title: Neurodegenerative causes of death among retired National Football League players.
abstract: OBJECTIVE
  To analyze neurodegenerative causes of death, specifically Alzheimer disease (AD), Parkinson disease, and amyotrophic lateral sclerosis (ALS), among a cohort of professional football players.
  
  
  METHODS
  This was a cohort mortality study of 3,439 National Football League players with at least 5 pension-credited playing seasons from 1959 to 1988. Vital status was ascertained through 2007. For analysis purposes, players were placed into 2 strata based on characteristics of position played: nonspeed players (linemen) and speed players (all other positions except punter/kicker). External comparisons with the US population used standardized mortality ratios (SMRs); internal comparisons between speed and nonspeed player positions used standardized rate ratios (SRRs).
  
  
  RESULTS
  Overall player mortality compared with that of the US population was reduced (SMR 0.53, 95% confidence interval [CI] 0.48-0.59). Neurodegenerative mortality was increased using both underlying cause of death rate files (SMR 2.83, 95% CI 1.36-5.21) and multiple cause of death (MCOD) rate files (SMR 3.26, 95% CI 1.90-5.22). Of the neurodegenerative causes, results were elevated (using MCOD rates) for both ALS (SMR 4.31, 95% CI 1.73-8.87) and AD (SMR 3.86, 95% CI 1.55-7.95). In internal analysis (using MCOD rates), higher neurodegenerative mortality was observed among players in speed positions compared with players in nonspeed positions (SRR 3.29, 95% CI 0.92-11.7).
  
  
  CONCLUSIONS
  The neurodegenerative mortality of this cohort is 3 times higher than that of the general US population; that for 2 of the major neurodegenerative subcategories, AD and ALS, is 4 times higher. These results are consistent with recent studies that suggest an increased risk of neurodegenerative disease among football players.
authors.affiliation: Centers for Disease Control and Prevention, The National Institute for Occupational Safety and Health, Division of Surveillance, Hazard Evaluations and Field Studies, Cincinnati, OH, USA. elehman@cdc.gov
authors.forename: Everett J
authors.initials: EJ
authors.lastname: Lehman
authors.forename: Misty J
authors.initials: MJ
authors.lastname: Hein
authors.forename: Sherry L
authors.initials: SL
authors.lastname: Baron
authors.forename: Christine M
authors.initials: CM
authors.lastname: Gersic
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001265:Athletic Injuries / Q000150:complications / Q000453:epidemiology / Q000401:mortality; D002423:Cause of Death; D015331:Cohort Studies; D005538:Football; D006801:Humans; D008297:Male; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000453:epidemiology / Q000209:etiology / Q000401:mortality; D012016:Reference Values; D012179:Retirement; D012189:Retrospective Studies