White Blood Cell Count and Incidence of Coronary Heart Disease and Ischemic Stroke, and Mortality from Cardiovascular Disease in African-American and White Men and Women: The Atherosclerosis Risk in Communities Study
Objective: To investigate the association between white blood cell (WBC) count and incidence of coronary heart disease (CHD) and ischemic stroke, and mortality from cardiovascular disease (CVD) in African-American and White men and women. Methods: We followed 13,555 African-American and white men and women, ages 45 to 64 years, who had a WBC count assessed at baseline. There were 488 incident CHD events, 220 incident strokes, and 258 deaths from CVD during an average of 8 years of follow-up. Results: After adjustment for age, sex, and ARIC field center, there was a direct association between WBC count and incidence of CHD (P <0.001 for trend) and stroke (P for trend <0.001), and mortality from CVD (P for trend <0.001) in African Americans. This association remained but was attenuated after further adjustment for multiple risk factors. The African Americans in the highest quartile of WBC count (≥7,000 cells/mm 3 ) had 1.9 times the risk of incident CHD (95% CI, 1.19, 3.09, P = 0.008), 1.9 times the risk of incident ischemic stroke (95% CI, 1.03, 3.34, P = 0.04), and 2.3 times the risk of CVD mortality (95% CI, 1.38, 3.72, P = 0.001) than did their counterparts in the lowest quartile of WBC count (<4,800 cells/mm 3 ). These associations were similar in whites and in never-smokers. Conclusions: An elevated WBC count is directly associated with increased incidence of CHD and ischemic stroke, and mortality from CVD in African-American and White men and women.