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. 2024 Oct 23;81(10):498-506.
doi: 10.1136/oemed-2024-109571.

Career duration and later-life health conditions among former professional American-style football players

Rachel Grashow  1   2 , Can Ozan Tan  3 , Julius Dewayne Thomas  4 , Heather DiGregorio  5   2 , Hang Lee  6 , Ran S Rotem  2 , Dean Marengi  2 , Douglas P Terry  7 , Shawn R Eagle  8 , Grant L Iverson  9   10   11   12 , Alicia J Whittington  5 , Ross D Zafonte  5   9 , Marc G Weisskopf #  5   2 , Aaron L Baggish #  5   13   14
Affiliations

Career duration and later-life health conditions among former professional American-style football players

Rachel Grashow et al. Occup Environ Med. .

Abstract

Objectives: Career duration is often used as a metric of neurotrauma exposure in studies of elite athletes. However, as a proxy metric, career length may not accurately represent causal factors, and associations with health outcomes may be susceptible to selection effects. To date, relationships between professional American-style football (ASF) career length and postcareer health remain incompletely characterised.

Methods: We conducted a survey-based cross-sectional cohort study of former professional ASF players. Flexible regression methods measured associations between self-reported career duration and four self-reported health conditions: pain, arthritis, mood and cognitive symptoms. We also measured associations between career duration and four self-reported ASF exposures: prior concussion signs and symptoms (CSS), performance enhancing drugs, intracareer surgeries and average snaps per game. Models were adjusted for age and race.

Results: Among 4189 former players (52±14 years of age, 39% black, 34% lineman position), the average career length was 6.7±3.9 professional seasons (range=1-20+). We observed inverted U-shaped relationships between career duration and outcomes (all p<0.001), indicating that adverse health effects were more common among men with intermediate career durations than those with shorter or longer careers. Similar findings were observed for play-related exposures (eg, CSS and snaps).

Conclusions: Relationships between ASF career duration and subsequent health status are non-linear. Attenuation of the associations among longer career players may reflect selection effects and suggest career length may serve as a poor proxy for true causal factors. Findings highlight the need for cautious use of career duration as a proxy exposure metric in studies of former athletes.

Keywords: Epidemiology; Occupational Health; Osteoarthritis; Wounds and Injuries.

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Conflict of interest statement

Competing interests: ALB has received funding from the National Institute of Health/National Heart, Lung and Blood Institute, the National Football Players Association and the American Heart Association and receives compensation for his role as team cardiologist from the US Olympic Committee/US Olympic Training Centers, US Soccer, US Rowing, the New England Patriots, the Boston Bruins, the New England Revolution and Harvard University. GLI has a clinical and consulting practice in forensic neuropsychology, including expert testimony, involving individuals who have sustained mild TBIs (including former athletes). He has received past research support or funding from several test publishing companies, including ImPACT Applications, CNS Vital Signs and Psychological Assessment Resources (PAR). He receives royalties from the sales of one neuropsychological test (WCST-64). He has received research funding as a principal investigator from the National Football League, and subcontract grant funding as a collaborator from the Harvard Integrated Program to Protect and Improve the Health of National Football League Players Association Members. He has received research funding from the Wounded Warrior Project. He acknowledges unrestricted philanthropic support from ImPACT Applications, the Mooney-Reed Charitable Foundation, the National Rugby League, Boston Bolts and the Schoen Adams Research Institute at Spaulding Rehabilitation. RDZ reported receiving royalties from Springer/Demos publishing for serving as coeditor of the text Brain Injury Medicine; serving on the scientific advisory board of Myomo, and onecare.ai; evaluating patients in the Massachusetts General Hospital Brain and Body–TRUST Programme, which is funded by the NFL Players Association and receiving grants from the NIH. MGW reported receiving grants from the NFL Players Association and the NIH during the conduct of the study. DPT serves on the Scientific Advisory Board for HitIQ and previously consulted for REACT Neuro. JDT serves as CEO of Mastery Development, Chief Health Innovation and Performance officer NESTRE Health and Performance, as Vice President of the Society for Sports Neuroscience, RG, HD, AJW and DM received grant funding from the NFL Players Association. No other disclosures were reported.

Figures

Figure 1
Figure 1. ORs (black) or β estimates (blue) with 95% CIs for four health outcomes by number of professional seasons. (A) chronic pain, (B) arthritis, (C) mental health problems (anxiety or depression) and (D) subjective cognitive symptoms (Neuro-QOL). All models adjusted for age, race and linemen status. Red line denotes null value of 1.0 for ORs and 0.0 for β estimates.
Figure 2
Figure 2. Spline regression models of number of professional seasons in relation to (A) chronic pain, (B) arthritis, (C) mental health problems (anxiety or depression) and (D) subjective cognitive symptoms for all positions (purple), and stratified by linemen (red) and non-linemen (blue). All models were adjusted for age, race and linemen status (unless stratified by this variable). Dashed line extrapolates the trend using the first slope and intercept identified by the piecewise linear regression for each outcome. X-axis visuals are limited to 20 seasons to protect participant identity.
Figure 3
Figure 3. Spline regression models of number of professional seasons in relation to (A) concussion signs and symptoms score, (B) mean snaps per game, (C) use of performance enhancing drugs and (D) number of active career surgeries. Splines shown for all positions (purple) and stratified by linemen (red) and non-linemen (blue). All models were adjusted for age, race and linemen status (unless stratified by this variable). Dashed line extrapolates the trend using the first slope and intercept identified by the piecewise linear regression for each outcome. X-axis visuals are limited to 20 seasons to protect participant identity.
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