Cardiovascular risk factors associated with insulin resistance in children persist into late adolescence

Fasting Serum IGFBP-1 as a Marker of Insulin Resistance in Diverse School Age Groups

Introduction

The known markers of insulin resistance in obese children are well studied. However, they require serial measurements and complicated calculations. The objective is to study IGFBP-1 and its relation with other known risk measures.

Materials and Methods

The study included 98 New York City school students of diverse ethnic/racial backgrounds (57 males and 41 females), 11-15 years of age. Subjects were enrolled in a cross-sectional study, and anthropometric measures were collected. They underwent fasting intravenous glucose tolerance tests (IVGTT), and glucose, insulin, lipids, IGFBP-1, adiponectin and inflammatory markers were collected.

Results

The subjects were stratified into 3 groups based upon the BMI Z-score. Out of all the subjects, 65.3% were in the group with a BMI Z-score <1 SDS, 16.3% subjects were in the group with a BMI Z-score of 1 to 2 SDS, and 18.4% of the subjects were in the group with a BMI Z-score of more than 2 SDS. The group with a BMI Z-score of more than 2 SDS had increased waist circumference (WC), body fat, increased fasting insulin, and triglycerides (TG). This group had decreased levels of adiponectin and HDL and low IGFBP-1 as compared to the group with BMI <1 SDS. The group with a BMI Z-score of 1 to 2 SDS had a decreased level of IGFBP-1 as compared to the group with a BMI Z-score less than 1 SDS. IGFBP-1 inversely correlated with age, WC, BMI, body fat, TG, and insulin levels. IGFBP-1 positively correlated with adiponectin and HDL levels.

Conclusion

IGFBP-1 in children can identify the presence of insulin resistance in the group with BMI 1 to 2 SDS, even before the known markers of insulin resistance such as elevated triglycerides and even before decreased HDL and adiponectin levels are identified.

Association of sodium intake with insulin resistance in Korean children and adolescents: the Korea National Health and Nutrition Examination Survey 2010

BACKGROUND

This study aimed to evaluate the relationship between sodium intake and insulin resistance indices.

METHODS

A total of 718 Korean children and adolescents (411 boys) aged 10-18 years who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) were included in the study. The urinary sodium to urinary creatinine ratio was used as a surrogate for sodium intake. The homeostatic model assessment of insulin resistance (HOMA-IR) and the quantitative insulin sensitivity check index (QUICKI) were used as indices of insulin resistance.

RESULTS

The mean urinary sodium to urinary creatinine ratio was 11.34 in males and 10.17 in females. The urinary sodium to urinary creatinine ratio was significantly positively correlated with HOMA-IR (r=0.165, p<0.001) and inversely correlated with QUICKI (r=-0.181, p<0.001) in Pearson's correlation analyses. In a multivariate linear regression analysis, the urinary sodium to urinary creatinine ratio was independently and significantly positively associated with HOMA-IR (β=0.073, p=0.018) and significantly inversely associated with QUICKI (β=-0.080, p=0.007) after adjustment for possible confounders. HOMA-IR was independently and significantly positively associated with the urinary sodium to urinary creatinine ratio (β=0.087, p=0.018), whereas QUICKI was independently and significantly negatively associated with the urinary sodium to urinary creatinine ratio (β=-0.097, p=0.009) after controlling for confounders.

CONCLUSIONS

Our results suggest that sodium intake, as estimated by the urinary sodium to urinary creatinine ratio, may be independently associated with insulin resistance in children and adolescents.

Association of the urinary sodium to urinary specific gravity ratio with metabolic syndrome in Korean children and adolescents: The Korea National Health and Nutrition Examination Survey 2010-2013

Objectives

This study aimed to evaluate the association between sodium intake and metabolic syndrome (MetS) in Korean boys.

Methods

A total of 1,738 boys aged 10–18 years were included in this study from the Korea National Health and Nutrition Examination Survey (KNHANES) during the years 2010–2013. Sodium intake was assessed using the urinary sodium excretion to urinary specific gravity ratio (U-Na to U-SG ratio).

Results

The median U-Na to U-SG ratio was 133.27 mmol/L (interquartile range: 95.66–178.50 mmol/L). Significant positive associations were found between the U-Na to U-SG ratio and the TG (P = 0.001 for trend) and TG concentrations, and these concentrations were significantly higher in boys with a U-Na to U-SG ratio in the highest quartile compared with those with a ratio in the lowest (P = 0.001) and second (P = 0.033) quartiles, as demonstrated through analysis of covariance (ANCOVA) after adjustment for possible confounders, including age, BMI standard deviation score, ferritin, vitamin D, house income, smoking, alcohol intake, physical activity, season, total intake, total energy intake, protein intake, fat intake, carbohydrate intake, and water intake. Significant inverse associations were found for the U-Na to U-SG ratio with the HDL-C (P = 0.033 for trend) and HDL-C levels, and these values were significantly lower in boys with a ratio in the highest quartile compared with those with a ratio in the second quartile (P = 0.020), as demonstrated through an ANCOVA. Although the trends did not reach statistical significance, a higher U-Na to U-SG ratio tended to be associated with higher SBP (P = 0.086 for trend), DBP (P = 0.063 for trend), and glucose levels (P = 0.099 for trend), as illustrated through ANCOVA. Boys with a ratio in the highest quartile exhibited a 1.73-fold increased risk for elevated TG (95% CI, 1.19–2.51) and a 2.66-fold increased risk for MetS (95% CI, 1.11–6.35) compared with those with a ratio in the lowest quartile, as demonstrated through multivariate logistic regression analyses after adjusting for confounders.

Conclusions

Our results suggest that high sodium intake may be significantly independently associated with MetS in Korean boys aged 10–18 years.

Fetuin-A as an Alternative Marker for Insulin Resistance and Cardiovascular Risk in Prepubertal Children

AIM

Fetuin-A plays a role in insulin resistance and cardiovascular disease. This study aims to determine the relationship between fetuin-A levels and cardiometabolic risk factors, as well as to investigate the effect of serum fetuin-A on insulin resistance indices to determine whether fetuin-A is an additional marker for insulin resistance in prepubertal children.

METHODS

A total of 99 prepubertal Korean children (59 males) aged from 6.0 to 10.0 years was included in this study. Subjects were divided into underweight/normal-weight and overweight/obese groups. Serum fetuin-A levels were measured using an enzyme-linked immunosorbent assay and were natural logarithm (ln)-transformed.

RESULTS

Serum fetuin-A concentrations were significantly elevated in overweight/obese children as compared with underweight/normal-weight children (P=0.029). Ln serum fetuin-A was significantly positively correlated with body mass index (BMI) standard deviation scores (SDSs) (r=0.239, P=0.017), triglyceride levels (r=0.285, P=0.004), ln insulin (r=0.377, P＜0.001), systolic blood pressure (BP) (r=0.274, P=0.006), and diastolic BP (r=0.304, P=0.006) and was significantly inversely correlated with high-density lipoprotein cholesterol (HDL-C) levels (r=-0.236, P=0.019). In univariate linear regression analysis, ln fetuin-A was significantly positively associated with the homeostasis model assessment of insulin resistance (HOMA-IR) (r=0.356, P＜0.001) and significantly inversely associated with the quantitative insulin sensitivity check index (QUICKI) (r=-0.309, P=0.002). Following adjustment for age, gender, BMI, and lipid profiles in multivariate linear regression analysis, fetuin-A was significantly positively associated with HOMA-IR (P=0.048) and marginally inversely associated with QUICKI (P=0.054).

CONCLUSIONS

Our results suggest that fetuin-A can be an alternative marker for insulin resistance and cardiovascular risk in prepubertal children.

Association between insulin-like growth factor binding protein-2 levels and cardiovascular risk factors in Korean children

Emerging evidence has indicated that insulin-like growth factor binding protein-2 (IGFBP-2) may be involved in the development of obesity and insulin resistance like IGFBP-1. The aim of this study was to measure serum IGFBP-2 levels in overweight and obese children and to compare these levels with those of controls. We also analyzed the associations between IGFBP-2 and insulin sensitivity indices and cardiovascular risk factors. 134 Korean children including 55 overweight and 59 obese subjects were enrolled. We measured anthropometric values and determined fasting serum levels of IGFBP-2, glucose, insulin, lipid profiles, and insulin sensitivity indices including the homeostatic model assessment of insulin resistance (HOMA-IR) and the Quantitative Insulin Sensitivity Check Index (QUICKI). The subjects were subgrouped based on body mass index (BMI) and pubertal stage, and association analyses between IGFBP-2 levels and measured factors were performed in each group. Serum IGFBP-2 levels in overweight or obese children were significantly lower than those of controls regardless of pubertal development. Serum IGFBP-2 levels were negatively correlated with weight, BMI, waist circumference, fasting insulin levels, and HOMA-IR but were positively correlated with QUICKI. The associations were stronger in pubertal children than those in prepubertal children. However, no association was observed between serum IGFBP-2 levels and auxological or metabolic parameters in children with normal BMIs. These results suggested that IGFBP-2 might be a promising marker for early recognition of insulin resistance, particularly in overweight or obese children, regardless of pubertal stage.

Adiposity, fitness and metabolic risk in children: a cross-sectional and longitudinal study

OBJECTIVE

To better understand the early development of cardiovascular disease, we examined the association of adiposity measures and cardiorespiratory fitness (CRF) with baseline values and changes in low-grade chronic inflammation and insulin resistance (IR) in school children.

METHODS

Eighty-three 1(st) and 5(th) grade children from a randomly selected control group of a physical activity intervention study (KISS) were prospectively studied during one academic year. Outcome variables included highly sensitive C-reactive protein (hs-CRP) and homeostasis assessment of IR (HOMA-IR). Adiposity measures included body mass index (BMI), waist circumference and the sum of skinfold thickness at four sites. CRF was assessed by the 20 m shuttle run test. All models were adjusted for age group, sex and pubertal group and included children who had a complete valid dataset for all variables.

RESULTS

Baseline metabolic markers correlated positively with measures of adiposity and inversely with CRF (all p ≤ 0.02). On average, longitudinal changes in hs-CRP concentration increased with high baseline BMI in boys and skinfold thickness in both genders (both p < 0.01). Increases in adiposity had an additional effect on these changes (adjusted R(2) of the models including baseline and change in adiposity 0.49-0.53, p < 0.001). On the other hand, longitudinal changes in HOMA-IR were positively related to changes in BMI and waist circumference (p ≤ 0.03). Increases in HOMA-IR, but not in hs-CRP concentrations, were associated with low baseline CRF (p = 0.01).

CONCLUSION

The relationship of baseline adiposity and CRF with increases in metabolic risk markers may have relevant implications for long-term cardiovascular risk. International Standard Randomised Controlled Trial Number (ISRCTN):

TRIAL REGISTRATION

isrctn.org 15360785.

Insulin-like growth factor binding protein: a possible marker for the metabolic syndrome?

Insulin-like growth factor (IGF) binding proteins (IGFBPs) moved on to contain both IGF high- and low-affinity binders, exerting mitogenic and metabolic actions through its complex interplay between IGF/insulin and its IGF/insulin-independent manner. Progress on the metabolic-related function of IGFBPs has been rapid in recent years. A wealth of studies in 3T3-L1 adipocytes and the transgenic mice models demonstrated that IGFBPs played important roles in the pathogenesis of obesity and insulin resistance. Studies conducted in humans demonstrated the close relation between IGFBPs and the components of the metabolic syndrome. Abnormal expression of IGFBP was detected in various states of the metabolic disorders, suggesting that it could be used as a convenient and sensitive marker of insulin resistance, identification of insulin-resistant individuals at high cardiovascular risk, and may be an earlier marker of the metabolic syndrome. These exciting findings bring us new insight into the elucidation of the metabolic syndrome, which may have important clinical implications.

Family history of diabetes, parental body mass index predict obesity in Latino children

PURPOSE

The purpose of this study is to examine the association between family history of diabetes (FHD), body mass index (BMI), and acculturation with children's BMI status.

METHODS

Baseline data from a randomized community intervention trial promoting healthy eating and physical activity were collected in children living in San Diego, California. A self-administered survey was completed by primary caregivers at each school assessing maternal diabetes, BMI, acculturation, and socioeconomic status (SES). Anthropometric data (height, weight, and BMI) from mothers and children were also collected.

RESULTS

A total of 812 caregivers completed the baseline survey. Adjusting for maternal age, marital status, and socioeconomic level, women who had been diagnosed with diabetes or gestational diabetes or who received diabetes treatment were significantly more likely to have overweight children. Maternal BMI was also associated with children's weight. Maternal acculturation level was marginally associated with children's BMI.

CONCLUSIONS

FHD, gestational diabetes, and BMI were associated with children's overweight status. More comprehensive interventions are needed to prevent obesity in Latino children and adults.

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.

Physical Activity: The Epidemic of Obesity and Overweight Among Youth: Trends, Consequences, and Interventions

Childhood and adolescent overweight and obesity are an epidemic problem in the United States. Studies show that approximately one third of youth are overweight or obese, representing a tripling since the 1960s and 1970s. The average male and female adult in the United States has gained 25 lbs and 24 lbs, respectively, since 1962. The body mass index of the average adult has increased from 25 to 28. Among youth, the average body mass index has increased from 21.3 to 24.1 since 1963. This increase in bodyweight among adults and youth is partially due to the decreased levels of physical activity. The economic and health consequences of this epidemic are enormous. Type 2 diabetes mellitus, a disease that was rare among youth 20 to 30 years ago, now represents as many as 45% of all cases of diabetes among youth. Cardiovascular risk factors are worsened in overweight and obese youth, and early evidence of atherosclerosis manifested by endothelial dysfunction and increased coronary artery calcium is present in a high percentage of overweight youth. Numerous psychosocial problems also are increased among overweight and obese youth. However, there are numerous examples in the scientific literature of successful approaches to the prevention and management of overweight and obesity in youth. This article summarizes statistics concerning the prevalence of overweight, obesity, and physical inactivity among youth; discusses the numerous physical and psychosocial consequences of overweight and obesity among youth; and presents information regarding interventions that have been demonstrated to be effective in preventing childhood and adolescent overweight and obesity.

Correlation between white blood cell count and metabolic syndrome in adolescence

BACKGROUND

Metabolic syndrome (MetS) is associated with increased risk for diabetes and coronary heart disease. Data suggest that MetS starts even in children. Thus, it is important to understand the role of MetS and the risks related to it. Furthermore, white blood cell count (WBCC) is available in routine examination and it has been proved to be related to risks of MetS.

METHODS

A total of 1657 subjects aged 14-19 years were enrolled, with normal WBCC (< or =10 x 10(9) cells/L). The subjects were divided into four quartiles according to WBCC (WBCC1-4, from the lowest to highest WBCC) in both genders.

RESULTS

The female subjects had significantly lower systolic blood pressure, fasting plasma glucose (FPG), triglyceride (TG), body mass index (BMI) and higher high-density lipoprotein-cholesterol (HDL-C) than the male subjects. When comparing the risks of the quartiles of WBCC, WBCC4 had significant higher BMI than WBCC1 and WBCC2 in both genders; and lower HDL-C than WBCC3 in male subjects. On multiple regression WBCC was positively related with BMI and TG and negatively related to HDL-C in male subjects. In female subjects only BMI was positively correlated with WBCC. Subjects with MetS did not have significant higher WBCC than those without MetS.

CONCLUSIONS

In adolescents with normal WBCC, BMI is significantly related to the levels of WBCC and is the earliest component of MetS to be noted in adolescents. Elevated TG and decreased HDL-C could also be important markers for future risk factors only in male subjects.

Insulin-like growth factor binding protein-1 to screen for insulin resistance in children

BACKGROUND

Diabetes and atherosclerosis are burgeoning health problems complicating obesity-associated insulin resistance (IR). Early detection of IR in children is a key to preventative strategies. Since peripheral insulin levels insensitively reflect hepatic insulin fluxes, we studied the insulin-regulated hepatic insulin-like growth factor binding proteins (IGFBPs)-1 and -3 as possible screening markers of childhood IR.

METHODS

The tolbutamide-modified frequently sampled intravenous glucose tolerance test (FSIVGTT) and the oral glucose tolerance test (OGTT) were performed in 118 subjects < 21 years old with obesity. The relationships between insulin sensitivity index by minimal modeling (SiIVGTT), other Sis derived from fasting and OGTT insulin and glucose values, and the candidate serum markers were sought.

RESULTS

Significant correlation was found between IGFBP-1 and SiIVGTT, similar to the correlations of insulin sensitivity indices with SiIVGTT. In children < or = 10 years old, correlation of IGFBP-1 with SiIVGTT was the strongest. All (100%) subjects with IR defined by SiIVGTT < 4.5 +/- 0.5 x 10(-4) min(-1) /(microIU/mL) had inappropriately low IGFBP-1 levels. IGFBP-3 was not correlated with SiIVGTT.

CONCLUSIONS

IGFBP-1 levels decrease with obesity and IR. We propose that in young subjects, especially children under the age of 10 years, IGFBP-1 is a convenient and sensitive marker of IR, whereas elevated fasting insulin is less sensitive but more specific.

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

OBJECTIVE

Distributions of serum concentrations of insulin among adolescents and young adults are poorly understood in the U.S. The objective of this study was to describe the distribution of serum insulin across demographic characteristics of U.S. adolescents and young adults.

RESEARCH DESIGN AND METHODS

A total of 1,791 male and female subjects aged 12-19 years who participated in the National Health and Nutrition Examination Surveys for 1999-2002 were included in the analyses.

RESULTS

Among male participants, serum concentrations of insulin increased from age 12 to 14 years before decreasing. Among female participants, concentrations were highest at age 13 years before decreasing steadily through age 19 years. Among participants aged 12-17 years but not those aged 18-19 years, females had higher mean log-transformed concentrations than males (P, Wald, F = 0.038 and 0.125, respectively) after adjusting for age and ethnicity. After adjusting for age and BMI percentile, mean log-transformed concentrations were higher in African-American females aged 12-17 years than in white or Mexican-American participants. No significant ethnic differences were found among female participants aged 18-19 years or male participants aged 12-19 years. Concentrations of insulin increased strongly with increasing levels of BMI.

CONCLUSIONS

These results provide detailed information about serum concentrations of insulin in a representative sample of U.S. adolescents and young adults and may be useful to monitor future trends of this risk factor for diabetes and cardiovascular disease.

A study on glucose metabolism in a small cohort of children and adolescents with kidney transplant

Post-transplant diabetes mellitus (PTDM) and impaired glucose tolerance are now considered among the major adverse events following organ transplantation. The present study was aimed at investigating the regulation of glucose metabolism in pediatric recipients of a kidney transplant (KT), receiving tacrolimus or cyclosporine A-based immunosuppression. Twelve subjects, eight males and four females, aged 12.1+/-3.8 yr, and with a mean time from KT of 45.6 months were enrolled in the study. All patients had a basal evaluation of fasting glucose (GF), fasting insulin (IF), C-peptide and glycated hemoglobin (HbA1c) levels. They then underwent oral glucose tolerance test (OGTT), with measurement of blood glucose and insulin concentration. Two children had impaired GF, associated with supernormal HbA1c levels, one patient showed impaired glucose tolerance, none had PTDM. Peripheral insulin resistance, as measured by quantitative insulin sensitivity check index (QUICKI) and homeostasis model assessment estimate of insulin sensitivity (HOMA-IR) index, was enhanced in 3 patients. Subsequently, GF significantly increased with time from transplant (p=0.01), while fasting C-peptide and the area under the curve of insulin correlated with creatinine clearance. In conclusion, our results, although generated in a small sample size, would suggest that long-term follow-up of children receiving a KT should extend to explore the response to oral glucose load and at least the basal measure of insulin response.