London, Jul 7 (IANS): Men with symptomatic Covid-19 and low testosterone are six times more likely to become severely ill and die from the disease, new research has shown.

The study, conducted by researchers at San Raffaele University Hospital in Milan, Italy, found that the lower the levels of testosterone, the higher the likelihood that male patients would need intensive care, be intubated on a ventilator and remain in hospital over a longer period.

For the study, the team compared 286 male Covid patients, who came to the emergency department, with 305 healthy male volunteers between February and May 2020.

Nearly 90 per cent of the patients had testosterone below 9.2 nanomoles per litre (nmol/l), compared to just 17 per cent of the healthy volunteers. Those with testosterone levels between 3-4 nmol/l and had mild symptoms or were admitted to hospital, while those admitted to ICU or died of the disease had just 0.7-1.0 nmol/l.

"At the start of the Covid pandemic, we were seeing far more men than women coming to hospital and suffering very severe forms of the disease. We immediately thought this might be related to male hormone levels, particularly testosterone," Professor Andrea Salonia, a specialist in urology and endocrinology at the hospital.

"But we never expected to see such a high proportion of Covid patients with these extremely low levels of testosterone, in comparison to a similar group of healthy men. The relationship is very clear: the lower the testosterone, the higher the severity of the condition and likelihood of death. I've never seen anything like it in my 25 years in the field," Salonia added.

However, since the team does not have data on the testosterone levels in the patients before they contracted Covid-19, they cannot say whether low testosterone was a pre-existing long-term condition that exacerbated the disease or whether it was caused by the SARS-COV2 virus.

"Testosterone does play a role in protecting men from disease. However, it's also possible that the virus itself is able to induce an acute reduction in testosterone levels, which then predisposes these men to a worse outcome," Salonia said.

The findings will be presented at the 2021 European Association of Urology congress (EAU21), which starts from July 8-12.