Decreased serum monocytes and elevated neutrophils as additional markers of insulin resistance in type 1 diabetes

Insulin resistance contributes to the high risk for cardiovascular diseases in type 1 diabetes. The differential white blood cell counts predict the future incidence of coronary artery disease. The study evaluated the associations of differential white blood cell count with insulin resistance in type 1 diabetic patients. Study included 353 patients with type 1 diabetes. Insulin sensitivity was measured by estimated glucose disposal rate (eGDR) calculated with the equation: eGDR = 24.31-(12.22xWHR)-(3.29xHT)-(0.57xHbA1c). The units were mgkg⁻¹ min⁻¹; WHR (waist to hip ratio); HT (hypertension). Monocyte count significantly correlated with insulin resistance measured by eGDR (r = 0.10, P = 0.04). Subjects in the upper quartile of the eGDR (>10.87 mgkg⁻¹ min⁻¹) had significantly higher levels of monocyte count (median 6.2 vs 5.4 %, P = 0.02), compared to those in the lowest quartile of eGDR (<7.82 mgkg⁻¹ min⁻¹). In a multiple logistic regression models adjusted for age, sex, duration of diabetes and BMI, monocyte and neutrophil levels were significantly associated with risk of insulin resistance in our subjects (OR = 0.79, and 1.03, P < 0.05). The odd ratios for insulin resistance decreased across baseline monocyte quartiles: 1, 0.75, 0.69, and 0.34. In contrast, odd ratios for insulin resistance increased across baseline neutrophil quartiles: 1, 0.95, 1.60 and 1.99. The significant independent association of monocytes and neutrophils with insulin resistance suggests that activation of the immune system may play a role in the pathogenesis of insulin resistance in type 1 diabetes.