Concern is growing over a link between repeated hits to the head and brain disease—and a new study adds fuel to the fire. Researchers studied donated brain samples from 85 deceased people who'd experienced frequent, mild episodes of traumatic brain injury, and found signs of a certain brain disease in 80% of them. Almost all had played sports, the New York Times notes. The disease, chronic traumatic encephalopathy, can result in memory loss, dementia, and depression; there is no cure.
The four-year study reviewed people from ages 17 to 98, and vastly expanded the number of known cases. The affected group included 50 football players, 33 of whom played in the NFL, including longtime Chicago Bear Dave Duerson. Also included were high school and college football players, pro boxers, and NHL players (Derek Boogard), as well as veterans. Researchers, however, weren't able to prove a link between CTE and repeated head trauma, nor could they offer a percentage-point risk of CTE among NFL players. "Still, this is probably more widespread than we think," says a co-author.