Testosterone levels play unexpected role in how men fare with COVID, study finds
Evidence collected throughout the pandemic shows men appear to fare worse with COVID-19, on average, than women. Among the many theories doctors and scientists have considered, hormonal differences were and still are at the top of the list of possible explanations.
Now, a new study suggests low levels of testosterone — the primary male sex hormone — are associated with more severe COVID-19 in men, increasing their risks for needing intensive care and dying while hospitalized. The more the hormone drops, the more those risks may increase, according to the paper published Tuesday in the journal JAMA Network Open.
The finding contradicts previous suspicions that higher testosterone levels naturally found in men may explain why men typically face worse disease outcomes.
The researchers said lower levels of the hormone seem to predict which patients were more likely to become very sick over the course of hospitalization, but they clarified their study does not prove the metric is a cause of severe COVID-19. Rather, it could “serve as a marker of some other causal factors.”
For now, the findings can inform ongoing clinical trials investigating hormone therapies, the researchers said, particularly those that are experimenting with blocking or lowering testosterone, or those increasing estrogen — the primary female sex hormone — as a treatment for men with COVID-19.
“The groups of men who were getting sicker were known to have lower testosterone across the board,” study first author Dr. Sandeep Dhindsa, an endocrinologist at Saint Louis University in Missouri, said in a statement. “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 two or three days.”
The team measured the levels of testosterone, estradiol — a form of estrogen — and a growth hormone called IGF-1 that helps maintain muscle mass in the blood of 90 men and 62 women with symptomatic COVID-19, who were admitted to the Barnes-Jewish Hospital in Missouri between March and May 2020. The hormones were measured again on days 3, 7, 14 and 28 during hospitalization.
No correlation between hormone levels and disease severity was found among women, but testosterone levels were linked to disease outcome in men, according to the study.
Upon hospital admission, men with severe COVID-19 had average blood testosterone levels of 53 nanograms per deciliter (any level below 250 is considered low in adult men). In comparison, men with less severe disease averaged at 151 nanograms per deciliter. Those with the most severe cases had average testosterone levels of 19 by day three in the hospital.
Throughout the study, 37 patients died from the disease, 25 of whom were men.
Other factors known to raise risks of severe COVID-19, including older age, diabetes and obesity, are also associated with lower blood testosterone levels, the researchers noted. Still, the study could not prove cause and effect.
What’s more, the team found that lower testosterone levels in men were linked to higher levels of inflammation and more gene activation associated with the functioning of sex hormones inside cells.
“In other words, the body may be adapting to less testosterone circulating in the bloodstream by dialing up its ability to detect and use the hormone,” the statement reads. ”The researchers don’t yet know the implications of this adaptation and are calling for more research.”
This story was originally published May 26, 2021 at 12:25 PM with the headline "Testosterone levels play unexpected role in how men fare with COVID, study finds."
