(ORDO NEWS) — Swedish and Finnish scientists compared the potential impact of high and low estrogen levels on the severity of coronavirus disease.
Low levels of estrogen may be associated with an increased risk of death due to coronavirus infection in older women, according to scientists from the University of Umeå and the University of Gothenburg in Sweden, as well as the University of Helsinki and the University Hospital of Helsinki in Finland.
Almost from the very beginning of the pandemic , it became clear that being male is one of the risk factors for Covid-19, while women, although not protected from infection, are less likely to experience adverse outcomes.
This means that there are biological differences between the sexes in terms of susceptibility to a severe form of the disease. And to some extent, according to the researchers, estrogen is responsible for this – or rather, estrogens as a subclass of steroid sex hormones, produced for the most part by the ovarian follicular apparatus.
Estrogen, unlike testosterone , downregulates important proteins such as the ACE2 membrane enzyme and TMPRSS2 protease that help SARS-CoV-2 enter the cell.
According to the authors of the new work, the majority of patients with breast cancer – the most common cancer among women in the world – have tumors that are positive for estrogen receptors, therefore, in order to avoid recurrence, they are prescribed adjuvant endocrine therapy after surgery.
This leads to a decrease in the level of estrogen in the body. At the same time, estrogen levels rise in women taking menopausal hormone therapy to relieve the symptoms of cessation of menstrual cycles.
It was on the data of such Swedish patients that scientists focused. They analyzed the opposite effects of their endocrine therapy and tested the hypothesis that elevated estrogen levels protect against death due to Covid-19.
From early February to mid-September 2020, 49,853 women in Sweden were diagnosed with coronavirus, 16,693 of them were between 50 and 80 years old.
The sample included 14,685 women: 227 (2%, group one) had previously been diagnosed with breast cancer and were taking drugs that suppress estrogen receptors; another 2,535 (17%, group 2), conversely, were prescribed hormone replacement therapy to increase estrogen levels and relieve menopausal symptoms. The control group consisted of 11,923 (81%) women who received no estrogen-targeted treatment.
“Pharmaceutical reduction in systemic estrogen levels increased the risk of death from Covid-19 by 2.35 times in the first group, but after adjusting for additional factors (age, annual income, level of education and comorbidities. – Approx. ed.) , this association ceased to be meaningful.
Interestingly, an increase in systemic estrogen levels reduced the likelihood of dying from coronavirus by 0.45 times, this figure remained significant even after controlling for other factors, ”the scientists write.
From the first group, 23 women (10.1%) died during the study, from the second – 54 (2.1%), from the control – 546 (4.6%). The average age of the dead is 73.2 years. It was expectedly associated with the risk of death from coronavirus infection: an additional year increased the probability by 1.15 times.
Each concomitant disease led to an increase in this indicator by 13%. Women with the lowest family incomes were almost three times more likely to not survive Covid-19 than those with the highest incomes.
Since the study was observational, it is impossible to establish the exact reason why estrogen affects the risk of dying from coronavirus. Also, scientists did not take into account data on the exact doses of drugs, body weight, bad habits, and the number of women from the first group was relatively small.
However, the authors of the work believe that they were able to confirm the relationship between estrogen levels and the chances of recovering after infection with SARS-CoV-2.
“Therefore, estrogen-raising drugs may play a role in therapy aimed at alleviating the severity of Covid-19 in postmenopausal women and should be explored in randomized controlled trials,” they concluded.
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