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Peer-reviewedCC BY-NCBMJ

Prevalence of chronic traumatic encephalopathy at death in National Football League players: retrospective population based cohort study, 2008-21

  • Daniel Hamed Daneshvar1,2,3
  • Christopher J. Nowinski4
  • Bobak Abdolmohammadi5
  • Charlotte B. Luster3
  • Madeline Uretsky6
  • Brett M. Martin7
  • Joseph N. Palmisano7
  • Jennifer Weuve8
  • Michael D. McClean8
  • Jonathan D. Cherry9,10,11
  • Brigid C. Dwyer12
  • Evan D. Feigel3
16 more authors
  • Michael J. Mastrodicasa3
  • Victor E. Alvarez10
  • Gil Dan Rabinovici13
  • William W. Seeley13
  • Lea T. Grinberg14,15,13
  • John F. Crary16
  • Thor D. Stein9,10,11
  • Lee E. Goldstein17
  • Douglas I. Katz12
  • ROSS D. ZAFONTE18
  • Yorghos Tripodis7
  • Robert C. Cantu5,19,20
  • Robert A. Stern5,12,19
  • Michael Louis Alosco5,12
  • Ann Carolyn McKee5,12,21
  • Jesse B Mez5,12,21
21 affiliations
  1. 1Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, USA
  2. 2Department of Physical Medicine and Rehabilitation, Massachusetts General Hospital, Boston, MA, USA
  3. 3Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA 02129, USA
  4. 4Concussion and CTE Foundation, Boston, MA, USA
  5. 5Boston University Alzheimer’s Disease and CTE Centers, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA
  6. 6Department of Psychological Science, University of Connecticut, Storrs, CT, USA
  7. 7Biostatistics and Epidemiology Data Analytics Center, Boston University School of Public Health, Boston, MA, USA
  8. 8Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA
  9. 9Department of Pathology and Laboratory Medicine, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA
  10. 10VA Bedford Healthcare System, US Department of Veteran Affairs, Bedford, MA, USA
  11. 11VA Boston Healthcare System, US Department of Veteran Affairs, Boston, MA, USA
  12. 12Department of Neurology, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA
  13. 13Memory and Aging Center, University of California, San Francisco, CA, USA
  14. 14Department of Laboratory Medicine and Pathology, Mayo Clinic in Florida, Jacksonville, FL, USA
  15. 15Department of Neuroscience, Mayo Clinic in Florida, Jacksonville, FL, USA
  16. 16Department of Pathology, Icahn School of Medicine, Mount Sinai, New York, NY, USA
  17. 17Department of Psychiatry, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA
  18. 18University of Missouri School of Medicine, Columbia, MO, USA
  19. 19Department of Neurosurgery, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA
  20. 20Department of Neurosurgery, Emerson Hospital, Concord, MA, USA
  21. 21Framingham Heart Study, Boston University School of Medicine, Boston, MA, USA
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Abstract

OBJECTIVES: To determine the range of possible prevalences of chronic traumatic encephalopathy (CTE) at death among National Football League (NFL) players and examine the association between CTE severity and risk of dementia. DESIGN: Retrospective population based cohort study. SETTING: NFL players from the era of hard-shell helmets (post-1949) in the US, including brain donors to the UNITE (Understanding Neurologic Injury and Traumatic Encephalopathy) and UCSF ADRC (University of California, San Francisco Alzheimer's Disease Research Center) brain banks. PARTICIPANTS: 1712 former NFL players who died during 2008-21, of whom 338 donated their brains for neuropathological evaluation. Personal information and causes of death according to the National Death Index (NDI) were obtained for all NFL players who died during the study period. Neuropathologists masked to clinical and playing histories assessed postmortem CTE diagnosis and stage IV CTE. Clinicians, masked to neuropathological status, reviewed donors' medical records and informant based clinical histories, to adjudicate a dementia diagnosis. MAIN OUTCOME MEASURES: The main outcome measures were the minimum (number of donors with CTE/total number of NFL deaths) and maximum (1-(number of donors without CTE/total number of NFL deaths)) CTE prevalence at death during the study period and the six years (2016-21) when brain donation was most frequent. To account for selection pressure of brain donation status, inverse probability weighting was used to estimate the association between stage IV CTE and study clinician diagnosed dementia. RESULTS: Among 1712 NFL players who died, 338 (19.7%) players' brains were studied, 315 (93.2%) of whom had a diagnosis of CTE; thus, among all 1712 NFL players who died, the possible CTE prevalence at death ranged between 18.5% and 98.7%. The possible prevalence at death during 2016 to 2021, when brain donation was most frequent, ranged between 24.5% and 97.7%. Among brain donors, 104 (30.8%) had stage IV CTE, 202 (59.8%) had study clinician diagnosed dementia (dementia onset: 63.4 years, standard deviation (SD) 12.5; death: 73.1 years, SD 10.5), and 63 (18.6%) had neurodegenerative disease listed as primary cause of death. In donors, stage IV CTE was associated with study clinician diagnosed dementia (risk ratio 1.44, 95% confidence interval 1.16 to 1.78; P<0.001). Only 40.6% of donors (n=82) with study clinician diagnosed dementia had neurodegenerative disease listed as the primary or secondary cause of death. CONCLUSIONS: At minimum, nearly a quarter of all former NFL players who died during 2016-21 had CTE neuropathology at death. Among NFL player brain donors, dementia diagnosed based on records before death was common and associated with stage IV CTE.

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Cite

BibTeXRIS
BibTeX
@article{daneshvar2026prevalence,
  title = {{Prevalence of chronic traumatic encephalopathy at death in National Football League players: retrospective population based cohort study, 2008-21}},
  author = {Daniel Hamed Daneshvar and Christopher J. Nowinski and Bobak Abdolmohammadi and Charlotte B. Luster and Madeline Uretsky and Brett M. Martin and Joseph N. Palmisano and Jennifer Weuve and Michael D. McClean and Jonathan D. Cherry and Brigid C. Dwyer and Evan D. Feigel and Michael J. Mastrodicasa and Victor E. Alvarez and Gil Dan Rabinovici and William W. Seeley and Lea T. Grinberg and John F. Crary and Thor D. Stein and Lee E. Goldstein and Douglas I. Katz and ROSS D. ZAFONTE and Yorghos Tripodis and Robert C. Cantu and Robert A. Stern and Michael Louis Alosco and Ann Carolyn McKee and Jesse B Mez},
  journal = {BMJ},
  year = {2026},
  month = aug,
  doi = {10.1136/bmj-2026-100418},
  url = {https://doi.org/10.1136/bmj-2026-100418},
  note = {CC BY-NC},
}
RIS
TY  - JOUR
TI  - Prevalence of chronic traumatic encephalopathy at death in National Football League players: retrospective population based cohort study, 2008-21
AU  - Daniel Hamed Daneshvar
AU  - Christopher J. Nowinski
AU  - Bobak Abdolmohammadi
AU  - Charlotte B. Luster
AU  - Madeline Uretsky
AU  - Brett M. Martin
AU  - Joseph N. Palmisano
AU  - Jennifer Weuve
AU  - Michael D. McClean
AU  - Jonathan D. Cherry
AU  - Brigid C. Dwyer
AU  - Evan D. Feigel
AU  - Michael J. Mastrodicasa
AU  - Victor E. Alvarez
AU  - Gil Dan Rabinovici
AU  - William W. Seeley
AU  - Lea T. Grinberg
AU  - John F. Crary
AU  - Thor D. Stein
AU  - Lee E. Goldstein
AU  - Douglas I. Katz
AU  - ROSS D. ZAFONTE
AU  - Yorghos Tripodis
AU  - Robert C. Cantu
AU  - Robert A. Stern
AU  - Michael Louis Alosco
AU  - Ann Carolyn McKee
AU  - Jesse B Mez
PY  - 2026
DA  - 2026/08/25
JO  - BMJ
DO  - 10.1136/bmj-2026-100418
UR  - https://doi.org/10.1136/bmj-2026-100418
AB  - OBJECTIVES: To determine the range of possible prevalences of chronic traumatic encephalopathy (CTE) at death among National Football League (NFL) players and examine the association between CTE severity and risk of dementia. DESIGN: Retrospective population based cohort study. SETTING: NFL players from the era of hard-shell helmets (post-1949) in the US, including brain donors to the UNITE (Understanding Neurologic Injury and Traumatic Encephalopathy) and UCSF ADRC (University of California, San Francisco Alzheimer's Disease Research Center) brain banks. PARTICIPANTS: 1712 former NFL players who died during 2008-21, of whom 338 donated their brains for neuropathological evaluation. Personal information and causes of death according to the National Death Index (NDI) were obtained for all NFL players who died during the study period. Neuropathologists masked to clinical and playing histories assessed postmortem CTE diagnosis and stage IV CTE. Clinicians, masked to neuropathological status, reviewed donors' medical records and informant based clinical histories, to adjudicate a dementia diagnosis. MAIN OUTCOME MEASURES: The main outcome measures were the minimum (number of donors with CTE/total number of NFL deaths) and maximum (1-(number of donors without CTE/total number of NFL deaths)) CTE prevalence at death during the study period and the six years (2016-21) when brain donation was most frequent. To account for selection pressure of brain donation status, inverse probability weighting was used to estimate the association between stage IV CTE and study clinician diagnosed dementia. RESULTS: Among 1712 NFL players who died, 338 (19.7%) players' brains were studied, 315 (93.2%) of whom had a diagnosis of CTE; thus, among all 1712 NFL players who died, the possible CTE prevalence at death ranged between 18.5% and 98.7%. The possible prevalence at death during 2016 to 2021, when brain donation was most frequent, ranged between 24.5% and 97.7%. Among brain donors, 104 (30.8%) had stage IV CTE, 202 (59.8%) had study clinician diagnosed dementia (dementia onset: 63.4 years, standard deviation (SD) 12.5; death: 73.1 years, SD 10.5), and 63 (18.6%) had neurodegenerative disease listed as primary cause of death. In donors, stage IV CTE was associated with study clinician diagnosed dementia (risk ratio 1.44, 95% confidence interval 1.16 to 1.78; P<0.001). Only 40.6% of donors (n=82) with study clinician diagnosed dementia had neurodegenerative disease listed as the primary or secondary cause of death. CONCLUSIONS: At minimum, nearly a quarter of all former NFL players who died during 2016-21 had CTE neuropathology at death. Among NFL player brain donors, dementia diagnosed based on records before death was common and associated with stage IV CTE.
SN  - 1756-1833
ER  -