Seoul, Aug 28 (IANS): Scientists have urged people with atrial fibrillation -- the most common heart rhythm disorder -- to quit smoking if they want to reduce stroke risk.

Previous studies have shown that smokers are more likely to develop atrial fibrillation and subsequent stroke.

"Smoking precipitates blood clots that could lead to a stroke, which may be why giving up lowers risk," said study author So-Ryoung Lee from the Seoul National University Hospital in South Korea.

"The remaining stroke risk after quitting might be through the damage already caused to the arteries -- called atherosclerosis," Lee added.

The study, presented at ESC Congress 2020 - The Digital Experience, examined the association between smoking cessation after newly diagnosed atrial fibrillation and the risks of stroke and all-cause death.

The researchers included the 97,637 Korean patients who had a national health check-up less than two years before being diagnosed with atrial fibrillation, and a second check-up within two years afterwards.

Patients were followed-up after the second check-up until the end of 2017 for the occurrence of stroke or death.

The average age was 61 years and 62 per cent were men.

Participants were classified according to smoking status before and after atrial fibrillation diagnosis: never-smoker, ex-smoker, quitter, current smoker.

The proportion of never smokers, ex-smokers, quitters, and current smokers was 51.2 per cent, 27.3 per cent, 6.9 per cent, and 14.6 per cent, respectively.

During a median three-year follow-up, there were 3,109 strokes and 4,882 all-cause deaths (10.0 per 1,000 person-years and 15.4 per 1,000 person-years, respectively).

Compared to current smokers, the findings showed that quitters had a 30 per cent lower probability of stroke and 16 per cent reduced likelihood of all-cause death.

According to the study, quitters remained at a higher risk compared with never-smokers.

The risks of stroke and all-cause death were raised by 19 per cent and 46 per cent, respectively, but these associations were consistently observed only in men.

New and persistent smokers had even greater risks of stroke compared to those who had never smoked. For new smokers, the probability was raised by 84 per cent and for persistent smokers it was elevated by 66 per cent.

The researchers noted that the benefits of quitting were less pronounced in those who had been heavy smokers before their atrial fibrillation diagnosis.