Objective: To compare association of complement C3 (C3) and high sensitive C-reactive protein (hs-CRP) with insulin resistance.
Subjects: A total of 587 non-diabetic Chinese aged 20-80 years were recruited.
Methods: Complement C3 and hs-CRP were measured by the rate nephelometry method and the particle enhanced immunoturbidimetric method, respectively, and their relationship to insulin resistance was assessed. Insulin resistance was defined as the upper quartile of HOMA2-IR.
Results: Complement C3 and hs-CRP were significantly higher in subjects with insulin resistance than those without. Complement C3 was the second strongest determinant of insulin in the study (β = 0.34, P < 0.001). By regression analysis, C3 was significantly associated with insulin resistance (OR = 3.78, P < 0.05), independent of waist circumference and other metabolic risk factors; however, hs-CRP was not. Receiver operating characteristic curve analysis indicated the best model predicting insulin resistance was one that included C3 and waist circumference (AUC = 0.741, P < 0.05).
Conclusion: Compared to hs-CRP, serum C3 might be a better inflammatory marker of insulin resistance in the non-diabetic Chinese population.