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A study published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association looks at concussion and long-term cognitive function among male rugby players.
Dr Susan Kohlhaas, Director of Research at Alzheimer’s Research UK, said:
“Collisions in sport is an area of increasing scrutiny for public health, however relatively little is known about the long-term impact of concussions received in rugby union.
“Findings from this study of ex-amateur elite level rugby union players adds to our understanding of the risks involved with professional sports. While we know exercise is good for our brain health, certain sports involving high energy collisions have been linked to risk of long-term neurological problems.
“There hasn’t been enough long-term research involving ex-rugby players for us to know what specific risks might be associated with a rugby career. Further research in a larger number of volunteers is required to establish if any link between concussions sustained on the rugby field and memory problems in later life exists.
“While the game of rugby has evolved over a number of years, so has the approach to managing concussions, and creating a safer game should continue to be an important for public health goal for all.
“Funding for dementia research lags behind funding for other conditions and we need to see this change. Only with increased funding for research into dementia will we be able to help reduce the number of dementia cases.”
Dr Neil Graham, Alzheimer’s Research UK Clinical Research Fellow based at the UK Dementia Research Institute’s Care Research and Technology Centre at Imperial College London, said:
“This is an important paper which looks at the effects of concussion in former elite male rugby players now in their late 60s/70s. The researchers found association of head injuries and later life cognitive problems in older players. This raises the question of an interplay of head injury, ageing and long-term brain health, although the study did not address this specifically.
“It remains important to clarify what type, or total amount of head injury poses the greatest risk of memory problems in later life, and whether these cognitive difficulties are static or progressive such as in dementia. Recent advances in biomarkers, which enable ultrasensitive diagnosis of brain injury and characterisation of its consequences, are likely to accelerate the longitudinal studies which are key to answering these important public health questions.”
Dr Davide Bruno, Senior Lecturer in Psychology, Liverpool John Moores University, said:
“This is a solid piece of research. They had access to a unique population, which is not easy to recruit, and employed a comprehensive cognitive battery to evaluate their intellectual status. The authors clearly acknowledge the limitations of the study and rightly emphasise the need for further research.
“The press release does a good job of representing the findings of the paper, albeit of course in a simplified version.
“This study is published in a top dementia journal, and it looks at dementia indirectly. They do not provide dementia diagnoses for players, but demonstrating cognitive decline is a way to show potential increased risk for dementia in a population.
“They did not have a control group as part of the study, but compared performance against expected scores from other available data. This is OK, but a better, future study should include its own control group.
“The fact that they did not find much of an effect of concussion is not totally surprising. The authors themselves in the introduction mention the importance of sub-concussive trauma. Basically, repeated non-concussive trauma to the head, which presumably a rugby player may experience without becoming concussed, is thought to lead to cognitive impairment and neurodegeneration (specifically CTE, mentioned in the Intro of the paper). So, the fact that they did not find effects of concussion is not terribly surprising. It would be ideal to be able to measure these non-concussive traumatic events (very hard to do though, especially retrospectively).
“As a matter of fact, in our own research (incidentally accepted yesterday in the Journal of Neuropsychology), we find that football (soccer) players show increased cognitive impairment in conjunction with heading the ball (i.e., non-concussive “trauma”), but not with reported head injuries. So, in a way, our results are consistent with these.
“Another related point is that they mention their players underperformed predicted (control) scores as they got older. I cannot verify this because it is in the supplementary tables, but this is consistent with the idea that overall the older rugby players underperformed compared to same-age controls. This may be due to repeated non-concussive traumatic events, which were not captured, although it is speculative.
“Age matters. Only the older ex-players showed concussion effects. As the authors say, this is probably due to high levels of cognitive reserve – in other words, these players were highly educated and it would take a longer time for issues to emerge. However, as also noted, this finding was driven by a small sample of 80+/3-concussion ex-players, so it might be fluke-y.
“However, taking reserve capacity (cognitive reserve) into consideration is very important, which is why more studies (in rugby, soccer, etc…) should target older, retied, ex-professionals (like we did in our paper), in order to test people at actual risk of showing cognitive impairment or signs of dementia.”
Prof Robert Howard, Professor of Old Age Psychiatry, UCL Division of Psychiatry, UCL, said:
“This is a sophisticated study that sheds important light on the potential links between sport-acquired head injury and cognitive decline. Overall, the occurrence of episodes of concussion and length of Rugby Union playing career were not related to cognitive function later in life. However, when the researchers looked just at those aged over 75 who had sustained at least 3 episodes of concussion, they did find evidence for cognitive impairment compared to those who had not been concussed.
“Although there are plenty of good reasons to avoid concussions in sport and other areas of life, this study suggests that they are unlikely to cause dementia on their own and appear to increase risk at the time of life when dementia is already most commonly seen.”
Prof David Curtis, Honorary Professor, UCL Genetics Institute, said:
“It is hard to draw any firm conclusions from this study. The sample size seems quite small and ex-players who had developed dementia might have been less likely to participate. There’s no very obvious effect of reported number of concussions on cognitive function in general. In the over-80s people reporting three or more concussions did have worse average function, apparently because some had developed dementia. However there were only 6 people in this category so I don’t think this constitutes strong evidence.”
‘Concussion and long-term cognitive function among rugby players—The BRAIN Study’ by Valentina Gallo et al. was published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association at 12:00 UK time on Wednesday 20 October.
DOI: 10.1002/alz.12455
Declared interests
Dr Susan Kohlhaas: “No conflicts.”
Dr Neil Graham: “I collaborate with several of the authors – Zetterberg, Kemp, Cross but have not been involved in this research.”
Dr Davide Bruno: “Dr Bruno refers to some of his own work on a similar topic in his comment.”
Prof Rob Howard: “No conflicts to report.”
Prof David Curtis: “I have no conflict of interest to declare.”
None others received.