RESUMO
OBJECTIVE: Our objective was to describe in children the relation of fatness and insulin resistance to the risk factors associated with the insulin resistance syndrome and to compare fasting insulin with the euglycemic insulin clamp as a measure of insulin resistance in children. STUDY DESIGN: This was a random selection of participants after blood pressure screening of 12,043 students in the fifth through eighth grades. Euglycemic insulin clamp studies with an insulin infusion rate of 1 mU/kg/min and a variable infusion of 20% glucose to maintain euglycemia, that is, plasma glucose at 5.6 mmol/L. Insulin sensitivity (M(lbm)) is defined as the amount of glucose required to maintain euglycemia (milligrams of glucose infused per kilogram lean body mass per minute). RESULTS: Body mass index was significantly correlated with fasting insulin and significantly inversely correlated with M(lbm). Fasting insulin was significantly correlated with systolic blood pressure in both sexes, all lipids, except high-density lipoprotein-cholesterol in males and triglycerides and high-density lipoprotein-cholesterol in females, but after adjustment was done for body mass index, it was significantly related only to triglycerides. M(lbm) was significantly correlated only with triglycerides and high-density lipoprotein-cholesterol, and this did not change after adjustment was done for body mass index. A clustering effect for the risk factors was seen in children in the lowest quartile of M(lbm) (highest degree of insulin resistance) compared with children in the highest quartile of M(lbm) (lowest degree of insulin resistance). CONCLUSIONS: As defined by M(lbm), there is an early association of insulin resistance, independent of body fat, with the risk factors. There is a significant relation between fasting insulin, as an estimate of insulin resistance, and the risk factors, but this is significantly influenced by body fatness. The clustering of risk factors according to level of M(lbm) suggests that adult cardiovascular disease is more likely to develop in children with the greatest degree of insulin resistance.
Assuntos
Técnica Clamp de Glucose , Insulina/sangue , Síndrome Metabólica , Obesidade/epidemiologia , Adolescente , Índice de Massa Corporal , Criança , Feminino , Humanos , Masculino , Síndrome Metabólica/fisiologia , Fatores de RiscoRESUMO
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.
Assuntos
Resistência à Insulina/fisiologia , Obesidade/complicações , Adolescente , Adulto , Fatores Etários , Índice de Massa Corporal , Feminino , Humanos , Modelos Lineares , Lipídeos/sangue , Masculino , Obesidade/sangue , Fatores de RiscoRESUMO
OBJECTIVE: To determine whether the lipid abnormalities observed in obese adolescents are associated with insulin resistance. METHODS: We evaluated the relationship between lipid levels and insulin resistance in 82 obese adolescents. Insulin resistance was assessed by fasting insulin level and sum of the insulin values after an oral glucose tolerance test in all 82, and were compared with data from 40 nonobese adolescents. Whole-body glucose uptake during euglycemic hyperinsulinemia (M value) was performed in 19 of the obese adolescents and compared with that of 24 nonobese young adults. RESULTS: The obese adolescents had significantly elevated low-density lipoprotein cholesterol (LDL-C) (3.09 +/- 0.73 mmol/L; 119 +/- 28.2 mg/dl) and triglycerides (1.22 +/- 0.62 mmol/L; 108 +/- 54.6 mg/dl) and low high-density lipoprotein cholesterol (HDL-C) levels (0.94 +/- 0.24 mmol/L; 36 +/- 9.1 mg/dl) when compared with values in the nonobese subjects. M values were significantly depressed in the obese compared with the nonobese subjects. Adiposity significantly correlated with low HDL-C and elevated triglyceride values. From the variables representing insulin resistance, the strongest correlation with the abnormal lipid profile was found for the M value. A stepwise multiple regression analysis revealed that the M value was the only step entered into the relationship for triglycerides and LDL-C, and both M value and fasting insulin were entered for HDL-C. CONCLUSION: In obese adolescents the degree of insulin resistance explains a significant portion of the variance in the levels of triglycerides, LDL-C, and HDL-C.