Objective: White blood cell (WBC) count has been associated with cardiometabolic risk, but the data for African Americans are conflicting. We determined whether WBC count predicts subclinical inflammation and cardiometabolic risk in African Americans, despite their known lower WBC count, compared to Caucasians.
Research design and methods: The study cohort consisted of 334 normoglycemic subjects (153 Caucasian, 181 African American) with parental type 2 diabetes (T2DM), mean (+/- SD) age 43.90 +/- 10.25 y and BMI 30.1 +/- 6.84 kg/m2. Each subject underwent clinical examination and a standard oral glucose tolerance test (OGTT) to document glycemic status. Blood specimens were obtained for determination of WBC counts, lipid profile and C-reactive protein (CRP) levels. Metabolic syndrome components were identified, using the NCEP cut-offs for waist circumference, blood pressure, HDL cholesterol and triglyceride levels.
Results: Leukocyte counts were lower by approximately 400/cm3 (P=.04) in African Americans than Caucasians, and were significantly correlated with waist circumference, HDL cholesterol, triglycerides and 2-h OGTT plasma glucose (P=.024-.0009), but not blood pressure in both races. Leukocyte counts significantly predicted the presence of three or more components of the metabolic syndrome similarly in African Americans (P=.0076) and Caucasians (P=.0078), as did CRP levels. Leukocyte counts correlated significantly with CRP levels in African Americans (r=.30, P<.0001) and Caucasians (r=.29, P=.0003).
Conclusions: Our data indicate that WBC count, despite being lower in African Americans than Caucasians, predicts low-grade inflammation and cardiometabolic risk with similar magnitude in normoglycemic African Americans and Caucasians with parental T2DM.