An update on the assessment and management of metabolic syndrome, a growing medical emergency in paediatric populations

In the last decades the increasing rate of obesity in children and adolescents worldwide has led to the onset in paediatric age of metabolic syndrome, a disease commonly associated to adulthood. Central obesity, dyslipidaemia, hyperglycaemia, and hypertension are typical features of metabolic syndrome that seem to hesitate often in type 2 diabetes, cardiovascular disease, non-alcoholic fatty liver disease, and many other clinical conditions. Thus preventing and curing metabolic syndrome in paediatric patients is becoming an urgent need for public health. While diagnostic criteria and therapy of metabolic syndrome in adults are very well defined, there is no consensus on the definition of metabolic syndrome in children and adolescents as well as on healing approaches. The aim of this review is to describe the recent advances on the pathogenesis and clinical outcomes of paediatric metabolic syndrome. We then detail the therapeutic strategies (i.e. dietary regimens, physical exercise, nutraceuticals, and medications) employed to manage the disease. Finally, we analyse the safety profile of the drugs used in children and adolescents by performing a retrospective review of paediatric adverse reactions reported in the FDA's Adverse Event Reporting System database.

25-Hydroxyvitamin D insufficiency discriminates cardiovascular risk factors accumulation in peri-pubertal boys undergoing overweight screening

The aim of this study was to evaluate the possible association between cardiometabolic risk factors accumulation and vitamin D status in a cohort of Italian normal weight and overweight male children. 108 boys enrolled in an andrological health prevention project underwent physical examination, anthropometric measurements, and fasting blood sampling. Serum blood glucose, HDL-cholesterol, triglycerides, parathyroid hormone, and 25-hydroxyvitamin D (25(OH)D) were measured. Cardiovascular risk factors were defined according to the National Cholesterol Education Program Adult Treatment Panel III modified for age. Lean and overweight subjects differed in terms of waist circumference (P < 0.001), HDL-cholesterol (P = 0.001), triglycerides (P = 0.001), systolic blood pressure (P < 0.001) and diastolic blood pressure (P = 0.002). Both groups had similar mean 25(OH)D levels (P = 0.160) and were below the sufficiency threshold: indeed only 24 % of normal weight had 25(OH)D ≥30 ng/ml, and even less in the overweight/obese group (8 %, P = 0.03 vs. normal weight). A significant accumulation of risk factors in course of 25(OH)D insufficiency was detected in both the whole cohort and in the normal weight group (P = 0.003 and P = 0.04, respectively) with odd ratios of 1.31 (1.16-1.49 95%CI) and 1.41 (1.18-1.69 95%CI), respectively. In course of vitamin D deficiency, the odd ratios were 2.24 (1.34-3.77 95%CI, P = 0.003) in the whole cohort and 2.40 (1.27-4.82 95%CI, P = 0.03) in lean subjects. We reported a considerable occurrence of cardiovascular risk factors in course of hypovitaminosis D in overweight/obese boys and even in lean subjects, which normally would not have been further evaluated by considering the sole BMI-related parameters. In this regard, 25(OH)D levels appear as a potential discriminating parameter able to identify male children at higher health risk.

Sex Hormone-Binding Globulin in Children and Adolescents

Sex hormone-binding globulin (SHBG) is a circulating glycoprotein that transports testosterone and other steroids in the blood. Interest in SHBG has escalated in recent years because of its inverse association with obesity and insulin resistance, and because many studies have linked lower circulating levels of SHBG to metabolic syndrome, type 2 diabetes, nonalcoholic fatty liver disease, polycystic ovary syndrome, and early puberty. The purpose of this review is to summarize molecular, clinical, endocrine, and epidemiological findings to illustrate how measurement of plasma SHBG may be useful in clinical medicine in children.

Adolescence and polycystic ovary syndrome: current concepts on diagnosis and treatment

BACKGROUND

Adolescence is a time characterised by changes in reproductive hormones and menstrual patterns, which makes it difficult to diagnose polycystic ovary syndrome (PCOS) in this population. The diagnosis of PCOS has a great physical and psychosocial impact on the young person. Despite the importance of a diagnosis of PCOS at adolescence, data available are limited.

AIMS

This review focuses on analysing markers of PCOS diagnosis and possible treatments in adolescence.

RESULTS

Although, during adolescence, diagnosis criteria of PCOS overlap with physiological changes including clinical manifestations of hyperandrogenism (acne and hirsutism), oligo/amenorrhoea, anovulation and ovarian microcysts, there is agreement that irregular menses and hyperandrogenaemia should be used to diagnose PCOS in this population. Moreover, considering that PCOS phenotype could change through the reproductive age and that adolescents display heterogeneous ovarian morphology, it has been proposed that diagnosis of PCOS should be confirmed after the age of 18. The first-line treatment for menstrual irregularity and hirsutism are oral contraceptive pills (OCPs) and for obesity and metabolic abnormalities are lifestyle changes. Insulin-sensitizer drugs, such as metformin, may be added to the treatment in the presence of metabolic alterations. Antiandrogen drugs may also be associated for treating moderate to severe hirsutism. During adolescence, physiological changes overlap with signs and symptoms of PCOS; thus the diagnosis criteria should be carefully considered. Regarding the treatment of adolescents with PCOS, non-pharmacological interventions include lifestyle changes. Pharmacological treatments comprise OCPs, antiandrogens and metformin, used isolated or combined.

CONCLUSIONS

During adolescence, physiological changes overlap with signs and symptoms of PCOS; thus the diagnosis criteria should be carefully considered. Regarding the treatment of adolescents with PCOS, non-pharmacological interventions include lifestyle changes. Pharmacological treatments comprise OCPs, antiandrogens and metformin, used isolated or combined.

Micro-RNAs Let7e and 126 in Plasma as Markers of Metabolic Dysfunction in 10 to 12 Years Old Children

BACKGROUND

Growing evidence shows that metabolic syndrome (MetS) is already starting in childhood however there is no consensus regarding how to diagnose this condition in pediatric population. Studies in adults show that altered levels of specific micro-RNAs are related with components of the MetS.

OBJECTIVE

We determined the plasma levels of four MetS-associated micro-RNAs (miR-126, miR-132, mir-145 and Let-7e) in 10 to 12 years old children with or without MetS traits.

DESIGN

Pediatric subjects were selected from a cohort of 3325 school-age children, and clustered by the absence (control, n = 30), or the presence of 1 (n = 50), 2 (n = 41) or 3 (n = 35) MetS traits according to Cook´s criteria. Micro-RNAs were isolated from plasma, and levels of miR-126, miR-132, miR-145 and Let-7e were determined by Taqman qPCR.

RESULTS

Regression analysis of the different MetS traits regarding the different miRNAs analyzed showed that Let-7e presented a negative association with HDL-C levels, but a positive correlation with the number of MetS traits. Levels of miR-126 presented a positive correlation with waist circumference, waist to hip ratio, BMI, and plasma triglycerides and VLDL-C. Levels of miR-132 showed a positive correlation with waist to hip ratio. Plasma levels of Let-7e were increased (~3.4 fold) in subjects with 3 MetS traits, and showed significant AUC (0.681; 95%CI = [0.58, 0.78]; p < 0.001) in the ROC analysis which were improved when miR-126 was included in the analysis (AUC 0.729; p < 0.001). In silico analysis of the interaction of proteins derived from mRNAs targeted by Let7 and miR-126 showed an important effect of both Let-7e and miR-126 regulating the insulin signaling pathway.

CONCLUSIONS

These results suggest that changes in the plasma levels of Let-7e and miR-126 could represent early markers of metabolic dysfunction in children with MetS traits.

Predictors of metabolic risk in childhood obesity

Most of the complications of juvenile obesity are due to metabolic disturbances induced by an excessive accumulation of fat which leads to chronic diseases like type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). Finding effective ways of identifying obese paediatric patients who are at increased risk of developing cardiovascular and metabolic complications has been recognised to be a promising strategy to improve prevention of complications of early obesity. Moreover, correctly identifying obese children who are already affected by metabolic co-morbidities should be a clinical priority. According to the state of the art summarised in this review, traditional metabolic variables included in the definitions of metabolic syndrome (MS), pre-diabetes, non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steato-hepatitis and, in obese girls, the presence of polycystic ovary syndrome are the best available longitudinal predictors of CVD and T2DM among obese children and adolescents. In clinical practice, traditional metabolic variables included in the definitions of MS should be assessed in all obese children and adolescents; fasting metabolic variables have been proposed to identify obese patients likely to be affected by impaired glucose tolerance or T2DM, and ultrasound has proved to be a valid surrogate for biopsy in the diagnosis of NAFLD. Further large longitudinal and cross-sectional studies are needed to improve our chances of identifying obese youth at the highest metabolic risk.

Self-management training for Chinese obese children at risk for metabolic syndrome: Effectiveness and implications for school health

This article reviews the results of a school-based self-management intervention for Chinese obese children at risk for metabolic syndrome. Twenty-eight Chinese obese children ( M age = 10 years) and their parents participated in the study. Metabolic syndrome risk factors were measured pre- and post-intervention. The risk factors included Body Mass Index, waist circumstance, systolic blood pressure, diastolic blood pressure, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, High-sensitivity C-reactive Protein, fasting plasma glucose, and fasting blood insulin. After 6 months of school-based self-management intervention, all risk factors with the exception of triglycerides and fasting plasma glucose changed significantly in the healthful direction ( p < 0.01). This pilot study offers promising implications for school interventions that are delivered by school-based practitioners collaborating with parents, teachers, and children. An individualized program based on a self-care and -management framework may have utility as a relatively cost-effective, school-based intervention to improve children’s health.

Hepatocyte nuclear factor 4 alpha polymorphisms and the metabolic syndrome in French-Canadian youth

Objectives

Hepatocyte nuclear factor 4 alpha (HNF4α) is a transcription factor involved in the regulation of serum glucose and lipid levels. Several HNF4A gene variants have been associated with the risk of developing type 2 diabetes mellitus. However, no study has yet explored its association with insulin resistance and the cardiometabolic risk in children. We aimed to investigate the relationship between HNF4A genetic variants and the presence of metabolic syndrome (MetS) and metabolic parameters in a pediatric population.

Design and Methods

Our study included 1,749 French-Canadians aged 9, 13 and 16 years and evaluated 24 HNF4A polymorphisms that were previously identified by sequencing.

Results

Analyses revealed that, after correction for multiple testing, one SNP (rs736824; P<0.022) and two haplotypes (P1 promoter haplotype rs6130608-rs2425637; P<0.032 and intronic haplotype rs736824-rs745975-rs3212183; P<0.025) were associated with the risk of MetS. Additionally, a significant association was found between rs3212172 and apolipoprotein B levels (coefficient: -0.14 ± 0.05; P<0.022). These polymorphisms are located in HNF4A P1 promoter or in intronic regions.

Conclusions

Our study demonstrates that HNF4α genetic variants are associated with the MetS and metabolic parameters in French Canadian children and adolescents. This study, the first exploring the relation between HNF4A genetic variants and MetS and metabolic variables in a pediatric cohort, suggests that HNF4α could represent an early marker for the risk of developing type 2 diabetes mellitus.

BMI as a mediator of the relationship between muscular fitness and cardiometabolic risk in children: a mediation analysis

Objective

Muscular fitness levels have been associated with cardiometabolic risk in children, although whether body weight acts as a confounder or as an intermediate variable in this relationship remains controversial. The aim of this study was to examine whether the association between muscular fitness and cardiometabolic risk factors is mediated by body mass index (BMI).

Design and Methods

Cross-sectional study using a sample of 1158 schoolchildren aged 8-11 years from the province of Cuenca, Spain. We measured anthropometrics and biochemical variables and we calculated a muscular fitness index as the sum of z-scores of handgrip dynamometry/weight and standing long jump, and we estimated a previously validated cardiometabolic risk index (CMRI). Linear regression models were fitted for mediation analysis to assess whether the association between muscular fitness and cardiometabolic risk was mediated by BMI.

Results

Children with normal weight (NW) had a better cardiometabolic risk profile than their overweight (OW) or obese (OB) peers after controlling for muscular fitness. Marginal estimated mean±SE values for NW, OW and OB categories of CMRI were -0.75±0.06<0.84±0.10<2.18±0.16 in boys and -0.73±0.06<0.96±0.10<2.71±0.17 in girls, both p<0.001. Children with higher levels of muscular fitness had a better cardiometabolic risk profile (CMRI marginal estimated mean±SE 1.04±0.13>0.05±0.09>-1.16±0.13 for lower, middle and upper quartiles of muscular fitness in boys and 1.01±0.16>0.10±0.09>-1.02±0.15 in girls, both p<0.001), but differences disappeared when controlling for BMI. BMI acted as a full mediator between muscular fitness and most cardiometabolic risk factors (Sobel test z=-11.44 for boys; z=-11.83 for girls; p<0.001 in CMRI mediation model) and as a partial mediator in the case of waist circumference (Sobel test z=-14.86 for boys; z=-14.51 for girls; p<0.001).

Conclusions

BMI mediates the association between muscular fitness and cardiometabolic risk in schoolchildren. Overall, good muscular fitness is associated with lower cardiometabolic risk, but particularly when accompanied by normal weight.

Ventilatory function and cardiovascular disease risk factors: a cross-sectional study in young adults

Background

The association between impaired lung function and cardiovascular disease (CVD) risk factors has been shown in adults. However, there is little evidence of such an association in young adults, particularly from South America, where the burden of CVD and chronic obstructive pulmonary disease (COPD) is as high as that observed in more developed countries. We therefore investigated the relation between CVD risk factors including metabolic syndrome (MS), and lung function status in young adults from Chile.

Methods

970 subjects from a sample of 998 adults born between 1974 and 1978 in Limache, Chile, were studied. A Spanish translation of the European Community Respiratory Health Survey (ECRHS) questionnaire was used. Forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC) were measured. Weight, height, waist circumference (WC), blood pressure, Homeostatic model assessment (HOMA-IR), triglycerides, high density lipoprotein (HDL), glycaemia, and metabolic syndrome (MS) were also assessed.

Results

The prevalence of MS was 11.8%. A lower FEV₁ and lower FVC were associated with having MS (β-coefficient -0.13; 95% Confidence Interval [CI] -0.21 to -0.05, and β-coefficient -0.18; 95% CI -0.27 to -0.09, respectively). Both spirometric measures were also negatively associated with having an elevated HOMA-IR (β-coefficient for FEV₁ -0.08; 95% CI -0.13 to -0.03, and β-coefficient for FVC -0.11; 95% CI -0.17 to -0.05). In males only, a lower FEV₁ and FVC were associated with having elevated triglycerides (β-coefficient highest vs. lowest tertile -0.13, 95% CI -0.24 to -0.03, and β-coefficient -0.13, 95% CI -0.25 to -0.01, respectively). In women, a higher FEV₁ and FVC were statistically significantly related to having higher levels of HDL. Ventilatory function was unrelated to hypertension or WC in this population.

Conclusion

In this population-based study of young adults, a poorer ventilatory function was associated with many CVD risk factors. Endeavours to understand better causality issues of such associations are warranted.

Metabolic syndrome

Metabolic syndrome is not a disease per se, but is a term that highlights traits that may have an increased risk of disease, approximately 2-fold for cardiovascular disease and 5-fold or more for type 2 diabetes mellitus. Obesity and insulin resistance are believed to be at the core of most cases of metabolic syndrome, although further research is required to truly understand the pathophysiology behind the syndrome and the gene-environment interactions that increase susceptibility. The mainstay of treatment remains lifestyle changes with exercise and diet to induce weight loss and pharmacologic intervention to treat atherogenic dyslipidemia, hypertension, and hyperglycemia.

Metabolic syndrome in Iranian youths: a population-based study on junior and high schools students in rural and urban areas

AIM

The present population-based study aimed to assess prevalence of metabolic syndrome and its related components in Iranian youth in the different sex, age, and residential subgroups.

METHOD

Overall, 1039 junior high school and 953 high school students were selected using multistage random sampling. Fasting blood sugar, total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were determined. Trained individuals measured waist circumference and blood pressure. Subjects with MetS were selected according to two definitions provided by the IDF and de Ferranti.

RESULTS

Among girls in intervention area, hypertriglyceridemia was more prevalent in rural than in urban areas using IDF definition. Significant differences were observed between boys in rural and urban areas regarding some components of metabolic syndrome including hypertriglyceridemia and high waist circumference. Besides, boys who are residents in urban areas had higher blood pressure, as well as higher waist circumference, than boys in rural areas.

CONCLUSION

Our youth population is at significant risk of developing metabolic syndrome, and the pattern of this phenomenon seems to be discrepant in boys as well as in rural and urban areas probably due to the different lifestyle aspects, genetic factors, and racial differences.