August 6, 2021

expert reaction to study looking at contact events in rugby union and blood flow in the brain

A study published in Experimental Physiology looks at contact events in rugby union and and blood flow in the brain.

Dr Susan Kohlhaas, Director of Research at Alzheimer’s Research UK, said:

“We know traumatic head injury is linked with an increased risk of dementia, but we don’t fully understand how these events set dementia-causing processes in motion.

“Collisions in sport is an area of increasing scrutiny for public health.  The findings from this small study in rugby union players help add to our incomplete understanding of the risks involved with professional sports and the aspects of biology that may underly cognitive changes over the short term.

“We know exercise is good for our brain health, but longer-term and larger studies with suitable control groups are needed to add weight to these exploratory findings into concussion, and short-term brain health.  One positive of the study is that researchers did look at a possible biological pathway for these events, however a link, if any, between concussion, blood flow, oxidative stress and long-term cognitive changes including dementia requires further research.

“To better understand the specific factors of a rugby professional’s career that might affect their brain health, future studies should also consider collisions in training.  Comparing rugby players with players of non-contact sports could also help to determine whether factors other than collisions could be playing a role in these findings.

“Funding for dementia research lags behind funding for other conditions.  We need to see this change.  Only with increased funding into dementia will we be able to help reduce the number of dementia cases, which are set to triple by 2050 and help bring about life-changing treatments.”

Prof Willie Stewart, consultant neuropathologist and Honorary Clinical Associate Professor at the University of Glasgow, said:

“Although a relatively small study in respect of number of rugby players followed, there are intriguing findings here that require pursuit in further research and, although there is suggestion that the measures here might have relevance to development of neurodegenerative disease, this is, at best, speculative.

“Importantly, there are no data on whether these changes are irreversible or might have resolved by the beginning of the next season, and so the longer term consequences and implications of these observations remain unknown.  Nor are there data to support the suggestion that these observations represent an ‘accelerated decline’, which would imply there are data on expected rate of decline and/or that observed changes might be irreversible.  Lastly, although it is suggested these data showed alteration in vascular reactivity which was linked to increase in free radicals, this is not shown; indeed, despite greater change in vascular reactivity among forwards the authors did not find a measurable difference between these groups in free radical measures.

“Nevertheless, if these observations can be confirmed in more robust studies, they should be of concern to both players and rugby authorities.  This work adds to the growing research characterising potential adverse brain health consequences of contact sport participation.  There is no question that all sports need do everything they can to reduce exposure to unnecessary head impacts and better recognise and manage head injury events when they occur.”

‘Contact events in rugby union and the link to reduced cognition: evidence for impaired redox-regulation of cerebrovascular function’ by Thomas Simon Owens et al. was published in Experimental Physiology at 02:00 UK time on Friday 6 August 2021.

DOI: 10.1113/EP089330

Declared interests

None received.