Previous studies have already confirmed that men have an increased risk of severe courses of Covid-19. An American research team recently found out why this could be the case: men with low testosterone levels in particular are particularly badly ill. In the future, testosterone therapies could help against this problem.
Study reveals new connections
Even at the beginning of the pandemic, it was already becoming apparent that men, on average, suffer more from Covid-19 than women. There has been much speculation as to whether this could be due to the differences in hormones. Initial suspicions suggested that high levels of testosterone in the blood increased the risk of severe Covid-19. The current study provided evidence for the first time that low testosterone levels in the blood are associated with more severe courses of Covid-19. However, it has not been proven that low testosterone could be a cause of serious illness from Covid-19. However, a low testosterone level still seems to be a marker for an increased risk of severe Covid-19 courses in men.
Low testosterone levels are associated with severe courses
According to the findings of the study, men were at an increased risk of severe Covid-19 courses if they had low testosterone levels when they were admitted to the hospital – compared to men who had more circulating testosterone in their blood. For this purpose, blood samples were examined from 90 men and 62 women who had been admitted to the Barnes-Jewish Hospital because of a SARS-CoV-2 infection. The hormone levels were determined on the third, seventh, 14th and 28th day of the hospital stay. In addition to testosterone, the level of estradiol – a form of the body’s own estrogen, as well as IGF-1 – a growth hormone that plays a role in maintaining muscle mass, similar to insulin, was also measured.
Women are excluded
The hormone levels were then compared with the severity of the disease. In women, however, there was no connection here. In men, only the testosterone level was linked to the severity of Covid-19. A blood testosterone level of 250 nanograms per deciliter or less is considered a low testosterone level in adult men. In the available data from the study, men with severe Covid-19 had an average testosterone level of 53 nanograms per deciliter. Men who had testosterone levels in excess of 150 nanograms per deciliter also developed less severe courses on average. The hardest hit were men with an average testosterone level of only 19 nanograms per deciliter.
Difficult courses could be better predicted
The researchers point out that other factors known to cause an increased risk of severe Covid-19 courses are also linked to lower testosterone levels. These include, for example, advanced age, obesity and diabetes. In addition, men who were measured to have low testosterone levels when they were admitted to the hospital also had a higher risk of requiring intensive care within the next three days. The research group concludes that low testosterone levels seem to be an important clue to predict severe progression.
Adaptation to testosterone discovered
Furthermore, lower testosterone levels in men were also associated with higher levels of inflammation. In these men, more genes were also active that enabled the body to take over the functions of the sex hormones circulating in the cells. This leaves open the assumption that the body may have adapted to less testosterone in the bloodstream, since the production of the hormone decreases more and more as the number of years of life increases. Above all, the effects of such an adjustment are currently unknown and must first be investigated in future studies. The team also wants to find out whether men who are recovering from Covid-19 or who are affected by Long-Covid can potentially benefit from testosterone therapy.