Study finds no link between hormone replacement therapy and asthma attacks

What did the study look at?

Asthma is a long-term condition that affects the airways and symptoms can change over time. Some people notice changes in their asthma during hormonal shifts such as the menopause. During this time, hormone replacement therapy (HRT) is sometimes used to help manage symptoms like hot flushes or sleep problems.

Because asthma can be influenced by hormones, some women worry that taking HRT might make their breathing worse or lead to more asthma attacks. This study looked at whether there is evidence to support this concern.

The researchers studied over 180,000 women in the UK aged 45 to 60 who had asthma. They used routinely collected health records and compared women who started HRT with women who did not use HRT. They followed participants over time to see whether asthma attacks were more common after starting HRT compared with non-use.

Asthma attacks, as defined by the study, included:

• taking steroid tablets,
• attending A&E,
• being admitted to hospital
• death related to asthma.

If more than one of these happened within 14 days, they were counted as a single attack.

Researchers also looked at whether results differed depending on factors such as body weight, smoking history, blood test results and type of HRT used.

What do the results show?

Women with asthma who used HRT were no more likely to have asthma attacks than women with asthma who did not use HRT.

After taking other factors into account, such as age, smoking, asthma severity and other health conditions, there was no evidence of a link between HRT use and asthma attacks.

The researchers also found no differences in results based on:

• body weight
• smoking history
• blood eosinophil levels (a marker linked to asthma activity)
• type of HRT used

Overall, the study did not find evidence that starting HRT increases the risk of asthma attacks in women with asthma.

Why is this important?

Hormone replacement therapy (HRT) is commonly used during the menopause to manage symptoms. Some women with asthma may be concerned that HRT might make their asthma worse or increase the risk of asthma attacks.

This study can help women and their healthcare professionals feel more confident when talking about HRT as part of menopause care. It suggests that HRT can be considered for menopause symptoms without increasing the risk of asthma attacks.

Read the original research paper: Hormone replacement therapy and the risk of asthma attacks: population-based cohort study