NFL
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Alongside the growing realization that football players often suffer numerous concussions that can permanently affect learning and memory, a new study suggests that NFL pros may also have an increased risk of dying from Alzheimer's and other brain diseases.

For the study, researchers looked at the health of nearly 3,500 National Football League players who had competed in at least five seasons between 1959 and 1988. The average age of the players was 57, and about 10 percent had died.

Of those, death certificates showed that NFL players were nearly four times more likely than the general population to die from Alzheimer's disease or Lou Gehrig's disease, also known as ALS.

Seven of the 334 deceased players had Alzheimer's and seven had ALS, the researchers report today in the journal Neurology.

Risks were highest in players who played high-speed positions, including quarterbacks, running backs, halfbacks, fullbacks, wide receivers, tight ends, defensive backs, safeties and linebackers. Compared to offensive and defensive linemen, they were more than three times more likely to die from neurodegenerative diseases.

The study adds to previous research, including evidence that retired football players who had suffered three or more concussions were five times more likely than normal to have mild cognitive disorders and three times more likely to suffer significant memory problems.

"Although the results of our study do not establish a cause-effect relationship between football-related concussion and death from neurodegenerative disorders," wrote the researchers, from the Centers for Disease Control and Prevention's National Institute for Occupational Safety and Health, "they do provide additional support for the finding that professional football players are at an increased risk of death from neurodegenerative causes."