When a government agency prepared a workplace safety fact sheet based on a study of degenerative brain disease in retired N.F.L.players, the organization invited several people to comment on a draft.
According to a memorandum obtained by The New York Times, most of the reviewers suggested simplifying the fact sheet so that players without a scientific background could better understand the findings. But one response stood out: a doctor on the N.F.L.'s head, neck and spine committee asked that a mention of chronic traumaticencephalopathy, or C.T.E., be removed.
C.T.E. is a degenerative brain disease that is closely related to Alzheimer's disease and is believed to be caused by repeated head trauma. It has been found posthumously in dozens of football players, provoking widespread concern about the sport's potential long-term cognitive effects.
Against this backdrop of public awareness, the N.F.L. has drastically shifted its position on head injuries in recent years, introducing rule changes and promoting education. But the league has expressed skepticism about the possibility of a link between on-field head injuries and C.T.E., a sentiment captured in the league doctor's request to the federal safety agency.
The doctor, who was not named in the internal memo, said references to C.T.E. should be removed because it was "not fully understood" and because it was not listed on the death certificates of the retired players in the study and thus lacked "epidemiological validity." He suggested that traumatic brain injury, or T.B.I., be used instead because it "may accomplish what you want to say in more established medical terms."
Researchers from the National Institute for Occupational Safety and Health, which wrote the fact sheet, rejected the league doctor's proposed change. Independent medical experts said such a request was inappropriate and not in line with prevailing research.
"That's what bugged me the most," said Jeffrey Kutcher, a neurologist and the director of Michigan NeuroSport at the University of Michigan, referring to the request to use traumatic brain injury instead of C.T.E. "It's a huge jump and it goes completely away from what the Niosh study showed."
Richard Ellenbogen, the chairman of the University of Washington's neurological surgery department and a co-chairman of the N.F.L.'s head, neck and spine committee, said he did not know which doctor suggested changing the text of the fact sheet.
But he said the doctor was correct in wanting to include a reference to traumatic brain injury. T.B.I. is a clinical diagnosis that can be identified in living patients, Ellenbogen said, while C.T.E. is a pathological diagnosis that so far can be found only through autopsies.
"Whoever said that is right," Ellenbogen said. "We've got to be careful because C.T.E. is a pathological diagnosis. We know that exists. That's been proven forever. What's important about this study is, if I played sports and had concussions, what's my chance of getting these?"
Ellenbogen said there was not enough research to answer that question. "Right now, people are on the razor's edge cutting the words," he said. "The problem is, the science isn't there yet. But we have to be clear. I'm agreeing with the Niosh study, but we just have to be more careful to make clear that C.T.E. is a pathological diagnosis and T.B.I. is a clinical diagnosis."
Like Ellenbogen, independent medical experts said they agreed with the agency when it wrote that there was no known "cause-effect relationship between football-related concussions and death from these neurodegenerative disorders," as well as the agency's statement that "professional football players are at increased risk of death" fromamyotrophic lateral sclerosis, Alzheimer's disease and Parkinson's disease.
The medical experts also expressed dismay that an N.F.L. doctor would point to the death certificates of former players in the study. C.T.E. is often diagnosed months after death, when brain samples are examined.
"This is an epidemiological entity, and at this point it definitely garners this title because of the number of players we have diagnosed with it," said Alexander K. Powers, an assistant professor of neurosurgery who specializes in sports-related brain and spine injuries at Wake Forest Baptist Medical Center. "There's plenty of research that is active. It's a robust field. It's not some orphan ambition."
The fact sheet, sent to retired N.F.L. players in January, summarized research published in September in the journal Neurology that found that players "may be at a higher risk of death associated with Alzheimer's and other impairments of the brain and nervous system than the general U.S. population."
Before publishing its fact sheet, Niosh asked three former players, a representative from the N.F.L. Players Association and a representative from the N.F.L. Player Care Foundation, an independent organization that assists retired players, to review and comment on a draft. The foundation asked for advice from the doctor on the head, neck and spine committee.
Niosh researchers rejected the proposed change because C.T.E. "resonated with the players who reviewed the draft and provided feedback" and was widely acknowledged. Using T.B.I. was also inappropriate because it described an injury that might result in a disorder like C.T.E. and was therefore not equivalent, said Ann Mobley, the health communications specialist at Niosh who wrote the fact sheet.
The debate over the long-term effects of head injuries in football has engaged neurosurgeons, neurologists, neuropsychologists and other researchers and clinicians. It has also led to lawsuits. Several thousand retired players have accused the N.F.L. of deliberating playing down the dangers of head injuries.
Everett Lehman, an epidemiologist at Niosh and the principal author of the original mortality study of more than 3,400 retired players, said his department must balance accuracy and clarity in its research. He said the N.F.L. doctor's request was misguided.
"I just think they are different things, and we didn't think it was important to include T.B.I.," he said. "Maybe whoever looked at it didn't carefully look at our paper."
http://www.nytimes.com/2013/03/28/sports/football/doctor-for-nfl-says-study-overstates-effects-of-cte.html?
