LAS VEGAS — Adolescents can be insulin resistant and have the risk factors of early heart disease, Dr. Alan Sinaiko said at the Fourth World Congress on the Insulin Resistance Syndrome.
Dr. Sinaiko has followed a cohort of about 400 Minnesota children from age 11 years to 23 years. In the study, he used an insulin clamp technique in which glucose and insulin are infused together to measure the glucose's uptake by muscle.
He has found that at 13 years, 2% of the patients have insulin resistance and the metabolic syndrome, and by 19 years, 9% do, according to adult standards. The percentage is higher (9% at age 15) if one uses the more lenient standards for children.
Insulin resistance in childhood predicts resistance as an adult, said Dr. Sinaiko, a professor of pediatrics at the University of Minnesota, Minneapolis. Weight makes a difference, worsening cardiovascular risk factors, but weight and insulin resistance seem independent of each other. An increase in body mass index seems worst.
Insulin resistance appears differently in children than in adults. In pediatrics, it is hard to judge resistance by fasting insulin, because the values vary greatly and children experience a reduction in insulin sensitivity as they progress though the Tanner stages. The sensitivity normalizes after puberty. Insulin sensitivity falls in males after puberty during their teens, but not in females. Males also have greater increases in blood pressure and triglycerides and a dip in HDL cholesterol, showing they accumulate heart disease risks at a young age.