A new study that included 6,007 male soccer players who played in the Swedish first division between 1924 and 2019 suggests they were 1.5 times more likely to develop a neurodegenerative disease compared to population controls.
According to research, published in ‘The Lancet Public Health’, elite footballers were at increased risk of developing the Alzheimer disease and other dementias, but their risk for motor neuron disease (including ALS) was not increased, and their risk for Parkinson’s disease was lower compared with controls.
Unlike outfield players, goalkeepers did not have an increased risk of dementia, supporting the hypothesis that mild head impacts sustained while heading the ball might explain the increased risk in outfield players.
1.5 times more likely
The observational study reveals that elite male soccer players were 1.5 times more likely to develop a neurodegenerative disease than the control population.
Among male soccer players in the Swedish first division, 9% (537 of 6,007) were diagnosed with neurodegenerative diseases, compared to 6% (3,485 of 56,168) of the control population.
Amateur and professional footballers
The footballers were both amateurs and professionals. Sweden was a prominent football nation during the 20th century and many of the top division players competed at the highest international level. However, due to ideals of sportsmanship and amateurism, football clubs in Sweden were not allowed to pay salaries to their footballers until the late 1960s.
In recent years, concern has grown about exposure to head injuries in soccer and the possibility that they increase the risk of neurodegenerative diseases later in life.
Study in Scotland
A previous study conducted in Scotland suggested that footballers were 3.5 times more likely to develop neurodegenerative diseases. Following these tests, some football associations put measures in place to reduce headings in younger age groups and in training environments.
Peter Ueda, Adjunct Professor at the Karolinska Institutetstates that “although the increased risk in our study is slightly less than in the previous study from Scotland, it confirms that elite footballers are at increased risk of neurodegenerative diseases later in life.”
“As more and more measures are called for to protect brain health in this sport, our study adds to the limited evidence base and may serve to guide decisions on how to manage these risks.”
The study used Swedish national health registries to search for records of neurodegenerative diseases (diagnoses, deaths, or use of prescription dementia drugs) in 6,007 male soccer players who had played in the Swedish first division between 1924 and 2019.
different risks
The players’ risk of neurodegenerative disease was compared with population controls, who were people matched with soccer players based on sex, age, and region of residence. The analysis broke down the risk of different neurodegenerative diseases, such as Alzheimer’s and other dementias, motor neuron disease and Parkinson’s disease. The risks between field players and goalkeepers were also compared.
Overall, the soccer players had a 1.5-fold increased risk of neurogenerative diseases compared to controls. 9% (537 of 6,007) of the soccer players compared to 6% (3,485 of 56,168) of the controls were diagnosed with a neurodegenerative disease.
The authors caution that although 9% of soccer players and 6% of controls were diagnosed with neurodegenerative disease during their study, most of the participants were still alive at the end of data collection, so it is likely that the lifetime risk of developing neurodegenerative disease for both groups is higher.
The risk of neurodegenerative disease was 1.5 times higher for outfield players compared to controls, but not significantly higher for goalkeepers compared to controls.
Consequently, in a direct comparison, field players had a 1.4 times higher risk of neurodegenerative disease than goalkeepers. See Table 3 for more details on the comparison of the results between the field players, the goalkeepers and the control population.
Peter Ueda points out that the findings “suggest that goalkeepers do not have the same risk of neurodegenerative diseases as outfield players. Unlike outfield players, goalkeepers do not usually head the ball, but are exposed to different environments and shooting styles.” similar lives during his football career and perhaps also after retirement.
“It has been hypothesized that repetitive mild head injuries sustained while heading the ball are the reason soccer players are at higher risk, and it could be that the difference in risk of neurodegenerative disease between these two types of players support this theory”, he remembers.
Soccer players had a 1.6 greater risk of Alzheimer’s and other dementias compared to controls: 8% (491 of 6,007) of soccer players were diagnosed with this disease, compared to 5% (2,889 of 56,168) of controls .
There was no significant increased risk for soccer players compared to controls for motor neuron disease, including ALS. The risk of Parkinson’s disease was lower among soccer players (see Table 2 for details). Overall mortality was slightly lower among soccer players compared to the control group (40% vs. 42%).
Björn Pasternak, principal investigator of the Karolinska Institutet, indicates that “the lower overall mortality observed among soccer players indicates that their general health status was better than that of the general population, probably because they maintained a good physical condition by playing soccer with frequency”.
“Physical activity is associated with a lower risk of dementia, so it could be hypothesized that the potential risks from head impacts are somewhat offset by good physical fitness,” he continues. good physical shape can also be the reason for lower risk of Parkinson’s disease.
The authors comment among the limitations of their study, that the generalization of the results to soccer players who play today is uncertain. Since neurodegenerative diseases often appear later in life, most of the players in the study who were old enough to have developed one of these conditions played elite soccer in the mid-20th century.
Since then, soccer has changed in many ways that can influence the risk of neurodegenerative diseases. Switching from leather balls to synthetic balls (which do not absorb water and become heavier), more rigorous training and better equipment, or a change to a style of play associated with less head injury may have reduced risk.
On the other hand, the risk could be higher among footballers who today train and play more intensively from an early age. The study also focused solely on elite male soccer players, so its generalizability to elite female players and to male and female amateur and youth players is uncertain.