Elevated white blood cell count in subjects with impaired glucose tolerance

OBJECTIVE - Impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) differ in their risk of all-cause and cardiovascular mortality, but previous cross-sectional studies have suggested little difference in their levels of lipids or blood pressure. We compared the white blood cell (WBC) count between subjects with IFG and IGT. RESEARCH DESIGN AND METHODS - The subjects were 4,720 nondiabetic Japanese men aged 24-84 years. Based on the 75-g oral glucose tolerance test, the subjects were classified into the following four groups: normal fasting glucose/normal glucose tolerance (n = 3,753), isolated IFG (n = 290), isolated IGT (n = 476), and IFG/IGT (n = 201). We compared the WBC count among the four groups and investigated variables that showed a significant association with the WBC count. RESULTS - The isolated IGT group had a significantly higher WBC count than the isolated IFG group (6,530 vs. 6,210/mm(3), P < 0.05). By stepwise analyses, age, triglycerides, HDL cholesterol, fasting insulin, and 2-h postchallenge plasma glucose (PG) showed an independent association with the WBC count (adjusted R-2 = 0.057). In the analysis stratified by smoking status, the WBC count was independently associated with 2-h PG and triglycerides, irrespective of smoking status. CONCLUSIONS - Individuals with isolated IGT had a significantly higher WBC count than those with isolated IFG. The WBC count was associated with 2-h PG and various components of the metabolic syndrome.