Abstract MP43: Association of White Blood Cell Count and Differential with the Incidence of Atrial Fibrillation: The Atherosclerosis Risk in Communities Study
Introduction: White blood cell (WBC) count was associated with incident atrial fibrillation (AF) in a small, community-based study. To date, the association of WBC count and differential with AF in a large cohort with extended follow-up has not been investigated.
Hypothesis: Individuals with higher WBC count will have an increased risk for AF, and it will be due to an increased risk of AF associated with higher granulocyte levels.
Methods: At baseline (1987-89), 14,500 men and women (75% white, 55% women, mean age 54) with available total WBC count and differential were free of AF from the Atherosclerosis Risk in Communities (ARIC) study, a biracial community-based cohort in the United States. Incident AF cases through 2009 were identified from electrocardiograms, hospital discharge codes, and death certificates. Cox proportional hazards regression was used to estimate hazard ratios and 95% confidence intervals for AF associated with WBC count and differential as quintiles and as a linear variable per one-unit standard deviation. The model was adjusted for age, sex, race, ARIC field center, cardiovascular risk factors and prevalent cardiovascular disease (CVD). Interactions by race and sex were tested.
Results: Over a median follow-up time of 20.6 years, 1,776 participants had incident AF. Higher total WBC count was associated with higher AF risk independent of CVD risk factors and baseline CVD (table). Also, higher granulocyte and monocyte counts were positively associated with AF risk while an inverse association was identified between lymphocyte count and AF after adjustment. No association was identified between eosinophils or basophils and AF. No significant interaction by sex or race was seen in any of these models.
Conclusion: High total WBC count, granulocyte count, and monocyte count were each associated with higher AF risk while there was an inverse association between lymphocyte count and AF risk. Systemic inflammation may underlie this association and requires further investigation for strategies to prevent AF.
- © 2013 by American Heart Association, Inc.