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Long-term Finnish study links smoking to fatal stroke risk

The study examined health and stroke fatality data for more than 15,000 pairs of twins in Finland.

Lähikuvassa silhuettina henkilö polttaa tupakkaa.
The study found that only the smoking twin developed a fatal cerebral haemorrhage, while the non-smoking twin did not. Image: Nella Nuora / Yle
  • Yle News

There appears to be a significant link between smoking and subarachnoid haemorrhage, a fatal kind of stroke, according to a new study published by Finnish researchers in the scientific journal, Stroke.

Subarachnoid haemorrhage (SAH) refers to a life-threatening type of stroke caused by bleeding in the space around the brain.

The researchers studied health data for more than 16,000 twins from the Finnish Twin Cohort, a national database of twins who were tracked for more than 40 years between 1976 and 2018.

They aimed to identify the factors at play when only one twin suffered a fatal cerebral haemorrhage. In addition to examining smoking habits, the researchers looked at data such as high blood pressure, physical activity, body mass index, education and alcohol use.

Best to reduce or avoid smoking

They concluded that smoking was the most important environmental factor that determined why only the smoking twin developed a fatal cerebral haemorrhage, while the non-smoking twin did not.

"Our findings confirm, for the first time, previous suspicions of an actual causal relation between smoking and fatal brain haemorrhage," Helsinki University doctoral student and researcher Ilari Rautalin said in a statement.

Although stroke treatment has developed over the years, subarachnoid bleeding is still one of the most deadly cerebral afflictions. Half of patients who suffer from it die within the first few months of an incident.

According to a release from the University of Helsinki, many previous studies have suggested that smoking posed a heightened risk, but none of them were able to draw a direct line between smoking and SAH.

Rautalin described the finding as historic and extremely important. Two other members of the research and publication team included Helsinki University Hospital neurosurgeon Miikka Korja and Helsinki University professor of genetic epidemiology Jaakko Kaprio.

The researchers emphasised the importance of quitting the smoking habit or avoiding it altogether to reduce the risk of fatal cerebral haemorrhage.