White blood cells count and incidence of type 2 diabetes in young men

Abstract

Objective: Association between white blood cell (WBC) count and diabetes risk has been recently suggested. We assessed whether WBC count is an independent risk factor for diabetes incidence among young healthy adults.

Research design and methods: WBC count was measured in 24,897 young (mean age 30.8 ± 5.36 years), normoglycemic men with WBC range of 3,000 to 12,000 cells/mm(3). Participants were periodically screened for diabetes during a mean follow-up of 7.5 years.

Results: During 185,354 person-years of follow-up, diabetes was diagnosed in 447 subjects. A multivariate model adjusted for age, BMI, family history of diabetes, physical activity, and fasting glucose and triglyceride levels revealed a 7.6% increase in incident diabetes for every increment of 1,000 cells/mm(3) (P = 0.046). When grouped in quintiles, a baseline WBC count above 6,900 cells/mm(3) had an independent 52% increase in diabetes risk (hazard ratio 1.52 [95% CI 1.06-2.18]) compared with the lowest quintile (WBC <5,400 cells/mm(3)). Men at the lowest WBC quintile were protected from diabetes incidence even in the presence of overweight, family history of diabetes, or elevated triglyceride levels. After simultaneous control for risk factors, BMI was the primary contributor of the variation in multivariate models (P < 0.001), followed by age and WBC count (P < 0.001), and family history of diabetes and triglyceride levels (P = 0.12).

Conclusions: WBC count, a commonly used and widely available test, is an independent risk factor for diabetes in young men at values well within the normal range.

Figure 1

Risk factor for diabetes and WBC count in young normoglycemic patients. Q1 to Q5 indicate increment WBC quintiles as they appear in Table 1. The dark bars indicate a significant change compared with the reference group. A: Joint effect of BMI and WBC count and the risk for incident diabetes. Data are adjusted for age, family history of diabetes, activity status, smoking status, blood pressure, triglycerides level, and fasting glucose. The reference group is in the lower WBC quintile at the lower (lean) BMI tertile. B: Joint effect of plasma triglycerides (TG) level and WBC count and the risk for diabetes. Data are adjusted for age, BMI, family history of diabetes, activity status, smoking status, and fasting glucose. Reference group is the lower WBC quintile at a normal (<150 mg/dL) TG level. C: Joint effect of family history of diabetes, WBC count, and the risk for diabetes. Data are adjusted for age, BMI of diabetes, activity status, smoking status, triglycerides level, and fasting glucose. Reference group is the lower WBC quintile without a family history of diabetes.