Examination of the Cross-Sectional Association between Insulin Resistance (HOMAIR) and an Inflammatory Marker (CRP) in a Representative Canadian Non-Diabetic Population

Abstract

Background: Insulin resistance (IR) can contribute to the development of type 2 diabetes. Asymptomatic individuals with high insulin resistance benefit from early interventions to prevent the progression to overt diabetes. Multiple causes of IR have been identified, many of which are reversible. It has been suggested that inflammation may contribute to IR. Our study aims to determine the association between insulin resistance and the inflammatory marker C - reactive protein (CRP) in the non-diabetic Canadian population and, furthermore, to examine potential differences in this association by gender, age, and at different serum levels of glucose and HbA1c. Methods: We examined 2963 non-diabetic adults who participated in the Canadian Health Measures Survey, which is a national cross-sectional survey of the general Canadian population. Insulin resistance was calculated by HOMAIR. Individuals with an acute or chronic condition or those who were taking a platelet aggregation inhibitor or HMG-CoA reductase inhibitor were excluded because it can interfere with CRP levels. A cut off level of 3mg/L was used to define high and low CRP. Multiple linear regression was performed for statistical analysis. Results: After adjusting for age, race, sex, smoking history, blood pressure, triglyceride, LDL, HDL, BMI, waist circumference and hip circumference, the insulin resistance, as reported by HOMAIR, was greater with high levels of CRP. HOMAIR for low and high CRP were 1.59 (95% CI: 1.51-1.61) and 2.76 (2.41-3.11) respectively in age group 18-30, 1.60 (1.55-1.65) and 2.58 (2.42-3.2.75) in age group 31-45 years, 1.68 (1.62-1.74) and 2.66 (2.47-2.86) in age group 46-60 years, and 1.82 (1.74-1.90) and 2.44 (2.26-2.62) in age group 61 and older. The results were statistically significant (P<0.01). Insulin resistance was also elevated with high CRP in both men and women. HOMAIR in men was 1.81 (1.77-1.86) and 2.88 (2.72-3.06) with low and high CRP respectively (p<0.05). Whereas in women it was 1.48 (1.44-1.51) and 2.43 (2.29-2.57) with low and high CRP respectively (p<0.05). Adjusted HOMAIR was also positively associated with CRP independent of the level of fasting glucose and HbA1c level. Conclusion: Our study demonstrated a significant and positive association between insulin resistance and inflammatory markers in the Canadian population. Future studies are needed to confirm our findings and determine role of anti-inflammatory drugs in the prevention of diabetes.