Insulin resistance syndrome in childhood: associations of the euglycemic insulin clamp and fasting insulin with fatness and other risk factors

Metabolic disturbances in children with narcolepsy: a retrospective study

STUDY OBJECTIVES

To determine the prevalence of metabolic syndrome (MS) in children with narcolepsy and to evaluate their clinical and sleep characteristics according to the different components of MS.

METHODS

This retrospective study consisted of 58 de novo children with narcolepsy (median age: 12.7 years, 48.3% of boys). The recently published MS criteria in a French population of children were used. Clinical and sleep characteristics were compared between groups with different components of MS.

RESULTS

MS was present in 17.2% of children with narcolepsy, among whom 79.3% presented with high homeostasis model assessment for insulin resistance (HOMA-IR), 25.9% with high body mass index, 24.1% with low high-density lipoprotein cholesterol (HDL-C), and 12.1% with high triglycerides. Patients with at least two MS components had more night eating behaviors and tended to have lower percentage of slow-wave sleep and more fragmented sleep. On multiple sleep latency test, they had shorter mean sleep latencies to rapid eye movement (REM), non-REM sleep and tended to have more sleep onset REM periods (SOREMPs) than those with less than two MS components.

CONCLUSIONS

Insulin resistance was found to be the core metabolic disturbance in obese as well as in nonobese children with narcolepsy. Children with narcolepsy with at least two MS components presented a more severe daytime sleepiness and a higher prevalence of night-eating behaviors than those with less than two MS components. Such children might benefit from early evaluation and management in order to prevent future complications.

Association between Obesity and Cardiovascular Disease Risk Factors in Different Age Groups of Adolescents: An Analysis of Data from the Korean National Health and Nutritional Examination Survey

We investigated the association between obesity and cardiovascular disease risk factors (CVDRFs) in adolescents. We performed a cross-sectional study using the data from 8149 adolescents, aged 10-18 years, included in the Korean National Health and Nutrition Examination Survey (2011-2020). Using the body mass index, we defined "overweight" (≥85th to <95th percentile) and "obese" (≥95th percentile). We analyzed the associations between obesity and CVDRFs (high blood pressure, abnormal lipid profiles, and high fasting glucose levels) by sex and age groups (early [10-12 years], middle [13-15 years], and late [16-18 years] adolescence). When analyzing all the subjects, being overweight was correlated with high blood pressure and abnormal all-lipid profiles in boys and high triglyceride and low high-density lipoprotein cholesterol levels in girls, while obesity was associated with all CVDRFs in both boys and girls. Analyzing separately in the age subgroups, the correlation between obesity and CVDRFs tended to be shown earlier in boys than in girls, and obesity tended to be associated with CVDRFs earlier than being overweight. The association between obesity and CVDRFs may begin to be shown at different periods of youth, depending on the degree of obesity, CVDRF variables, and sex.

Increased LRG1 Levels in Overweight and Obese Adolescents and Its Association with Obesity Markers, Including Leptin, Chemerin, and High Sensitivity C-Reactive Protein

Leucine-rich α-2 glycoprotein1 (LRG1) is a member of the leucine-rich repeat (LRR) family that is implicated in multiple diseases, including cancer, aging, and heart failure, as well as diabetes and obesity. LRG1 plays a key role in diet-induced hepatosteatosis and insulin resistance by mediating the crosstalk between adipocytes and hepatocytes. LRG1 also promotes hepatosteatosis by upregulating de novo lipogenesis in the liver and suppressing fatty acid β-oxidation. In this study, we investigated the association of LRG1 with obesity markers, including leptin and other adipokines in adolescents (11−14 years; n = 425). BMI-for-age classification based on WHO growth charts was used to define obesity. Plasma LRG1 was measured by ELISA, while other markers were measured by multiplexing assay. Median (IQR) of LRG1 levels was higher in obese (30 (25, 38) µg/mL) and overweight (30 (24, 39) µg/mL) adolescents, compared to normal-weight participants (27 (22, 35) µg/mL). The highest tertile of LRG1 had an OR [95% CI] of 2.55 [1.44, 4.53] for obesity. LRG1 was positively correlated to plasma levels of high sensitivity c-reactive protein (HsCRP) (ρ = 0.2), leptin (ρ = 0.2), and chemerin (ρ = 0.24) with p < 0.001. Additionally, it was positively associated with plasma level of IL6 (ρ = 0.17) and IL10 (ρ = 0.14) but not TNF-α. In conclusion, LRG1 levels are increased in obese adolescents and are associated with increased levels of adipogenic markers. These results suggest the usefulness of LRG1 as an early biomarker for obesity and its related pathologies in adolescents.

Coincidence of juvenile idiopathic arthritis and type 1 diabetes: a case-based review

The study was aimed to review a rare coexistence of type 1 diabetes (T1D) and juvenile idiopathic arthritis (JIA) regarding different clinical approaches to the management and treatment options. Medical complications of the two autoimmune disorders in children and adolescents have been evaluated, particularly in those treated with glucocorticosteroids (GCS) and insulin. A review of the literature regarding reports on concomitant T1D and JIA was conducted using resources available in Medline, Google Scholar, and Web of Science databases, with a specific focus on the combination of T1D and JIA in a pediatric population. The review was extended by our analysis of two patients treated in a single center for this comorbidity. Eligible reports of four cases were found, and including our two original records, a total of six pediatric patients (5 females) were analyzed, of which three had also other autoimmune diseases (thyroiditis, coeliac disease, autoimmune hepatitis), whereas four had been treated with a long-term GCS, and two were receiving biological therapy (etanercept or adalimumab). Only one of them had good metabolic control of diabetes. Diabetes in childhood may coexist with other autoimmune diseases, including rheumatologic conditions. Hyperglycemia can worsen JIA therapy by induction and maintaining inflammation. Using modern diabetes technologies (like personal insulin pumps and continuous glucose monitoring) helps to minimize the deteriorating effect of JIA exacerbations and the rheumatoid treatment on metabolic control of diabetes.

Non-HDL Cholesterol Levels in Childhood and Carotid Intima-Media Thickness in Adulthood

BACKGROUND

Elevated non-high-density lipoprotein cholesterol (HDL-C) levels are used to identify children at increased cardiovascular risk, but the use of non-HDL-C in childhood to predict atherosclerosis is unclear. We examined whether the National Heart, Lung, and Blood Institute classification of youth non-HDL-C status predicts high common carotid artery intima-media thickness in adulthood.

METHODS

We analyzed data from 4 prospective cohorts among 4582 children aged 3 to 19 years who were remeasured as adults (mean follow-up of 26 years). Non-HDL-C status in youth and adulthood was classified according to cut points of the National Heart, Lung, and Blood Institute and the National Cholesterol Education Program Adult Treatment Panel III. High carotid intima-media thickness (cIMT) in adulthood was defined as at or above the study visit-, age-, sex-, race-, and cohort-specific 90th percentile of intima-media thickness.

RESULTS

In a log-binomial regression analysis adjusted with age at baseline, sex, cohort, length of follow-up, baseline BMI, and systolic blood pressure, children with dyslipidemic non-HDL-C were at increased risk of high cIMT in adulthood (relative risk [RR], 1.29; 95% confidence interval [CI], 1.07-1.55). Compared with the persistent normal group, the persistent dyslipidemia group (RR, 1.80; 95% CI, 1.37-2.37) and incident dyslipidemia (normal to dyslipidemia) groups (RR, 1.45; 95% CI, 1.07-1.96) had increased risk of high cIMT in adulthood, but the risk was attenuated for the resolution (dyslipidemia to normal) group (RR, 1.17; 95% CI, 0.97-1.41).

CONCLUSIONS

Dyslipidemic non-HDL-C levels predict youth at risk for developing high cIMT in adulthood. Those who resolve their non-HDL-C dyslipidemia by adulthood have normalized risk of developing high cIMT in adulthood.

Utility of Different Blood Pressure Measurement Components in Childhood to Predict Adult Carotid Intima-Media Thickness

Childhood blood pressure (BP) levels predict adult subclinical atherosclerosis. However, the best childhood BP component for prediction has not been determined. This study comprised 5925 participants aged 3 to 18 years from 6 cohorts who were followed into adulthood (mean follow-up 25.8±6.2 years). Childhood BP was measured by using a standard mercury sphygmomanometer in all cohorts. Study-specific carotid intima-media thickness ≥90th percentile was used to define subclinical atherosclerosis. Per SD change in the predictor, childhood systolic BP (SBP; age- and sex-adjusted odds ratio [95% CI], 1.24 [1.13-1.37]), mean arterial pressure (1.10 [1.07-1.13]), and pulse pressure (1.15 [1.05-1.27]) were associated with increased adulthood intima-media thickness. In age- and sex-adjusted analyses, area under the receiver operating characteristic curves for SBP ( C value [95% CI], 0.677 [0.657-0.704]) showed significantly improved prediction compared with diastolic BP (0.669 [0.646-0.693], P=0.006) or mean arterial pressure (0.674 [0.653-0.699], P=0.01). Pulse pressure provided a C value that was not different from SBP (0.676 [0.653-0.699], P=0.16). Combining different BP components did not improve prediction over SBP measurement alone. Based on the associations with adult carotid intima-media thickness, cut points for elevated SBP were 105 mm Hg for 3- to 6-year-old boys, 108 mm Hg for 3- to 6-year-old girls, 108 mm Hg for 7- to 12-year-old boys, 106 mm Hg for 7- to 12-year-old girls, 123 mm Hg for 13- to 18-year-old boys, and 115 mm Hg for 13- to 18-year-old girls. Our analyses suggest that several childhood BP measurement components are related to adulthood carotid intima-media thickness. Of these, SBP provided the best predictive ability.

Obesity and insulin sensitivity effects on cardiovascular risk factors: Comparisons of obese dysglycemic youth and adults

BACKGROUND

Obesity and pubertal insulin resistance worsen cardiovascular (CV) risk factors in youth. It is unclear how the relationships of obesity and insulin resistance with CV risk compare to adults.

SUBJECTS AND METHODS

We evaluated 66 pubertal youth (mean ± SD: age 14.2 ± 2.0 years, body mass index [BMI] 36.6 ± 6.0 kg/m² , hemoglobin A1c [HbA1c] 38.5 ± 6.1 mmol/mol) and 355 adults with comparable BMI (age 52.7 ± 9.4 years, BMI 35.1 ± 5.1 kg/m² , HbA1c 39.8 ± 4.2 mmol/mol) participating in a multicenter study. Insulin sensitivity was quantified using hyperglycemic clamps. Assessment of CV risk factors was standardized across sites. Regression analyses compared the impact of insulin sensitivity and CV risk factors between youth and adults.

RESULTS

Obese pubertal youth were more insulin resistant than comparably obese adults (P < .001), but with similar slopes for the inverse relationship between insulin sensitivity and obesity. The impact of obesity on CV risk factors was explained by insulin sensitivity (P = NS after adjustment for sensitivity). The two age groups did not differ in relationships between insulin sensitivity and diastolic blood pressure, total cholesterol, and low-density lipoprotein (LDL) cholesterol, after adjusting for obesity. However, while systolic blood pressure (SBP) and high-density lipoprotein (HDL) cholesterol exhibited the expected direct and inverse relationships, respectively with insulin sensitivity in adults, these slopes were flat in youth across the range of insulin sensitivity (P ≤ .05 for group differences).

CONCLUSIONS

Effects of obesity on CV risk factors were attributable to insulin sensitivity in both groups. The relationships between insulin sensitivity and CV risk factors were similar in obese youth and adult groups except for SBP and HDL cholesterol.

CLINICAL TRIAL REGISTRATION

The RISE consortium studies are registered through Clinicaltrials.gov as NCT01779362 (Adult Medication Study); NCT01763346 (Adult Surgery Study); and NCT01779375 (Pediatric Medication Study). Clinical trial registration numbers: NCT01779362, NCT01779375 and NCT01763346 at clinicaltrials.gov.

The Complex Etiology of Childhood Obesity in Arabs Is Highlighted by a Combination of Biological and Socio-Economic Factors

Objectives: To identify predictors of childhood and adolescent obesity in Kuwaitis with Arab ethnicity.

Methods: A cross-sectional sample of 6–18 year-old schoolchildren was randomly selected from 244 public schools across all six governorates in the State of Kuwait. Anthropometric data were measured from 6,574 Arab Kuwaiti schoolchildren, and a structured questionnaire was used to collect information on possible risk factors associated with obesity. Overweight and obesity were defined in accordance with the Center for Disease Control and Prevention criteria.

Results: The prevalence of overweight and obesity in children (aged 6–18 years) were 17.7% and 33.7%, respectively. The likelihood of childhood obesity increased with birth weights >4.0 Kg [odds ratio (OR) = 2.3; p < 0.0001], maternal employment (OR = 1.26, p = 0.0006), maternal age at pregnancy >30 years (OR = 1.24; p = 0.0016) and family size of <6 members (OR = 1.16, p = 0.0106).

Conclusions: Public health professionals should be aware that advanced maternal age, maternal employment, smaller family size, and high birthweight may predict the risk of obesity in Kuwaiti Arab children and adolescents.

Urban environment as an independent predictor of insulin resistance in a South Asian population

Background

Developing countries, such as India, are experiencing rapid urbanization, which may have a major impact on the environment: including worsening air and water quality, noise and the problems of waste disposal. We used health data from an ongoing cohort study based in southern India to examine the relationship between the urban environment and homeostasis model assessment of insulin resistance (HOMA-IR).

Methods

We utilized three metrics of urbanization: distance from urban center; population density in the India Census; and satellite-based land cover. Restricted to participants without diabetes (N = 6350); we built logistic regression models adjusted for traditional risk factors to test the association between urban environment and HOMA-IR.

Results

In adjusted models, residing within 0–20 km of the urban center was associated with an odds ratio for HOMA-IR of 1.79 (95% CI 1.39, 2.29) for females and 2.30 (95% CI 1.64, 3.22) for males compared to residing in the furthest 61–80 km distance group. Similar statistically significant results were identified using the other metrics.

Conclusions

We identified associations between urban environment and HOMA-IR in a cohort of adults. These associations were robust using various metrics of urbanization and adjustment for individual predictors. Our results are of public health concern due to the global movement of large numbers of people from rural to urban areas and the already large burden of diabetes.

Electronic supplementary material

The online version of this article (10.1186/s12942-019-0169-9) contains supplementary material, which is available to authorized users.

The comparison of waist circumference, waist-to-hip ratio, and waist-to-height ratio among rural women adults in the North of Iran, between the years 2004 and 2013

BACKGROUND

Central obesity is a common health disorder, and the main objective of this study was to compare its changings among rural women in the north of Iran, between the years 2004 and 2013.

METHODS

Two cross-sectional studies were established on the 2839 and 2478 subjects in 2004 (first stage) and 2013 (second stage), respectively. Among 118 villages, 20 were selected using random sampling; they were the same in two studies. Central obesity was defined as waist circumference (WC) > 88 cm, waist-to-hip ratio (WHR) > 0.8, and waist-to-height ratio (WHtR) > 0.5.

RESULTS

The prevalence of central obesity in 2013 based on WC, WHR, and WHtR were 37.4%, 73.5%, and 67.8%, respectively. Compared with 2004, the prevalence of central obesity based on WHR increased as 5.4% (68.1% vs. 73.5%) (P = 0.001), whereas morbid obesity (WHtR > 0.6) based on WHtR decreased as 3.7% in 2013 (28.8% vs. 25.1%) (P = 0.004). Central obesity based on WHR significantly decreased in less or equal 24-year-old group (76.6% vs. 70.1%) (P = 0.003), while it increased in 25-34- (65.1% vs. 74.0%) and in equal or more than 35-year-old group (54.1% vs. 78.9%) (P = 0.001 for all). Moreover, morbid obesity decreased in all age, economic, and education groups (except uneducated one) (P < 0.050 for all).

CONCLUSION

Despite the decrease in central obesity based on WC and WHR indices in 2004-2013 duration, we found the evidence of a decline in sever obesity based on WHtR in that period. These trends have an alarm for health policy makers, not only in this area but also in same communities. Comprehensive studies are recommended to determine the best obesity indicator related to health in future.

Prevalence of underweight, overweight, and obesity in children and adolescents with type 1 diabetes: Data from the international SWEET registry

OBJECTIVE

To assess the prevalence of underweight (UW), overweight (OW), and obesity in children and adolescents with type 1 diabetes (T1D).

METHODS

An international cross-sectional study including 23 026 T1D children (2-18 years, duration of diabetes ≥1 year) participating in the SWEET prospective, multicenter diabetes registry. Body mass index SD score (BMI-SDS) was calculated using the World Health Organization BMI charts. Children were categorized as UW (BMI-SDS < -2SD), OW (+1SD < BMI-SDS ≤ +2SD), and obese (OB) (BMI-SDS > +2SD). Hierarchic regression models were applied with adjustment for sex, age, and duration of diabetes.

RESULTS

The prevalence of UW, OW, and obesity was: 1.4%, 22.3%, and 7.3% in males and 0.6%, 27.2%, and 6.8% in females. Adjusted BMI-SDS was significantly higher in females than in males (mean ± SEM: 0.54 ± 0.05 vs 0.40 ± 0.05, P < 0.0001). In males, BMI-SDS significantly decreased by age (P < 0.0001) in the first three age categories 0.61 ± 0.06 (2 to <10 years), 0.47 ± 0.06 (10 to <13 years), 0.34 ± 0.05 (13 to <16 years). In females, BMI-SDS showed a U-shaped distribution by age (P < 0.0001): 0.54 ± 0.04 (2 to <10 years), 0.39 ± 0.04 (10 to <13 years), 0.55 ± 0.04 (13 to <16 years). BMI-SDS increased by diabetes duration (<2 years: 0.38 ± 0.05, 2 to <5 years: 0.44 ± 0.05, and ≥5 years: 0.50 ± 0.05, P < 0.0001). Treatment modality did not affect BMI-SDS. Adjusted HbA1c was significantly higher in females than in males (8.20% ± 0.10% vs 8.06% ± 0.10%, P < 0.0001). In both genders, the association between HbA1c and BMI-SDS was U-shaped with the highest HbA1c in the UW and obesity groups.

CONCLUSIONS

The high rate of OW and obesity (31.8%) emphasize the need for developing further strategies to prevent and treat excess fat accumulation in T1D.

Cardiovascular and Metabolic Complications - Diagnosis and Management in Obese Children

The world at present is facing a burden of rising prevalence of obesity in children and adolescents. The developing countries are particularly facing the dual burden on under-nutrition and obesity. This is associated with appearance and clustering of cardiometabolic abnormalities at an early age with development of chronic complications early and possible decrease in life span of these children and adolescents. In adults this clustering has been termed as 'metabolic syndrome' with definitions that can be used universally. However, in children and adolescents there is no consensus on a uniform definition of metabolic syndrome that can be applicable across the age groups and various ethnicities. Further, as childhood is a period of growth and development, changes in body composition and insulin sensitivity that occur with puberty may influence the thresholds of components used to define metabolic syndrome. Children of South Asian ethnicity appear to be more predisposed to develop abnormalities of metabolic syndrome, possible due to their adverse body fat patterning and genetic influences. The definition of pediatric metabolic syndrome proposed by International Diabetes Federation is useful across different ethnicities. Presence of at least one component of metabolic syndrome should lead to detailed screening for other components and complications. A multimodality approach including therapeutic lifestyle changes targeted at the individual, family and community is essential for management. Pharmacotherapy for individual components may be required if initial management strategies fail to achieve the goals.

Gender-specific association of the rs6499640 polymorphism in the FTO gene with plasma lipid levels in Chinese children

The fat mass- and obesity-associated gene (FTO) is significantly associated with obesity, but the associations of FTO with obesity-related traits are not fully described. We aimed to investigate the association of the FTO single nucleotide polymorphism (SNP) rs6499640 with lipid levels in Chinese children. A total of 3503 children aged 6-18 years were included in the present study. Lipid levels were analyzed and the SNP rs6499640 was genotyped using the TaqMan Allelic Discrimination Assay. Statistically significant associations were found between rs6499640 and low-density lipoprotein cholesterol (LDL-C) (p = 0.008), total cholesterol (TC) (p = 0.005), and triglycerides (TG) (p < 0.001) in girls under a dominant model adjusted for age and BMI. No statistical significance was found between the SNP and lipid levels in boys. We demonstrated for the first time that the SNP rs6499640 in FTO is associated with LDL-C, TC, and TG in Chinese girls. Our study identified a new risk locus for lipid levels in children.

The International Childhood Cardiovascular Cohort (i3C) consortium outcomes study of childhood cardiovascular risk factors and adult cardiovascular morbidity and mortality: Design and recruitment

Although it is widely thought that childhood levels of cardiovascular (CV) risk factors are related to adult CV disease, longitudinal data directly linking the two are lacking. This paper describes the design and organization of the International Childhood Cardiovascular Cohort Consortium Outcomes Study (i3C Outcomes), the first longitudinal cohort study designed to locate adults with detailed, repeated, childhood biological, physical, and socioeconomic measurements and a harmonized database. I3C Outcomes uses a Heart Health Survey (HHS) to obtain information on adult CV endpoints, using mail, email, telephone, and clinic visits in the United States (U.S.) and Australia and a national health database in Finland. Microsoft Access, REsearch Data Capture (REDCap) (U.S.), LimeSurvey (Australia), and Medidata™ Rave data systems are used to collect, transfer and organize data. Self-reported CV events are adjudicated via hospital and doctor-released medical records. After the first two study years, participants (N = 10,968) were more likely to be female (56% vs. 48%), non-Hispanic white (90% vs. 80%), and older (10.4 ± 3.8 years vs. 9.4 ± 3.3 years) at their initial childhood study visit than the currently non-recruited cohort members. Over 48% of cohort members seen during both adulthood and childhood have been found and recruited, to date, vs. 5% of those not seen since childhood. Self-reported prevalences were 0.7% Type 1 Diabetes, 7.5% Type 2 Diabetes, 33% hypertension, and 12.8% CV event. 32% of CV events were judged to be true. I3C Outcomes is uniquely able to establish evidence-based guidelines for child health care and to clarify relations to adult CV disease.

Insulin sensitivity is reduced in children with high body-fat regardless of BMI

PURPOSE

To examine the association between insulin sensitivity and adiposity in children stratified according to their body mass index (BMI: normal weight, NW; overweight or obese, OW/OB) and body-fat percentage (BF%: adipose or NonAdipose), and determine whether cardiorespiratory fitness (CRF) ameliorates any deleterious associations.

METHODS

This prospective cohort study comprises a cross-sectional and longitudinal analyses of data collected at baseline and 2 years later on children (7.7-13.4 years) attending public school in Denmark. Levels of CRF were measured using the Andersen test, whereas BF% was measured by dual-energy X-ray absorptiometry (DXA). Fasting plasma glucose and insulin concentrations were measured and the homoeostatic model assessment of insulin resistance (HOMA-IR) used to assess insulin sensitivity.

RESULTS

Approximately 8% of children classified as normal weight by BMI had high BF% (NW + Adipose). Children with high BF% had significantly higher insulin (NW + adipose: 32.3%; OW/OB + Adipose: 52.2%) and HOMA-IR scores (NW + Adipose: 32.3%; OW/OB + Adipose: 55.3%) than children classified as NW without high BF% (reference group; NW + NonAdipose). Adjusting for CRF reduced this difference, but did not completely ameliorate these associations. Longitudinally, children with high BF% (OW/OB + Adipose or NW + Adipose) had significantly worse insulin sensitivity 2 years later than NW + NonAdipose children (All p < 0.001). The few children (n = 14) who improved their BMI or BF% during the 2 years follow-up, no longer had significantly worse insulin sensitivity than children with NW + NonAdipose.

CONCLUSION

High BF% in children is associated with significantly lower insulin sensitivity even when BMI is considered NW. Longitudinally, insulin sensitivity is lower in children with high BF% with or without high BMI. The CRF was a significant covariate in these models, but CRF did not completely ameliorate the effects of high BF% on insulin sensitivity.

Apelin, Nitric Oxide and Vascular Affection in Adolescent Type 1 Diabetic Patients

AIM

To evaluate the relationship of apelin and nitric oxide (NO) to endothelial dysfunction in type 1 diabetics.

PATIENTS AND METHODS

Sixty two type 1 diabetics and 30 healthy age and sex matched controls were included. Blood samples for apelin, NO, glycosylated hemoglobin (HbA1c), and lipid profile were collected. Albumin/creatinine ratio was assessed in urine. Flow mediated dilatation (FMD) via ultrasound was done.

RESULTS

The mean age of diabetics were 16.3 ± 1.5 yrs (14.0 - 19.0 yrs), and duration of disease, were 9.4 ± 2.9 yrs (5.0 - 16.5 yrs). FMD and FMD/nitrate mediated dilatation (NMD) ratio were lower in diabetics. NO was decreased, while apelin and albumin/creatinine ratio were increased significantly in diabetics. There was a positive correlation between apelin and HbA1c. On the contrary, NO had a negative correlation with HbA1c, albumin/creatinine ratio, LDL-c and OxLDL.

CONCLUSION

Diabetic patients had endothelial dysfunction and high apelin level, with no related to each other. High level of apelin is associated with bad glycemic control. Obesity had no role to increase in apelin level. NO is related to diabetic nephropathy and atherosclerosis. We recommend a further large study to evaluate the relationship of apelin with endothelial dysfunction.

Analysis of Factors Affecting the Body Mass Index in a National Sample of Iranian Children and Adolescents: Bootstrapping Regression

Background

This study aims to evaluate the effect of some factors, including birth weight, sex, age, waist circumference, family history of obesity, as well as some lifestyle factors as frequency of breakfast days and physical activity, on the body mass index among a nationally representative sample of Iranian children and adolescents by using bootstrapping regression.

Materials and Methods

This study was conducted as the third survey of a school-based surveillance system (CASPIAN-III study). Total participants were 5570 school students, aged 10-18 years, selected by multistage random cluster sampling from urban and rural areas of 27 provinces of Iran. Multiple linear regressions was used to evaluate the effect of various factors on obesity, but in our data the assumptions of this model violated, and possible solutions were not appropriate, therefore the bootstrapping regression based on the observations and errors resampling approaches was used as an alternative.

Results

The tests of significance showed that the effects of sex, age, waist circumference, family history obesity and frequency of breakfast days were clearly significant (P < 0.001). The effect of vigorous level of physical activity was significant in comparison to mild physical activity (P = 0.01). In comparison to low birth weight, medium and high birth weight had significant effect on obesity.

Conclusions

Bootstrap method is preferable in linear regression because of some theoretical properties like having any distributional assumptions on the residuals and hence allows for inference even if the errors do not follow normal distribution or constant error variance.

Impact of Lipid Measurements in Youth in Addition to Conventional Clinic-Based Risk Factors on Predicting Preclinical Atherosclerosis in Adulthood: International Childhood Cardiovascular Cohort Consortium

BACKGROUND

Data suggest that the prediction of adult cardiovascular disease using a model comprised entirely of adult nonlaboratory-based risk factors is equivalent to an approach that additionally incorporates adult lipid measures. We assessed and compared the utility of a risk model based solely on nonlaboratory risk factors in adolescence versus a lipid model based on nonlaboratory risk factors plus lipids for predicting high-risk carotid intima-media thickness (cIMT) in adulthood.

METHODS

The study comprised 2893 participants 12 to 18 years of age from 4 longitudinal cohort studies from the United States (Bogalusa Heart Study and the Insulin Study), Australia (Childhood Determinants of Adult Health Study), and Finland (The Cardiovascular Risk in Young Finns Study) and followed into adulthood when cIMT was measured (mean follow-up, 23.4 years). Overweight status was defined according to the Cole classification. Hypertension was defined according to the Fourth Report on High Blood Pressure in Children and Adolescents from the National High Blood Pressure Education Program. High-risk plasma lipid levels were defined according to the National Cholesterol Education Program Expert Panel on Cholesterol Levels in Children. High cIMT was defined as a study-specific value ≥90th percentile. Age and sex were included in each model.

RESULTS

In univariate models, all risk factors except for borderline high and high triglycerides in adolescence were associated with high cIMT in adulthood. In multivariable models (relative risk [95% confidence interval]), male sex (2.7 [2.0-2.6]), prehypertension (1.4 [1.0-1.9]), hypertension (1.9 [1.3-2.9]), overweight (2.0 [1.4-2.9]), obesity (3.7 [2.0-7.0]), borderline high low-density lipoprotein cholesterol (1.6 [1.2-2.2]), high low-density lipoprotein cholesterol (1.6 [1.1-2.1]), and borderline low high-density lipoprotein cholesterol (1.4 [1.0-1.8]) remained significant predictors of high cIMT (P<0.05). The addition of lipids into the nonlaboratory risk model slightly but significantly improved discrimination in predicting high cIMT compared with nonlaboratory-based risk factors only (C statistics for laboratory-based model 0.717 [95% confidence interval, 0.685-0.748] and for nonlaboratory 0.698 [95% confidence interval, 0.667-0.731]; P=0.02).

CONCLUSIONS

Nonlaboratory-based risk factors and lipids measured in adolescence independently predicted preclinical atherosclerosis in young adulthood. The addition of lipid measurements to traditional clinic-based risk factor assessment provided a statistically significant but clinically modest improvement on adolescent prediction of high cIMT in adulthood.

Gynecologic and andrologic dermatology and the metabolic syndrome

The relationship of sex hormones to obesity and inflammation has been extensively studied. Research on endogenous and exogenous sex steroids, including studies on animal models of metabolic syndrome (MetS), has indicated that sex hormones are involved in metabolic pathways relevant to MetS. Lower testosterone levels in men and higher levels in women increase risks of MetS and type 2 diabetes mellitus (T2DM). Lower levels of sex hormone-binding globulin increase risks of MetS and T2DM in both sexes. Skin diseases that are sex hormone mediated, such as polycystic ovary syndrome, acanthosis nigricans, acne vulgaris, and pattern alopecia, have been associated with insulin resistance. Insulin resistance increases the risk for metabolic and potentially cardiovascular complications, and patients with such skin diseases should be followed for a prolonged time to determine whether they develop these complications. Early intervention may help delay or prevent the onset of T2DM and decrease cardiovascular risks.

Childhood Age and Associations Between Childhood Metabolic Syndrome and Adult Risk for Metabolic Syndrome, Type 2 Diabetes Mellitus and Carotid Intima Media Thickness: The International Childhood Cardiovascular Cohort Consortium

Background

There is paucity of knowledge concerning the specific age in youth when the associations of metabolic syndrome (MetS) begin to be operative. Thus, we investigated the relation of age to the associations of childhood MetS with adult MetS, type 2 diabetes mellitus and high carotid intima‐media thickness.

Methods and Results

Five thousand eight‐hundred three participants were analyzed in 4 cohort studies (Cardiovascular Risk in Young Finns, Bogalusa Heart Study, Princeton Lipid Research Study, Insulin Study). International cutoffs and previously used 75th percentile cutoffs were used for children to define MetS and its components. Mean follow‐up period was 22.3 years. Logistic regression was used to calculate risk ratios and 95% confidence intervals. Childhood MetS and overweight were associated with over 2.4‐fold risk for adult MetS from the age of 5 years onward. Risk for type 2 diabetes mellitus was increased from the age of 8 (risk ratio, 2.6–4.1; 95% confidence interval, 1.35–6.76 and 1.12–7.24, respectively) onward for the 2 childhood MetS criteria based on international cut‐off values and for childhood overweight. Risk for high carotid intima‐media thickness was significant at ages 11 to 18 years in relation to childhood MetS or overweight (risk ratio, 2.44–4.22; 95% confidence interval, 1.55–3.55 and 2.55–5.66, respectively). Continuous childhood MetS score was associated with adult MetS from the age of 5, with type 2 diabetes mellitus from the age of 14 and with high carotid intima‐media thickness from the age of 11 years onward.

Conclusions

Adult MetS was predicted by MetS in childhood beginning at age 5. However, adult type 2 diabetes mellitus and subclinical atherosclerosis were not predicted by childhood data until after age 8. Body mass index measurement alone at the same age points provided similar findings.

Prevalence of childhood obesity in the state of Kuwait

BACKGROUND

Overweight and obesity have reached an epidemic in Kuwait, with the highest rate of adult obesity in the region. National estimates of childhood obesity in Kuwait are scarce. The purpose of this study is to evaluate the prevalence of overweight and obesity among school children in Kuwait.

METHODS

This is a cross-sectional study of a representative sample of 6-18 years old school children, randomly selected from 244 schools in Kuwait. Anthropometric data was measured from 6574 students in September 2012-June 2013. Overweight and obesity have been defined in accordance with the Centres for Disease Control and Prevention (CDC), International Obesity Task Force (IOTF) and World Health Organization (WHO) 2007 criteria.

RESULTS

The prevalence estimate overweight was based on the three different systems (CDC = 17.7%, IOTF = 23.3%, WHO = 21.6%). The prevalence of obesity was (CDC = 33.9%, IOTF = 28.2%, WHO = 30.5%). Boys had a higher percentage of obesity regardless of the classification system used.

CONCLUSIONS

The prevalence of childhood obesity is alarmingly high in the State of Kuwait and exceeds the prevalence rates reported from neighbouring countries and from North America.

Cardiovascular Health Promotion in Children: Challenges and Opportunities for 2020 and Beyond: A Scientific Statement From the American Heart Association

This document provides a pediatric-focused companion to "Defining and Setting National Goals for Cardiovascular Health Promotion and Disease Reduction: The American Heart Association's Strategic Impact Goal Through 2020 and Beyond," focused on cardiovascular health promotion and disease reduction in adults and children. The principles detailed in the document reflect the American Heart Association's new dynamic and proactive goal to promote cardiovascular health throughout the life course. The primary focus is on adult cardiovascular health and disease prevention, but critical to achievement of this goal is maintenance of ideal cardiovascular health from birth through childhood to young adulthood and beyond. Emphasis is placed on the fundamental principles and metrics that define cardiovascular health in children for the clinical or research setting, and a balanced and critical appraisal of the strengths and weaknesses of the cardiovascular health construct in children and adolescents is provided. Specifically, this document discusses 2 important factors: the promotion of ideal cardiovascular health in all children and the improvement of cardiovascular health metric scores in children currently classified as having poor or intermediate cardiovascular health. Other topics include the current status of cardiovascular health in US children, opportunities for the refinement of health metrics, improvement of health metric scores, and possibilities for promoting ideal cardiovascular health. Importantly, concerns about the suitability of using single thresholds to identify elevated cardiovascular risk throughout the childhood years and the limits of our current knowledge are noted, and suggestions for future directions and research are provided.

Premature Atherosclerotic Cardiovascular Disease in Childhood Cancer Survivors

Survival rates of childhood cancer have increased over the last 30 years, revealing a population with unique characteristics and risks. The effects of radiation and cardiotoxic chemotherapy predispose these children to both early and late cardiovascular disease. Cranial radiation also increases the likelihood of growth hormone deficiency, which leads to metabolic disturbances. Childhood cancer survivors are less likely to be active than their healthy siblings, and have a lower aptitude for physical activity. These issues are additive to the usual risks experienced by the general population, thereby significantly increasing the likelihood of premature cardiovascular disease. Early and regular screening and risk factor management in this population is recommended.

Relations among Adiposity and Insulin Resistance with Flow-Mediated Dilation, Carotid Intima-Media Thickness, and Arterial Stiffness in Children

OBJECTIVE

To determine the associations of adiposity and insulin resistance with measures of vascular structure and function in children.

STUDY DESIGN

A cross-sectional study included 252 children (age 15.1 ± 2.4 years; body mass index percentile 68.2 ± 26.5%; Tanner 2-5). Measurements of body fat percentage were obtained with dual-energy X-ray absorptiometry and visceral adipose tissue (VAT) with computed tomography. Insulin resistance was measured with hyperinsulinemic euglycemic clamp. Vascular measurements for endothelial function (brachial artery flow-mediated dilation [FMD]), vascular structure (carotid intima-media thickness [cIMT]), vascular stiffness (carotid incremental elastic modulus), and pulse wave velocity were analyzed by tertiles of adiposity and insulin resistance. Additional analyses with ANCOVA and linear regression were adjusted for Tanner, sex, race, and family relationship; FMD was also adjusted for baseline artery diameter.

RESULTS

FMD was positively associated with high adiposity (body mass index, body fat percentage, and VAT) (P < .01 all). Insulin resistance was not associated with FMD. cIMT was significantly, positively related to obesity, VAT, and insulin resistance (P < .05 all). No differences in carotid incremental elastic modulus and pulse wave velocity were observed in relation to adiposity or insulin resistance.

CONCLUSIONS

The findings suggest that adiposity is associated with higher FMD, and insulin resistance and VAT are associated with higher cIMT in children. Further research is needed to clarify the progression of these relations.

Visceral adipose tissue measured by DXA correlates with measurement by CT and is associated with cardiometabolic risk factors in children

BACKGROUND

Visceral adipose tissue (VAT) generally demonstrates a stronger relationship with cardiometabolic risk factors than total body fat or subcutaneous adipose tissue.

OBJECTIVES

The purpose of this study was to compare VAT estimated in children by total volume dual-energy X-ray absorptiometry (DXA) with a gold standard measurement, single slice (L4-L5) computed tomography (CT).

METHODS

A total of 329 (152 females, 177 males) children ages 6-18 years (mean age 12.3 ± 3.6) and with average body mass index percentile of 54.9% (3-99%) had their VAT estimated by both CT and DXA. Linear association between methods was measured using Pearson's correlation. Multiple linear regressions compared the associations between cardiometabolic risk factors and both CT-VAT and DXA-VAT, respectively.

RESULTS

In children, DXA-VAT was correlated significantly with CT-VAT, with a stronger relationship in overweight and obese children. Multiple regression analysis showed that both estimates of VAT were significantly associated with lipids and insulin sensitivity, measured by euglycaemic-hyperinsulinaemic clamp. Additionally, DXA-VAT was associated with diastolic blood pressure, homeostasis model of insulin resistance and fasting insulin, but CT-VAT was not.

CONCLUSION

In children, total volume DXA-VAT and single slice CT-VAT are significantly correlated and each demonstrates similar associations with cardiometabolic risk factors. This suggests that DXA is a useful and valid method for estimation of VAT in children.

Childhood wrist circumference is not a predictor of insulin resistance in adulthood

We sought to determine whether childhood wrist circumference predicts insulin resistance in adulthood. Measures were taken in prepubertal children and then approximately 30 years later in the same subjects as adults. Our findings suggest that wrist circumference in childhood is not a predictor of insulin resistance in adulthood.

Identification of sex-specific thresholds for accumulation of visceral adipose tissue in adults

OBJECTIVE

The purpose of this study was to measure the linearity of visceral adipose tissue (VAT) accumulation with measures of total body adiposity to determine whether a threshold exists and to explore the association with cardiometabolic risk factors in adults.

METHODS

Using a cross-sectional design, data were obtained from 723 adults (324 females) age 19-47 years. Body mass index ranged from 15 to 52 kg/m(2) . Segmented linear regression was used to identify sex-specific percent body fat thresholds at which VAT slope changes. Linear regression measured the association of VAT mass, total fat mass, and subcutaneous fat with cardiometabolic risk factors above and below each threshold.

RESULTS

Adiposity thresholds were identified at 23.4% body fat in males and 38.3% body fat in females beyond which the slope of VAT per unit of percent body fat increased to strongly positive. Males and females above these adiposity thresholds had significant dyslipidemia (P<0.001), increased insulin resistance (P<0.001), and higher fat mass across all depots.

CONCLUSIONS

From these cross-sectional data, the following were inferred: the accumulation of VAT mass is not linear with increasing adiposity; increases in visceral accumulation above threshold are associated with decreased insulin sensitivity and cardiovascular risk in males and females independent of total body fat.

Associations between estimated desaturase activity and insulin resistance in korean boys

OBJECTIVES

Obesity in childhood increases the risk of obesity in adulthood, and is predictive of the development of metabolic disorders. The fatty acid compositions of various tissues, including blood, are associated with obesity and obesity-associated disorders. Thus, tracking plasma phospholipid (PL) features and metabolic parameters in young individuals may strengthen the utility of fatty acid composition as an early biomarker of future metabolic disorders.

METHODS

Anthropometric and blood biochemical data were obtained from 131 Korean males aged 10.5 ± 0.4 years, and followed up at 2 years. We analyzed the plasma PL fatty acids according to obesity. Obese children were defined as those with a body mass index (BMI) greater than the 85(th) percentile for age and gender, based on Korean child growth standards.

RESULTS

Activities of lipid desaturases, stearyl-CoAD (SCD-16,16:1n-7/16:0), delta-6D (D6D, 20:3n-6/18:2n-6), and delta-5D (D5D, 20:4n-6/20:3n-6), were estimated. Obese individuals had significantly higher proportions of palmitoleic acid (16:1n-7) and dihomo-gamma linolenic acid (DGLA, 20:3n-6) at both baseline and follow-up than did lean individuals. The activities of SCD-16 and D6D were higher in obese than lean boys. The baseline SCD-16 activity level was positively associated with the baseline waist circumference (WC) and the metabolic risk score. The baseline D6D level was positively associated with WC and also with the homeostasis model of assessment of insulin resistance (HOMA-IR), a surrogate marker of insulin resistance (IR), and metabolic risk score at both baseline and follow-up.

CONCLUSION

In young Korean males, higher D6D activity predicts the future development of IR and associated metabolic disorders including dyslipidemia.

[Association of body mass index and aerobic physical fitness with cardiovascular risk factors in children]

Objective:

To identify the association between both, body mass index and aerobic fitness, with cardiovascular disease risk factors in children.

Methods:

Cross-sectional study, carried out in Itaúna-MG, in 2010, with 290 school children ranging from 6 to 10 years-old of both sexes, randomly selected. Children from schools located in the countryside and those with medical restrctions for physical activity were not included. Blood sample was collected after a 12-hour fasting period. Blood pressure, stature and weight were evaluated in accordance with international standards. The following were considered as cardiovascular risk factors: high blood pressure, high total cholesterol, LDL, triglycerides and insulin levels, and low HDL. The statistical analysis included the Spearman's coefficient and the logistic regression, with cardiovascular risk factors as dependent variables.

Results:

Significant correlations were found, in both sexes, among body mass index and aerobic fitness with most of the cardiovascular risk factors. Children of both sexes with body mass index in the fourth quartile demonstrated increased chances of having high blood insulin and clustering cardiovascular risk factors. Moreover, girls with aerobic fitness in the first quartile also demonstrated increased chances of having high blood insulin and clustering cardiovascular risk factors.

Conclusion:

The significant associations and the increased chances of having cardiovascular risk factors in children with less aerobic fitness and higher levels of body mass index justify the use of these variables for health monitoring in Pediatrics.

The relative contributions of the abdominal visceral and subcutaneous fat depots to cardiometabolic risk in youth

The aim of this study was to evaluate the association of abdominal visceral and subcutaneous fat, independent of total body fat, with cardiometabolic risk factors and insulin resistance among youth. Visceral and subcutaneous fat, percentage total body fat, insulin resistance (adjusted for lean body mass: Mlbm), blood pressure, glucose, insulin and lipids were obtained in 472 youth ages 6-18 years. Linear regression, adjusted for age, sex, race, Tanner stage and percentage total body fat, was used to evaluate associations of visceral and subcutaneous fat with cardiometabolic risk factors. Visceral fat was associated inversely with Mlbm (P = 0.003) and positively with fasting insulin (P = 0.002) and triglycerides (P = 0.002). Visceral fat levels above the mean were associated inversely with high-density lipoprotein (HDL) cholesterol (P = 0.002), and positively with systolic blood pressure (P < 0.0001) and non-HDL cholesterol (P < 0.0001). Subcutaneous fat was associated inversely with Mlbm (P = 0.003) and HDL cholesterol (P < 0.05), and positively with fasting glucose (P < 0.05), fasting insulin (P = 0.0003), systolic blood pressure (P = 0.005) and triglycerides (P = 0.003). Subcutaneous fat levels above the mean were associated with non-HDL cholesterol (P = 0.0002). These findings suggest that there may be a threshold level of visceral and subcutaneous fat (regardless of total body fat), that when exceeded in childhood, is more likely to be associated with many cardiometabolic risk factors. Triglycerides and insulin resistance appear to be associated with these fat depots at even lower thresholds of abdominal adiposity.

Impact of pubertal development on endothelial function and arterial elasticity

OBJECTIVES

Little is known about the relation of pubertal development on endothelial function and arterial elasticity in children and adolescents; therefore, we compared brachial artery flow-mediated dilation and carotid artery elasticity across Tanner (pubertal) stages in children and adolescents.

STUDY DESIGN

Blood pressure, fasting lipids, glucose and insulin, body fat, insulin sensitivity adjusted for lean body mass, brachial flow-mediated dilation (percent dilation and area under the curve), endothelium-independent dilation (peak dilation and area under the curve), and carotid artery elasticity were evaluated across pubertal stages (Tanner I vs Tanner II-IV vs Tanner V) in 344 children and adolescents (184 males, 160 females; ages 6 to 21 years).

RESULTS

One hundred twenty-four subjects (mean age 8.23 ± 0.15 years; 52 females) were Tanner stage I; 105 subjects (mean age 13.19 ± 0.17 years; 47 females) were Tanner stages II-IV; and 115 subjects (mean age 17.19 ± 0.16 years; 61 females) were Tanner stage V. There were no significant differences for any of the measures of vascular structure and function across pubertal stages.

CONCLUSION

Results of the current study indicate that smooth-muscle and endothelial function, as well as carotid artery elasticity, do not differ throughout pubertal development and that accounting for pubertal stage when reporting vascular data in children and adolescents may be unnecessary.

Relation between serum free fatty acids and adiposity, insulin resistance, and cardiovascular risk factors from adolescence to adulthood

The objective of this study was to describe longitudinal relations of serum total free fatty acids (FFAs) to insulin resistance (IR) and cardiovascular (CV) risk factors from adolescence into adulthood. The cohort included participants in a longitudinal study of obesity and IR with complete data, including anthropometric measures, FFAs, IR measured by euglycemic clamp, blood pressure, fasting serum lipids, and insulin at mean 15 and 22 years of age (n = 207) and their parents (n = 272). FFAs and IR were not significantly related at mean 15 years of age but were significantly related at mean age 22 years. FFA did not relate to BMI at either age. FFA at 15 years of age estimated IR at 22 years of age. In parents (mean age 51 years), FFA was significantly correlated with BMI, percent body fat, systolic blood pressure, LDL, and IR. Associations with all risk factors except IR in parents were attenuated by adjustment for BMI. Most 22 years of age correlations with parents were higher than corresponding 15 years of age correlations. This study finds that FFA is associated with IR starting in young adulthood. The relation between FFA and CV risk factors does not become significant until later adulthood. The results support a significant impact of early metabolic dysfunction on later CV risk.

Ideal cardiovascular health in young adult populations from the United States, Finland, and Australia and its association with cIMT: the International Childhood Cardiovascular Cohort Consortium

BACKGROUND

Goals for cardiovascular (CV) disease prevention were set by the American Heart Association in 2010 for the concept of CV health. Ideal CV health is defined by 7 CV health metrics: blood pressure, glucose, cholesterol, body mass index, and physical activity on recommended levels; nonsmoking; and a healthy diet. We studied the prevalence of ideal CV health and its associations with ultrasonographically measured carotid intima-media thickness (cIMT) cross-sectionally in 5 international populations.

METHODS AND RESULTS

Prevalence of ideal CV health was assessed among 5785 young adults (age, 36.6 ± 3.2 years) comprising 335 participants from the Minneapolis Childhood Cohort Studies (Minnesota), 723 from the Princeton Follow-up Study, 981 from the Bogalusa Heart Study (BHS), 1898 from the Cardiovascular Risk in Young Finns Study (YFS), and 1848 from the Childhood Determinants of Adult Health Study (CDAH). Only 1% of the participants had all 7 ideal CV health metrics. The number of ideal CV health metrics associated inversely with cIMT in the 4 cohorts in which cIMT was available: for each additional ideal CV health metric, cIMT was 12.7 μm thinner in Minnesota (P=0.0002), 9.1 μm thinner in BHS (P=0.05), 10.4 μm thinner in YFS (P<0.0001), and 3.4 μm thinner in CDAH (P=0.03).

CONCLUSIONS

The number of ideal CV health metrics was inversely associated with cIMT in the cohorts in which cIMT was available, indicating that ideal CV health metrics are associated with vascular health at the population level. Ideal CV health was rare in this large international sample of young adults, emphasizing the need for effective strategies for health promotion.

Cohort Profile: the international childhood cardiovascular cohort (i3C) consortium

This is a consortium of large children's cohorts that contain measurements of major cardiovascular disease (CVD) risk factors in childhood and had the ability to follow those cohorts into adulthood. The purpose of this consortium is to enable the pooling of data to increase power, most importantly for the follow-up of CVD events in adulthood. Within the consortium, we hope to be able to obtain data on the independent effects of childhood and early adult levels of CVD risk factors on subsequent CVD occurrence.

Leptin in pediatrics: A hormone from adipocyte that wheels several functions in children

The protein leptin, a pleiotropic hormone regulates appetite and energy balance of the body and plays important roles in controlling linear growth, pubertal development, cardiovascular function, and immunity. Recent findings in the understanding of the structure, functional roles, and clinical significance of conditions with increased and decreased leptin secretion are summarized. Balance between leptin and other hormones is significantly regulated by nutritional status. This balance influences many organ systems, including the brain, liver, and skeletal muscle, to mediate the essential adaptation process. The aim of this review is to summarize the possible physiological functions of leptin and its signaling pathways during childhood and adolescence including control of food intake, energy regulation, growth and puberty, and immunity. Moreover, its secretion and possible roles in the adaptation process during different disease states (obesity, malnutrition, eating disorders, delayed puberty, congenital heart diseases and hepatic disorders) are discussed. The clinical manifestations and the successful management of patients with genetic leptin deficiency and the application of leptin therapy in other diseases including lipodystrophy, states with severe insulin resistance, and diabetes mellitus are discussed.

Association of osteocalcin with obesity, insulin resistance, and cardiovascular risk factors in young adults

Low levels of osteocalcin (OCN), an osteoblast-specific hormone, have recently been associated with insulin resistance (homeostasis model assessment-insulin resistance (HOMA-IR)) and obesity, particularly in older adults. The aim of this study was to determine whether low levels of OCN would be associated with insulin resistance, obesity, and greater cardiovascular (CV) risk in young adults just emerging from adolescence. Undercarboxylated OCN and carboxylated OCN levels were measured on stored serum samples (total OCN = undercarboxylated OCN + carboxylated OCN) on 137 participants (67 males) at mean age 18.6 years (range 17-22 years). Insulin resistance was measured by hyperinsulinemic-euglycemic clamp (M(lbm)). Multivariable regression analyses with ln(OCN) as the independent variable were adjusted for age, sex, ethnicity, and BMI as indicated. Total OCN was inversely related to BMI, waist circumference, systolic blood pressure (SBP), interleukin (IL)-6, and directly related to M(lbm); only SBP remained significant (with M(lbm) P = 0.0560) after further adjustment for BMI. Carboxylated OCN was inversely related to BMI, waist circumference, SBP, low-density lipoprotein cholesterol (LDL-C), and directly related to adiponectin; SBP and adiponectin remained significant after further adjustment for BMI. There were no significant associations with undercarboxylated OCN. In summary, most associations with OCN were mediated via BMI. However, the significant associations of OCN with SBP, obesity, and adiponectin and borderline with M(lbm), suggest a potential role for OCN in the development of insulin resistance and CV risk that becomes more apparent with aging into older adulthood.

The High Prevalence of Overweight and Obesity in Mexican Children

OBJECTIVE

To establish the prevalence of overweight and obesity in Mexican children 10 to 17 years of age according to the percentiles from both the Centers of Disease Control and Prevention (CDC) and the International Obesity Task Force (IOTF).

RESEARCH METHODS AND PROCEDURES

Heights and weights were measured in children from nationally representative, randomly chosen households in the Mexican National Health Survey 2000. The study population consisted of 7862 boys and 8947 girls, 10 to 17 years of age. Measurements used were the percentage of children in the corresponding BMI categories for overweight and obesity specified by the CDC and the IOTF BMI percentiles.

RESULTS

The children were short, with mean Z scores for height by age varying from - 0.62 +/- 1.26 to -1.12 +/- 1.06 in boys and from -0.45 +/- 1.25 to -1.19 +/- 1.12 in girls. CDC-based overweight prevalences varied by age from 10.8% to 16.1% in boys and 14.3% to 19.1% in girls, with obesity prevalences from 9.2% to 14.7% in boys and 6.8% to 10.6% in girls; these prevalences did not relate to stunting. IOTF-based excess weight prevalences were similar, with higher overweight rates (boys, 15.4% to 18.8%; girls, 18.4% to 22.3%) but lower obesity rates (boys, 6.1% to 9%; girls, 5.9% to 8.2%).

DISCUSSION

Mexican children have one-half the overweight/obesity prevalences of U.S. Mexican-American children; however, there are higher rates in Northern Mexico, which is closer to the U.S. These escalating rates of excess weight demand new prevention, as well as management, policies.

Development of associations among central adiposity, adiponectin and insulin sensitivity from adolescence to young adulthood

OBJECTIVE

To examine associations of central adiposity, serum adiponectin and clamp-derived insulin sensitivity in a single longitudinal cohort from early adolescence to young adulthood.

METHODS

The cohort was examined three times at mean ages 15 years (n = 308), 19 years (n = 218) and 22 years (n = 163). Insulin sensitivity was measured with the euglycaemic hyperinsulinaemic clamp. Circulating adiponectin was measured by enzyme-linked immunosorbent assay. Computed tomography scans were used at mean age 22 to compute subcutaneous and visceral abdominal fat volume. Partial Pearson correlations and linear regression were used to examine cross-sectional associations at each examination.

RESULTS

The moderate negative correlation between waist circumference and adiponectin was significant and essentially unchanged from mean age 15 (-0.32, P < 0.0001) to mean age 22 (-0.29, P < 0.002), whereas the negative correlation between waist circumference and insulin sensitivity and the positive correlation between adiponectin and insulin sensitivity increased steadily in magnitude to mean age 22 (-0.29, P = 0.0002; and 0.32, P < 0.0001, respectively). In regression models including both visceral and subcutaneous fat, only visceral fat was significantly associated with insulin sensitivity, while only subcutaneous fat was nearly significantly associated with adiponectin.

CONCLUSIONS

This study shows that the significant negative relationship between waist circumference and adiponectin predated the development of significant relationships between insulin sensitivity and both waist circumference and adiponectin. It also shows that adiponectin is more closely related to subcutaneous fat and insulin sensitivity is more closely related to visceral fat in young adults.

Obesity modifies the relations between serum markers of dairy fats and inflammation and oxidative stress among adolescents

Pentadecanoic acid (15:0) and heptadecanoic acid (17:0), the dairy-specific saturated fatty acids have been inversely, while inflammation and oxidative stress have been positively related to the risk of cardiovascular disease (CVD). Both fatty acid metabolism and inflammation and oxidative stress may be influenced by adiposity. In the current cross-sectional analyses among adolescents (mean age 15 years), we determined whether overweight status modified the associations between dairy fatty acids (pentadecanoic acid (15:0) and heptadecanoic acid (17:0)) represented in serum phospholipids (PL) and markers of inflammation and oxidative stress. Six biomarkers for inflammation and oxidative stress were analyzed, including circulating adiponectin, C-reactive protein (CRP), cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), and urinary 15-keto-dihydro-PGF2α (15-keto) and 8-iso-PGF2α (F2-iso). Generalized linear regression analyses, adjusted for age, gender, race, tanner score, total energy intake and physical activity, revealed that PL dairy fatty acids were inversely associated with CRP, F2-iso and 15-keto in overweight, but not in normal weight adolescents (all P(interaction) < 0.05). However, higher level of PL dairy fatty acids was associated with lower IL-6 among all adolescents. Further adjustment for dietary intake of calcium, vitamin D, protein, total flavonoids, and ω-3 fatty acids did not materially change the findings. Dairy-specific saturated fats, i.e., 15:0 and 17:0 fatty acids, may contribute to the potential health benefits of dairy products, especially for overweight adolescents.

Increased adipose protein carbonylation in human obesity

Insulin resistance is associated with obesity but mechanisms controlling this relationship in humans are not fully understood. Studies in animal models suggest a linkage between adipose reactive oxygen species (ROS) and insulin resistance. ROS oxidize cellular lipids to produce a variety of lipid hydroperoxides that in turn generate reactive lipid aldehydes that covalently modify cellular proteins in a process termed carbonylation. Mammalian cells defend against reactive lipid aldehydes and protein carbonylation by glutathionylation using glutathione-S-transferase A4 (GSTA4) or carbonyl reduction/oxidation via reductases and/or dehydrogenases. Insulin resistance in mice is linked to ROS production and increased level of protein carbonylation, mitochondrial dysfunction, decreased insulin-stimulated glucose transport, and altered adipokine secretion. To assess protein carbonylation and insulin resistance in humans, eight healthy participants underwent subcutaneous fat biopsy from the periumbilical region for protein analysis and frequently sampled intravenous glucose tolerance testing to measure insulin sensitivity. Soluble proteins from adipose tissue were analyzed using two-dimensional gel electrophoresis and the major carbonylated proteins identified as the adipocyte and epithelial fatty acid-binding proteins. The level of protein carbonylation was directly correlated with adiposity and serum free fatty acids (FFAs). These results suggest that in human obesity oxidative stress is linked to protein carbonylation and such events may contribute to the development of insulin resistance.

Serial changes in norepinephrine kinetics associated with feeding dogs a high-fat diet

The role of increased sympathetic nervous system (SNS) activity in the pathogenesis of obesity hypertension and insulin resistance is controversial. Eight dogs were instrumented and fed a high-fat diet (HFD) for 6 weeks. Dogs were evaluated for changes in weight, blood pressure, insulin resistance, and norepinephrine (NE) kinetics using a two-compartment model. The HFD resulted in weight gain, hypertension, and insulin resistance. During the 6 weeks of the HFD, although plasma NE concentration trended toward increasing (P=.09), SNS, assessed by NE kinetic studies, significantly increased (P=.009). Within 1 week of starting the HFD, NE release into the extravascular compartment (NE(2)) increased from 3.44+/-0.59 microg/mL to 4.87+/-0.80 microg/mL (P<.01) and this increase was maintained over the next 5 weeks of the HFD (NE(2) at week 6 was 4.66+/-0.97 microg/mL). In addition to the increased NE(2) there was also a significant increase in NE clearance (P=.04). There were significant correlations between the increase in NE(2) and both the development of insulin resistance and hypertension. This study supports the hypothesis that activation of the SNS plays a pivotal role in the metabolic and hemodynamic changes that occur with weight gain induced by HFD.

Relation of circulating oxidized LDL to obesity and insulin resistance in children

INTRODUCTION

Circulating oxidized low-density lipoprotein (LDL), a marker of oxidative stress, is associated with obesity, insulin resistance, metabolic syndrome, and cardiovascular disease in adults. However, little is known about its relation to insulin resistance and cardiovascular risk factors in children. The purpose of this study was to assess the relation of oxidative stress, measured by circulating oxidized LDL, with measures of adiposity and insulin resistance in children.

METHODS

Oxidized LDL, measures of body fatness (body mass index: BMI, percent body fat, waist circumference, percent trunk fat, abdominal visceral and subcutaneous fat), insulin resistance with euglycemic insulin clamp (Mlbm), blood pressure, and blood lipids were obtained in 78 children. Oxidized LDL was compared between normal weight children (BMI < 85th percentile) and overweight/obese children (BMI ≥ 85th percentile) and levels were evaluated for associations with body fatness and insulin resistance.

RESULTS

Oxidized LDL levels were significantly higher in overweight/obese vs. normal weight children (p < 0.0001). Oxidized LDL was significantly correlated with BMI, percent body fat, waist circumference, percent trunk fat, abdominal visceral fat, and abdominal subcutaneous fat (all p-values <0.0001). Moreover, oxidized LDL was negatively correlated with Mlbm, even after adjustment for adiposity (p < 0.01).

CONCLUSIONS

Oxidized LDL is significantly associated with adiposity and with insulin resistance, independent of body fatness, in children. Oxidative stress may be independently related to the development of insulin resistance early in life, especially in obese youth.

Gender differences in vascular function and insulin sensitivity in young adults

To examine influence of insulin resistance and other clinical risk factors for the MetS (metabolic syndrome) on vascular structure and function in young adults. This cross-sectional study was conducted in a cohort of young adults (mean age 22 years) and their siblings participating in a longitudinal study of cardiovascular risk (n=370). Insulin sensitivity was determined by euglycaemic insulin clamp. EDD (endothelium-dependent dilation) was determined by flow-mediated dilation using high-resolution ultrasound imaging of the brachial artery. EID (endothelium-independent dilation) was determined by NTG (nitroglycerine)-mediated dilation. The diameter and cIMT (intima-media thickness) of the carotid artery were also measured. There was no significant difference between males and females for age or body mass index. However, males had significantly higher glucose and triacylglycerol (triglyceride) levels, while the females had significantly higher HDL-C (high-density lipoprotein-cholesterol) and insulin sensitivity (13.00 ± 0.33 compared with 10.71 ± 0.31 mg·kg-1 of lean body mass·min-1, P<0.0001). Although peak EDD was significantly lower (6.28 ± 0.26 compared with 8.50 ± 0.28%, P<0.0001) in males than females, this difference was largely explained by adjustment for brachial artery diameter (P=0.15). Peak EID also was significantly lower in males than females (20.26 ± 0.44 compared with 28.64 ± 0.47%, P<0.0001), a difference that remained significantly lower after adjustment for brachial artery diameter. Males had a significantly greater cIMT compared with females (females 0.420 ± 0.004 compared with males 0.444 ± 0.004 mm, P=0.01), but when adjusted for carotid diameter, there was no significant difference (P=0.163). Although there were gender differences in vascular function and structure in the young adult population examined in this study, many of the differences were eliminated simply by adjusting for artery diameter. However, the lower EID observed in males could not be explained by artery diameter. Future studies need to continue to examine influence of gender on EID and other measures of vascular function.

Preliminary data on the association between waist circumference and insulin resistance in children without a previous diagnosis

The aim of the present work was to study the association between different anthropometric parameters and insulin resistance (IR) in Spanish schoolchildren without a previous diagnosis. A total of 443 Spanish schoolchildren (9-11 years of age) were studied in this cross-sectional study. The anthropometric measurements collected were weight, height, body circumferences and skinfolds. Body mass index (BMI), waist/hip ratio, percentage body fat and fat-free body mass were determined. Overnight-fasted blood lipids, insulin and glucose levels were analysed, and estimation of IR, taking into account the homeostasis model assessment (HOMA), was calculated. The children with IR had higher serum triglycerides and insulin levels, were heavier and taller, and had a higher BMI, a larger waist circumference, a larger hip circumference, a larger waist/hip ratio and thicker bicipital and tricipital skinfolds than those who did not have IR. Age, sex, BMI and waist circumference explained 32.0% of the variance in the HOMA values; only sex, triglycerides and waist circumference independently influenced this variable. A 1-cm increase in waist circumference was associated with approximately a 3.8% increase in the mean HOMA value. The children with a waist circumference of over the p90 for their age and sex were at greater risk of showing IR as measured by the HOMA: odds ratio = 6.94 (2.01-23.91; P < 0.001). In conclusion, according to these results, waist circumference is the best anthropometric parameter associated with IR in children, and those with a waist circumference of over the p90 for their age and sex would appear to be at particular risk.