Youth football in England, Scotland and Northern Ireland now limits heading, and separate measures have been introduced to curb heading during training in the English and Scottish professional games.
In 2019, the FA- and PFA-funded Field study reported that footballers had a 3.5-times higher risk of neurodegenerative disease.
Since then, the FA has advised clubs to reduce high-impact headers in training, particularly from fast deliveries such as free-kicks and corners.
The Scottish Football Association has gone further, banning heading on the day before and the day after matches in the professional adult game.
In 2023, the PFA and Premier League launched a brain health fund to support former players and their families affected by dementia and other neurodegenerative conditions.
Researchers behind the latest study plan to keep monitoring the brain health of the retired players who took part, and say more work is needed to identify what drives brain changes, how symptoms evolve over time, and what can be done to help.
Snyder said the next step is to understand why these brain changes occur, the underlying biology, and their long-term consequences.
They also emphasized that one of the best ways to protect brain health is to minimize head injuries when playing sports.
If you have been affected by the issues raised in this article, you can find details of support organizations via Action Line.