• A study has provided further evidence of a link between smoking and bleeding in the brain
• External factors, such as smoking, have a much greater influence on the condition than genetics
• Not smoking, or quitting if you’ve already started, is, therefore, an essential component of primary prevention

Smokers have a significantly raised risk of dying from a bleeding stroke, a new study warns.

For the study, researchers analysed data from over 16 000 same-sex twin pairs in Finland. The twins were born before 1958 and followed for about 42 years (between 1976 and 2018).

During the follow-up, there were 120 deaths from subarachnoid haemorrhage (SAH). This is a type of bleeding stroke that occurs under the membrane that covers the brain. The median age at death was about 61.

Further evidence

Compared to nonsmokers, the risk of fatal bleeding in the brain was three times higher among heavy and moderate smokers, and 2.8 times higher among light smokers.

The findings were published on 17 September in the journal Stroke.

“Our study provides further evidence about the link between smoking and bleeding in the brain,” co-author Ilari Rautalin said in a journal news release. Rautalin is a sixth-year medical and PhD student at the University of Helsinki in Finland.

Unlike previous research, this study found that high blood pressure, lower levels of physical activity and being female weren’t significant factors in the risk of a fatal brain bleed.

The paper didn’t have data on nonfatal cases. And the researchers couldn’t assess the impact of previous smoking on these brain bleeds, because former smokers and never smokers were combined in the nonsmoking category.

Essential component of primary prevention

Still, “this long-term study in twins helps to confirm the link between subarachnoid haemorrhage and smoking,” said Dr Rose Marie Robertson, deputy chief science and medical officer of the American Heart Association (AHA).

“Not smoking, or quitting if you’ve already started, is an essential component of primary prevention,” added Robertson, co-director of the AHA Tobacco Center for Regulatory Science. She was not involved in the study.

A previous study of nearly 80 000 twins in Denmark, Finland and Sweden suggested that external risk factors, such as smoking, have a much greater influence on subarachnoid haemorrhage than genetics.

^{Image credit: iStock}