RESUMO
OBJECTIVE: It is controversial whether acanthosis nigricans is an independent marker of insulin resistance. In this study, we evaluated whether insulin resistance (as reflected by HOMA) was associated with acanthosis nigricans, Native American heritage, BMI, fasting insulin, and plasma lipids in Native American children and adolescents. DESIGN/METHODS: Retrospective chart review of Native American children (3.6 to 17.8 yrs) seen in 4 tribal or Indian Health Service clinics after referral for exceptionally high type 2 diabetes risk (family history, extreme obesity, and/or severe acanthosis nigricans). RESULTS: All but 2 had a family history of type 2 diabetes in at least one first or second degree relative, all but 3 had acanthosis nigricans (12 severe and 11 mild/not severe), and all but 2 were obese (BMI Z score of +3 to +8). Those with severe acanthosis nigricans had higher BMI and fasting insulin levels and lower HDL-C (p < 0.05) than those with acanthosis nigricans that was not severe. HDL-C correlated with BMI Z-score (p = 0.046) and approached significance with fasting insulin. HOMA correlated with BMI (p = 0.0005), with 82.4% of males and 33.3% of females having a HOMA greater than the 90th percentile for normal children. A multiple regression model indicated that acanthosis nigricans severity remained a predictor (p = 0.015) of HOMA after association of BMI Z score, Native American blood quantum, and gender were removed. CONCLUSIONS: These data indicate that among Native American children at high risk for developing type 2 diabetes, acanthosis nigricans is an independent marker of insulin resistance (as reflected by HOMA).
