Men with longer ring fingers face a lower risk of dying from Covid-19 and are more likely to suffer mild symptoms, researchers claim. Academics found coronavirus death rates in countries where men have shorter ring fingers were up to a third higher.
Ring finger length is determined by how much testosterone a foetus is exposed to when growing in the womb, the experts said. The more testosterone a male is exposed to in the womb, the longer their ring finger will be, it is believed, according to a story on The Daily Mail.com.
Testosterone is thought to be protective against severe Covid-19 by increasing the number of ACE-2 receptors in the body. Scientists believe the coronavirus, officially called SARS-CoV-2, enters the body and causes infection through these receptors.
But studies also suggest that high levels of ACE-2 receptors can protect against lung damage, which the coronavirus can cause. The new study, carried out by Swansea University, found men with low testosterone levels are twice as likely to die of Covid-19 than men with higher levels.
Mounting evidence has shown men are more likely to die from the coronavirus than women – but scientists have been unable to determine exactly why this is. In England and Wales, the Covid-19 death rate for men is 97.5 per 100,000 people compared to 46.5 for females, according to the Office for National Statistics.
Scientists believe men are less likely to wash their hands, may not seek medical help, and have more underlying health conditions that make them more vulnerable. But testosterone could be one of the key reasons why so many men are dying from coronavirus, doctors believe.
Swansea University experts added to the theory that men who have low testosterone levels are at more at risk of Covid-19 than other men. They looked at data of 200,000 people in 41 countries where the researchers had already measured the finger lengths of volunteers.
Some researchers believe finger lengths reflect a foetus’s exposure to testosterone and other hormones that guide development in the womb. The index finger and the ring finger was measured to the closest millimetre. The first measurement is divided by the second measurement to get the 2D:4D ratio.
The smaller the digit ratio, the longer the ring finger is. The country with the smallest average male right hand digit ratio was Malaysia, with 0.976. The higher the digit ratio, the shorter the ring finger is. Bulgaria has the highest male right hand digit ratio, with 0.99.
Researchers found that in countries where the male digit ratio was smaller, including Malaysia, Russia and Mexico, the case fatality rate of Covid-19 was lower. And in countries where the male digit ratio was higher, including the UK, Bulgaria and Spain, the case fatality rate was higher.