Women who smoke have increased risk of brain bleeds

by Bruce Sylvester: Researchers report that bleeding inside the lining of the brain, subarachnoid hemorrhage, happens at a significantly higher rate among smokers, especially female smokers, than among non-smokers. The findings appeared on July 21, 2016 in the journal Stroke.

“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 investigator Joni Valdemar Lindbohm, M.D., a physician in neurosurgery and public health at the 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 emphasize the importance of effective smoking cessation strategies.”

Subjects included 65,521 adults in Finish national health surveys which have, since 1972, obtained health information from randomly selected participants through questionnaires and physical examinations. Just over 50 percent of the subjects were women, with an average age was 45 years at enrollment.

Average follow-up was 21 years from enrollment until first stroke, death or end of study on December 31, 2011.

While cigarette smoking correlated to increased risk of subarachnoid hemorrhage among men and women, the highest increased risk was among women .

Specifically, among light smokers (1 to 10 cigarettes per day), women were 2.95 times more likely to have subarachnoid hemorrhage compared to non-smokers. Male light smokers were 1.93 times more likely have subarachnoid hemorrhage than non-smokers. 

Women who smoked 11 to 20 cigarettes per day were 3.89 times more likely to have subarachnoid hemorrhage compared to non-smokers, and men who smoked similar daily amounts of cigarettes per day were 2.13 times more likely to have subarachnoid hemorrhage compared to non-smokers.

Women who smoked 21 to 30 cigarettes per day were more than 8.35 times likely to have subarachnoid hemorrhage compared to female non-smokers, and men who smoked similar amounts of cigarettes per day were 2.76 times more likely to have subarachnoid hemorrhage compared to non-smokers

Notably, the bleeding risk decreased significantly among former smokers.

“There is no safe level of smoking,” Lindbohm said. “Naturally the best option is never to start. Quitting smoking, however, can reduce the risk for subarachnoid hemorrhage in both sexes.”

The authors noted that, according to the American Heart Association, subarachnoid hemorrhage accounts for three percent of all strokes, and smoking is the probably most important modifiable risk factor in preventing subarachnoid hemorrhage.