[Obese children with benign acanthosis nigricans and insulin resistance: analysis of 19 cases]

The prevalence of obesity and of type 2 diabetes mellitus in children have increased in the Chinese population over the past two decades, and thus diabetes prevention has become a major concern of public health agencies. Identification of individuals at risk for diabetes is an essential first step in designing and implementing intervention programs. Insulin resistance is the hallmark of the pathophysiology of type 2 diabetes mellitus. Subjects with hyperinsulinemia and impaired glucose tolerance are well accepted as being at high risk for diabetes. Acanthosis nigricans (AN) has been proposed as a reliable marker of hyperinsulinemia, but its utility for predicting hyperinsulinemia has not been systematically evaluated in obese children. In order to further explore the relationship between obese childhood with benign acanthosis nigricans and insulin resistance and type 2 diabetes mellitus, we examined 19 obese children with benign acanthosis nigricans.

Nineteen of seventy six obese children (25%) with BMI over 25 enrolled in the Children' Hospital of Zhejiang University School of Medicine fromJune 1st to September 1st in 2003 were studied. Skin biopsies were performed in these 19 obese children with acanthosis nigricans for final diagnosis. Levels of glucose, insulin, and glucose/insulin ratio were measured on fasting blood specimens and anthropometric parameters including waist/hip ratio, fat mass, body fat percentage and body mass index were examined. Oral glucose tolerance tests were also performed in these 19 children with benign acanthosis nigricans.

Anthropometric parameters including waist/hip ratio, fat mass, body fat percentage and body mass index as well as fasting insulin level in acanthosis nigricans group were significantly higher than that of healthy controls (P < 0.01). Fasting glucose to insulin ratio (FGIR) of these 19 obese children with benign acanthosis nigricans was 4.27 +/- 0.53, indicating apparent insulin resistance. One of them was diagnosed as type 2 diabetes mellitus and ten of them showed impaired oral glucose tolerance.

Childhood benign acanthosis nigricans is tightly associated with obesity, hyperinsulinemia, insuline resistance and type 2 diabetes mellitus, and may be used as a reliable index of insulin resistance.