Clinical question How often do obese children with acanthosis nigricans (AN) have diabetes or other impairments of glucose control?
Bottom line Twenty-nine percent of obese children with AN have impaired glucose control compared with 12% of obese children without AN. These children are also more likely to have elevated BP and are less likely to exhibit delayed physical development. (Level of evidence = 2b–)
Synopsis These authors recruited children from primary care pediatricians' offices. They do not report how the children were selected beyond their inclusion criteria: aged 8 to 14 years, no corticosteroid use for at least 1 month, and no chronic disease associated with autoimmune disorders. All children underwent assessments including demographic, socioeconomic, and medical information, including BP, family history, anthropomorphic assessments, Tanner staging, and a quantitative assessment of their necks to assess the presence or absence of AN. Finally, all children consumed a diet rich in carbohydrates for 3 days and completed a glucose tolerance test (GTT). The authors used the American Diabetes Association criteria for abnormal glucose homeostasis: any combination of impaired fasting glucose, impaired glucose tolerance, or diabetes on the basis of the GTT. They identified 236 children with AN and 51 without AN. Only one child had a normal body mass index (BMI); 14 had a BMI between the 85th and 95th percentile. Although the prevalence of overweight and obesity among American children is high, the proportion in this study seems excessive, raising a concern about recruitment bias. The BMI z-score (a way of comparing BMI across different age groups) was nearly the same in children with AN and children without AN (2.3 vs 2.1). Among the children with AN, 27% had systolic BP above the 95th percentile compared with 14% of the children without AN. Although the average age of each group was the same, only 18% of the children with AN were prepubertal by Tanner staging compared with 41% of the children without AN. Finally, 29% of the children with AN had abnormal glucose homeostasis compared with 12% of those without AN. Because clinicians are wired to look for AN in obese children, these data may be skewed. We need a study in which clinicians assess consecutive children in the same systematic manner as in this study so we can estimate the overall prevalence of AN, regardless of weight, and its association with impaired glucose control.
Brickman WJ, Huang J, Silverman BL, Metzger BE. Acanthosis nigricans identifies youth at high risk for metabolic abnormalities.
J Pediatr. 2010;156(1):87-92.
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