According to research published in JAMA Neuroloy, former professional football players who have experienced concussion symptoms are more likely to report low testosterone and erectile dysfunction (ED). However, investigators note that concussion symptoms were self-reported and results do not explain the cause-effect relationship between concussion and ED.
Study authors also note that possible causes such as diabetes, heart disease or sleep apnea were all accounted for while age had no bearing.
The survey featured more than 3400 former NFL players and was carried out by researchers from the Harvard T.H. Chan School of Public Health and Harvard Medical School.
The team of scientists suggest that one explanation could be a blow to the brain's pituitary gland which influences hormonal changes. Similar research in the past has suggested a higher prevalence of ED and neurohormonal dysfunction in people who have suffered head trauma or traumatic brain injury.
Meanwhile, sleep apnea and prescription pain medication also contributed to testosterone and ED.
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"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," says lead study author Rachel Grashow from the Harvard T.H. Chan School of Public Health.
In the study, volunteers, aged between 24 and 89, were asked to describe their experience with concussion - how often they received blows to the head or neck, whether it made them feel dizzy, nauseated or disoriented and whether it resulted in headaches, loss of consciousness or vision impairment.
They were then categorised into four groups based on their type of symptoms they had.
Following that, they then reported their medication use for either low testosterone or ED.
Interestingly, those who had suffered the most concussion-related symptoms were two and half times more likely to report taking medication for low testosterone or have a medical professional recommend treatment, compared to men who documented the fewest concussion symptoms.
At the same time, those at the top end of the concussion scale were nearly two times more likely to report taking medication for ED or have a medical professional recommend treatment than those at the other end of the scale.
Total loss of consciousness was the biggest risk factor.
Even former players who presented the fewest amount of concussion symptoms were at risk of low testosterone.
In total, nearly one in five reported low testosterone while 23 per cent reported ED. Meanwhile, just under 10 per cent reported both.
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"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," adds senior study author Andrea Roberts from 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.
Importantly, prompt evaluation of ED is critical because it can signal the presence of other conditions, including heart disease and diabetes. The findings also suggest that it may be important for clinicians to assess all patients with concussion history for the presence of neurohormonal changes.
