Former National Football League (NFL) players had higher overall mortality than those who played Major League Baseball (MLB), a head-to-head comparison of elite professional athletes of similar ages showed.
At the end of follow-up, NFL players had a 26% higher rate of all-cause deaths, including a threefold greater likelihood of dying of neurodegenerative disease and more than twofold increased risk of dying from cardiovascular disease, Marc Weisskopf, PhD, ScD, of the Harvard T.H. Chan School of Public Health in Boston, and colleagues reported in .
The number of additional deaths from neurodegenerative conditions was low, but may raise questions about sport-specific differences in disease development and mechanisms. "Even a single preventable or premature death is one too many, so it is critical for scientists and clinicians to pursue further research into teasing out the reasons behind this increased mortality," Weisskopf said in a statement.
Previous research has suggested American football players have . While a small study compared deaths among longstanding NFL players and replacements who played during an NFL players' strike and found no difference in overall death rates, the current analysis is the first to compare deaths of NFL players with another group of professional career athletes.
The study also comes at a time when new evidence about head trauma and chronic traumatic encephalopathy (CTE) among NFL players is emerging.
In this retrospective analysis, Weisskopf and co-authors looked at 3,419 NFL and 2,708 MLB players, all of whom played for at least five seasons, using the National Death Index for vital status and causes of death from 1979 to 2013. NFL players started playing professionally at an average age of 21.8; MLB players started at a mean age of 23.3.
Overall, there were 517 deaths at a mean age of 59.6 in the NFL group, and 431 deaths at a mean age of 66.7 in the MLB group.
Compared with MLB players, NFL players had significantly elevated rates of all-cause mortality (HR 1.26, 95% CI 1.10-1.44), including deaths from neurodegenerative (HR 2.99, 95% CI 1.64-5.45) and cardiovascular (HR 2.40, 95% CI 2.03-2.84) disease.
Cardiovascular disease was named as an underlying or contributing cause of 498 deaths (14.5%) in the NFL group and 225 deaths (8.3%) in the MLB cohort. Neurodegenerative conditions were named in 39 NFL deaths and 16 MLB deaths (1.6% and 0.6%, respectively). NFL players showed a significantly elevated mortality rate from Parkinson's disease, but no significant differences in dementia, Alzheimer's disease, and amyotrophic lateral sclerosis (ALS) death rates.
Overall, the elevated risk translated into 21 more all-cause deaths, 77 more cardiovascular deaths, and 11 more neurodegenerative disease per 1,000 NFL players than MLB players by age 75, Weisskopf and co-authors calculated.
Body composition may account for risk differences, they wrote: "American-style football players generally have higher body mass indexes, an indirect measure of body composition, than baseball players, possibly underlying the elevated cardiovascular disease mortality in our results."
"This study illuminates the importance of former players taking an active step in seeking a comprehensive health evaluation from their doctor," added co-author Ross Zafonte, DO, of Harvard ľֱ School in Boston. "They should ensure they are closely monitored for both cardiovascular and neurological issues, some of which may be treatable."
An important point is that these findings are from athletes who played mainly from the 1960s to the 1980s, noted Zachary Kerr, PhD, MPH, of the University of North Carolina at Chapel Hill, and colleagues, in an . "Of course, American-style football is a sport that allows for intentional contact, and there may be an inherent risk of injury involved for athletes of any era," they wrote. "Yet, American-style football has arguably evolved into a safer sport now in part owing to rules such as banning 'spearing.'"
The study had several limitations: the race of all players was not known, nor was information about genetics, family history, or lifestyle and environmental factors. There may be differences between NFL and MLB players not specific to their sport, the researchers noted. Over the years, training regimens, helmet design and use, and smoking prevalence have changed, they added.
Disclosures
This research was supported by the Spaulding Research Institute and the National Institutes of Health.
Researchers reported relationships with the National Institute for Occupational Safety and Health, the Football Players Health Study at Harvard University which is funded by the NFL, Oakstone, Myomo, Oxeia Biopharmaceuticals, elminda, BioDirection, the Salah Foundation, the ALS Association, ALS Finding a Cure, Amylyx, Target ALS, the Spastic Paraplegia Foundation, MGH, the ALS Therapy Fund, the NFL Players Association, the Sidney R. Baer, Jr. Foundation, Harvard Catalyst, Neuroelectrics, StarLab, Constant Therapy, Neosync, Neuronix, Cognito, the NIH, the American Heart Association, the American Society of Echocardiography, the Department of Defense; U.S. Soccer, U.S. Rowing, the New England Patriots, the Boston Bruins, and the New England Revolution.
The editorialists reported no conflicts.
Primary Source
JAMA Network Open
Nguyen VT, et al "Mortality among professional American-style football players and professional American baseball players" JAMA Netw Open 2019; DOI: 10.1001/jamanetworkopen.2019.4223.
Secondary Source
JAMA Network Open
Kerr ZY, et al "Considerations for present and future research on former athlete health and well-being" JAMA Netw Open 2019; DOI: 10.1001/jamanetworkopen.2019.4222.