White blood count as a predictor of glucose tolerance and insulin sensitivity:: the role of inflammation in the pathogenesis of type 2 diabetes

Background and objective: Chronic subclinical activation of the immune system is probably involved in the pathogenesis of type 2 diabetes. In the present study we examined whether an association exists between a non-specific inflammatory marker such as white blood count (WBC) and factors relevant to the pathogenesis of type 2 diabetes. Patients and methods: The statistical association between WBC and glucose tolerance, insulin secretion and insulin sensitivity estimated in an oral glucose tolerance test (OGTT, n = 607) or measured during an euglycemic clamp (N = 280) was determined in non-diabetic individuals. Results: WBC was positively correlated with body weight (r = 0.32, p < 0.001) and postprandial (2-hour) blood glucose during the OGTT (r=0.22, p < 0.001) independent of sex, age and percentage body fat. WBC negatively correlated with insulin sensitivity both measured by the euglycemic clamp (r = -0.23, p < 0.001) and estimated from the OGTT (r = -0.34, p < 0.001). This relationship remained significant upon adjusting for sex, age and percentage body fat. No relationship between WBC and insulin secretion independent of percentage body fat and insulin sensitivity was found (p = 0.95). Conclusion: An increase in WBC is associated with deterioration of glucose tolerance. This is mostly explained by reduced insulin sensitivity. These results are compatible with the hypothesis that chronic subclinical inflammation is involved in the pathogenesis of type 2 diabetes.