Researchers in London have found evidence of chronic traumatic encephalopathy (CTE) in the brains of four retired football players who developed dementia. CTE, which has previously been linked to boxing and American football, is a progressive neurological disease found in people who sustain repeated head injuries. The study, which suggests the need for further research in this area, is published today in Acta Neuropathologica.
From 1980 to 2010, 14 retired football players with dementia took part in regular assessments of memory and thinking skills. They had all been regular players from childhood or their early teens, and had continued to play for an average of 26 years, with 13 playing professionally. Of the 14, six reported a single episode of concussion during their careers and all were reported to regularly head the ball. They developed dementia symptoms at an average age of 64 years, and lived with the condition for an average of 10 years. Six of the ex-footballers donated their brains to research when they died, allowing a team of specialists to assess the changes that had occurred in their brains.
When the researchers studied the donated brain tissue, four of the six cases were confirmed as having CTE, a condition that causes progressive damage to the brain but that can only be distinguished from diseases like Alzheimer’s by studying brain tissue post-mortem. All six cases showed the accumulation of proteins known to build up in more common causes of dementia, but in four people these changes were found alongside evidence of CTE.
While the study could not pinpoint the specific events or activities in the lives of the footballers that had contributed to the damage observed in their brains, the authors called for more studies investigating the link between repetitive head impacts from playing football and the risk of dementia.
Dr David Reynolds, Chief Scientific Officer at Alzheimer’s Research UK, said:
“Links between head injury and dementia are just beginning to be explored in more detail and this study showing evidence of CTE in a small number of retired football players, highlights the need for further research. Other disease processes were at play in these individuals, and this will also have contributed to the symptoms they experienced. We can’t tell what ultimately caused these players to develop dementia and this study doesn’t suggest that people who play football are at a greater risk of dementia than the general population.
“While we know that concussion and severe head injury can have a negative effect on brain function, we do not know the consequences of repetitive, low-impact blows to the head, such as those from heading a football. Long-term studies following large groups of people with appropriate controls are needed to better understand any links between playing football and dementia.
“The causes of dementia are complex and it is likely that the condition is caused by a combination of age, lifestyle and genetic factors. Further research is needed to shed light on how lifestyle factors such as playing sport may alter dementia risk, and how this sits in the context of the well-established benefits of being physically active.”