Aim: White blood cell (WBC) count or C-reactive protein (CRP) level alone may not fully indicate the chronic inflammation causing type 2 diabetes. We examined both WBC count and CRP level, independently and in combination, as predictive markers for type 2 diabetes and also considered the influence of obesity and other individual characteristics on the relationship. Materials and Methods: In total, 9,706 participants were enrolled with WBC < 10*109/L and CRP < 10 mg/L using data from the Yuport Medical Checkup Center Study. The cumulative incidence of type 2 diabetes [defined either as known diabetes, fasting plasma glucose ≥ 7.0 mmol/L, or HbA1c ≥ 6.5% (47.5 mmol/mol)] was measured. Hazard ratios (HRs) were estimated using a Cox proportional hazards model. Results: During study period, 272 men (5.5%) and 113 women (2.4%) progressed to diabetes. The progression to diabetes was predicted by both increased baseline levels of WBC count [adjusted HR = 1.29 (95% CI: 1.04-1.60)] and CRP level [1.39 (1.10-1.74)], even after adjusting for possible confounders. The combined presence was more predictive of diabetes than either alone in a four-groups analysis [1.75 (1.28-2.40)]. In addition, the elevated HRs of either or both higher WBC and CRP levels were observed across four subgroups of body mass index (BMI), including low BMI, and people who had at least one occurrence of dyslipidemia. Conclusion: Increased WBC counts and CRP levels were predictive for type 2 diabetes and the combination augmented the risk of diabetes, regardless of whether the BMI was high or low.
Keywords: C-reactive protein; Type 2 diabetes mellitus; body mass index; chronic inflammation; white blood cell count.