NFL Dementia Deaths Often Miss Neurodegenerative Diagnosis

Fewer than one-third of former National Football League (NFL) players who died following a clinician-adjudicated diagnosis of dementia had a neurodegenerative disease (NDD) listed as the underlying cause of death on their official death certificate, according to a new cohort study published online today in JAMA Network Open.¹ This gap between clinical diagnosis and legal cause-of-death records potentially suggests that studies relying on death certificates substantially undercount neurodegenerative mortality in this population, with implications for how occupational brain injury risk is measured and communicated to players, families, and policymakers.

Who Was the Patient Population?

The study drew on 202 male brain donors from the UNITE (Understanding Neurologic Injury and Traumatic Encephalopathy) Brain Bank, recruited between February 2008 and December 2021. All had clinician-adjudicated dementia, determined by consensus review of medical records, informant interviews, and validated cognitive and functional scales, double-blinded to eventual neuropathology results. Donors died at a mean (SD) age of 73.1 (10.5) years, 78.7% had a college degree or a higher level of education, 27.7% reported Black or African American race, and 70.8% reported being of a White race.

Ninety-six percent of the entire study population also had confirmed chronic traumatic encephalopathy (CTE) on autopsy, echoing earlier UNITE Brain Bank findings that CTE was present in 96% of examined NFL brains.²

Death Certificates That Named a Neurodegenerative Cause

Only 62 of 202 donors (30.7%) had an NDD listed as the underlying cause of death; another 20 (9.9%) had NDD noted only as a contributing cause. Among the remaining dead persons, cardiovascular disease (32.9%), unspecified “other” causes (35.0%), cancer (11.4%), injury (7.9%), and suicide (2.1%) were listed. Donors whose death certificates named an NDD were older at death (78 vs 71 years) and more likely to be White (82.3% vs 65.7%) compared with those without NDD certification.

In adjusted logistic regression models, markers of disease severity beyond the presence of dementia alone were associated with higher odds of NDD certification. Worse informant-rated executive function as measured by the BRIEF-A Global Executive Composite T-score, cognitive complaints evaluated via the BRIEF-A Metacognition Index T-score and Cognitive Difficulties Scale total score, and functional impairment looked at through the Functional Activities Questionnaire total score were modestly associated with higher odds:

• BRIEF-A Global: OR, 1.04 (95% CI, 1.01-1.06; P = .008)
• BRIEF-A Metacognition Index: OR, 1.03 (95% CI, 1.01-1.06; P = .01
• Cognitive Difficulties Scale: 1.02 (95% CI, 1.01-1.03; P = .006)
• Functional Activities Questionnaire: 1.13 (95% CI, 1.06-1.21; P < .001)

In comparison, high Alzheimer disease burden carried the strongest association (OR, 5.27; 95% CI, 1.93-14.40; P = .001), followed by Thal phase 4 amyloid staging (OR, 4.50; 95% CI, 1.39-14.60; P = .01), frontotemporal lobar degeneration (OR, 4.48; 95% CI, 1.61-12.50; P = .004), frequent diffuse plaques (OR, 4.21; 95% CI, 1.56-11.38; P = .005), history of emergency department treatment for a head injury (OR, 4.11; 95% CI, 1.72-9.82; P = .002), moderate to severe plaques (OR, 3.42; 95% CI, 1.55-7.54; P = .002), and Braak stage IV to VI tau pathology (OR, 2.99; 95% CI, 1.54-5.79; P = .001). Residing in memory care or a nursing home (OR, 2.29; 95% CI, 1.16-4.56; P = .02) at death was also linked to higher odds of NDD certification, although, unlike the other factors, this association did not hold after adjustment.

Overall, the authors reported, “Only 30.7% of former NFL players with clinician-adjudicated dementia had NDD listed as the underlying cause of death, with more severe disease associated with NDD death certification.”

How Do These Results Compare With Broader Underreporting Trends?

Their pattern is consistent with wider literature on dementia undercounting outside football. A systematic review of population-based cohorts found dementia listed on only 7.2% to 41.8% of death certificates of patients with documented diagnoses.³ Prior NFL mortality studies have relied on this same underlying-cause field to estimate occupational neurodegenerative risk,^4,5 a field the new analysis found misses an estimated 69% of dementia-related deaths, raising questions about how accurately those earlier studies captured true NDD burden.

Because NFL players tend to have lower mortality from competing causes, such as cardiovascular disease, the study authors argued that certificate-based undercounting could disproportionately distort mortality statistics used to evaluate player safety. The authors also pointed to systematic underreporting among Black players as a compounding factor. The NDD-certified donors were more likely to be White (82.3%) than those without NDD certification (65.7%).

The Impact on Player Health Policy

The study authors highlight a policy wrinkle: decedents in memory care or nursing home facilities were more likely to receive NDD certification than those receiving home care, a distinction that intersects with the NFL’s 88 Plan, which funds more than $100,000 annually in home care benefits for players with qualifying neurological conditions.⁶ If that benefit keeps more players at home rather than in facilities, the authors suggest, it could inadvertently contribute to lower rates of NDD certification. Previous research also shows that in the broader Alzheimer disease space, incomplete capture of dementia-related mortality and cost data complicates population health planning and resource allocation for managed care organizations and payers.⁷

The present study authors call for population-level frameworks capable of identifying NDD cases in living individuals across the full severity spectrum, rather than relying solely on death certificate data, to more accurately capture disease burden and inform surveillance and resource decisions going forward.

References

1. Luster CB, Nowinski CJ, Abdolmohammadi B, et al. Neurodegenerative disease death certification among National Football League players with dementia. JAMA Netw Open. 2026;9(9):e2631614. doi:10.1001/jamanetworkopen.2026.31614
2. Caffrey M. College football player's brain disease highlights youth risk, 10 years after report that inspired film. AJMC^®. January 4, 2016. Accessed August 31, 2026. https://www.ajmc.com/view/college-football-players-brain-disease-highlights-youth-risk-10-years-after-report-that-inspired-film
3. Romero JP, Benito-León J, Louis ED, Bermejo-Pareja F. Underreporting of dementia deaths on death certificates: a systematic review of population-based cohort studies. J Alzheimers Dis. 2014;41(1):213-221. doi:10.3233/JAD-132765
4. Lehman EJ, Hein MJ, Baron SL, Gersic CM. Neurodegenerative causes of death among retired National Football League players. Neurology. 2012;79(19):1970-1974. doi:10.1212/WNL.0b013e31826daf50
5. Nguyen VT, Zafonte RD, Chen JT, et al. Mortality among professional American-style football players and professional American baseball players. JAMA Netw Open. 2019;2(5):e1942234. doi:10.1001/jamanetworkopen.2019.4223
6. Deubert CR, Cohen IG, Lunch HF. Comparing health-related policies & practices in sports: the NFL and other professional leagues. Petrie-Flom Center for Health Law Policy, Biotechnology, and Bioethics, Harvard Law School. May 17, 2017. Accessed August 31, 2026. https://footballplayershealth.harvard.edu/wp-content/uploads/2017/05/Harvard-Comparative-League-Analysis-5.15.17.pdf
7. Skaria AP. The economic and societal burden of Alzheimer disease: managed care considerations. AJMC. September 12, 2022. Accessed August 31, 2026. https://www.ajmc.com/view/the-economic-and-societal-burden-of-alzheimer-disease-managed-care-considerations