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

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.

Secular trends of blood pressure and body size in a multi-ethnic adolescent population: 1986 to 1996.

OBJECTIVES: To determine the levels and time trends of blood pressure and body size in a healthy population of youth. STUDY DESIGN: Minneapolis, Minnesota, fifth through eighth grade public school children (aged 10 to 14 years) were surveyed in 1986 and 1996. Blood pressure, height, and weight were measured by technicians trained to the same rigorous protocol at each time period, and comparisons were made between the 2 groups (1986 and 1996). RESULTS: In 1986 and 1996, 8222 and 10,241 children, respectively, were measured with participation rates of over 93%. African American, Hispanic, Native American, Asian, and non-Hispanic white groups were all represented. Systolic blood pressure was significantly higher and diastolic blood pressure lower in 1996 than in 1986 in all ethnic and gender groups. Weight and body mass index (wt/ht2) were significantly higher in all groups in 1996. Adjustment for body size largely eliminated the systolic blood pressure differences but had no effect on measured diastolic blood pressure. CONCLUSIONS: Body size and systolic blood pressure are rising among school children. Weight and body mass index show substantial increases over 10 years (1986-1996). Diastolic blood pressure fell for unclear reasons. These changes may have future health implications for cardiovascular disease, as these youth move into adulthood.