Former National Football League players had nearly four times the neurodegenerative mortality of the general US population despite lower overall mortality. Accounting for competing mortality risks, researchers found the excess remained approximately threefold higher, suggesting the association was not fully explained by the longer survival of elite athletes.

Researchers conducted a population-based retrospective cohort study of all current and former National Football League (NFL) players who debuted from 1960 to 2019 and played at least one regular- or postseason game. The analysis included 19,824 players contributing more than 518,000 person-years of follow-up. National Death Index records from 1979 through 2023 were matched with Sports Reference, LLC, data, and mortality was compared with that of the age-, sex-, race-, and calendar year-standardized US population. Differences by playing position, race, career duration, and age at death were also examined. Sensitivity analyses were performed to assess whether competing causes of death could explain the findings.

During follow-up, 1,994 players died, including 178 from neurodegenerative disease. Although overall mortality was 30% lower than expected, neurodegenerative mortality was nearly fourfold higher than that of the general population. Mortality from amyotrophic lateral sclerosis, all-cause dementia, and Parkinson disease was also approximately four times higher than expected.

The excess neurodegenerative mortality was not uniform across the cohort. Players in speed positions had higher neurodegenerative mortality than nonspeed players and about twice the mortality from all-cause dementia. Players whose careers lasted at least 5 years had higher neurodegenerative, dementia, and Parkinson disease mortality than those with shorter careers. Non-White players had higher mortality from amyotrophic lateral sclerosis than White players, although researchers observed no racial differences for the other neurodegenerative outcomes. Players who died before age 60 also had higher neurodegenerative mortality than older players relative to age-standardized population rates.

To determine whether the lower mortality from cancer, cardiovascular disease, injury, suicide, and other causes among elite athletes could account for the findings, researchers performed a competing-risk analysis. They found that neurodegenerative mortality remained approximately threefold higher than expected after accounting for these survivorship advantages, indicating that differential survivorship alone did not explain the observed association.

Researchers noted several limitations. The observational, retrospective design precludes conclusions about causality. Death certificates may misclassify neurodegenerative causes of death, and chronic traumatic encephalopathy could not be identified because it is not routinely recorded as an underlying cause of death. In addition, football participation, playing position, and career duration served as proxies for repetitive head impact (RHI) exposure rather than direct measures of cumulative exposure. The findings also apply only to male NFL players and may not be generalizable to other football populations.

The findings provide additional evidence that former NFL players experienced higher neurodegenerative mortality than the general population while also demonstrating lower overall mortality. Researchers reported that the excess neurodegenerative mortality persisted even after accounting for the survivorship advantages associated with elite athletic participation.

"These results strongly support the increased risk of RHI exposure-related neurodegenerative mortality among NFL players that cannot be explained by differential survivorship, reinforcing the need for policies limiting RHI exposure and supporting evaluation of healthspan-focused interventions," wrote lead study author Charlotte B. Luster, of the Department of Physical Medicine and Rehabilitation at Spaulding Rehabilitation Hospital, and colleagues.

Disclosures: Charlotte B. Luster and Michael J. Mastrodicasa reported receiving clinical funding from the Brain and Body Program funded by the NFL Players Association outside the submitted work. Several coauthors reported additional relationships with the NFL, the NFL Players Association, or related organizations. Full disclosure statements are available with the published article.

Source: eClinicalMedicine