2019-09-18 02:49:28
Former professional football players who have experienced concussion symptoms, including loss of consciousness, disorientation or nausea after a head injury, are more likely to report low testosterone and erectile dysfunction (ED), according to research published in JAMA Neurology.
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.
The researchers caution that their findings are observational--based on self-reported concussion symptoms and indirect measures of ED and low testosterone.
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. However, the findings do reveal an intriguing and 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, these 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.
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.
The link between history of concussion and ED was present among both the older and the younger players-- those under age 50 in this case- -the analysis showed, and it persisted over time.
“We found the same association of concussions with ED among both younger and older men in the study, and we found the same risk of ED among men who had last played twenty years ago,” said study senior author Andrea Roberts, a researcher at the Harvard T.H. Chan School of Public Health. “These findings suggest that increased risk of ED following head injury may occur at relatively young ages and may linger for decades thereafter.”
Given that ED is both fairly common and easily treatable, those who experience symptoms are encouraged to report them to their physicians, the researchers said.
—Harvard Medical School
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