The Mass General Brigham, Boston University, and the Concussion & CTE Foundation recently performed a study of NFL players and found evidence linking professional football careers with long-term neurological health issues. The cohort study is reportedly the largest mortality study in NFL players to date. Not so surprisingly, the findings point to some major neurological concerns. 

The study included 19,824 former NFL players and compared them to the general population. These athletes played between 1960 and 2019 and played at least one NFL game in their careers. The researchers confirmed that NFL players have a 3.94-times higher rate of neurodegenerative mortality compared to the general population. This number includes a higher mortality rate for amyotrophic lateral sclerosis (4.5 times more), all-cause dementia (3.8 times more), and Parkinson’s disease (3.88 times higher).

“A fourfold increase in dementia rates from a presumed environmental cause is immense—and brain bank studies indicate that CTE is the primary explanation,” one of the co-senior authors, and the associate director of the Boston University Alzheimer’s Disease Research Center and co-director of clinical research at the BU CTE Center, Jesse Mez, told the Harvard Gazette.

“One of the things that has been thought to be a reason that some NFL players have higher rates of dementia is that they’re so big, and they have such poor eating habits, they have increased rates of heart issues and blood vessel issues, more sleep apnea, which can increase dementia rate,” co-senior author Dr. Daniel Daneshvar, and chair of Physical Medicine and rehabilitation at Mass General Brigham and Harvard Medical School, told ESPN.

“But what we found is they’re actually dying from these other things at a lower rate than the general population. So the most likely explanation for this elevated rate of neurodegenerative disease in NFL players is CTE [chronic traumatic encephalopathy].”

For the league, these statistics mandate an evolution. The intersection of the sport with chronic neurological issues has now become a central topic in player advocacy. 

The debate around this was reignited after former Tennessee Titans running back Chris Johnson revealed that he was diagnosed with ALS at the age of 39. The three-time Pro Bowler set an NFL record by racking up 2,509 total yards from scrimmage, combining both rushing and receiving yards.

“There’s no history of ALS in my family,” Johnson told GMA. “That’s one of the reasons this disease can be so shocking. It can happen to someone who never expected it.”

In the aforementioned study, it was also found that “speed” players are more prone to neurodegenerative and all-cause dementia mortality, compared to non-speed positions.

Other notable players who suffer from such diseases are Steve Gleason and Brett Favre, who suffer from ALS and Parkinson’s, respectively.

Today, the former running back cannot use his hands properly and uses a speech device to communicate. He said that he struggles to hold things even though he’s getting treatment after being diagnosed early. Before that, he noticed that he wasn’t feeling as strong as he used to.

Many celebrities have voiced their support for Johnson, who has four kids. The ice bucket challenge is getting traction nearly 10 years after it first went viral. Figures like Marshawn Lynch, Deion Sanders, Aaron Donald, Vince Young, and others have participated in the challenge, sending their love to Johnson during this tough time.