SEATTLE: a large study offers further evidence of a link between traumatic brain injuries and dementia later in life, with repeated and severe injuries representing the greatest danger.
Researchers analyzed 36 years of health records of 2.8 million people in Denmark, where a national health system allows to explore far-reaching connections.
In general, the risk was small. About 95 percent of people who suffered a brain injury never developed dementia.
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Overall, the risk of dementia was 24 percent higher for people with a traumatic brain injury compared to people who did not have it. The study was published on Tuesday in the journal Lancet Psychiatry. A study of 3.3 million people in Sweden earlier this year showed similar results.
Despite the size of the studies, they do not solve the scientific questions – or the social debate – about brain injuries caused by sports, wars, car accidents or domestic violence. .
Scientists know that a blow to the head can damage brain cells, but they do not know exactly how it could lead to later cognitive problems, said lead researcher Dr. Jesse Fann of the University of Washington School of Medicine. in Seattle. .
This type of study can not prove a cause and effect relationship, but the researchers tried to eliminate the possible effect of age, sex, marital status and health, including depression. And they analyzed other types of trauma, such as broken bones, and found that brain injuries were more closely related to dementia.
In a commentary in the journal, Dr. Carol Brayne of the faculty of medicine at the University of Cambridge in England wrote that improvements in care means that more people survive brain injuries, so it is crucial to understand more about its long-term effects.