SOURCES: Robert Stern, Ph.D., professor, neurology, neurosurgery, anatomy and neurobiology, Boston University School of Medicine, and director, BU's Alzheimer's Disease Center Clinical Core and the Chronic Traumatic Encephalopathy Center, Boston, Mass.; Christopher Filley, M.D., professor, neurology, University of Colorado School of Medicine, Aurora; Jan. 28, 2015, Neurology
WEDNESDAY, Jan. 28, 2015 (HealthDay News) -- As football fans prepare to watch the 49th Super Bowl this Sunday, a new study suggests that boys who start playing tackle football before the age of 12 may face a higher risk for neurological deficits as adults.
The concern stems from an assessment of current memory and thinking skills among 42 former National Football League players, now between the ages of 40 and 69. Half the players had started playing tackle football at age 11 or younger.
The bottom line: Regardless of their current age or total years playing football, NFL players who were that young when they first played the game scored notably worse on all measures than those who started playing at age 12 or later.
"It is very important that we err on the side of caution and not over-interpret these findings," said study co-author Robert Stern, a professor of neurology, neurosurgery, anatomy and neurobiology at Boston University's School of Medicine. "This is just one research study that had as its focus former NFL players. So we can't generalize from this to anyone else.
"At the same time," Stern added, "this study provides a little bit of evidence that starting to hit your head before the age of 12 over and over again may have long-term ramifications. So the question is, if we know that there's a time in childhood where the young, vulnerable brain is developing so actively, do we take care of it, or do we expose our kids to hit after hit after hit?"
Stern, who is also the director of the Alzheimer's Disease Center Clinical Core and director of clinical research at the Chronic Traumatic Encephalopathy Center at the university, reported the findings with his colleagues in the Jan. 28 issue of Neurology.
The study authors pointed out that, on average, children who play football between the ages of 9 and 12 experience between 240 and 585 head hits per season, with a force that is comparable to that experienced by high school and college players.
In 2011, investigators recruited former NFL players to participate in an ongoing study called DETECT. The players' average age was 52, and all had played at least two years in the NFL and 12 years of "organized football." All had sustained a comparable number of concussions throughout their careers.
All had a minimum six-month history of mental health complaints, including problems with thinking clearly, behavior and mood.
All underwent a standardized battery of neurological testing to assess learning, reading and verbal capacities, as well as memory and planning skills.
The result: all the players performed below average on several of the assessments. But by many measures, the overall mental functioning of those who started playing before age 12 registered roughly 20 percent below that of those who started at age 12 and older.
For example, the early start group performed worse in terms of immediate and delayed verbal-recall tests, and were deemed less mentally "flexible" than the 12-and-up group.
While the researchers found a link between age at which players started to play football and later mental functioning, it didn't prove cause and effect.
"Now I want to be clear that we're not talking about the impact of concussions here," Stern said. "I know that the emphasis of late has been on concussions. But what I'm more concerned about are all of those repetitive hits that we refer to as sub-concussive trauma. The player may have no complaints at all, no obvious problems. But their brain is jostled over and over again inside the skull, right at the time when it's trying to do its best to grow and develop.
"So, this should not be taken as a definitive study that leads to policy or rule changes," he added. "Participation in youth sports is tremendously beneficial. But parents should be aware of this. And if there is an option to play, say, flag football at that age -- where one can learn all of the important social skills of team participation and have as much fun, but take the brain out of it -- then I say we should do that."
That thought is seconded by Dr. Christopher Filley, author of an editorial accompanying Stern's study, and a professor of neurology at the University of Colorado School of Medicine in Aurora.
"These players who were studied all wore helmets throughout their entire playing careers," he said. "But we don't think helmets have much of an effect on preventing brain injury. The game is inherently violent. That may not be the case if we're talking about touch football. But if it's to be played with the rules that are now favored, there will always be an inherent risk, regardless.
"Now, obviously there are benefits to physical activity and team sports," Filley added. "But the potential is that the younger brain is more vulnerable to injury than the older brain, which is why I think this is an important study, and a cautionary tale. It's not the final word on the issue. We need more data. But this a tough conversation that is definitely worth having."
Visit the U.S. Centers for Disease Control and Prevention for more on concussions in football.