Soccer players develop CTE from repeated headers of the ball.

The finding

What the evidence shows

Research has found an association between heading a soccer ball and higher rates of dementia and CTE-like brain pathology in former players, including a large study showing ex-footballers were several times more likely to die of neurodegenerative disease. But experts are careful to call this a likely contributing factor rather than a proven cause, since other factors in players' lives could play a role and a direct causal link from heading to CTE has not been firmly established. Stating flatly that players develop CTE from headers presents an unsettled research question as a settled fact.