A medical study has reached an unsettling conclusion for NFL players: their risk of certain diseases is massively increased.

Unwelcome news from the NFL: A study by the Mass General Brigham health system, Boston University, and the Concussion & CTE Foundation concludes that NFL players have an almost four times higher risk of dying from neurodegenerative diseases than the general population.

“This is the clearest population-level evidence we’ve ever had that NFL players die at a truly and measurably higher rate due to neurodegenerative diseases,” says Dr. Daniel Daneshvar, Chair of Physical Medicine and Rehabilitation at Mass General Brigham.

He adds: “This study shows that when we look at athletes who have played in an NFL game—including nearly 20,000 players—and take all official causes of death into account, the result is the same: NFL players die from dementia and Parkinson’s disease three to four times more often than would be expected.”

The broad term “neurodegenerative diseases” includes ALS, Parkinson’s, and dementia.

NFL players generally live longer

Important: The length of an NFL career is a key factor in the risk. Athletes who play five or more seasons in the NFL have “nearly twice the risk” of dying from such a disease than those who played only one to four years.

“A fourfold increase in dementia rates due to a suspected environmental cause is enormous—and the studies suggest that CTE is the main cause,” said Dr. Jesse Mez, associate director of the Alzheimer’s Research Center at Boston University.

The good news: NFL players generally live longer than non-NFL players.

Previous study with similar findings

According to the studies, “the same genetic, environmental, medical, and behavioral characteristics that enable people to become professional athletes—such as exceptional physical and cognitive performance, resilience, self-discipline, as well as lower smoking rates and fewer serious premature illnesses and injuries—also contribute to longer overall survival.”

An earlier study of 19,423 players who had played in at least one NFL game between 1960 and 2019 had already concluded that professional football players have a four times higher risk of developing ALS.