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Brain Injury in the NFL

Posted on by Everett Lehman, MS

It’s that time of year again—football season.  While pro, college and pee wee football players and fans across the country prepare for the annual rituals of the game, questions of safety linger on the sidelines.  A new study from the National Institute for Occupational Safety and Health (NIOSH) finds that National Football League (NFL) players may be at a higher risk of death associated with Alzheimer’s and other impairments of the brain and nervous system than the general U.S. population. These results are consistent with recent studies by other research institutions that suggest an increased risk of neurodegenerative disease among professional football players.

The paper, “Neurodegenerative causes of death among retired National Football League players,” published in the journal Neurology looked at a cohort of 3,439 NFL players with at least five playing seasons between 1959-1988. While NFL players on average live longer than the average American male, the new research found that the overall risk of death associated with neurodegenerative disorders was three times higher among the study group than the general U.S. population.  The risk for two major subcategories, Alzheimer disease and ALS (also known as Lou Gehrig’s disease), was four times higher for the NFL players.

In addition to the overall comparison with the general population, the study also compared the deaths of players associated with neurodegenerative disorders based on playing positions.  More neurodegenerative deaths were observed among players in “speed” positions (quarterback, running back, halfback, fullback, wide receiver, tight end, defensive back, safety, and linebacker) compared with players in “non-speed” positions (all defensive and offensive linemen).  Other research studies have shown that speed players may be at higher risk of concussion since they can build considerable momentum prior to the point of being tackled or tackling another player. Offensive and defensive linemen usually engage other players soon after the football is snapped, mitigating the potential to build up momentum to a tackle or a block.

Study limitations

While our study is consistent with  other recent studies that have found increased risk of neurodegeneration among NFL football players, our research has several limitations.  Some of the limitations are listed below.

  • It is not possible to determine from our study the cause of the increased risk of death from neurodegenerative disorders.  Research suggests that football players who have experienced one or more concussive blows to the head are at increased risk of neurologic disorders but our study does not establish a cause-effect relationship between football-related concussions and death from neurodegenerative disorders.
  • Since our cohort was limited to longer-term professional players, our findings may not be applicable to those who play for a shorter term or high school and college football players.  The magnitude of risk may depend on the intensity and frequency of brain injuries incurred over a number of years.
  • The study relied on death certificate information for causes of death; at the time of analysis only 10 percent of the participants had died. Of the 334 players who had died, Alzheimer’s, ALS, and Parkinson’s Disease were listed for 17 of them. The small number of deaths used in the study only allowed us to place players into two broad position categories.  We were not able to identify potentially important differences in neurodegenerative mortality risk across the various positions included within the speed position group.
  • Other studies have suggested that Chronic Traumatic Encephalopathy (CTE), which can exhibit symptoms similar to Alzheimer’s disease and ALS, may occur years after sustaining football-related concussions. Since CTE is a newly confirmed diagnosis, it is possible that some deaths attributed to Alzheimer’s or ALS on death certificates may actually have been related to CTE. A brain autopsy is necessary to diagnose CTE and distinguish it from Alzheimer’s or ALS; no death certificate would have listed CTE as a cause.
  • We did not have information on environmental, genetic or other risk factors for neurologic disorders.

Additional studies to quantify the cumulative effects of brain injuries, in particular the relative effects of concussive-level injuries, will be of particular importance in understanding the underlying disease mechanisms not only in football but other sports where head injuries are common such as soccer, boxing, horse racing and hockey.

Everett Lehman, MS

Mr. Lehman is an occupational epidemiologist and deputy division director  in NIOSH’s Division of Surveillance, Hazard Evaluations & Field Studies.

See also NFL Players Tackling Heart Disease

Posted on by Everett Lehman, MS

16 comments on “Brain Injury in the NFL”

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    This is the reason I play soccer (football to the rest of the world) instead of American Football; no brain injuries for me thanks.

    It is true that concussion is several times more likely to occur during (American-style) football play than during soccer, but concussions are not rare in soccer. In one study of high school sports during the 2005-2006 sports season, approximately 21,000 boys and 29,000 girls received concussions while playing soccer.1 About 1,000 of the soccer-related concussions required treatment in an emergency room.2 So soccer players are at risk of concussion and steps should be taken to minimize that risk whenever possible; if concussions do occur, they should be treated properly. An excellent source of information on the identification, management and treatment of concussion in youth sports can be found at the following Centers for Disease Control and Prevention website:

    1. Gessel LM, Fields SK, Collins CL, Dick RW, Comstock RD. Concussions Among United States High School and Collegiate Athletes. J Athl Train. 2007; 42(4): 495–503.
    2. Gilchrist J, Thomas KE, Xu L, McGuire LC, Coronado VG. Nonfatal sports and recreation related traumatic brain injuries among children and adolescents treated in emergency departments in the United States, 2001-2009. MMWR 2011: 60(39);1337-1342.

    I am a brain injury lawyer in St. Louis and have dealt with a number of TBI cases. No question repetitive and even a single incidence of head trauma causes TBI. But I was always curious beyond this, what is the effect of TBI on the family? Recently, there was an interesting study done by Eleonore Bayen, MD (part of the PariS-TBI study) investigating the predictors of informal care burden 1 year after a TBI. The study concludes informal caregivers suffer significant health problems and subjective sense of burden caring for loved ones with brain injury. So, the effects of brain injury are not limited to the victim alone- they transcend to the caregiver, which is a huge issue.

    As an injury lawyer based in Miami, I completely agree with Ryan: there is far more damage to any brain injury than meets the eye.

    This article is very helpful, I think it is true that a concussion is more likely to occur several times during play football.

    Having injuries in playing close contact sports is inevitable especially the American football. Even in playing soccer. The players of these two sports almost have the same injuries.

    its being nice to see the safety measures are now taken so seriously at the sports planet futsal thanks you GOV for making sports so safe for us and our children, i am a big fan of soccer

    This is a great blog I wasn’t aware this was such a problem we have lots of head injuries with kids playing football in the UK. I think I will write about this on my site

    I would also prefer that my kids play soccer instead of American football. Soccer is by no means ian injury free sport, as has been pointed out by others comments here, but it is very rare to see any retired professional soccer player or a long time player suffer from any of the aggravated issues that seem to plague football players and boxers, to name two types of athletes who endure frequent head-related blows.

    As someone who loves football, in fact I can’t for 2014 NFL picks. Its a very interesting article, I think athlete or players should take care of their health. It’s a good thing that the government is now paying attention for sports to be safe.

    This is a great blog I wasn’t aware this was such a problem we have lots of head injuries with kids playing football in the UK. I think I will write about this on my site

    Concussion has just recently, started to become taken seriously in the UK. It is a potentially a massive problem waiting to happen in MMA also, with some retired fighters already reporting pugilist dementia. Having had concussion 5 time myself I wrote a short article on the topic []

    This is a great blog I wasn’t aware this was such a problem we have lots of head injuries with kids playing football in the UK. I think I will write about this on my site

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