London: Smoking more than 20 cigarettes a day almost triples the chances of suffering a potentially fatal brain haemorrhage, a new study has warned.
The study found that quitting reduces the danger but heavy smokers who give up tobacco are still twice as much at risk as people who have never smoked.
Korean researchers investigated 426 cases of subarachnoid haemorrhage (SAH) between 2002 and 2004, the `Daily Mail` reported.
Patients were compared with a group of 426 people and matched for age and sex who had never experienced a brain bleed.
SAH occurs when a bulge in a weakened artery, called an aneurysm, bursts in the brain.
The chances of surviving are only about 50 percent, and victims who live often face a lifetime of disability.
Study participants who smoked were more likely to have suffered an SAH than non-smokers, scientists found.
The more people smoke, the more at risk they were. After adjusting for other factors such as salt intake, weight and family history of diabetes, smokers were on average 2.84 times more likely to have a brain haemorrhage as non-smokers.
Giving up tobacco for at least five years dramatically reduced the overall risk to 59 percent.
But people with a history of heavy smoking - defined as smoking 20 or more cigarettes a day - were still 2.3 times more likely to have an SAH than those who had never smoked.
"We have demonstrated that cigarette smoking increases the risk of SAH, but smoking cessation decreases the risk in a time dependent manner, although this beneficial effect may be diminished in heavy smokers," researchers, led by Dr Chi Kyung Kim, from Seoul National University Hospital, said.
"To forestall tragic SAH events, our results call for more global and vigorous efforts for people to stop smoking," they said.
Previous research has indicated that the risk of an aneurysm in former smokers disappears after 10 to 15 years. However, these studies were considered too limited or small to draw reliable conclusions.
The study was published in the Journal of `Neurology, Neurosurgery and Psychiatry`.