New research sheds further light on the dangers and risks of playing full-contact American football professionally.

A new study conducted by the Concussion & CTE Foundation in conjunction with Mass General Brigham and Boston University found NFL players have a higher risk of death due to neurogenerative disease at a rate four times greater than the general population.

As a medical term, 'neurogenerative disease' includes ALS, MS, Parkinson's, Alzheimer's, dementia and Huntington's disease among others.

The study also found that players who were in the NFL for five or more seasons had 'nearly double the risk' of neurogenerative death compared to those who played four seasons or fewer.

'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 Dr. Daniel Daneshvar, the Chair of Physical Medicine and Rehabilitation at Mass General Brigham 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 and Parkinson's disease three to four times more often than they should.'

While neurogenerative conditions occur more frequently in NFL players, these athletes generally live longer than non-NFL players. 

The study says, '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.'

However, an all-too-common condition in NFL players - chronic traumatic encephalopathy (CTE) - appears to be the primary cause.

'A fourfold increase in dementia rates from a presumed environmental cause is immense — and brain bank studies indicate that CTE is the primary explanation,' said Dr. Jesse Mez, 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.'

A previous study of over 19,000 players who took the field in at least one NFL game from 1960 through 2019 found that pro football players had a risk of developing ALS which was four-times greater than the general population.

Despite this grim reality, NFL players are aware of these risks as research linking football to neurogenerative issues have been linked for decades. 

Additionally, there are plenty of other sports - including hockey, soccer and combat sports - which involve hits to the head.