Chronic traumatic encephalopathy (CTE) is a "rare phenomena" and youth football is safer than riding a bike or skateboard, a Pittsburgh Steelers neurosurgeon and NFL medical consultant said Wednesday in response to the retirement of San Francisco 49ers linebacker Chris Borland.
Borland told ESPN's "Outside the Lines" this week that he wants to protect himself from the risk of future brain injury. Appearing on NFL Network, Dr. Joseph Maroon -- who advises the NFL on head, neck and spine injury -- said the game "has never been safer" and downplayed the risk of CTE based on current data.
"I think the problem of CTE, although real, is it's being overexaggerated and being extrapolated to youth football and to high school football," Maroon said.
Maroon said he reviewed all known cases of CTE, a progressive degenerative brain disease related to head trauma and found in dozens of retired athletes in football and other sports, from 1954 to August 2013.
"We came up with 63 total cases of CTE [and] in the last two years a few more," he said. "But there have been 30-40 million kids who have played football during that period of time. It's a rare phenomena. We have no idea the incidence. There are ... more injuries to kids falling off bikes, scooters, falling in playgrounds than there are in youth football. I think again, it's never been safer. Can we improve? Yes. We have to do better all the time to make it safer."
Chris Nowinski of the Boston-based Sports Legacy Institute, disagreed with Maroon. He told Mark Fainaru-Wada of ESPN.com that "the [Centers for Disease Control] found that regarding concussions, football is the most dangerous activity for boys age 10-14, causing more emergency department visits for brain injuries than both riding a bike or a skateboard. For ages 5-9, there are more brain injuries resulting from football than skateboarding.
"The most likely reason that more 5-9-year-old boys go to the ER with brain injuries resulting from bike accidents is that far more boys ride bikes than play football. It is unfortunate that this important information is being miscommunicated in the media."
He added: "In addition, it is not just concussions that make football dangerous for the brain, but it is also hundreds of subconcussive blows per year. Riding a bike or a skateboard are not known to cause hundreds of impact to the head in a year.
CTE can only be diagnosed in a postmortem examination of the brain. Maroon's study, found in abstract here, examined a total of 153 cases of CTE, of which 63 were in former football players. The paper concludes: "[T]he incidence of CTE remains unknown due to the lack of large, longitudinal studies. Furthermore, the neuropathological and clinical findings related to CTE overlap with many common neurodegenerative diseases. Our review reveals significant limitations of the current CTE case reporting and questions the widespread existence of CTE in contact sports."
Said Nowinski: "As to whether CTE is rare in the general population, that is true. CTE has never been found in an individual who was not exposed to significant brain trauma. It has been found in the vast majority of NFL players and professional boxers who have been studied, but the true risk in that population is unknown because of the absence of a test for CTE in the living."
On Borland's retirement, Maroon said: "When an athlete is fearful of any injury, it's time to get out. You can't play with apprehension in any sport and be as good as you can be. He obviously came to that conclusion himself. ... However, I really believe it's never been safer in terms of the sport. The rule changes, the safer tackling techniques, the medical management of concussions is so much better than it ever has been in the history of this sport."