Even after controlling for potentially important factors, women appear to have a lower incidence of severe COVID-19 infection than men. This is also true of other recent serious viral infections like MERS (Middle East Respiratory Syndrome).

New study published today in the journal BMJ found that an older woman’s oestrogen levels may be associated with her odds of dying from COVID-19, with higher levels of the hormone appearing to protect against severe infection.

According to the researchers, it may be worthwhile to investigate additional hormone treatment to reduce the severity of COVID-19 infection in women who have previously gone through menopause.

Even after controlling for potentially important factors, women appear to have a lower incidence of severe COVID-19 infection than men. This is also true of other recent serious viral infections like MERS (Middle East Respiratory Syndrome).

As a result, it’s been proposed that oestrogen may play a part in the gender divide. To learn more, the researchers evaluated the impact of increasing and decreasing oestrogen levels on the severity of COVID-19 infection.

They analyzed national data from the Swedish Public Health Agency (all individuals who tested positive for SARS-CoV-2); Statistics Sweden (socioeconomic characteristics); and the National Board of Health and Welfare (causes of death).

Between February 4 and September 14, 2020, 49,853 women in Sweden were diagnosed with COVID-19, 16,693 of whom were between the ages of 50 and 80.

The study sample included 14,685 women in total: 227 (2%) had been previously diagnosed with breast cancer and were on oestrogen blocker drugs (adjuvant therapy) to curb the risk of cancer recurrence (group 1), and 2535 (17%) were taking hormone replacement therapy (HRT) to boost their oestrogen levels in a bid to relieve menopausal symptoms (group 2).

Some 11,923 (81%) 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% lower among women on HRT (group 2). 

After accounting for potentially influential factors, such as age, annual disposable income, educational attainment, and coexisting health conditions, the odds of dying from COVID-19 remained significantly lower (53%) for women on HRT (group 2).

Unsurprisingly, age was significantly associated with the risk of dying from COVID-19, with each extra year associated with 15% greater odds, while every additional coexisting condition increased the odds of death by 13%. 

And those with the lowest household incomes were nearly 3 times as likely to die as those with the highest.

This is an observational study, and as such, can’t establish cause. There were no data on the precise doses of HRT or oestrogen blocker drugs or their duration, nor on weight or smoking, while the number of women in group 1 on adjuvant therapy was relatively small.

These factors may have been influential. But the researchers conclude: “This study shows an association between oestrogen levels and COVID-19 death. 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.”

Source: 10.1136/bmjopen-2021-053032

Image Credit: Getty

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