The white blood cell count: its relationship to plasma insulin and other cardiovascular risk factors in healthy male individuals

OBJECTIVES: To evaluate the relationships of total and differential white blood cell (WBC) count to the components of the so-called insulin resistance syndrome. SUBJECTS AND DESIGN: The study population consisted of a random sample of 90 38-year-old healthy men with normal glucose tolerance. INTERVENTIONS: A 75 g oral glucose tolerance test was performed in all participants. MAIN OUTCOME MEASURES: Total and differential WBC count, lipids, blood pressure, plasma glucose, C-peptide and insulin (at fasting and 2 h after glucose load). RESULTS: Total WBC count correlated consistently with plasma 2-h glucose (r = 0.38; P < 0.001), fasting and 2-h postload insulin (r = 0.26 and r = 0.33; P < 0.01-0.001, respectively) and C-peptide (r = 0.28 and r = 0.32; P < 0.01-0.001) concentrations. Smokers had significantly higher total leukocytes (P < 0.01), neutrophils and lymphocytes than nonsmokers. Furthermore, total WBC count correlated positively with body mass index, blood pressure, plasma triglycerides, fibrinogen, and negatively with HDL cholesterol concentration. As differential WBC count, most variables correlated essentially to neutrophils and/or lymphocytes, whereas plasma insulin and C-peptide concentrations correlated essentially to lymphocytes and monocytes, but not to neutrophils. In a multiple linear regression analysis, only 2-h plasma glucose (P < 0.01) and fibrinogen (P < 0.05) were positive predictors of total WBC count after adjusting for all potentially confounding variables. CONCLUSIONS: The results indicate that increased, albeit normal, WBC count associates with the cluster of metabolic and haemodynamic disorders typical of the insulin resistance syndrome, and suggest that increased WBC count may be yet another component of this syndrome.