DETERMINATION OF INSULIN RESISTANCE AND BETA CELL FUNCTION IN HEALTHY OBESE AND NON-OBESE INDIVIDUALS

Abstract

Background: Insulin resistance is the basic metabolic disorder associated with obesity. Beta cell function is closely related with insulin resistance. Little is known about insulin resistance and beta cell function in healthy obese and non-obese local population.
Objective: To determine insulin resistance and beta cell function in healthy obese and nonobese individuals of the local population.
Study Design: Case control study
Place andDuration of Study: AFIP Rawalpindi in collaboration with Department of Medicine Military Hospital (MH) Rawalpindi, from Aug 2008 to Mar 2009.
Methods: Eighty obese (n=40) and non-obese (n=40) subjects were selected by non-probability convenience sampling. Plasma insulin, glucose, and serum total cholesterol were estimated in fasting state. Insulin resistance was calculated by HOMA-IR and beta cell function by HOMA-β equation.
Results: Significant differences were observed between obese and non-obese individuals regarding insulin resistance, beta cell function, and BMI and serum total cholesterol. Mean insulin resistance in obese group was found to be 11.1 ± 5.1(range 7.0-16.2) and in non-obese group it was 0.9± 0.4 (range 0.5-1.3). This difference was highly significant (p=0.001). There was a highly significant difference between the two groups in term of beta cell function with mean rank 60.1 for obese group and 20.9 non obese groups (Asym sig. 2 tailed 0.000). Also the correlation (r = 0.064) between insulin resistance and beta cell function in obese group is highly significant (p = 0.000). Mean serum leptin levels were lower (6.3 ng/ml) in non-obese, and high (57.2 ng/ml) in the obese group.
Conclusions: Insulin resistance is found higher in obese individuals. Beta cell function is significantly different between obese and non obese groups.