Abstract

To study the sensitivity of body mass index (BMI), waist circumference (WC) and Acanthosis Nigricans (AN) to recognize insulin resistance in children, A cross-sectional school-based study was conducted in a semi-rural environment in the Kerala state of India. A total of 283 children between the ages of 10 to 17 were evaluated. The selected children underwent clinical evaluation which included measurement of height, weight, waist circumference and blood pressure. Acanthosis nigricans was recorded as present or absent on close visual inspection of neck area. Fasting blood samples were collected to determine blood sugar, Insulin and lipids.  Associations were summarized using cross-tabulations and analyzed using SPSS package, version 10.1.  The prevalence of insulin resistance was 35%, which was estimated using homeostasis model assessment of insulin resistance (HOMA-IR). Among the children studied, 30% had waist circumference above 75^th percentile and 18.7% had BMI above 85^th percentile. Acanthosis nigricans was diagnosed in 39.6% of the study population. Significantly high prevalence of insulin resistance was noticed among the children either with waist circumference exceeding 75^th percentile or with BMI more than 85^th percentile or the ones with Acanthosis Nigricans. The most sensitive physical marker of insulin resistance was acanthosis nigricans (90%) and the most specific was BMI (91%). The sensitivity of these parameters can be increased to 94% and negative predictive value to 96% by combining them together. Easily identifiable physical markers can effectively predict insulin resistance among children. This would be of relevance to many South Asian countries where resources are scarce, but the insulin resistance and the associated diabetes mellitus and cardiovascular morbidity are highly prevalent and is increasing exponentially. We should look into the possibilities of designing simple screening programs for early identification of at-risk children, which would be helpful in implementing strategies to reverse these metabolic changes at an early stage.

Key words: Risk factors, diabetes, insulin resistance, acanthosis nigricans, body mass index (BMI), waist circumference.