London: Women indulging in smoking are more at risk of developing bleeding inside the lining of the brain, also known as subarachnoid hemorrhage, a study has warned. Subarachnoid hemorrhage is a condition of bleeding in the lining between the brain's surface and underlying brain tissues. The findings showed that although cigarette smoking was linked to an increased risk of subarachnoid hemorrhage among both sexes, women faced the highest risk. "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 lead author Joni Valdemar Lindbohm, Physician at the University of Helsinki in Finland. Further, 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. 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. "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," Lindbohm explained. However, quitting smoking has been found to significantly decrease the risk among former smokers. "There is no safe level of smoking," Lindbohm said, adding "naturally the best option is never to start. Quitting smoking, however, can reduce the risk for subarachnoid hemorrhage in both sexes." In addition, subarachnoid hemorrhage also accounts for three per cent of all strokes, according to the American Heart Association. Smoking is perhaps the most important modifiable risk factor in preventing subarachnoid hemorrhage, with the highest population attributable risk of any subarachnoid hemorrhage risk factor, the researchers noted. For the study, published in the journal Stroke, the team included 65,521 adults from Finish national surveys. Slightly more than half of participants were women, and their average age was 45 years. The average follow-up was 21 years from study enrolment until first stroke, death or study completion on December 31, 2011.