Smoking raises brain-lining hemorrhage risk more for women

A woman smokes in the shadows outside Southwark Crown Court in central London (Copyright Reuters 2016)

Smokers, especially female smokers, have a higher risk of subarachnoid hemorrhage - bleeding inside the lining of the brain - compared with nonsmokers, according to a new study.

Based on previous studies, smoking seems to account for at least one third of all cases of subarachnoid hemorrhage, and women suffer bleeding in the brain almost twice as often as men, the authors write in the journal Stroke.

"Our surprising finding was that the elevated risk in women was explained by vulnerability to smoking," lead author Dr. Joni Valdemar Lindbohm of the Department of Public Health at the University of Helsinki in Finland.

"Smoking may decrease estrogen levels and cause early menopause which further lowers estrogen levels," Lindbohm told Reuters Health by email. "This decrease may cause vessel walls to degrade and make them rupture prone."

Subarachnoid hemorrhage becomes much more common for women after age 55, he noted.

In the study, even light smoking boosted hemorrhage risk considerably (for both men and women), Lindbohm said, though it decreased again after quitting smoking.

The researchers studied 65,000 people in a group that had filled out lifestyle questionnaires every five years since 1972 and were recruited in random samples from various areas in Finland. The participants answered questions on alcohol consumption, history of high blood pressure and high blood pressure medications, smoking and socioeconomic status. Nurses measured their blood pressure, height, weight and blood cholesterol.

The researchers tracked participants until the end of 2011. During that time there were 492 subarachnoid hemorrhages, 266 of them among women.

Smokers were more likely to suffer a hemorrhage, especially women. Compared to nonsmokers, women who smoked more than 20 cigarettes per day were eight times as likely to suffer a brain hemorrhage, and men who smoked that much were almost three times as likely to suffer a hemorrhage.

Former smokers had lower hemorrhage risk than current smokers.

"The authors speculate that the stronger effects of smoking among women would have to do with an interaction with female hormones," said Dr. Ale Algra, professor of Clinical Epidemiology of Cerebrovascular Diseases at Utrecht Stroke Center in The Netherlands. "However, I think that the truth is that we do not yet really understand this observation."

All smokers should try to quit smoking for a variety of health reasons, Algra, who was not involved in the new study, told Reuters Health by email.

"Approximately 20 percent of all subarachnoid hemorrhage patients die suddenly away from hospitals and up to 45 percent of all subarachnoid hemorrhage patients die," Lindbohm said. "In addition, most survivors suffer from a range of neurological and/or psychological conditions."

Female smokers should definitely try to stop smoking and treat their high blood pressure aggressively, with the help of health care providers when necessary, Lindbohm said.

SOURCE: http://bit.ly/2aeXAdr Stroke, online July 21, 2016.