A new study has found cases of chronic traumatic encephalopathy (CTE) and Alzheimer's disease in a small sample size of former professional soccer players. 

From 1980 to 2010, researchers at the University College of London followed 14 retired male soccer players with dementia until their deaths. Thirteen of the 14 participants had played professionally. The families of six participants allowed the researchers to conduct postmortem examinations to look into the cause of their dementia and the researchers confirmed that four of the six had CTE, which is a progressive neurodegenerative disease thought to be caused by repeated head injuries. All six had symptoms of Alzheimer's disease.

The study was published in Acta Neuropathologica on Wednesday. 

While the study was limited in size, it marks the first time that CTE has been confirmed in a group of retired soccer players.

CTE has most commonly been found in players that participated in contact sports and sustained repeated concussions. A large number of former American football players have been confirmed to have had CTE through postmortem examinations, which has led to a concussion crisis in the NFL. 

Concerns about head trauma in soccer started to develop in England after striker Jeff Astle died at the age of 59 in 2002. Astle's death was attributed to repeatedly heading heavy, leather balls.

But before the publication of the new study Wednesday, only four former soccer players (including Astle) had been confirmed to have CTE. The study suggests that the cause of CTE could be related to repeated head impacts from head-to-head collisions with other players and heading the ball. 

In 2015, U.S. Soccer, in an effort to protect younger soccer players, announced that players under 10 should not head the ball, while players 11 through 13 should limit the amount of heading. 

-- Jamie Goldberg | jgoldberg@oregonian.com

503-853-3761 | @jamiebgoldberg

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