By Steven Reinberg
WEDNESDAY, Sept. 30 (HealthDay News) -- Former professional football players suffer from Alzheimer's disease or other memory-related conditions at rates far higher than the general population, a new study commissioned by the National Football League shows.
And retired players between the ages of 30 and 49 are 19 times more likely to struggle with memory problems than similarly aged men who never played professional football, the study found.
The findings could have implications that reach far beyond the National Football League, which has said in the past that there's no reliable research to establish the proof of cognitive problems among former players.
Head injuries are not uncommon among college and high school players. University of Florida star quarterback Tim Tebow, the best collegiate player in the nation last year, suffered a head injury during a game on Saturday that briefly left him unconscious on the field. He continued to undergo post-concussion tests Tuesday.
And a study published last year in The American Journal of Sports Medicine examined severe head injuries among high school football players between 1989 and 2002. The researchers found that high school players had more than triple the risk of sustaining catastrophic head trauma compared to college players. High school athletes suffered 0.67 such injuries per 100,000 players, compared with 0.21 injuries per 100,000 college players.
The new study of former pro players has not been peer-reviewed, but the results mirror several other recent studies suggesting a link between dementia and head injuries. The results of the study, conducted by the University of Michigan's Institute for Social Research, were first reported Wednesday by The New York Times.
"Single incidents of concussion or head injury with loss of consciousness is a fairly well-established risk factor for subsequent Alzheimer's disease that shows up in big epidemiological projects," said Greg Cole, a professor of medicine and neurology at the University of California, Los Angeles David Geffen School of Medicine.
"Typically, head injury is found to roughly double the risk for developing dementia," added Cole, who's also associate director of the Mary S. Easton Center for Alzheimer's Disease Research. "But if victims also have the most common genetic risk factor [ApoE4], present in about 20 percent of the population and which similarly increases risk by itself, the combined risk is much higher, around tenfold or more. Animal model studies show this relationship is probably causal because head injury can really speed Alzheimer's pathology. All of this makes it pretty clear to experts studying AD [Alzheimer's disease] that in individuals with some preexisting genetic risk for Alzheimer's, repeated head injury should be expected to make dementia much more likely."
For the NFL survey, the Michigan researchers contacted 1,063 retired players by phone late last year. The players, who had to have played at least three seasons to qualify for the survey, were asked a series of questions on a series of topics, including questions on health, financial well-being and satisfaction with life. Most of the questions came from the standard National Health Interview Survey. That way, answers could be compared to previously collected data from the general population. In some cases, a player's wife answered the questions.
The Michigan researchers found that, among players aged 50 and older, 6.1 percent of them said they had received a dementia-related diagnosis -- five times higher than the national average of 1.2 percent.
Players between the ages of 30 and 49 had a dementia-related diagnosis rate of 1.9 percent -- 19 times higher than the national average of 0.1 percent, according to the survey.
The study authors acknowledged that phone surveys aren't a foolproof scientific method to determine rates of diagnosed dementia.
Dr. Daniel P. Perl, director of neuropathology at the Mount Sinai School of Medicine in New York City, told the Times that he considered the new survey significant. "I think this complements what others have found -- there appears to be a problem with cognition in a group of NFL football players at a relatively young age," he said.