Smoking and risk of atrial fibrillation in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study

• Type of Material: Article
• Authors: Muhammad Imtiaz Ahmad, Wake Forest School of Medicine; Candice D. Mosley, University of Alabama Birmingham; Wesley T. O'Neal, Emory University; Suzanne Judd, Emory University; Leslie A. McClure, Drexel University; Virginia J. Howard, University of Alabama Birmingham; George Howard, University of Alabama Birmingham; Elsayed Z. Soliman, Wake Forest School of Medicine
• Language: English
• Date: 2018-02-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2017 Japanese College of Cardiology
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.jjcc.2017.07.014
• Title of Journal or Parent Work: Journal of Cardiology
• ISSN: 0914-5087
• Volume: 71
• Issue: 2
• Start Page: 113
• End Page: 117
• Grant/Funding Information: This research project is supported by a cooperative agreement U01NS041588 from National Institute of Neurological Disorders and Stroke, National Institutes of Health, Department of Health and Human Service.; WTO is supported by the National Heart, Lung, And Blood Institute of the National Institutes of Health under award F32HL134290.
• Keywords: Smoking; Humans; African Continental Ancestry Group; Cohort Studies; Aged; Electrocardiography; Atrial Fibrillation; Atrial fibrillation; Female; REGARDS study; Middle Aged; Male; Prevalence; Risk Factors
• Research Categories: Health Sciences, Medicine and Surgery; Health Sciences, Epidemiology

Abstract

Background: Whether smoking increases the risk of atrial fibrillation (AF) remains debatable due to inconsistent reports. Methods: We examined the association between smoking and incident AF in 11,047 participants from the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study, one of the largest biracial, population-based cohort studies in the USA. Baseline (2003–2007) cigarette smoking status and amount (pack-years) were self-reported. Incident AF was determined by electrocardiography and history of a prior physician diagnosis at a follow-up examination conducted after a median of 10.6 years. Results: During follow-up, 954 incident AF cases were identified; 9.5% in smokers vs. 7.8% in non-smokers; p < 0.001. In a model adjusted for socio-demographics, smoking (ever vs. never) was associated with a 15% increased risk of AF [OR (95%CI): 1.15(1.00, 1.31)], but this association was no longer significant after further adjustment for cardiovascular risk factors [OR (95% CI): 1.12 (0.97, 1.29)]. However, heterogeneities in the association were observed among subgroups; the association was stronger in young vs. old participants [OR (95%CI): 1.31 (1.03, 1.67) vs. 0.99 (0.83–1.18) respectively; interaction p-value = 0.005] and in those with vs. without prior cardiovascular disease [OR (95%CI): 1.18 (0.90, 1.56) vs. 1.06 (0.90, 1.25) respectively; interaction p-value 0.0307]. Also, the association was significant in blacks but not in whites [OR (95%CI): 1.51 (1.12, 2.05) vs. 0.99 (0.84, 1.16), respectively], but the interaction p-value did not reach statistical significance (interaction p-value = 0.65). Conclusions: The association between smoking and AF is possibly mediated by a higher prevalence of cardiovascular risk factors in smokers, but there is marked heterogeneity in the strength of this association among subgroups which may explain the conflicting results in prior studies.