SWANSEA, United Kingdom — Your risk of ending up in the hospital with COVID-19 may literally be in your own hands. A new study finds finger length displays a link to a person’s sex hormone levels. What does this have to do with COVID-19? Researchers at Swansea University say a patient’s testosterone levels play a key role in how sick they get after infection.
Previous studies show that having a longer ring finger is a sign of higher testosterone levels in the womb. On the other hand, a longer index finger signals higher levels of estrogen. Typically, men have longer ring fingers and women have longer index fingers.
The new study examined this link between the sex hormones before birth and during puberty and the rate of COVID hospitalizations. Their findings reveal that people with “feminized” short little fingers in comparison to their other digits end up suffering more severe cases of COVID-19. Moreover, people who have larger size differences between the fingers on their left and right hands are at even greater risk.
The link between testosterone and coronavirus
Although most people only experience mild COVID symptoms, the elderly and men are more likely to have a severe case that requires urgent care. This has led scientists to wonder if a man’s testosterone levels play a role in disease severity.
One theory is that high testosterone levels cause COVID to worsen. However, another study links low levels in elderly men to a severe case of the virus.
To figure out which is right, the team examined the size ratios of the 2nd, 3rd, 4th, and 5th digits on the hands of over 150 people. Fifty-four of these individuals were COVID-19 patients, while the others served as a healthy control group.
Specifically, the results show bigger differences between the 2D:4D and 3D:5D ratios on each person’s hands had a connection to a more severe case of COVID-19.
“Our findings suggest that COVID-19 severity is related to low testosterone and possibly high estrogen in both men and women,” says Professor John Manning in a university release.
“’Feminized’ differences in digit ratios in hospitalized patients supports the view that individuals who have experienced low testosterone and/or high estrogen are prone to severe expression of COVID-19. This may explain why the most at-risk group is elderly males,” the researcher continues. “This is significant because if it is possible to identify more precisely who is likely to be prone severe COVID-19, this would help in targeting vaccination. Right-Left differences in digit ratios (particularly 2D:4D and 3D:5D) may help in this regard.”
Could testosterone drugs defeat the pandemic?
Currently, study authors say there are several trials examining anti-androgen (testosterone) drugs which may help treat COVID-19. At the same time, scientists are also looking at testosterone as a possible anti-viral medication against COVID.
“Our research is helping to add to understanding of Covid-19 and may bring us closer to improving the repertoire of anti-viral drugs, helping to shorten hospital stays and reduce mortality rates,” Prof. Manning adds. “The sample is small but ongoing work has increased the sample. We hope to report further results shortly.”
This isn’t the first study to link finger length to seemingly unrelated topics. A previous study connected children’s finger length to their mother’s income as well as vulnerability to childhood illnesses.
The study is published in the journal Scientific Reports.