Trends in Serum Insulin, C-Peptide and IR Levels in Non-Diabetic Young Adults – A Case Control Study

Background: Insulin resistance (IR), Body Mass Index (BMI), Waist Circumference (WC), Waist to Hip ratio (WHR) at risk levels have been identified as major predisposary factors for the development of Metabolic Syndrome (MS). Objectives: To compare the trends in serum insulin, C-peptide and IR levels in non-diabetic obese and non-obese young adults (20-40 years). Methods: The study was designed as a case control study and was conducted to compare serum parameters and selected anthropometric parameters in obese subjects (n=50) and non-obese subjects (n=50). After obtaining written consent, 100 non – diabetic (fasting blood sugar < 100 mg/ dL) aged between 20-40 years were recruited for the study. The study was conducted at the clinic of Family Medicine, University of Sri Jayewardenepura after obtaining ethical clearance from ethics review committee of University of Sri Jayewardenepura. According to BMI subjects were categorized as obese (BMI ≥ 25 kgm-2) and non-obese (BMI ≤ 25 kgm-2). WC, Hip Circumferences were measured and WHR was calculated. Fasting serum glucose (Glucose oxidase kit), serum insulin and serum C-peptide (ELISA method) levels were measured and IR was calculated according to HOMA-IR equation. Results: Among the parameters assessed; anthropometric parameters WC (p= 0.000) and WHR (P= 0.03) and biochemical parameters IR (P=0.003), fasting serum insulin (P = 0.006), glucose (P = 0.022) and C peptide (P=0.012) showed a significant difference in the obese group when compared to non-obese group. Higher number of hyperinsulinaemic (40%) and IR (38%) subjects were in the obese category compared to non-obese category (Hyperinsulinaemia: 6% and IR: 8%). Conclusions: In healthy non-diabetics, the obese group had significantly higher WC, WHR, IR, serum insulin and C-peptide levels indicating the risk of developing non-communicable diseases. In addition to the known risk factor (WC, WHR, Insulin, and IR) significant elevation of c-peptide in obese individuals might have the potential of being a promising screening tool in obese subjects.