Endocrine Abstracts

Introduction: Insulin resistance (IR) is a fundamental defect in type 2 diabetes mellitus (T2DM) which is reported to be associated with other components of the metabolic syndrome including obesity and atherogenic dyslipidaemia. Routine measurement of insulin resistance in clinical practice is not practical, but other routinely measured clinical variables could predict the presence of IR. We aimed to determine the association of IR with obesity indices and lipid parameters in Nigerian patients with T2DM.

Patients and methods: One hundred and ten patients with T2DM who were not on insulin therapy were included in the study. Anthropometric indices including weight, height, waist and hip circumference were measured. We also measured fasting serum insulin (ELISA), fasting blood glucose and lipid profile. Insulin resistance was calculated using the Homeostasis Model Assessment for IR (HOMA-IR). Correlational analysis and linear regression was used to determine the association of IR with waist circumference and obesity indices.

Results: The mean age of the study subjects was 60.9±9.7 years and 69.1% were females. The mean±S.D. of body mass index (BMI), waist circumference (WC) and waist-hip-ratio (WHR) were 27.1±5.0 kg/m², 95.3±10.3 cm and 0.97±.07 respectively. The median (range) HOMA-IR was 1.65 (0.50–7.00). IR had a positive correlation with BMI (r=0.26, P=0.007), waist circumference (r=0.28, P=0.003), but not with WHR (r=0.075, P=0.433). IR was also positively correlated with serum triglycerides (r=0.28, P=0.03), but not with, total cholesterol, HDL, LDL cholesterol or estimated GFR. On linear regression analysis, serum triglycerides remained associated with IR (log₁₀), independently of waist circumference or BMI.

Conclusion: Insulin resistance increased with WC, BMI and serum triglycerides. WC and BMI are better indices of IR compared to WHR.