“The groups of men who were getting sicker were known to have lower testosterone across the board,” said study author Sandeep Dhindsa, MD, an endocrinologist at Saint Louis University.
“We also found that those men with COVID-19 who were not severely ill initially, but had low testosterone levels, were likely to need intensive care or intubation over the next 2 or 3 days. Lower testosterone levels seemed to predict which patients were likely to become very ill over the next few days.”
Hormone Effect Seen Among Men Only
The scientists looked at other hormones but found that only levels of testosterone were linked with COVID-19 disease severity in men. Among women, there were no differences in any hormone levels according to COVID-19 disease severity, including levels of testosterone (women have small amounts of testosterone), or estrogen.
The testosterone concentrations in men with severe disease were not affected by other known risk factors for COVID-19 severity, including age, body mass index, underlying conditions such as diabetes or heart disease, smoking and race.
However, the low testosterone levels did significantly track with signs of inflammation.
Importantly, however, the results don’t necessarily prove that lack of testosterone is causing more severe cases of COVID-19, the researchers said.
They note that testosterone concentrations are known to drop by as much as 50% when men are admitted to the hospital, even for routine elective surgeries.
Drops in testosterone are also normal after traumatic brain injury and heart attack.
To further test the relationship between testosterone and COVID-19, the researchers are now focusing on the hormone’s effects on long-term symptoms of COVID-19.
“We are now investigating whether there is an association between sex hormones and cardiovascular outcomes in ‘long COVID-19’, when the symptoms linger over many months,” said Diwan, a cardiologist.
In the meantime, the results should give pause for researchers studying whether hormonal treatment may help fight COVID-19. For example, one study was looking at giving estrogen to men with COVID-19.
“These data suggest caution should be practiced with approaches that antagonize testosterone signaling or supplement estrogen to treat men with severe COVID-19,” the authors stress.
“Our study results suggest that, unlike the common presumption, testosterone may not be a propagator of COVID-19 severity in either gender,” they conclude. “On the contrary, it may be protective in men.”