Smoking doubles risk of atrial fibrillation

Results from a large, United States based cohort study show that current smokers double their risk of developing atrial fibrillation (AF) compared to people who have never smoked, after more than 13 years of follow-up.  The study, published in the August edition of HeartRhythm, the official journal of the Heart Rhythm Society, indicates a trend towards significantly lower risk of developing AF for those who quit smoking cigarettes versus those who continue to smoke.

According to the Heart Rhythm Society, AF is a very common heart rhythm disorder with more than 2 million people in the United States diagnosed with AF and about 160,000 new cases identified each year.  While several risk factors have been identified for AF, including obesity, hypertension and diabetes, the association between smoking and AF is less clear.

Between 1987 and 1989, the Atherosclerosis Risk in Communities (ARIC) study enrolled a population-based cohort of over 15,000 black and white participants aged 45-64 years.  All participants were questioned at baseline about the number of cigarettes smoked per day, smoking status (current, former or never) and age at smoking initiation or cessation.

Study analysis conducted by Alanna Chamberlain, PhD, and co-authors, reports 876 incident AF events during an average 13-year follow-up period.  The risk of AF was found to be 1.32 times greater among former smokers and twofold higher in current smokers than in never smokers.  In addition, compared to never smokers, former heavy smokers had an 89% increased risk of developing AF, while current heavy smokers had a 131% increased risk, indicating that quitting smoking lowers the risk of developing AF.  Specifically, there was a 12% lower risk of AF among individuals who quit smoking versus individuals who continued smoking.

“AF is a serious health issue that decreases quality of life and significantly increases the risk of stroke,” stated co-author Alanna M. Chamberlain, PhD, MPH, Department of Health Sciences Research at Mayo Clinic in Rochester, Minnesota. “It is my hope that our study findings will shed more light on the impact that smoking has on cardiovascular diseases, and help individuals realize they can play a role in preventing the development of atrial fibrillation.”

These results support previous findings that smoking increases the risk of AF development.  The findings also show that associations between smoking and AF do not differ between blacks and whites, despite overall AF incident rates being lower in blacks.  Furthermore, this is the first study to document differences in AF development between participants who remained smokers throughout the study follow-up and those who stopped smoking.  Future studies may choose to focus on the role of smoking cessation in the prevention of AF development.

For more information about this study, please visit www.heartrhythmjournal.com.