Former England hooker Steve Thompson, pictured celebrating the team's 2003 World Cup final win / © AFP/File
Coordinated international research is vital to boost understanding of the link between brain injuries in people playing sport and the development of dementia, a report said on Tuesday.
It comes after a group of former rugby players decided to sue governing bodies World Rugby, the Rugby Football Union and the Welsh Rugby Union for allegedly failing to protect them from permanent injury.
The claimants include ex-Wales captain Ryan Jones and England's 2003 World Cup-winning hooker Steve Thompson, with many of the ex-players diagnosed with early-onset dementia and other irreversible neurological impairments.
Multiple studies have shown a link between brain injuries and an increased risk of developing neurodegenerative disease, and that ex-professional athletes are at an increased risk of developing such conditions.
Previous research from Glasgow consultant neuropathologist Willie Stewart showed ex-professional footballers were 3.5 times more likely to die from neurodegenerative diseases than the general population.
The new report from Alzheimer's Research UK and the Health Policy Partnership says there is a need for an international consortium of researchers and funding bodies to better understand the connection.
"There are many limits to existing research that make it difficult to compare data and draw overarching conclusions," states the report titled "Dementia and sport: research priorities for the future".
"Studies are often not comparable, with different methodologies and definitions used for key measures. Methods of assessment and the duration of follow-ups also vary considerably.
"An international research consortium could help to coordinate research efforts and ensure consistent methodologies and definitions across different studies."
The report also recommended setting up longer-term studies and to widen the focus of studies beyond elite male athletes to cover the risk factors to other groups including children, adolescents and women.
Alzheimer's Research UK will invest £500,000 ($600,000) to develop the research priorities identified in the report.
TV presenter Hayley McQueen, whose father Gordon, a former Scotland and Manchester United defender, is living with vascular dementia, welcomed the report.
"Witnessing first-hand the devastation that dementia poses to individuals, their families, and friends, it's about time people got around the table, and worked toward greater understanding so we can act with certainty," she said.
"It is also important that children, teenagers, other genders and people playing grassroots sports are included in research, as scientists have shown they display different risk, injury and recovery patterns to adult, male athletes."