Could length of one’s fingers provide a clue to how ill one might get after contracting COVID-19?

by Medically Speaking Team March 28, 2022

Could length of one’s fingers provide a clue to how ill one might get after contracting COVID-19?

A longer ring finger is widely recognised as a marker of higher levels of testosterone prenatally, whereas a longer index finger is a marker of higher levels of oestrogen. Men tend to have longer ring fingers, while women tend to have longer index fingers.

Swansea University is involved in a new study that is looking into the relationship between sex hormone levels in the womb and during puberty and Covid hospitalizations.

The majority of people who contract the virus only have minor symptoms. However, when it comes to patients who require hospital care, the rates vary according to age (with the elderly being the most affected) and gender (with males experiencing a higher severity than females).

This has prompted scientists to dig deeper into the relationship between testosterone and Covid-19 severity. One hypothesis links high testosterone levels in severe cases to a poor prognosis, while another links low testosterone levels in elderly men to a poor prognosis.

Professor John Manning of the Applied Sports Technology, Exercise and Medicine (A-STEM) research team has been working with colleagues from the Medical University of Lodz in Poland and Sweden’s Karolinska University Hospital to look more closely at digit ratios (ratios of the second, third, fourth, and fifth digits) as predictors of Covid-19 symptom severity.

The researchers discovered that patients with “feminised” short little fingers relative to their other digits have a higher risk of hospitalisation, and that patients with large right hand–left hand differences in ratios 2D:4D and 3D:5D have a significantly higher risk of hospitalisation.

These preliminary findings were recently published in the journal Scientific Reports.

According to Professor Manning: “Our findings suggest that the severity of Covid-19 is associated with low testosterone and possibly high oestrogen in both men and women.

“‘Feminized’ differences in digit ratios in hospitalised patients support the theory that individuals who have had low testosterone and/or high oestrogen levels are predisposed to severe Covid-19 expression. This could explain why elderly males are the most vulnerable group.

“This is significant because identifying more precisely who is likely to be prone to severe Covid-19 would aid in targeting vaccination. Differences in digit ratios between the right and left sides (particularly 2D:4D and 3D:5D) may be useful in this regard.”

Several anti-androgen (testosterone) drug trials are currently underway as a treatment for Covid-19. In contrast, testosterone is being studied as an anti-viral against Covid-19.

“Our research is contributing to our understanding of Covid-19 and may bring us closer to improving the repertoire of antiviral drugs, allowing us to shorten hospital stays and reduce mortality rates,” he added.

Professor Manning stated that the team’s work would now be resumed: “The sample size is small, but ongoing work has increased it. We hope to have more information soon.”

His previous research in the field demonstrated how the length of children’s fingers correlates with the income level of their mothers and indicates susceptibility to diseases that begin in the womb.