White Blood Cell Count and Risk of Incident Atrial Fibrillation (From the Framingham Heart Study)

Abstract

Several studies have reported that inflammatory markers are associated with atrial fibrillation (AF). White blood cell (WBC) count is a widely available and broadly utilized marker of systemic inflammation. We sought to investigate the association between increased WBC count and incident AF, and whether this association is mediated by smoking, myocardial infarction and heart failure. We examined participants in the Framingham Heart Study Original Cohort. Cox proportional hazard regression analysis was used to examine the relation between WBC count and incident AF over 5-year follow-up period. We adjusted for standard AF risk factors, and smoking, previous myocardial infarction, as well as interim myocardial infarction and heart failure prior to incident AF. Our sample consisted of 936 participants, mean age was 76±6 years and 61% were women. Median WBC count was 6.4*109/L (25th-75th percentile 5.6*109/L- 7.8*109/L). During a median follow-up of 5 years, 82 participants (9%) developed new-onset AF. After adjusting for standard risk factors for AF, increased WBC count was significantly associated with incident AF, with a hazard ratio per standard deviation (0.26*109/L) increase of 2.22, (95% confidence interval, 1.10–4.48; P=0.03). We found no substantive differences adjusting for smoking, previous myocardial infarction, interim myocardial infarction and heart failure. In conclusion, in our community-based sample, increased WBC count was associated with incident AF during 5-years of follow-up. Our findings provide additional evidence for the relation between systemic inflammation and AF.

Clinical Analysis of Association of Cystatin C and Atrial Fibrillation

“…It was demonstrated that atrial fibrillation is closely associated with inflammation regardless of the duration of atrial fibrillation. However, this study showed no significant relationship between white blood cell count and risk of incident atrial fibrillation, which differs from the result of the Framingham Heart Study [19].…”

EHRA/HRS/APHRS/SOLAECE expert consensus on atrial cardiomyopathies: definition, characterization, and clinical implication

“…268 Subsequent studies have demonstrated relationships between several different serologic markers of inflammation and AF, including IL-6, 269 TNF-a, 270 aldosterone 271 and simple white blood cell counts. 272 Analyses of multiple inflammatory biomarkers within the same study have suggested that IL-6 and osteoprotegerin 273 may be especially important. The relationship between IL-6 and AF may be mediated by left atrial enlargement.…”

A score of low-grade inflammation and risk of mortality: prospective findings from the Moli-sani study

“…6,[13][14][15][16] More recently, a pro-inflammatory action of blood platelets has been proposed, 17 whereas the neutrophil-to-lymphocyte ratio better expresses an early inflammatory cellular response. 18,19 Evidence of the individual contribution of each of the above mentioned inflammatory biomarkers to different health outcomes is scarce.…”