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Medical News & Perspectives
Quick Uptakes
January 29, 2020

Concussions Linked With Erectile Dysfunction in Football Player Study

JAMA. Published online January 29, 2020. doi:10.1001/jama.2019.21883

The Super Bowl generates gut-busting menus, fierce rivalries, and possibly some unexpected health consequences for the game’s players. A recent JAMA Neurologystudy found that the more concussion symptoms former National Football League (NFL) players had during their careers, the more likely they were to have been prescribed medication for low testosterone levels or erectile dysfunction (ED) later in life. Knowing that head injuries may cause sexual dysfunction could help more men and their physicians overcome the stigma of ED and talk about treatment.

What’s New

The research fills a knowledge gap. One large study found an association between ED and single traumatic brain injuries in the general Taiwanese population. So far, only small studies have linked elite athletes’ head injuries with hormone insufficiencies and sexual dysfunction. With 3409 participants, this is the first large study to make the connection in athletes and to show a dose-response relationship: as self-reported concussion symptoms increased so did the odds of having indicators of ED and low testosterone levels. The study was also large enough to assess a variety of confounding factors.

The Design

The research is part of the Football Players’ Health Study, a Harvard University project to understand US-style football’s health risks and benefits. For the ED study, participants on average were about 53 years old and had played around 7 seasons. Former offensive linemen made up the largest group of respondents, almost 22%.

Researchers tallied concussion symptom scores by adding up the number of head injury–related symptoms that retired players reported on questionnaires, like loss of consciousness, seizures, or memory problems. The researchers grouped the players into quartiles based on their scores and then examined whether the groupings were associated with the athletes’ self-reported low testosterone and ED medication recommendations or prescriptions.

They also adjusted for the players’ demographic characteristics, current health factors, and football-related exposures (like the position they played, their body mass index at the time, and their self-reported performance-enhancing drug use).

What We’ve Learned

  • Nearly 23% of participants reported that a physician had recommended or prescribed ED medication—indicators of having the condition—and half of those participants were currently taking it.

  • More than 18% of participants said they had been recommended or prescribed low testosterone medication, with about 40% of those participants currently taking it.

  • Higher concussion symptom scores were associated with greater odds of ED and low testosterone indicators.

  • Current prescription pain medication use and sleep apnea, along with other health factors, statistically mediated some of the relationship between concussions and ED and low testosterone.

  • Even after adjusting for all covariates, compared with players in the lowest concussion symptom quartile, those in the highest quartile had almost twice the odds of having ED indicators and nearly 2½ times the odds of having low testosterone indicators.

The Caveats

The researchers acknowledged several limitations. Concussion symptoms and indicators of sexual dysfunction and low testosterone were all self-reported, and the concussion symptom scale isn’t a validated tool. Plus, 97 players who responded to the study survey didn’t answer questions about ED.

However, men are more likely to underreport than overreport ED, which suggests that the observed association actually could be underestimated. According to the researchers’ unpublished data, 50% of the participants who chose not to answer the ED indicators question were likely to have ED based on other health factors.

Additionally, self-reported concussion symptoms may be a more reliable measure than diagnosed concussions, in part because at least 30% of concussions may go undiagnosed. When the researchers reanalyzed the relationship based solely on loss of consciousness—an easily recalled symptom—the dose response association remained.

The Mechanism

It could come down to the pituitary gland, “the master controller of hormone function in the brain and throughout the body,” the study’s lead author, Harvard’s Rachel Grashow, PhD, said in an interview. Head hits could damage sensitive tissue that connects the gland to the rest of the brain, cutting it off from blood supply and neuronal communication. “It all sort of fits together that head hits might damage the pituitary and that might compromise the pituitary’s function to create downstream effects on testosterone and, ultimately, erectile dysfunction,” Grashow said.

The Clinical Implications

“Based on the results of this study, we hope that former NFL players experiencing symptoms of sexual dysfunction or low testosterone will be newly motivated to speak to their clinicians about their concerns,” Grashow said, adding that ED can also indicate the presence of more systemic issues like hypertension, sleep apnea, cardiovascular disease, and diabetes.

Grashow also urged clinicians to raise these issues with patients—whether they’re nonathletes, veterans, or participants in contact sports, including mixed martial arts, hockey, boxing, and soccer. “Importantly, medications for these conditions are considered safe and effective, so men need not suffer in silence,” she said.

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