Association of TNF-alpha with insulin resistance in type 2 diabetes mellitus

Background & objectives: TNF-alpha is an adipocytokine that has been implicated in the development of insulin resistance. Dysregulation of TNF-alpha production has been implicated in a variety of human diseases including type 2 diabetes mellitus. We aimed to find out the association of TNF-alpha levels with insulin resistance, body mass index and waist hip ratio; and to elicit its role with respect to duration of the disease, if any. Methods: 50 type-2 diabetic patients attending Narayana Medical Hospital, Nellore, were studied. Body mass index and Waist hip ratio were calculated. Homeostasis model assessment method was used to calculate insulin resistance (HOMA IR) and per cent beta cell function (HOMA B). Insulin was estimated by chemiluminescence method and TNF-alpha by ELISA method. The subjects were arbitrarily categorized into three groups based on duration of diabetes. Group 1 included subjects with diabetes of less than 5 yr duration, group 2 included diabetics of 6-10 yr duration and group 3 greater than 10 yr duration. Results: Our study revealed a significant correlation between TNF-alpha levels and BMI (P=0.006), the correlation being stronger in males when compared to females. A significant correlation was found between per cent beta cell function and TNF-alpha (P=0.008). TNF-alpha correlated significantly with HOMA IR, HOMA B and insulin, in group 2 diabetes. Interpretation & conclusions: Our results suggest the possible role of TNF-alpha in the pathogenesis of type-2 diabetes mellitus and the importance of reducing obesity to prevent elevated levels of the cytokine and related complications.