Test tube with Corona virus name label is seen in this illustration taken on January 29, 2020. [Photo/Agencies]

Figures also reveal which professions are at greatest risk of becoming ill

Men are more likely to die from the novel coronavirus than women and the reason could be due to high levels of an enzyme in their lungs that helps the disease take hold there, according to a study.

The gender discrepancy was first noted in China where death rates showed that 2.8 percent of men who caught the virus had died, compared with 1.7 percent of women. In most countries, the number of deaths from the virus among men is shown to be higher.

The study, published in the European Heart Journal on Monday, identified higher concentrations of angiotensin-converting enzyme 2, or ACE2, in male subjects compared to the women.

All 3,500 people studied, from 11 European countries, were elderly and had heart failure and none of them were infected with the novel coronavirus.

It comes as data published in the United Kingdom showed male security guards and drivers have very high COVID-19 related death rates.

According to new figures released by the UK's Office for National Statistics, workers in low-skilled jobs are the most likely to die after contracting COVID-19, with male security guards among those with the highest death rates.

Male construction workers, taxi drivers, bus and coach drivers, plant processing workers and chefs are also among those with the highest novel coronavirus death rates.

Healthcare workers, including doctors and nurses, were not found to have a higher mortality rate compared with others of the same age and sex. There was a slightly raised rate among care home workers.

The enzyme study authors said ACE2 is found in several organs including the lungs, and it binds with coronaviruses like the one that causes COVID-19, and allows them to more easily infect healthy cells.

Co-leader of the study, Adriaan Voors, a professor of cardiology at the University Medical Center Groningen, told the European Society of Cardiology that "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".

Although the research was undertaken before the virus outbreak, when new research began to point to ACE2 as key to the way the novel coronavirus gets into cells, the ACE2 enzyme study team saw important overlaps with its study.

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

In a statement critiquing the study, the European Society of Cardiology discussed its limitations. It said the study looked only at ACE2 concentrations in plasma, not in tissues such as lung tissue, so it cannot be sure that concentrations in the blood are similar to those seen in tissues. It added that it is the ACE2 in lung tissue that is thought to be key to lung infection.

The statement also said the study's conclusions are mainly restricted to heart failure patients, and that the patients did not have COVID-19.