An observational study tracking more than 6,000 male soccer players in Sweden’s top professional league between 1924 and 2019 found they were 1.5 times more likely to develop neurodegenerative diseases than their non-footballing counterparts.
As reported by Health Policy Watch, the Swedish study adds to observational data on a cohort of Scottish pro soccer layers published in The New England Journal of Medicine in 2021. That study found the athletes were three and a half times more likely to develop neurodegenerative diseases than the control group and three times more likely to have a neurodegenerative disease listed as their cause of death than an average person.
In both studies, however, overall mortality was found to be slightly lower among the footballers.
“While the risk increase in our study is slightly smaller than in the previous study from Scotland, it confirms that elite footballers have a greater risk of neurodegenerative disease later in life,” said Peter Ueda, an assistant professor at Karolinska Institutet, the academic institution that ran the study. “As there are growing calls from within the sport for greater measures to protect brain health, our study adds to the limited evidence-base.”
Concerns about the impact of professional sports on the brains of athletes have risen sharply in the past decade, with alarm bells in American football circles ringing as early as 2007, Health Policy Watch reported.
Yet before the publication a 2017 paper by researchers at University College London, only four European football (soccer) players were known to have had chronic traumatic encephalopathy (CTE). Today, that number is in the thousands.
While the academics differed on CTE risk calculations, both the Swedish and Scottish studies made an interesting observation: goalkeepers were at the lowest risk. Goalkeepers, unlike other players on the field, rarely head the ball. Repeated head impacts are believed to be the root cause of CTE, as they cause hundreds of small lesions within the brain that impair its function over time.
“It has been hypothesized that repetitive mild head trauma sustained through heading the ball is the reason football players are at increased risk, and it could be that the difference in neurodegenerative disease risk between these two types of players supports this theory,” Ueda said.
Experts from the Boston University Hospital Brain Bank who have been leading the charge on raising awareness of CTE in sports are more confident, according to Health Policy Watch.
“The cumulative exposure to these mild repetitive head impacts is what we believe leads the player to a risk for CTE,” Dr Mary Ann McKee told the American Academy of Neurology, as reported by Health Policy Watch. “In fact, in all our studies, if we look at the number of concussions, it doesn’t relate to CTE or CTE severity.”
The Swedish and Scottish studies also did not control for length of each athlete’s career, a factor which American researchers have found to be highly significant, Health Policy Watch reported.