Subarachnoid hemorrhage more commonly caused by environmental factors than genes

Sep 20, 2010

The large Nordic twin study investigating the heritability of subarachnothe role of genetic factors underlying the development of SAH suggests that the role of genetic factors underlying the development of SAH is less than previously believed.

The prevalence of subarachnoid haemorrhage (SAH) is almost three times as high in Finland and Japan as among other nationalities. In Finland, some 1,000 cases are diagnosed every year, with almost half of the cases ending in death. SAH predominantly affects the working age population. Haemorrhage occurs when an aneurysm, a balloon-like bulge in the wall of the cerebral artery, ruptures.

Cerebral aneurysms and haemorrhages from ruptured aneurysms have been studied extensively in Finland. Töölö Hospital of Helsinki University Central Hospital (HUCH) in Helsinki is one of the best-known centres for the neurosurgical treatment of SAH in the world.

During the past few decades, the has been regarded as playing a significant role in the development of SAH. Contrary to this belief, however, a twin study recently published in the renowned journal Stroke showed that environmental factors account for most of the susceptibility to develop SAH Conducted in Finland, Sweden and Denmark, the study is the largest population level twin study in the world.

"This information is important for the families of SAH patients and for doctors," says Miikka Korja, head of the research team and neurosurgeon at the HUCH Neurosurgery Department. "On an average, close family members of SAH patients have a low risk of developing SAH, and this risk may be further reduced by modifying lifestyle and . This means that instead of screening the close family members of SAH patients, the focus of preventive treatment may now be increasingly shifted to the efficient management of hypertension and intervention. This is what we do with other cardiovascular diseases as well."

The Nordic study combined data on almost 80,000 pairs of twins over several decades. All in all, the follow-up time of all of the twin pairs corresponds to a staggering 6 million person-years.

The researchers nevertheless emphasize that there are rare cases of families among whose members SAH is significantly more common than in the overall population. In these cases are the principal cause underlying the development of the disease. The challenge is to identify these rare families and provide accurate genetic counselling and preventive treatment.

Explore further: Senegal closes border as UN warns on Ebola flare-up

Provided by University of Helsinki

not rated yet
add to favorites email to friend print save as pdf

Related Stories

How movement lubricates bone joints

Dec 05, 2006

Taking a cue from machines that gently flex patients’ knees to help them recover faster from joint surgery, bioengineering researchers at UC San Diego have shown that sliding forces applied to cartilage surfaces ...

Aneurysms don't occur earlier in second generation

Feb 23, 2009

People whose parents or aunts and uncles have had a brain aneurysm are more likely to have one themselves, indicating that genetic risk factors passed down by generation are responsible. Prior studies had suggested that ...

Recommended for you

Nigeria confirms two new Ebola cases

7 hours ago

Two new cases of Ebola have emerged in Nigeria and, in an alarming development, they are outside the group of caregivers who treated an airline passenger who arrived with Ebola and died, Health Minister Onyebuchi ...

Senegal closes border as UN warns on Ebola flare-up

12 hours ago

Senegal has become the latest country to seal its border with a west African neighbour to ward off the deadly Ebola virus, as the new UN pointman on the epidemic said preparations must be made for a possible flare-up of the ...

Climate change could see dengue fever come to Europe

12 hours ago

Dengue fever could make headway in popular European holiday destinations if climate change continues on its predicted trajectory, according to research published in open access journal BMC Public Health.

American Ebola doc: 'I am thrilled to be alive'

20 hours ago

Calling it a "miraculous day," an American doctor infected with Ebola left his isolation unit and warmly hugged his doctors and nurses on Thursday, showing the world that he poses no public health threat ...

User comments : 0