DALLAS — Children who meet criteria for metabolic syndrome are ninefold more likely to develop cardiovascular disease and threefold more likely to develop diabetes before age 50 than are individuals who didn't meet those criteria as children, John A. Morrison, Ph.D., said at the annual scientific sessions of the American Heart Association.
Metabolic syndrome in adults is known to at least double cardiovascular disease and diabetes risks, but little is known about the adult consequences of pediatric metabolic syndrome. This gap convinced Dr. Morrison, professor of pediatrics at the University of Cincinnati and a researcher at Cincinnati Children's Hospital Medical Center, to gather data using a 30-year follow-up of participants in the National Heart, Lung, and Blood Institute-sponsored Lipid Research Clinics Study.
He presented 30-year follow-up data on 917 subjects from 573 families who were 5–19 years old when they participated in the Lipid Research Clinics in the mid-1970s. As children, just 12 met National Cholesterol Education Program Adult Treatment Panel-III criteria for metabolic syndrome. Those criteria work poorly in children, who seldom exhibit the full adult expression of abnormalities in waist circumference, blood pressure, and lipids. For that reason, pediatric researchers often use the more appropriate age-adjusted Cook criteria; by this standard, 41 subjects had pediatric metabolic syndrome.
At 30-year follow-up, 21 participants had developed known cardiovascular disease and 52 had diabetes. The risk of cardiovascular disease in young adulthood was 8.5-fold greater in subjects who had metabolic syndrome as a youth than in those who didn't. The risk of diabetes was increased 3.2-fold—and among those participants who had pediatric metabolic syndrome as well as a parental history of diabetes, the risk climbed to 5.3-fold.
In another study, Dr. Morrison found preteen central adiposity was the key precursor to subsequent development of metabolic syndrome during adolescence.
The study involved 1,175 girls, about half of whom were black and the rest white, who participated in the NHLBI-sponsored Growth and Health Study. Of those who had an elevated waist circumference at age 11 years and who still had an increased waist circumference at age 18–19, the prevalence of metabolic syndrome was 12% at the latter age, a rate roughly sixfold greater than typical in young adulthood. In contrast, metabolic syndrome did not develop in any of the participants who no longer had an increased waist circumference at age 18–19 (Pediatrics 2005;116:1178–82).
“The take-home message here is identify who's at risk and act on it,” he said.
In a separate presentation, Aaron S. Kelly, Ph.D., said several biochemical markers of cardiovascular risk show promise for identifying at-risk children even before they develop metabolic syndrome. These fall under the headings of adipocytokines, markers of systemic oxidative stress, and inflammatory markers.
He reported on 34 children. One-third were of normal weight and healthy. Another third were overweight but otherwise healthy. The rest were overweight and met at least three of the Cook modified criteria for metabolic syndrome.
Levels of the adipocytokine leptin—known to be related to insulin resistance—increased stepwise from the normal to the overweight to the metabolic syndrome subjects. So did levels of C-reactive protein and interleukin-6 as well as 8-isoprostane, a marker of systemic oxidative stress thought to be involved in the early stages of the atherosclerotic process.
In contrast, levels of adiponectin—which is associated with insulin sensitivity—were highest in the normal weight children and lowest in the overweight ones with metabolic syndrome, according to Dr. Kelly of the St. Paul (Minn.) Heart Clinic and the University of Minnesota, Minneapolis.
Metabolic syndrome did not develop if waist circumference was no longer increased at age 18–19. DR. MORRISON