CTE found in 99% of brains studied of former players
Researchers studying the link between football and chronic traumatic encephalopathy found that 99 percent of the brains donated by families of former NFL players showed signs of the neurodegenerative disease, according to a new study published Tuesday.
In all, researchers from Boston University School of Medicine and the VA Boston Healthcare System examined 202 brains that belonged to men who played football at all levels and were later donated for research. They found CTE in 177 of them — 87 percent.
While they found evidence of the disease across all levels of play, the highest percentage was found among those who competed at the highest level; all but one of the 111 brains belonging to ex-NFL players were diagnosed postmortem with CTE.
“Obviously, this doesn’t represent the prevalence in the general population, but the fact that we’ve been able to gather this high a number of cases in such a short period of time says that this disease is not uncommon,” said neuropathologist Ann McKee, the researcher credited with some of the most high-profile CTE diagnoses. “In fact, I think it’s much more common than we currently realize. And more importantly, this is a problem in football that we need to address and we need to address now in order to bring some hope and optimism to football players.”
McKee cautions that the study has some limitations and doesn’t attempt to pinpoint a CTE rate. The brains studied were mostly donated by concerned families, which means they weren’t random and not necessarily representative of all men who have played football.
“A family is much more likely to donate if they’re concerned about their loved one — if they’re exhibiting symptoms or signs that are concerning them, or if they died accidentally or especially if they committed suicide,” she said. “It skews for accidental deaths, suicide and individuals with disabling or discomforting symptoms.”
While the study isn’t focused on causality, McKee says it provides “overwhelming circumstantial evidence that CTE is linked to football.”
The study marks the largest CTE case series ever published. The research was drawn from a brain bank established and maintained by the VA Boston Healthcare System, Boston University School of Medicine and the Concussion Legacy Foundation.
The 177 brains found to have CTE belonged to former players who had an average of 15 years of football experience. In addition to the NFL diagnoses, the group included three of 14 who played at the high school level, 48 of 53 who played in college, nine of 14 who competed semiprofessionally and seven of eight who played in the Canadian Football League.
“To me, it’s very concerning that we have college-level players who have severe CTE who did not go on to play professionally,” McKee said. “That means they most likely retired before the age of 25 and we still are seeing in some of those individuals very severe repercussions.”