Retired male rugby players aged 50 and over who have had at least three concussions in their careers have no worse average cognitive function overall compared with those who sustained none, one or two concussions, a study has found.
The BRAIN study, funded by the Drake Foundation and conducted with assistance from England's Rugby Football Union (RFU), also found no relation between the number of rugby-related concussions and players' positions or career lengths.
The study, which worked with 146 retired elite players, found no worsening of cognitive function in the group overall and in players under the age of 75.
However, 14 of the 48 players over 75 who had suffered at least three concussions during their careers had significantly worse cognitive function on average than those who had experienced none, one or two concussions.
Those players, or 29per cent of the over 75s who had sustained at least three concussions, could be at greater risk of problems such as memory loss, the study found.
All the players in the study had featured for either England, Oxford University or Cambridge University in the pre-professional era of rugby, with the authors saying more research was needed into those who have played more recently.
"The agreed group of participants were aged 50+ principally because of the greater likelihood that we might detect any neurocognitive decline if present," RFU medical services director Simon Kemp said in a statement.
"It is important to also conduct research with younger retired players."
A group of former rugby players filed a class-action lawsuit against World Rugby and other governing bodies in December, alleging their failure to protect them led to early onset of dementia.
The governing bodies have said they take player safety "very seriously".
Last month, World Rugby announced new guidelines limiting full contact training to 15 minutes per week, following their six-point welfare plan in July which included brain health care for former players.
The Drake Foundation said it had surveyed 508 adults involved in rugby and found two-thirds of respondents believed the sport needed fundamental law changes to make it safer.
The research, published earlier this month, found 62per cent of adults involved in grassroots rugby were concerned about its long-term effects on brain health, while 61per cent believed the sport had become more dangerous since turning professional in 1995.
"The Drake Foundation is calling on rugby's authorities to give this immediate consideration to protect the sport we love and the current and future generations who play it," founder James Drake said in a statement.
"In my view it's a sport that has become ostensibly less safe for the players involved and my concerns are reflected by our research this month."
(Reporting by Hritika Sharma in Bengaluru; Editing by Ken Ferris)