Brain Bleeds More Common in Smokers, Research Shows

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Quitting reduces risk of burst aneurysm

Smoking greatly increases the risk of potentially fatal brain bleeding caused by a burst aneurysm, a new study warns.

An aneurysm is a bulge in a weakened artery. If an aneurysm bursts, blood leaks into the brain. The chances of surviving a burst aneurysm are about 50 percent, and survivors often have lifelong disabilities.

Researchers compared 426 people in South Korea who suffered brain bleeds between 2002 and 2004 with 426 people who did not have a brain bleed. The participants' average age was 50.

The brain bleed group had a larger number of smokers and people with a family history of stroke and high blood pressure. Slightly less than 38 percent of those who had a brain bleed were current smokers, compared with a little more than 24 percent in the comparison group.

After accounting for other factors such as weight, salt intake and family history of diabetes, the researchers found that smokers were nearly three times more likely to have a brain bleed than nonsmokers. The longer and more heavily a person smoked, the greater their risk for a brain bleed.

Overall, quitting smoking reduced the risk of a brain bleed by 59 percent after five years or more, reducing the risk to the level of nonsmokers. However, former heavy smokers (20 or more cigarettes a day) were still more than twice as likely to have a brain bleed as people who had never smoked.

Smoking causes short-term effects such as thickening of the blood and increased blood pressure, both of which increase the risk of a brain bleed. These effects can be reversed by stopping smoking, explained Dr. Chi Kyung Kim, of Seoul National University Hospital's neurology department, and colleagues.

But smoking also causes permanent changes in the structure of artery walls, and these changes may be greater in heavy smokers, the authors said in a journal news release.

The study revealed a link between smoking and the risk of a brain bleed, but it did not prove cause and effect.

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This study has been published online Aug. 30 in the Journal of Neurology, Neurosurgery and Psychiatry:

Kim CK, Kim BJ, Ryu W, Lee S, Yoon B. Impact of smoking cessation on the risk of subarachnoid haemorrhage: a nationwide multicentre case control study. J Neurol Neurosurg Psychiatry doi:10.1136/jnnp-2012-302538 

More information

The U.S. National Institute of Neurological Disorders and Stroke has more about brain aneurysm.