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JAMA Neurol. 2019 Aug 26. doi: 10.1001/jamaneurol.2019.2664. [Epub ahead of print]

Association of Concussion Symptoms With Testosterone Levels and Erectile Dysfunction in Former Professional US-Style Football Players.

Author information

Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, Massachusetts.
Football Players Health Study, Harvard Medical School, Boston, Massachusetts.
Environmental and Occupational Medicine and Epidemiology Program, Harvard T. H. Chan School of Public Health, Boston, Massachusetts.
Neuroendocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston.
Harvard Medical School, Boston, Massachusetts.
Massachusetts General Hospital Diabetes Center, Boston.
Department of Medicine, Harvard Medical School, Boston, Massachusetts.
Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, Massachusetts.
Massachusetts General Hospital, Harvard Medical School, Boston.
Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
Channing Division of Network Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
Cardiovascular Performance Program, Massachusetts General Hospital, Boston.
Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia.
Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Dana Farber Cancer Institute, Boston, Massachusetts.



Small studies suggest that head trauma in men may be associated with low testosterone levels and sexual dysfunction through mechanisms that likely include hypopituitarism secondary to ischemic injury and pituitary axonal tract damage. Athletes in contact sports may be at risk for pituitary insufficiencies or erectile dysfunction (ED) because of the high number of head traumas experienced during their careers. Whether multiple symptomatic concussive events are associated with later indicators of low testosterone levels and ED is unknown.


To explore the associations between concussion symptom history and participant-reported indicators of low testosterone levels and ED.

Design, Setting, and Participants:

This cross-sectional study of former professional US-style football players was conducted in Boston, Massachusetts, from January 2015 to March 2017. Surveys on past football exposures, demographic factors, and current health conditions were sent via electronic and postal mail to participants within and outside of the United States. Analyses were conducted in Boston, Massachusetts; the data analysis began in March 2018 and additional analyses were performed through June 2019. Of the 13 720 male former players eligible to enroll who were contacted, 3506 (25.6%) responded.


Concussion symptom score was calculated by summing the frequency with which participants reported 10 symptoms, such as loss of consciousness, disorientation, nausea, memory problems, and dizziness, at the time of football-related head injury.

Main Outcomes and Measures:

Self-reported recommendations or prescriptions for low testosterone or ED medication served as indicators for testosterone insufficiency and ED.


In 3409 former players (mean [SD] age, 52.5 [14.1] years), the prevalence of indicators of low testosterone levels and ED was 18.3% and 22.7%, respectively. The odds of reporting low testosterone levels or ED indicators were elevated for previously established risk factors (eg, diabetes, sleep apnea, and mood disorders). Models adjusted for demographic characteristics, football exposures, and current health factors showed a significant monotonically increasing association of concussion symptom score with the odds of reporting the low testosterone indicator (highest vs lowest quartile, odds ratio, 2.39; 95% CI, 1.79-3.19; P < .001). The ED indicator showed a similar association (highest quartile vs lowest, odds ratio, 1.72; 95% CI, 1.30-2.27; P < .001).

Conclusions and Relevance:

Concussion symptoms at the time of injury among former football players were associated with current participant-reported low testosterone levels and ED indicators. These findings suggest that men with a history of head injury may benefit from discussions with their health care clinicians regarding testosterone deficiency and sexual dysfunction.

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