The relationship between a head injury and risk of dementia remains shrouded in mystery: some studies suggest that the risk is high, others say that they have found no connection between the two factors.
The team coordinated by Kristine Yaffe, professor at the California University in San Francisco analyzed the medical records of 281,540 American veterans aged at least 55 years for which dementia was not diagnosed at the beginnings of the study.
Yaffe has shown that the risk of developing dementia during the study (7 years) was over twice as high in veterans presenting brain injury (15.3% compared with 6.85 for the soldiers who had no brain damage).
“The data make us believe that the skull-brain trauma in older veterans may predispose them for the appearance of dementia symptoms. This condition raises concerns regarding possible long term consequences in case of such traumas produced to younger veterans”, said Yaffe.
For scientists, this issue is important because brain traumas a very current condition, which occurs mainly from falls or traffic accidents.
“Brain trauma is considered also the typical wound of the conflicts in Iraq and Afghanistan, which affects 22% of victims and 59% of injuries related to explosions”, said the study coordinator.
Several mechanisms could explain this risk. According to scientists, amyloid plaques are formed similar to those present in the brains of people suffering from Alzheimer’s disease, in up to 30% of patients with brain trauma that don’t survive injuries, regardless of their age.
American football and cognitive disorders
A study was coordinated by Professor Christopher Randolph at Loyola University Medical Center in Chicago, on former football players.
5,413 retired members of the National Football League Players’ Association responded to a survey in 2008 aimed particularly to memory problems (including Alzheimer’s disease screening questionnaire, called the AD8).
Just over 35% of respondents with a mean age of 61, had a score that let AD8 foresee the risk of dementia. By way of comparison, according to the report in 2011 of Alzheimer’s Association, 13% of Americans aged 65 are affected by the Alzheimer’s disease.
The researchers used survey data to identify the former football players suffering from mild cognitive impairment (memory impairment, language, etc.). They found that former athletes were affected more compared with individuals who had the same socio-demographic characteristics but who did not have a history of professional sports.
These results, considered by scientists as preliminary, strengthen the hypothesis that repeated head trauma, for many years, while practicing football, can lead to early onsetof age-related neurodegenerative diseases, such as Alzheimer’s disease.