A study of NFL players has found a link between head trauma and erectile dysfunction, as well as low testosterone levels.
The research — based on a survey of more than 3,400 former NFL players representing the largest study cohort of former professional football players to date — was conducted by investigators at the Harvard T.H. Chan School of Public Health and Harvard Medical School as part of the ongoing Football Players Health Study at Harvard University, a research program that encompasses a constellation of studies designed to evaluate various aspects of players’ health across their lifespans.
While the results do not prove a cause-effect link between concussion and ED, nor do they explain exactly how head trauma might precipitate the onset of ED, the investigators noted, the findings do reveal what a press releases stated as a “powerful link between history of concussions and hormonal and sexual dysfunction, regardless of player age.”
Notably, the ED risk persisted even when researchers accounted for other possible causes, such as diabetes, heart disease or sleep apnea, for example. Taken together, the researches contend the findings warrant further study to “tease out the precise mechanism behind it.”
One possible explanation, the research team said, could be injury to the brain’s pituitary gland that sparks a cascade of hormonal changes culminating in diminished testosterone and ED. This biological mechanism has emerged as a plausible explanation in earlier studies that echo the current findings, such as reports of higher ED prevalence and neurohormonal dysfunction among people with head trauma and traumatic brain injury, including military veterans and civilians with head injuries.
The new findings also suggest that sleep apnea and use of prescription pain medication contribute to low testosterone and ED. It remains unclear whether they do so independently, as consequences of head injury or both, the researchers said.
“Former players with ED may be relieved to know that concussions sustained during their NFL careers may be contributing to a condition that is both common and treatable,” said study lead author Rachel Grashow, a researcher at the Harvard T.H. Chan School of Public Health.
Men who reported the highest number of concussion symptoms were two-and-a-half times more likely to report receiving either a recommendation for medication or to be currently taking medication for low testosterone, compared to men who reported the fewest concussion symptoms. Men with the most concussion symptoms were nearly two times more likely to report receiving a recommendation to take ED medication or to be currently taking ED medication than those reporting the fewest symptoms. Players who reported losing consciousness following head injury had an elevated risk for ED even in the absence of other concussion-related symptoms.
Notably, even former players with relatively few concussion symptoms had an elevated risk for low testosterone, a finding that suggests there may be no safe threshold for head trauma, the team said.
Of all participants, 18 percent reported low testosterone and nearly 23 percent reported ED. Slightly less than 10 percent of participants reported both.