NFL Players at Risk for Death From Alzheimer's, ALS

Megan Brooks

September 05, 2012

September 5, 2012 — Professional football players in the United States have about a 3-fold higher risk for death from neurodegenerative disease than their peers in the general US population, a new study shows.

They have a 4-fold higher risk for death from Alzheimer's disease (AD) or amyotrophic lateral sclerosis (ALS), results suggest.

The findings "are consistent with recent studies that suggest an increased risk of neurodegenerative disease among football players," say the authors, led by Everett J. Lehman, MS, an epidemiologist with the National Institute for Occupational Safety and Health, in Cincinnati, Ohio.

The study is published online September 5 in Neurology.

"Important" Study

"These data do support the concept that professional football players may have an increased risk of developing a neurodegenerative disease," Jeffrey S. Kutcher, MD, associate professor in the Department of Neurology at the University of Michigan, and director of Michigan NeuroSport, told Medscape Medical News. "It's an important study that further describes this relationship," added Dr. Kutcher, who was not involved in the study.

Lehman and colleagues examined causes of death (through 2007) from AD, ALS, and Parkinson's disease (PD) in 3439 NFL players who played at least 5 seasons from 1959 to 1988. The cohort is relatively young (median age at date last observed, 57), and only 10% are deceased, the authors note.

The NFL players had an overall decreased mortality rate relative to the general US male population (standardized mortality ratios [SMRs], 0.53; 95% confidence interval [CI], 0.48 - 0.59).

However, the NFL players had a significantly increased mortality rate from neurodegenerative causes. A neurodegenerative cause was listed as the underlying cause of death in 10 players (SMR, 2.83; 95% CI, 1.36 - 5.21) and as a contributing cause in 17 (SMR, 3.26; 95% CI, 1.90 - 5.22).

Among neurodegenerative causes, the highest risk was for ALS (SMR, 4.31; 95% CI, 1.73 - 8.87) and AD (SMR, 3.86; 95% CI, 1.55 - 7.95). NFL players had a non–statistically significant increased risk of dying from PD (SMR, 1.69; 95% CI, 0.35 - 4.94).

Speed Position Players Most Vulnerable

It is not surprising that player position had an impact on risk.

Researchers found a greater number of neurodegenerative deaths among players in "speed" positions such as quarterback, running back, wide receiver, and linebacker, compared with players in nonspeed positions such as defensive and offensive linemen (SMR, 3.29; 95% CI, 0.92 - 11.7).

"This may be due to the fact that 'speed' players are able to build up considerable momentum prior to the point of being tackled or tackling another player," Lehman told Medscape Medical News. "The magnitude of risk may depend on the intensity and frequency of brain injuries occurring over a number of years," he added.

Lehman also noted that although a greater number of neurodegenerative deaths were observed among speed players, investigators were not able to determine whether football-related concussions led to these deaths.

Dr. Kutcher, a member of the American Academy of Neurology, emphasized that the study "doesn't speak to causality, of course, further highlighting the need for well-done basic science and clinical research. It is also extremely important to note that the football population had an overall decreased mortality rate," he added.

The potential neurologic impact of playing in the NFL is highlighted in a recent study of retired NFL players, in which one third met criteria for mild cognitive impairment (MCI), despite an average age of 61 years.

These findings were presented at the 2011 Alzheimer's Association International Conference and were reported by Medscape Medical News at that time.

Risk at High School, College Level Unknown

Lehman emphasized that the study examined only long-term, professional athletes, whose training and exposures are very different from those of short-term professionals and nonprofessionals participating at the high school or college level. "Additional research would be needed to determine the potential risks for those individuals," he said.

Still, the authors note in their article that recent autopsy studies have reported pathologic findings of chronic traumatic encephalopathy (CTE) in college-age and professional football players with relatively short playing careers.

Although the current study looked at causes of death specifically from AD, ALS, and PD, as shown on death certificates, research now suggests that CTE may be the "true primary or secondary factor in some of these deaths," the authors note.

"If future research strengthens the relationship between concussive/subconcussive impacts to the head and neurodegenerative diseases, the public health implications could be significant," Lehman told Medscape Medical News.

NFL Committed to Research

In related news, the Foundation for the National Institutes of Health (FNIH) announced today that the NFL will donate $30 million in support of research on serious medical conditions prominent among athletes and relevant to the general population. This is the largest philanthropic gift given by the NFL during the League's 92-year history.

With this contribution, the NFL becomes the founding donor to a new Sports and Health Research Program, which will be conducted in collaboration with institutes and centers at the National Institutes of Health (NIH).

The FNIH says that the potential relationship between traumatic brain injury and late-life neurodegenerative disorders, especially AD, is one potential topic of research.

Other potential topics of study include CTE, concussion, chronic degenerative joint disease, the transition from acute to chronic pain, sudden cardiac arrest in young athletes, and heat- and hydration-related illness and injury.

The FNIH hopes to welcome other donors, including additional sports organizations, to the collaboration. "We are looking forward to working with the NFL and other organizations to conduct research on a host of medical conditions affecting athletes," Story C. Landis, PhD, director of the National Institute of Neurological Disorders and Stroke, said in a statement. "Findings from this research will provide us with better ways to detect, diagnose, and treat these conditions, and in some cases even prevent their occurrence."

NFL commissioner Roger Goodell said, "We hope this grant will help accelerate the medical community's pursuit of pioneering research to enhance the health of athletes past, present, and future. This research will extend beyond the NFL playing field and [will] benefit athletes at all levels and others, including members of our military."

The study was supported by the National Institute for Occupational Safety and Health. The authors and Dr. Kutcher have disclosed no relevant financial relationships.

Neurology. Published online September 5, 2012. Abstract


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