Smoking is one of the main risk factors of Subarachnoid hemorrhage.
Bleeding inside the lining of the brain or subarachnoid hemorrhage is significantly more common among smokers, especially women, a new study has found.
Subarachnoid hemorrhage results from bleeding into the lining between the brain's surface and underlying brain tissue, researchers said.
Although these are more common among women than they are among men, the reasons for this difference were unclear.
While smoking is the main risk factor, researchers have now examined the association between smoking habits and subarachnoid hemorrhage.
"Female sex has been described as an independent risk factor for subarachnoid hemorrhage, but we found strong evidence that the elevated risk in women is explained by vulnerability to smoking," said Joni Valdemar Lindbohm from University of Helsinki in Finland.
"Our results suggest that age, sex and lifestyle risk factors play a critical role in predicting which patients are at risk for subarachnoid hemorrhage and emphasise the importance of effective smoking cessation strategies," said Lindbohm.
Although cigarette smoking was linked to an increased risk of subarachnoid hemorrhage among both sexes, women faced the highest risk.
Researchers found that among light smokers (1 to 10 cigarettes per day), women were 2.95 times more likely to have subarachnoid hemorrhage compared to non-smokers, while men who smoked comparable amounts of cigarettes were 1.93 times more likely.
Women who smoked 11 to 20 cigarettes per day were 3.89 times more likely to have subarachnoid hemorrhage compared to non-smokers, while men who smoked comparable amounts of cigarettes were 2.13 times more likely, researchers said.
Women who smoked 21 to 30 cigarettes per day were more than 8.35 times likely to have subarachnoid hemorrhage compared to non-smokers, while men who smoked comparable amounts of cigarettes were 2.76 times more likely, they said.
The study found that subarachnoid hemorrhage risk significantly decreased among former smokers. Women and men that quit smoking more than six months earlier had comparable risk to non-smokers.
"There is no safe level of smoking. Naturally the best option is never to start. Quitting smoking, however, can reduce the risk for subarachnoid hemorrhage in both sexes," said Lindbohm.
The study participants included 65,521 adults in Finish national surveys. Slightly more than half of participants were women, and their average age was 45 years. The findings were published in the journal Stroke.