The condition, also known as AF, is the most common heart arrhythmia in the United States, affecting about 2 million people.
During an episode of AF, abnormal electrical activity in the heart causes its upper two chambers to beat in a rapid, uncoordinated rhythm; the arrhythmia itself is not life-threatening, but over time AF can contribute to stroke or heart failure in some people.
While smoking is a well-known risk factor for heart disease, it has not been clear whether the habit boosts the risk of AF specifically.
The new findings, reported in the American Heart Journal, suggest that it does -- even after a smoker quits.
Researchers found that of nearly 5,700 Dutch adults age 55 and older, current smokers and former smokers were about 50 percent more likely to develop AF over 7 years.
The bottom line, lead researcher Jan Heeringa said, is that AF "has to be added to the long list of diseases" linked to smoking.
"An independent effect of smoking on atrial fibrillation has never been found, until now, in our study," noted Heeringa, of Erasmus Medical Center in Rotterdam, the Netherlands.
