How do hormones affect women’s experience of COVID-19?

13th October 2021 – By Aaruthy Suthahar

Two women sitting on a bench looking at the ocean

Post-menopausal women have lower levels of the female sex hormone oestrogen and appear to be at higher risk of developing serious complications of COVID-19, according to research from the COVID Symptom Study app.

Pre-menopausal women who took the combined oral contraceptive pill were less likely to develop COVID-19 and had a lower rate of admission into hospital. However, this was not the case for post-menopausal women taking hormone replacement therapy (HRT).

On the one hand, the team identified that the use of hormone replacement therapy was linked to an increased rate of predicted COVID-19. On the other hand, the HRT results need be considered with caution due to the lack of information about HRT type, route of administration and duration of treatment.

Over the COVID-19 pandemic, widespread research has detected that adult men of all ages have higher chances of developing serious complications compared with women. In addition, post-menopausal women who contract COVID-19 have been shown to have more severe complications.

The team analysed the link between COVID-19 and its severity in women taking oestrogen in the form of the combined contraceptive pill and in menopausal women undergoing hormone replacement therapy. 

The researchers analysed information supplied by hundreds of thousands of women logging their symptoms on the Zoe COVID Symptom Study app between May and June 2020, including members from the TwinsUK cohort. The team also used further health information collected through TwinsUK in their analysis.

Joint first author Dr Karla Lee explained:

“We hypothesised that pre-menopausal women with higher oestrogen levels would have less severe COVID-19 when compared to women of the same age and BMI who had been through the menopause, and our findings supported this. Additionally, when we compared a younger group of women on the combined oral contraceptive pill (COCP) with a similar group not taking the COCP we saw less severe COVID amongst those taking the COCP, suggesting hormones in the COCP may offer some protection against COVID-19. More research is certainly needed to further our knowledge.”

Joint first author Dr Ricardo Costeira said:

“Thanks to women of the COVID Symptom Study app we were able to show, with relatively large numbers, the significance of studying the sex hormone oestrogen in relation to COVID-19. We hope that results from our study can help inform ongoing biomedical research and clinical trials in the field.”

Senior author Dr Jordana Bell said: 

“We would like to thank all of the women who participated in the COVID Symptom Study app and our TwinsUK members for their contributions towards this study, and would encourage everyone to keep logging on the app.”

Costeira et al. (2021) Estrogen and COVID-19 symptoms: Associations in women from the COVID Symptom Study. PLOS ONE.

Can bacteria beat the belly fat?

5th July 2019 – by Paz Garcia

Man measuring his waist with a tape measure

Gut bacteria play an important role in the accumulation of fat around the midriff, a new TwinsUK study has found.

This makes gut bacteria a prime target for developing effective weight-management strategies.

Currently, over 12% of the global population is considered obese, up from 5% in 1975. In the UK, nearly 25% of the population is obese. Existing weight loss strategies however that focus on diet or exercise have not been very effective.

TwinsUK researcher Dr Caroline Le Roy explained:

“We know that fat that sits around the organs in the abdomen is harmful and can lead to heart disease, cancer and type 2 diabetes. Our research shows that gut bacteria play a key role in fat accumulation. We hope our findings will lead to more effective weight-loss strategies.”

The work was published today in Scientific Reports .

What did they do?

The gut is home to trillions of bacteria which help us to digest our food.

The team wanted to find out the role of gut bacteria in the accumulation of visceral fat – which surrounds the organs in the abdomen – and how it relates to diet.

The researchers analysed stool samples and diet questionnaires from over 1,700 TwinsUK participants.

What did they find?

They found that certain diet nutrients and gut bacteria affect the accumulation of visceral fat in different ways.

The team identified 93 groups of bacteria linked to visceral fat levels. Of these, 85 groups were linked with lower fat levels and 8 with higher fat levels.

Nutrients such as protein and cholesterol were associated with greater visceral fat. Other nutrients, including fibre, magnesium and vitamin E however were linked with lower visceral fat.

Further analysis found that the effect of fibre, magnesium and vitamin E on fat might be partly mediated by gut bacteria.

Intriguingly, the role of certain nutrients on visceral fat depended on the presence of gut bacteria, but in contrast, specific gut microbes appeared to affect fat accumulation regardless of dietary intake.

What does this mean?

Overall, differences in gut bacteria explain differences in visceral fat levels to a greater extent than nutrients alone.

The researchers stress in their paper that their findings do not prove causal relationships. Further research will need to check whether and how certain nutrients and gut bacteria actively cause accumulation of visceral fat, accounting for differences in lifestyle.

This work however brings us one step closer to understanding the importance of good diets and a healthy gut for overall health.

TwinsUK researcher Dr Jordana Bell said:

“I’d like to thank our twins who so generously give up their time and samples to make this research possible. It’s because of them that we’re beginning to unravel the relationships between food, gut bacteria and abdominal fat.”


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