One reason men are more likely to die from the coronavirus than women could be due to high levels of a particular enzyme in their lungs which helps the coronavirus take hold there, according to a new study.

The study, of more than 3,500 people, was published on May 10 in the European Heart Journal, a peer-reviewed publication.

It found higher concentrations of angiotensin-converting enzyme 2 (ACE2) in male subjects compared to the women. The sample size was selective: all 3,500 people were elderly and had heart failure.

None of them were infected with the coronavirus. But the researchers involved believe that other research on how ACE2 interacts with the virus can help explain the disparity in death rates between men and women.

ACE2, found in several organs including the lungs, binds with coronaviruses like the one which causes COVID-19, and allows them to more easily infect healthy cells, according to one of the study authors.

Adriaan Voors is a professor of cardiology at the University Medical Center Groningen, in the Netherlands, where the study was led.

He told the European Society of Cardiology: "High levels of ACE2 are present in the lungs and, therefore, it is thought to play a crucial role in the progression of lung disorders related to COVID-19."

Another author, Iziah Sama of UMC Groningen, said: "When we found that one of the strongest biomarkers, ACE2, was much higher in men than in women, I realised that this had the potential to explain why men were more likely to die from COVID-19 than women."

Studies from six different countries have found that men are 50 percent more likely than women to die from COVID-19, as Business Insider has previously reported.

The gender gap for infections has not been quite as stark across the world - in South Korea, for example, men are in the minority, while in New York they are a slight majority.

Researchers have raised several other theories about why men seem to be more vulnerable overall to the virus, aside from ACE2 receptors.

Men tend to be more prone to preexisting conditions that worsen the virus, such as high blood pressure or diabetes. In many countries, men also smoke more than women, and some studies have shown men are less likely to wash their hands.

This article was originally published by Business Insider.

More from Business Insider: