Association of Playing High School Football With Cognition and Mental Health Later in Life

Abstract

Importance: American football is the largest participation sport in US high schools and is a leading cause of concussion among adolescents. Little is known about the long-term cognitive and mental health consequences of exposure to football-related head trauma at the high school level.

Objective: To estimate the association of playing high school football with cognitive impairment and depression at 65 years of age.

Design, setting, and participants: A representative sample of male high school students who graduated from high school in Wisconsin in 1957 was studied. In this cohort study using data from the Wisconsin Longitudinal Study, football players were matched between March 1 and July 1, 2017, with controls along several baseline covariates such as adolescent IQ, family background, and educational level. For robustness, 3 versions of the control condition were considered: all controls, those who played a noncollision sport, and those who did not play any sport.

Exposures: Athletic participation in high school football.

Main outcomes and measures: A composite cognition measure of verbal fluency and memory and attention constructed from results of cognitive assessments administered at 65 years of age. A modified Center for Epidemiological Studies' Depression Scale score was used to measure depression. Secondary outcomes include results of individual cognitive tests, anger, anxiety, hostility, and heavy use of alcohol.

Results: Among the 3904 men (mean [SD] age, 64.4 [0.8] years at time of primary outcome measurement) in the study, after matching and model-based covariate adjustment, compared with each control condition, there was no statistically significant harmful association of playing football with a reduced composite cognition score (-0.04 reduction in cognition vs all controls; 97.5% CI, -0.14 to 0.05) or an increased modified Center for Epidemiological Studies' Depression Scale depression score (-1.75 reduction vs all controls; 97.5% CI, -3.24 to -0.26). After adjustment for multiple testing, playing football did not have a significant adverse association with any of the secondary outcomes, such as the likelihood of heavy alcohol use at 65 years of age (odds ratio, 0.68; 95% CI, 0.32-1.43).

Conclusions and relevance: Cognitive and depression outcomes later in life were found to be similar for high school football players and their nonplaying counterparts from mid-1950s in Wisconsin. The risks of playing football today might be different than in the 1950s, but for current athletes, this study provides information on the risk of playing sports today that have a similar risk of head trauma as high school football played in the 1950s.

Conflict of interest statement

Conflict of Interest Disclosures: None reported.

Figures

Figure 1.. Postmatching Distributions of Primary Outcomes

A, Postmatching distributions of the composite cognition score in 2003 for football players (T), all controls (C), nonsport controls (C1), and other sport controls (C2). B, Distributions of the modified Center for Epidemiological Studies’ Depression Scale (CES-D) score in 2003. The lower limits of the boxes indicate the weighted, empirical second, third, sixth, 13th, and 25th percentiles (from bottom to top), and the upper limits indicate the 98th, 97th, 94th, 87th, and 75th percentiles (from top to bottom). The sizes of the outliers are proportional to their weights. The red cross indicates the weighted sample mean, and the black horizontal line indicates the weighted sample median. The points beyond are outliers beyond the 98th and second percentiles.

Figure 2.. Longitudinal Trajectories of Outcomes Adjusted for Covariates

Longitudinal trajectories of estimated mean cognitive test and modified Center for Epidemiological Studies’ Depression Scale (CES-D) scores for football players, with mean values of the covariates among football players (blue line) along with 95% CIs at each time point. Also shown are the counterfactual trajectories for the same individuals (ie, with mean values of the covariates among football players) had they not played football (orange line). P values are shown for testing the null hypothesis that the change in mean scores between successive ages for football players and controls, adjusted for covariates, are equal. WAIS-R indicates Wechsler Adult Intelligence Scale–Revised.