A prospective study in obese children and adolescents shows that the metabolic syndrome is prevalent among such youngsters and increases as obesity becomes worse. The authors defined the metabolic syndrome as three or more of the following: body mass index that exceeds the 97th percentile; elevated triglyceride levels; a high systolic or diastolic blood pressure; a low level of high-density lipoprotein (HDL) cholesterol; and impaired glucose tolerance. These criteria were modified from Centers for Disease Control and Prevention (CDC) criteria for adults.
Investigators took a variety of baseline measures and administered a standard glucose tolerance test to 439 obese children and adolescents (4 to 20 years of age) and, as a comparison group, 51 of their siblings, 31 of whom were overweight but not obese. Values for glucose, insulin, insulin resistance, triglycerides, and systolic blood pressure, as well as the prevalence of impaired glucose tolerance, rose with increasing obesity, as did the level of C-reactive protein and interleukin-6, putative biomarkers of inflammation and potential predictors of adverse cardiovascular outcomes. HDL cholesterol and adiponectin, a biomarker of insulin sensitivity, decreased.
Moderately and severely obese black subjects had, on average, a lower triglyceride level and a higher HDL cholesterol level than similar white and Hispanic subjects. The percentage of subjects with impaired glucose tolerance increased directly with the severity of obesity in subjects in all racial and ethnic groups, even after adjustment for sex, pubertal status, and race or ethnic group.
Commentary: As the prevalence of obesity increases, we'll need to become well-versed not only in prevention and treatment of this condition but also in identifying and treating its complications. The metabolic syndrome is one such complication: In adults, its presence increases the risk of heart disease independently of the low-density lipoprotein cholesterol level. The CDC describes this syndrome as equal to smoking as a risk factor for early heart disease.