Risk of Neurodegenerative Diseases Higher in Pro-soccer Players, Research Suggests

Results from a study conducted by the University of Glasgow suggest that neurodegenerative diseases such Alzheimer’s, amyotrophic lateral sclerosis and Parkinson’s disease, could be more likely to develop in professional soccer players, compared with the general population.

Where Was the Research Carried Out?

The research was sponsored by the Football Association and the Professional Footballer’s Association in the UK and was carried out by Dr Willy Stewart at the University of Glasgow in Scotland. The research findings were recently published in the New England Journal of Medicine.

What Kind of Study Was it?

This was a retrospective cohort study. It’s an approach that takes existing information about different groups that are similar in some ways but also have important differences. It is often used to determine if there is a link for a particular health problem in a certain demographic or group of people, in this case, former soccer players.

What Did the Study Involve?

The research team at the University of Glasgow had access to the records of 7,600 Scottish, former professional soccer players, all-male and born between 1900 and 1976. They compared this to data from 23,000 men from the general population born during the same period.

The team were looking for any evidence that members of the soccer cohort were more or less likely to suffer from certain illnesses or disease compared to the control group.

What Were the Results of the Study?

First of all, the soccer players were less likely to die from heart disease and cancer, possibly because of their healthier lifestyle compared to the general population. They were, however, more likely to be diagnosed with one of a range of different neurodegenerative diseases.

• Overall, the former professional soccer players were 3.5 times more likely to die from a neurodegenerative disorder.
• There was a two-fold increased risk for Parkinson’s in the soccer cohort.
• There was a five-fold increase in risk for Alzheimer’s in the soccer cohort.
• The former soccer players were 4.9 times more likely to be prescribed dementia medicine.

The research also suggested that there was a four-fold risk increase of former professional soccer players developing amyotrophic lateral sclerosis, compared to the general population.

Whilst the difference in the incidence of these neurodegenerative diseases was higher compared to the general population, it should be noted that the general incidence of these diseases was still very low.

Interpretations From the Researchers

There has been widespread reporting of the findings by Dr Willy Stuart and much of it has surrounded the potential impact of heading the ball in soccer and its potential relation to Alzheimer’s. The study does not, in fact, make that correlation and both Stuart and other neurophysiologists have been quick to point this out.

For example, Bob Stern at Boston University expressed caution that these results do not mean that every amateur playing soccer or contact sports, whether adult or child, is at risk. More research needs to be undertaken.

Greg Clarke, Chairman of the Football Association, was quick to point out:

“The study does not determine whether the cause is due to concussions suffered by the group of professional footballers, or concussion management, or heading of the football, or style of play, or the design and composition of footballs over the years, or personal lifestyle, or some other factor.”

Having said that, the FA have recently re-issued their concussion guidelines and coaching practice for children playing the game. There are no plans, at this stage at least, of changing the way the game is organized for younger footballers.

Dr Stewart also points out that the research study looked across a range of different health outcomes. The fact that soccer players are less likely to die of illnesses such as heart disease and cancer has largely been overlooked by the media.

There have been changes in the game in recent years that may contribute to better outcomes in later life. The new footballs that are used are lighter than the old ones used just a few decades ago.

For some groups, the research certainly raises questions about whether children should be allowed to head the ball in soccer. The USA already has strict rules in place.

Children under ten cannot head the ball and any heading training is introduced gradually. For example, 11 to 12-year-old children can be taught in training but that is limited to just 30 minutes per week.