Temporal association between obesity and hyperinsulinemia in children, adolescents, and young adults: the Bogalusa Heart Study

Prevalence of type 2 diabetes mellitus and impaired glucose tolerance in obese Argentinean children and adolescents

The aim of this study was to evaluate the prevalence of type 2 diabetes mellitus (DM2) and impaired glucose tolerance (IGT) in obese children and adolescents and to examine insulin resistance and insulin secretion. We studied 427 asymptomatic obese patients. DM2 and IGT were diagnosed by an oral glucose tolerance test. Insulin resistance and P-cell function were assessed by using homeostasis model assessment (HOMA), insulin/glucose index (I/GI), fasting insulin and insulin sensitivity index (ISI-composite). Thirty patients showed IGT (7%) and seven had DM2 (1.6%). The mean age was 10.7 +/- 3.5 years, the diabetic group being significantly older than the normal group (p < 0.01). The mean body mass index was 30 +/- 5.3 kg/m2 without significant differences between groups. beta-Cell function declined significantly in the patients with IGT and DM2, and insulin resistance increased significantly. Given the rather high prevalence of glucose metabolism impairment, children with obesity should undergo glucose tolerance testing for appropriate therapeutic intervention.

Cardiovascular risk factors in youth with implications for aging: the Bogalusa Heart Study

Evidence that cardiovascular (C-V) risk factors are identifiable in childhood and are predictive of future C-V risk is now irrefutable. That levels of C-V risk factors track or persist over time is important, since such phenomenon confers a life-long burden of C-V risk and indicates subtle and progressive changes in the C-V system. C-V risk factors occur often in constellation and central obesity and the attendant insulin resistance/hyperinsulinemia underlie the comorbid conditions of dyslipidemia, hypertension, thrombosis, and inflammation, among others. Autopsy studies and non-invasive subclinical C-V imaging studies in youth clearly link the multiple risk factor burdens to adverse C-V system changes. The application of multiple risk factors profiling in young individuals in conjunction with non-invasive measurements of vascular changes can promote successful aging and encourage preventive cardiology beginning in early life.

Insulin resistance and weight gain in postmenopausal women of diverse ethnic groups

OBJECTIVE

This study was conducted to examine the influence of insulin resistance on weight change in postmenopausal women of various ethnic groups.

SUBJECTS

Data were obtained from 3389 women (60% White, 20% Black, 12% Hispanic, and 8% Asian/Pacific Islander), ages 50-79, enrolled in either the Women's Health Initiative Clinical trial or Observational Study, whose blood samples were selected randomly from the full cohort of 161 809 women for analyses.

MEASUREMENTS

Glucose, insulin, and lipids were measured on fasting serum samples drawn at baseline and after 3 y of follow-up. Weight, height, waist circumference, and blood pressure were measured. Physical activity and energy intake were assessed via questionnaire. Insulin resistance was estimated using the HOMA (homeostasis model) calculation.

RESULTS

Average age was 62 y, average BMI (body mass index) was 27.4 kg/m2, and average weight change was a gain of 0.4 kg in 3 y. In a multivariate analysis, insulin resistance and insulin concentrations were independent predictors of increases in weight in White women (P=0.002 and 0.004, respectively) and in the combined group (P=0.027 and 0.039). For the whole group, after adjustment for other covariates, those in the highest quartile of insulin resistance gained 0.4 kg in 3 y, whereas those in the lowest quartile lost 0.06 kg. Similar trends were found for insulin resistance and weight gain in Hispanic and Asian/Pacific Islander women, but they did not reach statistical significance. In Black women, no relation was seen between either insulin or insulin resistance and weight change. A significant interaction between obesity and insulin resistance was observed (P=0.002 for White women and 0.032 for the whole group), so that there is weight gain with increasing insulin resistance in the leaner women, but weight loss with increasing insulin resistance in the most obese.

CONCLUSION

Insulin resistance appears to be a predictor of weight gain in postmenopausal women, except for the most obese women. The effect is more pronounced in women who have a lower BMI, and the effect was not seen in the Black women who as a group had a higher BMI.

Hostility predicts metabolic syndrome risk factors in children and adolescents

The authors tested in 134 African American and European American children whether hostility measured at study entry predicted the metabolic syndrome risk factors an average of 3 years later. Hostility was measured with the Cook-Medley Hostility Scale (W. W. Cook & D. M. Medley, 1954) and with ratings of Potential for Hostility from interview responses. Metabolic syndrome was based on having at least 2 of the following risk factors above the 75th percentile of scores for their age, race, and gender group: body mass index, insulin resistance index, ratio of triglycerides to high-density lipoprotein cholesterol, and mean arterial blood pressure. Children who exhibited high hostility scores at baseline were likely to exhibit the metabolic syndrome at the follow-up. The results highlight the potential importance of early prevention and intervention of behavioral risk factors for cardiovascular disease.

Plasma leptin, fatty acids, and tumor necrosis factor-receptor and insulin resistance in children

OBJECTIVE

To evaluate the effect of plasma leptin, nonsterified fatty acids (NEFAs), and tumor necrosis factor-receptor 1 (TNFR1) on plasma insulin and insulin-resistance status in children.

RESEARCH METHODS AND PROCEDURES

One thousand thirty-two children (521 boys and 511 girls) were included in this study. We measured plasma insulin and leptin levels by radioimmunoassay, plasma NEFA levels by enzymatic acyl-coenzyme A synthase-acyl-coenzyme A oxidase spectrophotometric methods, and TNFR1 levels by enzyme-linked immunosorbent assay. We calculated insulin resistance index (IRI) using homeostasis model assessment and calculated insulin-resistance syndrome summary score (IRS) by adding the quartile ranks from the distribution of systolic blood pressure (BP), serum triglyceride, high-density lipoprotein-cholesterol (inverse), and insulin levels.

RESULTS

Overweight children had higher BP, plasma leptin, and insulin levels and higher IRI and IRS than normal-weight children. Plasma leptin and TNFR1 were positively correlated with insulin levels, IRI, and IRS. The correlation coefficients of leptin and TNFR1 in IRI were 0.53 and 0.12, respectively, for boys and 0.25 and 0.18, respectively, for girls. In multivariate regression analyses, TNFR1 was positively associated with insulin level and IRI in girls; NEFA was positively associated only with IRS. Plasma leptin levels were significantly positively associated with insulin levels, IRI, and IRS, even after adjusting for BMI and other potential confounders.

DISCUSSION

Overweight children had higher BP, plasma insulin, and leptin levels and adverse insulin-resistance status than normal-weight children. Plasma leptin levels, rather than NEFA and TNFR1, may play a significant role in the development of hyperinsulinemia and insulin resistance in children.

Longitudinal changes in risk variables of insulin resistance syndrome from childhood to young adulthood in offspring of parents with type 2 diabetes: the Bogalusa Heart Study

The occurrence of metabolic abnormalities related to insulin resistance syndrome in nondiabetic offspring of type 2 diabetic parents is known. However, information is lacking on the timing and the course of development of the components of this syndrome from childhood to adulthood in the offspring of parents with diabetes. This aspect was examined in a community-based cohort with (n = 303) and without (n = 1,136) a parental history of type 2 diabetes followed longitudinally since childhood (ages 4 to 17 years; mean follow-up period, 15 years) by repeated surveys. Offspring with parental diabetes versus those without such history had significantly excess generalized and truncal adiposity as measured by body mass index (BMI) and subscapular skinfold beginning in childhood, higher levels of fasting insulin and glucose and homeostasis model assessment index of insulin resistance (HOMA-IR) from adolescence, and higher levels of low-density lipoprotein (LDL) cholesterol and triglycerides and lower levels of high-density lipoprotein (HDL) cholesterol in adulthood. Many of these risk variables changed adversely at an increased rate in offspring of diabetic parents. In a multivariate analysis, parental diabetes was an independent predictor of longitudinal changes in adiposity, glucose, insulin, HOM-IR, systolic and diastolic blood pressure, and LDL cholesterol in the offspring, regardless of race and gender. As young adults, the offspring of diabetic parents had a higher prevalence of generalized (BMI > 30, 36% v 16%, P =.0001) and visceral (waist > 100 cm, 15% v 6%, P =.0001) obesity, hyperinsulinemia indicative of insulin resistance (insulin > 18 microU/mL, 15% v 8%, P =.0001), hyperglycemia (>or=110 mg/dL, 2% v 0.5%, P =.02), high LDL cholesterol (>or=160 mg/dL, 11% v 7%, P =.02), low HDL cholesterol (<40 mg/dL for males and <50 mg/dL for females, 40% v 31%, P =.004), high triglycerides (>or=150 mg/dL, 23% v 15%, P =.0001), and hypertension (>140/90 mm Hg, 11% v 6%, P =.004). Thus, the offspring of diabetic parents displayed excess body fatness beginning in childhood and accelerated progression of adverse risk profile characteristics of insulin resistance syndrome from childhood to young adulthood. These observations have important implications for early prevention and intervention.

Childhood obesity in Canada: a review of prevalence estimates and risk factors for cardiovascular diseases and type 2 diabetes

Childhood obesity in Canada has become increasingly prevalent over the past 2 decades. Despite inconsistencies regarding different anthropometric indicators, cut-offs, and reference populations, both regional and national investigations have revealed high numbers of overweight and obese children and adolescents. A number of risk factors and health consequences have been associated with increased levels of body fatness in youth. Specifically, risk factors for cardiovascular diseases (CVD) and type 2 diabetes are known to develop early in life and tend to emerge in clusters among overweight youngsters. Unhealthy lifestyle behaviours (i.e., physical inactivity), a genetic disposition, and a centralized body fat distribution, all contribute to increased risk. In order to prevent future generations of children from experiencing increased morbidity and mortality as overweight and obese adults, coordinated efforts at all levels (family, school, community, and government) must be established with a long-term commitment to promote healthy nutrition and physical activity behaviours in our youth.

Childhood risk factors predict adult risk associated with subclinical cardiovascular disease. The Bogalusa Heart Study

Cardiovascular risk factors begin in childhood and are predictive of cardiovascular risk in adulthood. Observations in the Bogalusa Heart Study have shown an important correlation of clinical risk factors in early life with anatomic changes in the aorta and coronary vessels with atherosclerosis and cardiac and renal changes related to hypertension. These observations have been extended by echo Doppler studies of carotid artery intima media thickness (IMT). A close association of risk factors in young adults, 20-38 years of age, occurs with IMT, and a marked increase is noted as numbers of risk factors increase. More extensive changes seem to occur in the bulb or bifurcation area. This area may be an earlier marker of disease. Observations of risk factors in young individuals and noninvasive studies of structural changes of the cardiovascular system have strong implications for prevention by cardiologists.

Thyroid hormones before and after weight loss in obesity

BACKGROUND

Little is known about changes in thyroid function in obese children. An influence of leptin on thyroid hormone synthesis has been proposed.

AIMS

To examine thyroid function and leptin concentrations in obese children.

METHODS

Triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH), and leptin were measured in 118 obese children (aged 4.5-16 years); thyroid function was also determined in 107 healthy children of normal weight. T3, T4, and TSH were analysed in 55 obese children who had achieved weight reduction and in 13 obese children who had not achieved weight reduction after one year based on normal energy diet.

RESULTS

TSH, T3, and T4 were significantly higher in obese children compared to those of normal weight. Twelve per cent of the obese children had TSH, 15% had T3, and 11% had T4 concentrations above the twofold standard deviation of normal weight children. The degree of overweight correlated with T3, T4, and TSH. Thyroid hormones did not correlate significantly with leptin. A reduction in overweight showed a significant decrease in T3, T4, and leptin serum concentrations, but there was no significant change in TSH.

CONCLUSION

Peripheral thyroid hormones (T3, T4) and TSH are moderately increased in obese children; weight reduction leads to a long term decrease in the peripheral thyroid hormones but not in TSH. There is no necessity to treat the increased serum TSH.

Upper abdominal obesity, insulin resistance and breast cancer risk

PURPOSE

A majority of prospective studies show breast cancer risk to be higher in obese postmenopausal women with upper abdominal adiposity than in those with overall adiposity. The evidence is more limited and inconsistent in the case of premenopausal women. The review examines evidence that aberrant insulin signalling may be involved in the promotion of mammary carcinogenesis. The aetiology and concomitants of abdominal visceral obesity are examined.

MECHANISMS

Clinical and experimental evidence suggests that the higher breast cancer risk associated with greater abdominal visceral obesity may be related to aberrant insulin signalling through the insulin receptor substrate 1 pathway, leading to insulin resistance, hyperinsulinaemia and increased concentrations of endogenous oestrogen and androgen. The putative role of aberrant insulin signalling in the promotion of mammary carcinogenesis may help to explain clinical relationships between breast cancer risk and age at menarche, pregnancies and onset of obesity.

CONCLUSION

Overall adiposity in women adversely affects breast cancer risk mainly by greater exposure of mammary epithelial tissue to endogenous oestrogen. Upper abdominal adiposity appears to involve an additional effect related to the presence of insulin resistance. Aetiological factors in the development of hyperinsulinaemic insulin resistance are still uncertain but may involve aberrant susceptibility genes in adipocyte insulin receptors or in the insulin receptor substrate 1 pathway. Epigenetic factors are also likely to contribute, including high free fatty acid levels and obesity. Dietary fatty acids, particularly polyunsaturated fatty acids, are known to regulate adipocyte differentiation through the nuclear peroxisome proliferator-activated receptor gamma, and may also have a role in insulin resistance. These aetiological factors are likely to be relevant to the high risk of postmenopausal breast cancer in industrialised Western populations.

Emergence of obesity and cardiovascular risk for coronary artery disease: the Bogalusa Heart Study

The underlying determinants of cardiovascular risk are governed by both genetic and lifestyle factors. One of the major adverse outcomes of unhealthy lifestyles is obesity, the genesis of which begins in childhood. Obesity, an important risk factor for atherosclerotic cardiovascular disease, type 2 diabetes, and hypertension, persists (tracks) strongly from adolescent years to adulthood. Secular trends toward increased obesity in the past 25 years have occurred in children and adults alike. Of interest, baseline adiposity precedes hyperinsulinemia in all age groups, independently of race, sex, and baseline insulin levels. Adiposity is an independent predictor of the risk of developing the cluster of risk variables of the metabolic syndrome X, beginning in childhood. Exposure to a multiple risk factor burden over time enhances the development of coronary atherosclerosis and hypertensive cardiovascular disease. In fact, autopsy studies in youths have shown that the extent of fibrotic atherosclerotic plaques in coronary arteries, measured antemortem, increases markedly with the presence of syndrome X risk variables. Further, in overweight children, insulin levels are associated with left ventricular mass. In young people, overnutrition, coupled with physical inactivity, leads to weight gain. Since obesity, unhealthy dietary habits, and a sedentary lifestyle are interrelated and modifiable, prevention and intervention must begin in early life. (c)2001 CHF, Inc.

Predictability of childhood adiposity and insulin for developing insulin resistance syndrome (syndrome X) in young adulthood: the Bogalusa Heart Study

The occurrence of insulin resistance syndrome (syndrome X) is common in the general population. However, information is scant on the childhood predictors of syndrome X. This study examined the relative contribution of childhood adiposity and insulin to the adulthood risk of developing syndrome X in a biracial (black-white) community-based longitudinal cohort (n = 745; baseline age, 8-17 years; mean +/- SD follow-up period, 11.6 +/- 3.4 years). The four criterion risk variables considered were the highest quartile (specific for age, race, sex, and study year) of 1) BMI, 2) fasting insulin, 3) systolic or mean arterial blood pressure, and 4) total cholesterol to HDL cholesterol ratio or triglycerides to HDL cholesterol ratio. Clustering was defined as the combination of all four risk variables. In addition to the criterion risk variables, clustered adults had adverse levels of total cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, diastolic blood pressure, and glucose compared with those who did not cluster (P < 0.001). Childhood variables, except glucose, showed adverse trends with increasing number of criterion risk variables present in adulthood (P for trend, 0.01-0.0001). The proportion of individuals who developed clustering as adults increased across childhood BMI (P for trend <0.0001) and insulin (P for trend <0.01) quartiles. The relationship to childhood BMI remained significant even after adjusting for childhood insulin. In contrast, corresponding association with childhood insulin disappeared after adjusting for childhood BMI. In a logistic regression model, childhood BMI and insulin were significant predictors of adulthood clustering, with BMI being the strongest and showing a curvilinear relationship. Using an insulin resistance index instead of insulin did not change the above findings. These results indicate that childhood obesity is a powerful predictor of development of syndrome X and underscore the importance of weight control early in life.

Dietary glycemic index and glycemic load, and breast cancer risk: a case-control study

BACKGROUND

Certain types of carbohydrates increase glucose and insulin levels to a greater extent than others. In turn, insulin may raise levels of insulin-like growth factors, which may influence breast cancer risk. We analyzed the effect of type and amount of carbohydrates on breast cancer risk, using the glycemic index and the glycemic load measures in a large case-control study conducted in Italy.

PATIENTS AND METHODS

Cases were 2,569 women with incident, histologically-confirmed breast cancer interviewed between 1991 and 1994. Controls were 2588 women admitted to the same hospital network for a variety of acute, non-neoplastic conditions. Average daily glycemic index and glycemic load were calculated from a validated 78-item food frequency questionnaire.

RESULTS

Direct associations with breast cancer risk emerged for glycemic index (odds ratio, OR for highest vs. lowest quintile = 1.4; P for trend <0.01) and glycemic load (OR = 1.3; P < 0.01). High glycemic index foods, such as white bread, increased the risk of breast cancer (OR = 1.3) while the intake of pasta, a medium glycemic index food, seemed to have no influence (OR = 1.0). Findings were consistent across different strata of menopausal status, alcohol intake, and physical activity level.

CONCLUSIONS

This study supports the hypothesis of moderate, direct associations between glycemic index or glycemic load and breast cancer risk and, consequently, a possible role of hyperinsulinemia/insulin resistance in breast cancer development.

Evaluation of the insulin resistance syndrome in 5- to 10-year-old overweight/obese African-American children

OBJECTIVE

To characterize the insulin sensitivity of overweight and obese 5- to 10-year-old (Tanner stage 1-3) African-American children screened for participation in a diabetes prevention study and to identify the association of insulin sensitivity with obesity, hyperlipidemia, and hypertension.

RESEARCH DESIGN AND METHODS

Measures of insulin resistance (homeostasis model assessment) and insulin sensitivity (Matsuda and DeFronzo's whole-body insulin sensitivity) were calculated from a 2-h oral glucose tolerance test in 137 African-American children recruited into a diabetes prevention study. Measures of lipids (LDL, HDL, total cholesterol, and triglycerides), blood pressure, and body composition were obtained for a subset of the children.

RESULTS

In response to a glucose challenge, girls and older and heavier children produced significantly more insulin. As BMI increased, there was a statistically significant decrease in insulin sensitivity, particularly in girls. Insulin sensitivity was inversely correlated with increases in blood pressure, triglycerides, subcutaneous fat, the percentage of total body fat, and Tanner stage, but it was not correlated with LDL and HDL.

CONCLUSIONS

Reduced insulin sensitivity and the cluster of risk factors known as the insulin resistance syndrome (IRS) are already apparent in these overweight African-American children. Young African-American girls, in particular, already show evidence of hyperinsulinemia in response to a glucose load, suggesting that the early stages of metabolic decompensation that lead to type 2 diabetes are already occurring. Monitoring of those risk factors known to be part of IRS should become part of routine medical care for overweight or obese African-American children.

Adiposity in childhood predicts obesity and insulin resistance in young adulthood

OBJECTIVE

To determine whether adiposity in children predicts adiposity, insulin resistance, and abnormal lipid levels in young adults.

STUDY DESIGN

Children (n = 31) were recruited into an epidemiologic study at age 13.3 +/- 0.3 years and had blood pressure, weight, and height measured. They were reevaluated at age 21.8 +/- 0.3 years at which time the measurements were repeated, a euglycemic insulin clamp was performed, and fasting lipid levels were measured. All values are expressed as mean +/- SEM. Data were analyzed by analysis of variance and linear regression analysis.

RESULTS

Body mass index (BMI) in childhood (22.6 +/- 0.6) was highly correlated with BMI in young adulthood (26.9 +/- 0.9). Childhood BMI was also inversely correlated with young adult glucose utilization (r = -0.5, P = .006) and positively correlated with total cholesterol (r = 0.37, P = .05), and low-density lipoprotein (LDL) cholesterol (r = 0.48, P = .01).

CONCLUSIONS

These data confirm that adiposity in childhood is a strong predictor of young adult adiposity. In addition, these results demonstrate that cardiovascular risk in young adulthood is highly related to the degree of adiposity as early as age 13.

The effects of metformin on body mass index and glucose tolerance in obese adolescents with fasting hyperinsulinemia and a family history of type 2 diabetes

OBJECTIVES

The prevalence of type 2 diabetes in American adolescents has increased markedly during the past generation. Although the factors that contribute to the development of type 2 diabetes are complex and not wholly elucidated, the triad of severe obesity, hyperinsulinemia, and a family history of type 2 diabetes places a child at an increased risk for development of the disease. Current approaches to the prevention of type 2 diabetes, including dietary counseling and exercise, have had limited success. We reasoned that drugs that increase glucose tolerance in diabetic patients might prove useful in preventing the progression to glucose intolerance in high-risk patients. To that end, we conducted a double-blind, placebo-controlled study of the effects of metformin on body mass index (BMI), serum leptin, glucose tolerance, and serum lipids in obese adolescents with fasting hyperinsulinemia and a family history of type 2 diabetes.

METHODS

The study population consisted of 29 white and black adolescents aged 12 to 19 years. All had BMIs exceeding 30 kg/m(2). Criteria for enrollment included: 1) a fasting insulin concentration exceeding 15 microU/mL; and 2) at least 1 first- or second-degree relative with type 2 diabetes. All patients had fasting plasma glucose concentrations <110 mg% and hemoglobin A1c concentrations </=6.0%. All had normal linear growth and sexual development for age, with no marked hirsutism, severe acne, or menstrual irregularities characteristic of polycystic ovary syndrome. Eight participants had acanthosis nigricans. After baseline laboratory studies including a rapidly sampled intravenous glucose tolerance test, patients were randomized to receive metformin (500 mg twice daily) or a placebo for a total of 6 months. The effects of metformin on BMI standard deviation score, serum leptin, glucose tolerance, and serum lipids were analyzed. The study was double-blinded and included no specific dietary restrictions.

RESULTS

Metformin caused a decline of 0.12 standard deviation in BMI in study participants (-1.3% from baseline), and a 5.5% reduction in serum leptin in girls. In contrast, BMI and serum leptin rose 0.23 standard deviation (2.3%) and 16.2%, respectively, in the placebo group during the treatment period. Metformin caused a progressive decline in fasting blood glucose (from a mean of 84.9 to 75.1 mg%) and a reduction in fasting insulin levels (from 31.3 to 19.3 microU/mL). In contrast, fasting glucose levels in the placebo group rose slightly from 77.2 to 82.3 mg%, and fasting insulin levels did not change. Insulin sensitivity, as assessed by the ratio of fasting insulin to glucose concentrations and the quantitative insulin sensitivity check index (1/[log fasting insulin + log fasting glucose]) and homeostasis model assessment insulin resistance index (fasting insulin x fasting glucose/22.5) indices, increased slightly in the metformin-treated participants. However, the insulin sensitivity measured using Bergman's minimal model did not change. There were also no significant changes in glucose effectiveness, hemoglobin A1c, serum lipids, or serum lactate in the metformin or placebo groups. Metformin was tolerated well by the majority of patients. Transient abdominal discomfort or diarrhea occurred in 40% of treated participants; there were no episodes of vomiting or lactic acidosis.

CONCLUSIONS

The treatment of obesity and insulin resistance in adults often proves ineffective because the vicious cycle leading to type 2 diabetes may have become entrenched and, to some extent, may be irreversible. Early detection and therapy of the obese adolescent with a family history of type 2 diabetes may interrupt the cycle of weight gain and insulin resistance that leads to glucose intolerance in adulthood. Through its ability to reduce fasting blood glucose and insulin concentrations and to moderate weight gain, metformin might complement the effects of dietary and exercise counseling and reduce the risk of type 2 diabetes in selected patients.

Plasma leptin concentrations and obesity in relation to insulin resistance syndrome components among school children in Taiwan--The Taipei Children Heart Study

OBJECTIVE

Leptin, an adipose tissue-derived product of the obesity (OB) gene, is an important regulator of energy metabolism and may be associated with the occurrence of insulin resistance and diabetes in humans. The purpose of this study was to evaluate the association of plasma leptin concentration with obesity and the components of insulin resistance syndrome (IRS) among school children in Taiwan.

METHODS

After multistage sampling of 85 junior high schools in Taipei, we randomly selected 1,264 children (617 boys and 647 girls) aged 12-16y. Obesity measurements included body mass index (BMI) and waist-to-hip circumference ratio (WHR). We calculated an IRS summary score for each individual by adding the quartile ranks from the distribution of systolic blood pressure (BP), serum triglyceride (TG), HDL-cholesterol (inverse), and insulin levels.

RESULTS

Boys had a higher BMI and WHR, BP and IRS score and lower leptin, insulin, TG and HDL-C levels than girls. BMI, WHR and plasma leptin levels were significantly associated with the IRS summary score and each of its components in both genders. Children with higher plasma leptin levels (> 75th percentiles) have significantly higher BP, TG, insulin levels and IRS score than children with low leptin levels. The associations between plasma leptin level and the IRS components and score were still significant after adjusting for BMI in boys, but less so in girls. In both genders, after adjusting for WHR, plasma leptin levels were still significantly associated with the IRS components and summary score (P< 0.001). The final model that included the standard covariates, BMI and leptin, but not WHR, was the most predictive of the IRS summary score among school children.

CONCLUSIONS

Insulin resistance syndrome in childhood, characterized by high blood pressure, dyslipidemia, and hyperinsulinemia, may be an early marker of cardiovascular risk. From the present BMI and leptin in combination are the most predictive markers of insulin resistance syndrome among school children in Taiwan.