Low oestrogen levels in elderly women may increase their risk of death due to COVID-19, according to a study that suggests exploring hormone therapy to reduce infection severity. 

The study, published in the open-access journal BMJ Open, showed that age was significantly associated with the risk of dying from COVID-19, with each extra year associated with 15 per cent greater odds, while every additional coexisting condition increased the odds of death by 13 per cent. The findings thus suggest that supplemental hormone treatment may be worth exploring to curb the severity of COVID-19 infection in women who have already gone through menopause. It is because, during menopause, oestrogen levels decrease in women.

"This study shows an association between oestrogen levels and COVID-19 death," said Karin Welen from the Department of Urology, at the University of Gothenburg in Sweden. "Consequently, drugs increasing oestrogen levels may have a role in therapeutic efforts to alleviate COVID-19 severity in postmenopausal women and could be studied in randomised control trials," Welen said.

The researchers, together with those from the University of Umea in Sweden and the University of Helsinki in Finland, compared the potential effects of boosting and reducing oestrogen levels on COVID-19 infection severity.

The study sample included 14,685 women in total: 227 (2 per cent) had been previously diagnosed with breast cancer and were on oestrogen blocker drugs (adjuvant therapy) to curb the risk of cancer recurrence, and 2,535 (17 per cent) were taking hormone replacement therapy (HRT) to boost their oestrogen levels in a bid to relieve menopausal symptoms.

Some 11,923 (81 per cent) women acted as the comparison group as they weren't on any type of treatment, either to enhance or reduce their systemic oestrogen levels. Analysis of all the data showed that compared with no oestrogen treatment, the crude odds of dying from COVID-19 were twice as high among women on oestrogen blockers (group 1), but 54 per cent lower among women on HRT (group 2). However, the researchers said, "this is an observational study, and as such, can't establish the cause".