NFL Players Face Fourfold Higher Neurodegenerative Mortality in Largest-Ever Cohort Study
Key Insights
A cohort study of nearly 20,000 NFL players found they were four times more likely to die from neurodegenerative diseases compared to the general population.
Players had 3.8-fold higher all-cause dementia (search) mortality and 3.88-fold higher Parkinson's disease (search) mortality, with rates remaining threefold higher after adjusting for known risk factors.
Those dying before age 60 showed more than 12-fold increased neurodegenerative death rates, and players with 5+ seasons had nearly double the risk versus those with shorter careers.
A landmark cohort study from Mass General Brigham (search), Boston University, and the Concussion & CTE Foundation (search) has produced what researchers are calling the clearest population-level evidence to date that National Football League players face dramatically elevated risks of dying from neurodegenerative disease. Published in eClinicalMedicine, the study examined health records of 19,824 NFL players who competed between 1960 and 2019, revealing that while players had lower all-cause mortality on average, they were four times more likely to experience neurodegenerative mortality than the general population.
"This is the clearest population-level evidence we have ever had that NFL players are dying due to neurodegenerative disease at real and measurably higher rates," said co-senior author Daniel Daneshvar, MD, PhD, Chair of Physical Medicine and Rehabilitation at Mass General Brigham (search) and Harvard Medical School and director of the HealthSpan Lab. "This study demonstrates that, when looking at athletes who have played in an NFL game, including nearly 20,000 players, across every official cause of death, the result is the same: NFL players are dying of dementia (search) and Parkinson's disease (search) three to four times more often than they should."
Quantifying the Risk Across Disease Categories
The retrospective cohort study, the largest of its kind to date, found that NFL players had nearly four-times higher neurodegenerative mortality overall. Breaking down the data by specific conditions, players experienced 3.8-times higher mortality from all-cause dementia (search) and 3.88-times higher mortality from Parkinson's disease (search). When researchers accounted for other known risk factors, neurodegenerative mortality remained three times higher for players compared to the general population.
The findings were particularly stark for younger former players. Those who died before age 60 had more than 12-fold increased rates of neurodegenerative death compared to the general population. Additionally, players with longer careers—defined as five or more seasons—had nearly double the risk of neurodegenerative death compared to those with shorter careers spanning one to four seasons, reinforcing a dose-response relationship between years of play and brain disease risk that has been identified in studies of chronic traumatic encephalopathy (search) (CTE).
"A fourfold increase in dementia (search) rates from a presumed environmental cause is immense—and brain bank studies indicate that CTE is the primary explanation," said study co-senior author Jesse Mez, MD, MS, Associate Director of the Boston University Alzheimer's Disease Research Center and Co-Director of Clinical Research at the BU CTE Center. "To put that in perspective, heavy lead exposure, which was banned from paint and gasoline in the U.S. due to its neurological and cardiovascular consequences, leads to a 2-to-3 times greater rate of dementia and a 1.5 times greater rate of cardiovascular death."
The STARS Effect: A Paradox of Health and Vulnerability
One of the study's most striking findings was that NFL players had significantly lower overall mortality than the general population despite their dramatically elevated neurodegenerative disease rates. Players were less likely to die from cancer, cardiovascular disease, and suicide—underscoring that this is a population that is generally healthier yet still dying of brain disease at higher rates.
To explain this paradox, the researchers introduced a new concept called the Selection Through Athletic Resilience Survivor (STARS) effect. The STARS effect posits that the same genetic, environmental, medical, and behavioral characteristics that enable individuals to become professional athletes—such as exceptional physical and cognitive performance, resilience, self-discipline, as well as lower rates of smoking and serious early illnesses and injuries—also contribute to longer overall survival. Higher educational attainment and better access to medical care may further offset the effects of other health conditions later in life.
These advantages make the elevated rates of neurodegenerative disease even more striking because NFL players would otherwise be expected to have lower rates of brain disease than the general population due to these health advantages. The STARS effect suggests that the fourfold increase in neurodegenerative disease found in NFL players may actually underrepresent the true relationship between playing in the NFL and neurodegenerative disease.
Notably, neurodegenerative disease deaths were highest in athletes who tend to have the fewest comorbidities. Linemen, who tend to be heavier with higher body mass index and related comorbidities including sleep apnea, had half the dementia (search) mortality compared to non-linemen.
Implications for Player Health and Safety
The findings build upon a previous study of 19,423 players who played at least one NFL game from 1960 through 2019, which concluded that professional football players had a risk of developing ALS (search) that was four times higher than the general population. Neurodegenerative diseases, including dementia (search), ALS, and Parkinson's disease (search), affect tens of millions of people worldwide. While age is typically the biggest risk factor for developing these conditions, studies have consistently revealed that individuals with repetitive head impact exposure—like NFL players—also have higher incidence of the diseases.
The dose-response relationship between career length and neurodegenerative mortality adds further weight to the causal link between repetitive head impacts and long-term brain health outcomes. The research team emphasized that the findings should inform ongoing discussions about player safety across all sports involving head trauma, including hockey, soccer, boxing, and other combat sports.