Is neurodegenerative disease the unsuspected killer of contact sport athletes?

Over the years, correlation between neurodegenerative diseases and contact sports has been studied. It has been identified that athletes that play contact sports such as rugby, football and American football are at greater risk of developing a neurodegenerative disease due to their career.

A neurodegenerative disease affects the brain, causing loss of brain cells and brain shrinkage1. The symptoms of these diseases vary: Dementia is associated with memory loss and cognitive problems (i.e. Alzheimer’s Disease, which primarily displays memory loss, later progressing into disorientation, confusion and difficulty controlling limbs), motor neuron disease is identifiable through its ability to rapidly deteriorate an individual's ability to walk, talk or chew and swallow, and Parkinson’s disease can be identified through consistent tremors, inability to maintain balance and walk, as well as issues with sleeping and memory.2

These neurodegenerative diseases have been linked with traumatic

1 Emma Russel, ‘Neurodegenerative disease and lifelong health in footballers’, Biological Sciences Review, Vol.35, No. 2 brain injury (an injury resulting from an external trauma, i.e., a soccer ball), which was first recognized around a century ago. This was known as dementia pugilistica or ‘punch-drunk syndrome’. This was first identified in boxers, as many had taken blows to the head, leading them to develop symptoms such as coordination problems, confusion, memory loss and other symptoms similar to Parkinson’s disease. This was later renamed and is now known as chronic traumatic encephalopathy (CTE).

CTE is now recognized in not only boxers, but in athletes who play contact sports. A striking characteristic of CTE is the tau protein, which usually is found in cells in order to stabilize the microtubules of a cell’s cytoskeleton. However, in CTE, the tau protein forms clumps often close to blood vessels and in the depths and grooves of the brain. This results in the development of neurodegenerative diseases as the protein has the ability to interact and change the system of neurotransmissions in the body, leading to certain difficulties in control of limbs.

To support the idea of athletes playing contact-sports being more at risk of neurodegenerative diseases, the University of Glasgow carried

2 Unknown, https://www.mayoclinic.org/diseasesconditions/alzheimers-disease/symptomscauses/syc-20350447,accessed on November 6th 2022

out a FIELD (Football’s Influence on Lifelong health and Dementia risk) study, which investigated the health outcomes of football players in comparison to the general population. The study found that the risk of death from Alzheimer’s disease was around five times greater in former footballers than in the general male population. Moreover, the number of deaths from motor neuron disease was quadruple that of the general male population and the deaths from Parkinson’s disease was double. The cause of these increased risks has been linked with traumatic brain injury, which is now recognized to contribute to around 3% of Dementia cases worldwide. It is the only identified factor in that directly correlates contact-sports and an increase in risk of neurodegenerative diseases.

While some research has been conducted, further insight is needed, especially into female contact-sports. This is because while professional female football is still relatively new (originated in the 1990’s), research has found that males and females have been affected differently by traumatic brain injuries. Women tend to show more severe symptoms, however the main reason behind this has not yet been identified, as it could be a variety of biological and genetic differences that males and females have.

In conclusion, it is clear that athletes who play non-contact sports have a significantly higher risk of developing a neurodegenerative disease which could lead to premature death. There have been multiple investigations on former athletes such as Jeff Astor (football player for Notts county and West Bromwich Albion), Mike Webster (Pittsburg Steelers footballer), Muhammad Ali (boxer), and Lou Gehrig (baseball player), which have shown a direct link of traumatic brain injuries (due to career in contact-sports) to neurodegenerative disease development. While prevention of brain injuries in contact-sports is virtually impossible, minimizing the damage caused by these injuries, educating athletes on concussions and adjusting rules and regulations of these sports could make a significant improvement to the risks of these sports, and allow researchers to further investigate and find methods of protection.

By Alisa A (L6)