Age, sex, and ethnic variations in serum insulin concentrations among U.S. youth: findings from the National Health and Nutrition Examination Survey 1999-2002

Positive association between blood ethylene oxide levels and metabolic syndrome: NHANES 2013-2020

Purpose

The exposure of Ethylene oxide (EO) is linked to systemic inflammatory response and various cardiovascular risk factors. Hemoglobin's binding to ethylene oxide (HbEO) was used to measure serum EO level. This research aims to explore the association between metabolic syndrome (MetS) and HbEO, and between HbEO and components of metabolic syndrome.

Method

This research included 1842 participants from 2013 to 2020 in National Health and Nutrition Examination Survey (NHANES) database. Weighted logistic regression models were used to analyze the relationship between HbEO and metabolic syndrome risk, using odds ratio (OR) and 95% confidence interval (CI). The restricted cubic spline plot explores whether there is a dose-response relationship between HbEO and MetS risk. Subgroup analysis was performed to analyze study heterogeneity.

Results

Significant differences were found in gender, educational level, marital status, diabetes status and hypertension among different groups (P < 0.001, P = 0.007, P = 0.003, P < 0.001, P < 0.001, respectively). The serum HbEO level exhibited positive correlation with metabolic syndrome risk in Q2 level (OR=1.64, 1.04~2.48), Q3 level (OR=1.99, 1.29~3.08), and Q4 level (OR=2.89, 1.92~4.34). The dose-response association suggested a possible linear association between serum HbEO and metabolic syndrome risk (P-overall=0.0359, P-non-linear=0.179). L-shaped association was found between HbEO and the risk of MetS in female population, obese population and mid-age and elder population (P-overall<0.001, P-non-linear=0.0024; P-overall=0.0107, P-non-linear=0.0055 P-overall<0.001 P-non-linear=0.0157).

Conclusion

This study indicates a linear correlation between MetS and HbEO, with MetS risk escalating as HbEO levels increase. The prevalence of MetS varies depending on BMI, age and gender, and these factors can also influence MetS prevalence when exposed to EO.

Distribution of OGTT-Related Variables in Patients with Cystic Fibrosis from Puberty to Adulthood: An Italian Multicenter Study

Background: Insulin secretion and glucose tolerance is annually assessed in patients with cystic fibrosis (PwCF) through oral glucose tolerance tests (OGTTs) as a screening measure for cystic fibrosis-related diabetes. We aimed to describe the distribution and provide reference quartiles of OGTT-related variables in the Italian cystic fibrosis population. Methods: Cross-sectional study of PwCF receiving care in three Italian cystic fibrosis centers of excellence, from 2016 to 2020. We performed a modified 2-h OGTT protocol (1.75 g/kg, maximum 75 g), sampling at baseline and at 30-min intervals, analyzing plasma glucose, serum insulin, and C-peptide. The modified OGTT allowed for the modeling of β cell function. For all variables, multivariable quantile regression was performed to estimate the median, the 25th, and 75th percentiles, with age, sex, and pancreatic insufficiency as predictors. Results: We have quantified the deterioration of glucose tolerance and insulin secretion with age according to sex and pancreatic insufficiency, highlighting a deviation from linearity both for patients <10 years and >35 years of age. Conclusions: References of OGTT variables for PwCF provide a necessary tool to not only identify patients at risk for CFRD or other cystic fibrosis-related complications, but also to evaluate the effects of promising pharmacological therapies.

Using optimal subset regression to identify factors associated with insulin resistance and construct predictive models in the US adult population

BACKGROUND

In recent decades, with the development of the global economy and the improvement of living standards, insulin resistance (IR) has become a common phenomenon. Current studies have shown that IR varies between races. Therefore, it is necessary to develop individual prediction models for each country. The purpose of this study was to develop a predictive model of IR applicable to the US population.

METHOD

In total, 11 cycles of data from the NHANES database were selected for this study. Of these, participants from 1999 to 2010 (n = 14931) were used to establish the model, and participants from 2011 to 2020 (n = 13,646) were used to validate the model. Univariate and multivariable logistic regression was used to analyze the factors associated with IR. Optimal subset regression was used to filter the best modeling variables. ROC curves, calibration curves, and decision curve analysis were used to determine the strengths and weaknesses of the model.

RESULTS

After screening the variables by optimal subset regression, variables with covariance were excluded, and a total of seven factors (including HDL, LDL, ALB, GLB, GLU, BMI, and waist) were finally included to establish the prediction model. The AUCs were 0.851 and 0.857 in the training and validation sets, respectively, and the Brier value of the calibration curve was 0.153.

CONCLUSION

The optimal subset predictive model proposed in this study has a great performance in predicting IR, and the decision curve analysis shows that it has a high net clinical benefit, which can help clinicians and epidemiologists easily detect IR and take appropriate interventions as early as possible.

Fasting C-peptide values among adolescents in the National Health and Nutrition Examination Surveys

AIM

To report fasting C-peptide values and variations across demographics in healthy non-diabetic adolescents included in the National Health and Nutrition Examination Surveys (NHANES) dataset.

RESEARCH DESIGN AND METHODS

In this analysis, we used fasting C-peptide data from the 1999 to 2004 NHANES dataset for participants aged 12 to <18 years (n = 2063).

RESULTS

The mean ± SE age of the participants was 14.99 ± 0.06 years. The participants included 992 girls and 1071 boys, and more than 80% of participants had a body mass index (BMI) percentile of <85%. Among boys, the most notable finding was the increase in geometric mean C-peptide level from 0.51 nmol/L at age 12, to 0.65 nmol/L at age 15 years. Among girls, levels fluctuated around a geometric mean of 0.67 nmol/L. Girls had significantly higher mean log-transformed C-peptide concentrations than boys (P < 0.0001) after adjusting for age, race and BMI percentile category. After adjusting for age and BMI percentile category, non-Hispanic Black boys and girls had significantly lower C-peptide levels than non-Hispanic White (P = 0.0026 and P = 0.0093) and Mexican American boys and girls (P < 0.0001 and P < 0.0001), respectively. Despite these findings, both insulin and homeostatic model assessment of insulin resistance were greater in non-Hispanic Black compared to non-Hispanic White participants.

CONCLUSIONS

Here we describe fasting C-peptide levels in a non-diabetic adolescent population. These data provide crucial insight into evaluating racial differences in endogenous insulin release and clearance and will provide novel information which can be used in assessing residual β-cell function and response to intervention therapy.

Differential DNA Methylation and Cardiometabolic Risk in African American Mother-Adolescent Dyads

BACKGROUND

Cardiovascular disease disproportionately affects African Americans as the leading cause of morbidity and mortality. Among African Americans, compared to other racial groups, cardiovascular disease onset occurs at an earlier age due to a higher prevalence of cardiometabolic risk factors, particularly obesity, hypertension and type 2 diabetes. Emerging evidence suggests that heritable epigenetic processes are related to increased cardiovascular disease risk, but this is largely unexplored in adolescents or across generations.

MATERIALS AND METHODS

In a cross-sectional descriptive pilot study in low-income African American mother-adolescent dyads, we examined associations between DNA methylation and the cardiometabolic indicators of body mass index, waist circumference, and insulin resistance.

RESULTS

Four adjacent cytosine and guanine nucleotides (CpG) sites were significantly differentially methylated and associated with C-reactive protein (CRP), 62 with waist circumference, and none to insulin resistance in models for both mothers and adolescents.

CONCLUSION

Further study of the relations among psychological and environmental stressors, indicators of cardiovascular disease, risk, and epigenetic factors will improve understanding of cardiovascular disease risk so that preventive measures can be instituted earlier and more effectively. To our knowledge this work is the first to examine DNA methylation and cardiometabolic risk outcomes in mother-adolescent dyads.

Evaluation of lipid ratios and triglyceride-glucose index as risk markers of insulin resistance in Iranian polycystic ovary syndrome women

BACKGROUND

Insulin resistance has a vital role in the pathophysiology of polycystic ovary syndrome (PCOS). Previous investigations have shown that some lipid ratios could be a simple clinical indicator of insulin resistance (IR) in some disorders and ethnicities. The present study was conducted to evaluate the correlation between triglyceride to HDL-cholesterol (TG/HDL-C), total cholesterol to HDL-cholesterol (TC/HDL-C), as well as fasting triglyceride-glucose (TyG) indices with IR (as measured by homeostasis model assessment of IR (HOMA-IR), quantitative insulin sensitivity check index (QUICKI) and fasting glucose to insulin ratio (FGIR)) among the Iranian women diagnosed with PCOS.

METHODS

In the current study, a total of 305 women with PCOS were evaluated. TG/HDL-C, TC/HDL-C, and TyG indices were calculated. Fasting insulin level was measured using ELISA technique. IR was defined as a HOMA-IR value of ≥2.63, FG-IR value of < 8.25, and QUICKI value of < 0.33.

RESULTS

The insulin-resistant (IR) and insulin-sensitive (IS) groups, established by the HOMA-IR, FG-IR, and QUICKI values were different in terms of TG/HDL-C, TC/HDL-C, and TyG indices. These indices were associated with IR even after adjusting for age and BMI. ROC curve analyses showed that TyG, TG/HDL-C, and TC/HDL-C strongly predicted HOMA-IR with area under the curve (AUC) of 0.639, 0.619, and 0.623, respectively (P < 0.05). Further, TC/HDL-C was a good predictor of FG-IR with AUC of 0.614 (P = 0.04).

CONCLUSION

TyG, TG/HDL-C, and TC/HDL-C indices might be good indicators of IR among Iranian women diagnosed with PCOS.

The Lymphatic System in Obesity, Insulin Resistance, and Cardiovascular Diseases

Obesity, insulin resistance, dyslipidemia, and hypertension are fundamental clinical manifestations of the metabolic syndrome. Studies over the last few decades have implicated chronic inflammation and microvascular remodeling in the development of obesity and insulin resistance. Newer observations, however, suggest that dysregulation of the lymphatic system underlies the development of the metabolic syndrome. This review summarizes recent advances in the field, discussing how lymphatic abnormality promotes obesity and insulin resistance, and, conversely, how the metabolic syndrome impairs lymphatic function. We also discuss lymphatic biology in metabolically dysregulated diseases, including type 2 diabetes, atherosclerosis, and myocardial infarction.

Elevated triglyceride-to-HDL cholesterol ratio is an indicator for insulin resistance in middle-aged and elderly Taiwanese population: a cross-sectional study

Background

Previous studies have reported that the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio could be a simple clinical indicator of insulin resistance (IR), but the results indicated that there were heterogeneities between different ethnicities. We aimed to investigate the association between TG/HDL-C and IR (as measured by homeostasis model assessment of IR [HOMA-IR]), and establish a clinical prediction rule for IR in middle-aged and elderly Taiwanese.

Methods

A total of 398 subjects were recruited, and each subject completed a questionnaire that included personal and medical history data, and underwent anthropometric measurement and blood sampling. IR was defined as HOMA-IR index value ≥2.0. Chi-squared test, independent two-sample t-test, Pearson’s correlation coefficient, and multiple logistic regression were used to evaluate the association between IR and TG/HDL-C ratio. A receiver operating characteristic (ROC) analysis was conducted to evaluate the ability of the developed clinical prediction rule to correctly discriminate between subjects of IR positive and IR negative groups.

Results

A significant association between IR and TG/HDL-C ratio was identified with a Pearson’s correlation coefficient of 0.35 (p-value< 0.001). In multiple logistic regression, high BMI (OR = 1.23; 95% C.I. = 1.13–1.33), hypertension (OR = 1.90; 95% C.I. = 1.12–3.21), diabetes mellitus (OR = 5.44; 95% C.I. = 2.93–10.08) and high TG/HDL ratio (OR = 1.45; 95% C.I. = 1.23–1.72) were significantly associated with the risk of elevated HOMA-IR.

The area under ROC curves for TG/HDL-C ratio was 0.729 and the optimal threshold value was 2.197 where the corresponding of sensitivity and specificity were 72.4 and 65.1%.

Conclusions

Our findings showed that the elevated TG/HDL-C ratio was significantly associated with IR and could be used as an indicator of IR among the middle-aged and elderly population in Taiwan. It is clinically available, thus eliminating any additional costs. Future research is warranted to investigate the use of TG/HDL-C ratio combined with other risk factors for predicting IR under diverse ethnic backgrounds.

Percentile curves for cardiometabolic disease markers in Canadian children and youth: a cross-sectional study

Background

The objective of this study to develop percentile curves for cardiometabolic disease markers in a population-based sample of Canadian children and youth.

Methods

The analysis used data from 6116 children and adolescents between 6 and 19 years of age who participated in the Canadian Health Measures Survey cycles 1 (2007/2009), 2 (2009/2011), and 3 (2012/2013). Total cholesterol, HDL cholesterol, and hemoglobin A1c levels as well as fasting levels of triglycerides, insulin, and homeostasis model assessment insulin resistance were measured using standardized procedures. Age- and sex-specific centiles for all markers were calculated using Cole and Green’s LMS method.

Results

With the exception of hemoglobin A1c, all markers showed age- and sex-related differences during childhood and adolescence.

Conclusions

We have developed centile curves for cardiometabolic disease markers in Canadian children and adolescents and demonstrated age and sex differences that should be considered when evaluating these markers in this age group.

Prevention of Type 2 Diabetes in U.S. Hispanic Youth: A Systematic Review of Lifestyle Interventions

CONTEXT

Prevalence of type 2 diabetes mellitus (T2DM) in youth has increased rapidly in recent decades along with rises in childhood obesity. Disparities in risk and prevalence of T2DM are evident in Hispanic youth when compared with non-Hispanic whites. Targeted diabetes prevention programs have been recommended to reduce risk prior to adulthood in this population. This systematic review explores the effectiveness of lifestyle-based diabetes prevention interventions for Hispanic youth.

EVIDENCE ACQUISITION

PubMed, PsycINFO, Web of Science, and CENTRAL were searched from database inception to March 1, 2017, for studies that evaluated lifestyle-focused prevention trials targeting U.S. Hispanic youth under age 18 years. Fifteen publications met criteria for inclusion.

EVIDENCE SYNTHESIS

Of the 15 studies, 11 were RCTs; four were uncontrolled. Interventions were heterogeneous in intensity, content, and setting. Duration of most trials was 12-16 weeks. Mean age of participants ranged from 9.8 to 15.8 years, sample sizes were generally small, and the majority of participants were overweight (BMI ≥85th percentile). Three studies reported statistically significant reductions in mean BMI, four in BMI z-score, and six in fasting glucose/insulin. Study quality was moderate to high. Effect sizes were generally small to medium.

CONCLUSIONS

Evidence for the impact of lifestyle-based diabetes prevention interventions targeting U.S. Hispanic youth remains limited. Few interventions demonstrated success in reducing BMI and glucose regulation and follow-up times were brief. More studies are needed that recruit larger samples sizes, extend follow-up times, explore innovative delivery modalities, and examine effectiveness across sex and age.

Serum lipoprotein ratios as markers of insulin resistance: a study among non-diabetic acute coronary syndrome patients with impaired fasting glucose

BACKGROUND & OBJECTIVES

Recent data suggest that insulin resistance can predict cardiovascular disease independently of the other risk factors, such as hypertension, visceral obesity or dyslipidaemia. However, the majority of available methods to evaluate insulin resistance are complicated to operate, expensive, and time consuming. This study was undertaken to assess whether serum lipoprotein ratios could predict insulin resistance in non-diabetic acute coronary syndrome (ACS) patients.

METHODS

Ninety non-diabetic patients with impaired fasting glucose admitted with a diagnosis of ACS were included in the study. At the time of admission fasting glucose and insulin concentrations were measured. The homeostatic model assessment-insulin resistance (HOMA-IR) was used for insulin resistance. The fasting serum total cholesterol (TC), triglycerides (TG) and high density lipoprotein cholesterol (HDL-C) levels were checked, and then TC/HDL-C and TG/HDL-C ratios were calculated. The areas under the curves (AUC) of the receiver operating characteristic (ROC) curves were used to compare the power of these serum lipoprotein ratios as markers.

RESULTS

Lipoprotein ratios were significantly higher in patients with HOMA-IR index > 2.5 as compared to patients with index <2.5 (P < 0.05). Both TG/HDL-C and TC/HDL-C ratios were significantly correlated with HOMA-IR (P<0.05). The area under the ROC curve of the TG/HDL-C and TC/HDL-C ratio for predicting insulin resistance was 0.80 (95% CI, 0.67 to 0.93), 0.78 (95% CI, 0.65 to 0.91), respectively.

INTERPRETATION & CONCLUSIONS

The findings of this study demonstrate that serum lipoprotein ratios can provide a simple means of identifying insulin resistance and can be used as markers of insulin resistance and cardiovascular diseases risk in adult non-diabetic patients.

Lean body mass may explain apparent racial differences in carotid intima-media thickness in obese children

BACKGROUND

Racial differences in carotid intima-media thickness (cIMT) have been suggested to be associated with the disproportionally high prevalence of cardiovascular disease in black adults. The objective of this study was to evaluate the effects of cardiovascular risk factors on the racial differences seen in cIMT in obese children.

METHODS

Obese subjects aged 4 to 21 years were recruited prospectively. Height, weight, blood pressure, fasting insulin, glucose, lipid panel, high-sensitivity C-reactive protein, and body composition by dual-energy x-ray absorptiometry were obtained. B-mode carotid imaging was analyzed by a single blinded physician.

RESULTS

A total of 120 subjects (46 white, 74 black) were enrolled. Black subjects exhibited greater cIMT (0.45 ± 0.03 vs 0.43 ± 0.02 cm, P < .01) and higher lean body mass index (19.3 ± 3.4 vs 17.3 ± 3.2 kg/m², P = .02) than white subjects. Simple linear regression revealed modest associations between mean cIMT and race (R = 0.52, P < .01), systolic blood pressure (R = 0.47, P < .01), and lean body mass (R = 0.51, P < .01). On multivariate regression analysis, lean body mass remained the only measure to maintain a statistically significant relationship with mean cIMT (P < .01).

CONCLUSIONS

Black subjects demonstrated greater cIMT than white subjects. The relationship between race and cIMT disappeared when lean body mass was accounted for. Future studies assessing the association of cardiovascular disease risk factors to cIMT in obese children should include lean body mass in the analysis.

Influence of adiposity on insulin resistance and glycemia markers among U.K. Children of South Asian, black African-Caribbean, and white European origin: child heart and health study in England

OBJECTIVE

Ethnic differences in type 2 diabetes risk between South Asians and white Europeans originate before adult life and are not fully explained by higher adiposity levels in South Asians. Although metabolic sensitivity to adiposity may differ between ethnic groups, this has been little studied in childhood. We have therefore examined the associations among adiposity, insulin resistance, and glycemia markers in children of different ethnic origins.

RESEARCH DESIGN AND METHODS

Cross-sectional study of 4,633 9- to 10-year-old children (response rate 68%) predominantly of South Asian, black African-Caribbean, and white European origin (n = 1,266, 1,176, and 1,109, respectively) who had homeostasis model assessments of insulin resistance (HOMA-IR), glycemia markers (HbA1c and fasting glucose), and adiposity (BMI, waist circumference, skinfold thicknesses, and bioimpedance [fat mass]).

RESULTS

All adiposity measures were positively associated with HOMA-IR in all ethnic groups, but associations were stronger among South Asians compared to black African-Caribbeans and white Europeans. For a 1-SD increase in fat mass percentage, percentage differences in HOMA-IR were 37.5% (95% CI 33.3-41.7), 29.7% (25.8-33.8), and 27.0% (22.9-31.2), respectively (P interaction < 0.001). All adiposity markers were positively associated with HbA1c in South Asians and black African-Caribbeans but not in white Europeans; for a 1-SD increase in fat mass percentage, percentage differences in HbA1c were 0.04% (95% CI 0.03-0.06), 0.04% (0.02-0.05), and 0.02% (-0.00 to 0.04), respectively (P interaction < 0.001). Patterns for fasting glucose were less consistent.

CONCLUSIONS

South Asian children are more metabolically sensitive to adiposity. Early prevention or treatment of childhood obesity may be critical for type 2 diabetes prevention, especially in South Asians.

Age related metabolic syndrome among hemodialysis patients in gorgan, iran

People with metabolic syndrome are at high risk for developing cardiovascular disease. The present study aimed to determine the age related metabolic syndrome of hemodialysis patients. The biochemical parameters and demographic information were registered. The prevalence of metabolic syndrome was significantly high in ages 50-59 and 60-69 years in hemodialysis patients when compared with other age groups (P< 0.05). There was elevated frequency of metabolic syndrome from age 50-59 and 40-49 years in male and female hemodialysis patients, respectively. The frequency of metabolic syndrome in female subjects (65.27%) was higher than male (47.14%, P<0.05). The prevalence of metabolic syndrome was high in ages 50-59 years in males and females. There was a significant difference in hemodialysis patients with metabolic syndrome in ages 50-59 years in males and from ages 40-49, 50-59 and 60-69 years in females (P< 0.05). Our results show that 25.71%, 18.57% and 2.86% males and 36.11%, 20.83% and 8.33% females had three, four and five criteria for metabolic syndrome, respectively. The results of this study showed that females patients were more affected than males. This may depended on the specific lifestyle alterations among females and males patients in this area.

The association between acanthosis nigricans and dysglycemia in an ethnically diverse group of eighth grade students

OBJECTIVE

The purpose of this study was to describe the prevalence of acanthosis nigricans (AN) and to quantify its association with dysglycemia in an ethnically diverse group of eighth-grade students.

DESIGN AND METHODS

Data were collected in 2003 from a cross-sectional study of students from 12 middle schools in three US states. Sex, race/ethnicity, and pubertal status were self-reported. Anthropometric measures were recorded. Trained staff identified the presence and severity of AN by inspection of the back of the neck. Fasting and 2 h blood samples were analyzed for impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and high-risk glycated hemoglobin (A1C), respectively, defined as ≥100 mg/dl, ≥140 mg/dl, and ≥ 5.7-6.4%.

RESULTS

Overall, 25.0%, 58.2%, and 16.8% were Black, Hispanic, and White, respectively. AN was present among 406/1,438 (28.2%) of students: 39% among Black, 30% among Hispanic, and 5.4% among White. IGT and high-risk A1C were present among 2.1%, and 12.4%, respectively. In multivariate logistic modeling after adjusting for gender, family history of diabetes, BMI percentile, and pubertal staging, the presence (vs. absence) of AN was associated with a 59% increased likelihood of high-risk A1C: (P = 0.04), twice the likelihood of IGT (P = 0.06), and 47% greater likelihood of IGT/IFG combined (P < 0.0001). Adjustment for insulin attenuated the ORs by 25-70%.

CONCLUSION

In a racially/ethnically diverse sample of US adolescents, AN was common, occurring in 28% of the sample. AN was associated with a 50-100% increased likelihood of dysglycemia even after consideration of established diabetes risk factors.

Lessons learned from the HEALTHY primary prevention trial of risk factors for type 2 diabetes in middle school youth

The HEALTHY trial was designed to take a primary prevention approach to risk factors for type 2 diabetes in youth, primarily obesity. The study involved over 6,000 students at 42 middle schools across the U.S. Half received an integrated intervention program of components addressing the school food environment, physical education, lifestyle behaviors, and promotional messaging. The intervention was designed to be more comprehensive than previous efforts, and the research was amply funded. Although the primary objective of reducing the percentage of overweight and obesity in schools that received the intervention program, as compared with control schools, was not obtained, key secondary outcomes indicated an intervention effect. In retrospect, senior investigators involved in the study's design, conduct, and analysis discuss weaknesses and strengths and offer recommendations for future research efforts that address prevention of childhood obesity from a public health perspective.

The association between the triglyceride to high-density lipoprotein cholesterol ratio with insulin resistance (HOMA-IR) in the general Korean population: based on the National Health and Nutrition Examination Survey in 2007-2009

AIMS

This study explores the association between the ratio of triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) and insulin resistance according to waist circumference in the general Korean population.

METHODS

7623 participants were selected from the Korean National Health and Nutrition Examination Survey (KNHANES) conducted during 2007-2009 and included in this cross-sectional study. Insulin resistance was defined as the values equal to or greater than the 75th percentile of the homeostasis model assessment of insulin resistance (HOMA-IR).

RESULTS

Positive correlation was found between the ratio of TG and HDL-C and other variables such as waist circumference, total cholesterol, and HOMA-IR for both men and women. The odds ratios (ORs) (95% confidence interval) for insulin resistance for the highest quartile of TG/HDL-C were 2.48 in men and 3.05 in women. The significant relationship between the TG/HDL-C ratio and insulin resistance was not only maintained across all quartiles of waist circumference but also seemed to be enhanced in the higher quartiles of waist circumference.

CONCLUSION

In the general Korean population, there seems to be a linear association between TG/HDL-C ratio and insulin resistance, regardless of degrees of waist circumference.

Ethnic Differences in Carotid Intima-Media Thickness Between UK Children of Black African-Caribbean and White European Origin

Background and Purpose—

UK black African-Caribbean adults have higher risks of stroke than white Europeans and have been shown to have increased carotid intima-media thickness (cIMT). We examined whether corresponding ethnic differences in cIMT were apparent in childhood and, if so, whether these could be explained by ethnic differences in cardiovascular risk markers.

Methods—

We conducted a 2-stage survey of 939 children (208 white European, 240 black African-Caribbean, 258 South Asian, 63 other Asian, 170 other ethnicity), who had a cardiovascular risk assessment and measurements of cIMT at mean ages of 9.8 and 10.8 years, respectively.

Results—

Black African-Caribbean children had a higher cIMT than white Europeans (mean difference, 0.014 mm; 95% CI, 0.008–0.021 mm; P <0.0001). cIMT levels in South Asian and other Asian children were however similar to those of white Europeans. Among all children, cIMT was positively associated with age, systolic and diastolic blood pressure and inversely with combined skinfold thickness and serum triglyceride. Mean triglyceride was lower among black African-Caribbeans than white Europeans; blood pressure and skinfold thickness did not differ appreciably. However, adjustment for these risk factors had little effect on the cIMT difference between black African-Caribbeans and white Europeans.

Conclusions—

UK black African-Caribbean children have higher cIMT levels in childhood; the difference is not explained by conventional cardiovascular risk markers. There may be important opportunities for early cardiovascular prevention, particularly in black African-Caribbean children.

Early emergence of ethnic differences in type 2 diabetes precursors in the UK: the Child Heart and Health Study in England (CHASE Study)

BACKGROUND

Adults of South Asian origin living in the United Kingdom have high risks of type 2 diabetes and central obesity; raised circulating insulin, triglyceride, and C-reactive protein concentrations; and low HDL-cholesterol when compared with white Europeans. Adults of African-Caribbean origin living in the UK have smaller increases in type 2 diabetes risk, raised circulating insulin and HDL-cholesterol, and low triglyceride and C-reactive protein concentrations. We examined whether corresponding ethnic differences were apparent in childhood.

METHODS AND FINDINGS

We performed a cross-sectional survey of 4,796 children aged 9-10 y in three UK cities who had anthropometric measurements (68% response) and provided blood samples (58% response); ethnicity was based on parental definition. In age-adjusted comparisons with white Europeans (n = 1,153), South Asian children (n = 1,306) had higher glycated haemoglobin (HbA1c) (% difference: 2.1, 95% CI 1.6 to 2.7), fasting insulin (% difference 30.0, 95% CI 23.4 to 36.9), triglyceride (% difference 12.9, 95% CI 9.4 to 16.5), and C-reactive protein (% difference 43.3, 95% CI 28.6 to 59.7), and lower HDL-cholesterol (% difference -2.9, 95% CI -4.5 to -1.3). Higher adiposity levels among South Asians (based on skinfolds and bioimpedance) did not account for these patterns. Black African-Caribbean children (n = 1,215) had higher levels of HbA1c, insulin, and C-reactive protein than white Europeans, though the ethnic differences were not as marked as in South Asians. Black African-Caribbean children had higher HDL-cholesterol and lower triglyceride levels than white Europeans; adiposity markers were not increased.

CONCLUSIONS

Ethnic differences in type 2 diabetes precursors, mostly following adult patterns, are apparent in UK children in the first decade. Some key determinants operate before adult life and may provide scope for early prevention.

Adiposity is inversely related to insulin sensitivity in relatively lean Chinese adolescents: a population-based twin study

BACKGROUND

Adolescence is a critical period for rising adiposity and falling insulin sensitivity (IS), but the independent relation between adiposity and IS remains understudied.

OBJECTIVE

The objective was to examine which adiposity measures are most strongly associated with IS in nondiabetic adolescents, whether sex-difference exists, and to what degree genetic or environmental factors affect the adiposity-IS relation.

DESIGN

The study included 1613 rural Chinese adolescents (888 males) aged 13-20 y from a population-based twin cohort. We used graphic plots and linear mixed models to examine the relation of anthropometric and dual-energy X-ray absorptiometry-based measures of adiposity with IS [QUantitative Insulin-sensitivity ChecK Index (QUICKI), fasting serum insulin (FSI), homeostasis model assessment of insulin resistance (HOMA-IR)] and structural equation models to estimate genetic/environmental influences on these associations.

RESULTS

In graphic analyses, participants in the highest quintile (quintile 5) of waist circumference (WC) and percentage body fat (%BF) had the lowest QUICKI and the highest FSI and HOMA-IR values for all age-sex groups. In regression models adjusted for age, Tanner stage, zygosity, and physical activity, all adiposity measures showed inverse associations with IS in both sexes, but WC explained the largest fraction of variance in IS measures (10-14%). Of the phenotypic correlations between adiposity measures and IS (-0.28 to -0.38), 74-85% were attributed to shared genetic factors and 15-26% to common unique environmental factors in both sexes.

CONCLUSIONS

In these relatively lean Chinese adolescents, WC and %BF (quintile 5) are the adiposity measures most consistently and strongly associated with decreased IS in both sexes. To a large degree, shared genetic factors contribute to this association.

Growth curves for cardio-metabolic risk factors in children and adolescents

OBJECTIVE

This study developed percentile curves for anthropometric (waist circumference) and cardiovascular (lipid profile) risk factors for US children and adolescents.

STUDY DESIGN

A representative sample of US children and adolescents from the National Health and Nutrition Examination Survey from 1988 to 1994 (NHANES III) and the current national series (NHANES 1999-2006) were combined. Percentile curves were constructed, nationally weighted, and smoothed using the Lambda, Mu, and Sigma method. The percentile curves included age- and sex-specific percentile values that correspond with and transition into the adult abnormal cut-off values for each of these anthropometric and cardiovascular components. To increase the sample size, a second series of percentile curves was also created from the combination of the 2 NHANES databases, along with cross-sectional data from the Bogalusa Heart Study, the Muscatine Study, the Fels Longitudinal Study and the Princeton Lipid Research Clinics Study.

RESULTS

These analyses resulted in a series of growth curves for waist circumference, total cholesterol, LDL cholesterol, triglycerides, and HDL cholesterol from a combination of pediatric data sets. The cut-off for abnormal waist circumference in adult males (102 cm) was equivalent to the 94(th) percentile line in 18-year-olds, and the cut-off in adult females (88 cm) was equivalent to the 84(th) percentile line in 18-year-olds. Triglycerides were found to have a bimodal pattern among females, with an initial peak at age 11 and a second at age 20; the curve for males increased steadily with age. The HDL curve for females was relatively flat, but the male curve declined starting at age 9 years. Similar curves for total and LDL cholesterol were constructed for both males and females. When data from the additional child studies were added to the national data, there was little difference in their patterns or rates of change from year to year.

CONCLUSIONS

These curves represent waist and lipid percentiles for US children and adolescents, with identification of values that transition to adult abnormalities. They could be used conditionally for both epidemiological and possibly clinical applications, although they need to be validated against longitudinal data.

HEALTHY study rationale, design and methods: moderating risk of type 2 diabetes in multi-ethnic middle school students

The HEALTHY primary prevention trial was designed and implemented in response to the growing numbers of children and adolescents being diagnosed with type 2 diabetes. The objective was to moderate risk factors for type 2 diabetes. Modifiable risk factors measured were indicators of adiposity and glycemic dysregulation: body mass index > or =85th percentile, fasting glucose > or =5.55 mmol l(-1) (100 mg per 100 ml) and fasting insulin > or =180 pmol l(-1) (30 microU ml(-1)). A series of pilot studies established the feasibility of performing data collection procedures and tested the development of an intervention consisting of four integrated components: (1) changes in the quantity and nutritional quality of food and beverage offerings throughout the total school food environment; (2) physical education class lesson plans and accompanying equipment to increase both participation and number of minutes spent in moderate-to-vigorous physical activity; (3) brief classroom activities and family outreach vehicles to increase knowledge, enhance decision-making skills and support and reinforce youth in accomplishing goals; and (4) communications and social marketing strategies to enhance and promote changes through messages, images, events and activities. Expert study staff provided training, assistance, materials and guidance for school faculty and staff to implement the intervention components. A cohort of students were enrolled in sixth grade and followed to end of eighth grade. They attended a health screening data collection at baseline and end of study that involved measurement of height, weight, blood pressure, waist circumference and a fasting blood draw. Height and weight were also collected at the end of the seventh grade. The study was conducted in 42 middle schools, six at each of seven locations across the country, with 21 schools randomized to receive the intervention and 21 to act as controls (data collection activities only). Middle school was the unit of sample size and power computation, randomization, intervention and primary analysis.

Ethnic, gender, and age-related differences in patients with the metabolic syndrome

The metabolic syndrome is a clustering of cardiovascular risk factors and is associated with an increased risk of developing diabetes, cardiovascular disease, and kidney disease. Epidemiologic studies have demonstrated differences in prevalence by age, gender, and ethnicity. The prevalence of the metabolic syndrome increases with age through the sixth decade of life among men and seventh decade among women. Most, but not all, studies reported a higher prevalence of the metabolic syndrome among women compared with men. Although the metabolic syndrome is more common among Mexican Americans compared with non-Hispanic whites and blacks, among men the metabolic syndrome is more common among non-Hispanic whites than non-Hispanic blacks; the reverse is true among women. Understanding the basic pathophysiology underlying the metabolic syndrome may help explain the age, gender, and ethnic differences in its prevalence and guide preventive and therapeutic efforts.

Risk factors for type 2 diabetes in a sixth- grade multiracial cohort: the HEALTHY study

OBJECTIVE

HEALTHY is a 3-year middle school intervention program designed to reduce risk factors for type 2 diabetes. The prevalence of diabetes risk factors at baseline in a cohort of 6,358 sixth-grade students is reported.

RESEARCH DESIGN AND METHODS

Forty-two schools at seven U.S. sites were randomly assigned to intervention or control. Students participated in baseline data collection during fall of 2006.

RESULTS

Overall, 49.3% of children had BMI >or=85th percentile, 16.0% had fasting blood glucose >or=100 mg/dl (<1% had fasting blood glucose >or=126 mg/dl), and 6.8% had fasting insulin >or=30 microU/ml. Hispanic youth were more likely to have BMI, glucose, and insulin levels above these thresholds than blacks and whites.

CONCLUSIONS

Sixth-grade students in schools with large minority populations have high levels of risk factors for type 2 diabetes. The HEALTHY intervention was designed to modify these risk factors to reduce diabetes incidence.

Does the association of the triglyceride to high-density lipoprotein cholesterol ratio with fasting serum insulin differ by race/ethnicity?

Background

The triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio has been reported to be as closely correlated with insulin resistance as is the fasting serum insulin concentration (FSI), and therefore it is seen as a clinically useful way to identify the concomitant presence of insulin resistance and dyslipidemia. However, conflicting findings exist for the association of the TG/HDL-C ratio with FSI by race/ethnicity.

Methods

The associations of FSI concentration, serum triglyceride concentrations, and HDL-C were analyzed using log-binomial regression analyses and receiver operating characteristic (ROC) curve analysis among nondiabetic adults (n = 2652, aged ≥ 20 years, 51.2% men) in the United States.

Results

After adjustment for potential confounding effects, the prevalence ratio of hyperinsulinemia was 2.16 (95% confidence interval [CI], 1.74 to 2.08) when using a single cutoff point of 3.5, and 2.23 (95% CI, 1.83 to 2.72) when using race/ethnicity-specific cutoff points of 3.0 for non-Hispanic whites and Mexican Americans and 2.0 for non-Hispanic blacks for the TG/HDL-C ratio. The area under the ROC curve of the TG/HDL-C ratio for predicting hyperinsulinemia was 0.77 (95% CI, 0.74 to 0.79), 0.75 (95% CI, 0.69 to 0.77), and 0.74 (95% CI, 0.69 to 0.76) for non-Hispanic whites, non-Hispanic blacks, and Mexican Americans, respectively.

Conclusion

There was a significant association between the TG/HDL-C ratio and FSI among three major racial/ethnic groups in the United States. Our results add further support to the notion that the TG/HDL-C ratio may be a clinically simple and useful indicator for hyperinsulinemia among nondiabetic adults regardless of race/ethnicity.

Markers of insulin resistance are associated with fatness and fitness in school-aged children: the European Youth Heart Study

AIMS/HYPOTHESIS

Our aim was to examine the association between markers of insulin resistance and: (1) body fat and waist circumference, taking into account cardiorespiratory fitness in school-aged children; and (2) cardiorespiratory fitness at differing levels of body fat and waist circumference.

SUBJECTS AND METHODS

This was a cross-sectional study of 873 children aged 9.6 +/- 0.4 years from Estonia and Sweden. Weight, height and waist circumference were measured. Body fat was expressed as the sum of five skinfold thicknesses. Cardiorespiratory fitness was estimated by a maximal cycle-ergometer test. The studied markers of insulin resistance were fasting insulin and glucose, and homeostasis model assessment (HOMA).

RESULTS

HOMA and fasting insulin were positively associated with body fat and waist circumference after adjusting for cardiorespiratory fitness, age, pubertal status and study location. HOMA and fasting insulin were negatively associated with cardiorespiratory fitness in children in the third (highest) tertile of body fat and waist circumference after controlling for sex, age, pubertal status and study location. Fasting glucose was negatively associated with cardiorespiratory fitness in children in the third (highest) tertile of waist circumference, but it was not associated when body fat was taken into account.

CONCLUSIONS/INTERPRETATION

In school-aged children, HOMA and fasting insulin are significantly associated with body fat and waist circumference. In addition, cardiorespiratory fitness explains a significant proportion of the HOMA and fasting insulin variance in those children with high levels of body fat and waist circumference. The findings suggest that the deleterious consequences ascribed to high fatness could be counteracted by having high levels of cardiorespiratory fitness.