Relation Between Acanthosis Nigricans and Insulin Sensitivity in Overweight Hispanic Children at Risk for Type 2 Diabetes

Relation Between Acanthosis Nigricans and Insulin Sensitivity in Overweight Hispanic Children at Risk for Type 2 Diabetes Hassan A. Kobaissi , DPM 1 , Marc J. Weigensberg , MD 2 , Geoff D.C. Ball , PHD 1 , Martha L. Cruz , DVM, PHD 1 , Gabriel Q. Shaibi , BS 3 and Michael I. Goran , PHD 1 4 1 Department of Preventive Medicine, University of Southern California, Health Sciences Campus, Los Angeles, California 2 Department of Pediatrics, University of Southern California, Health Sciences Campus, Los Angeles, California 3 Department of Biokinesiology and Physical Therapy, University of Southern California, Health Sciences Campus, Los Angeles, California 4 Department of Physiology and Biophysics, University of Southern California, Health Sciences Campus, Los Angeles, California Address correspondence and reprint requests to Michael I. Goran, PhD, Associate Director, Institute for Prevention Research, Professor of Preventive Medicine and Physiology & Biophysics, Keck School of Medicine, University of Southern California, 1540 Alcazar St., Rm. 208-D, Los Angeles, CA 90033. E-mail: goran{at}usc.edu Abstract OBJECTIVE —To investigate in a population of Hispanic children if 1 ) the presence of acanthosis nigricans (AN) is related to insulin sensitivity ( S i ) independent of adiposity and 2 ) scale scoring AN severity adds to the clinical estimation of insulin sensitivity, above and beyond the presence or absence AN alone. RESEARCH DESIGN AND METHODS —The study population, 131 Hispanic overweight children (mean BMI percentile 97.0 ± 3.1, 72 boys, 59 girls, ages 8–13 years, mean Tanner stage 2.4 ± 1.5) with a family history of type 2 diabetes, underwent a physical examination of the neck to determine AN absence or presence (0–1), AN extent score (0–4 scale), AN texture score (0–3 scale), and an AN combined score (extent + texture; 0–7 scale). S i was measured by the frequently sampled intravenous glucose tolerance test and minimal modeling. Multivariate linear regression analysis was used to determine the role of BMI and AN in predicting S i . RESULTS —BMI was the main predictor of S i , explaining ∼41% of the variance. The presence of AN explained an additional 4% of the variability in S i ; scale scoring of AN extent or texture did not significantly improve the prediction. CONCLU S IONS —Although AN is an independent risk factor for insulin resistance in overweight Hispanic children at risk for type 2 diabetes, body adiposity is the primary determinant of insulin