Marc Suárez-Calvet
Researcher at the Barcelonabeta Brain Research Center and the Neurology Service of the Hospital del Mar (Barcelona)
Several studies have shown that sports involving repeated blows to the head (such as boxing, rugby or ice hockey) may increase the risk of dementia or neurodegenerative disease. In the case of football, the most popular sport, some evidence also points to this association, although the results of studies to date have been inconsistent.
The study recently published in The Lancet Public Health follows 6,007 footballers who played in the Swedish top division between 1924 and 2019 and concludes that they are 1.5 times more at risk of neurodegenerative disease than the general population. Specifically, 8.9% of the football players developed a neurodegenerative disease, a significantly higher percentage than the general population (6.2%). The risk of Alzheimer's disease or other dementias was significantly increased in football players, while there were no differences in the risk of other diseases, such as Parkinson's disease or amyotrophic lateral sclerosis. Considering that physical exercise is a protective factor for the development of any type of dementia, this association may even be underestimated.
A very important finding of the study is that this increased risk does not occur in the 510 goalkeepers studied, who tend to hit the ball less with their heads, but in the rest of the players. This could indicate that repeated headers are responsible for the increased risk of Alzheimer's and neurodegenerative diseases. However, it should be remembered that a cause-effect relationship cannot be established in an observational study. An important limitation of the study is that only men have been studied, studies should also be carried out in women.
This study (and others with similar results) has important implications. They should make us reflect on the need to minimise repeated head-butting and head-butting in sport, even if it is of low intensity. This is especially important in childhood and adolescence, where the brain is still developing.