Hormone Replacement Therapy and Asthma: Is there a link?

Use of Hormone Replacement Therapy by Women Age 40-65 Increases Asthma Like Symptoms.

A new study suggests that the use of estrogen or estrogen/ progesterone hormone replacement therapy (“HRT”) increases the risk of asthma-like symptoms in women ages 40-65.

The study compared how frequently women using HRT were prescribed corticosteroid inhalers compared to women who did not. A total of 379,649 women were included in the study, including 34,533 patients with asthma-like symptoms and 345,116 were control participants without asthma.

Results showed that women who were receiving HRT had a significantly increased risk of needing a steroid inhaler for asthma-like symptoms. In medical terms, the adjusted hazard ratio was 1.63 (95% CI, 1.55-1.71;) for developing new asthma compared with those not receiving hormone replacement. Further, women with asthma-like symptoms who eventually discontinued HRT were likely to no longer need any kind of asthma treatment.  In other words, the asthma-like issues were present only while using HRT.

Comment

This study caught my attention given the potential impact of HRT on immune function.   It is well known nowadays that use of estrogen and progesterone containing birth control and even hormone replacement might increase the risk of developing some types of autoimmune diseases. Some examples include inflammatory bowel disease, systemic lupus, and interstitial cystitis. The risk if some autoimmune diseases may even be reduced by HRT. So the topic is by no means straightforward.

Further study is needed to understand if hormone replacement therapy potentially affects various types of immune mediated hair loss - such as alopecia areata or scarring alopecia.  To date, it appears for most women HRT does not affect the course of the condition all that much.

Among women with frontal fibrosing alopecia (FFA), it seems that hormone replacement is more commonly used than for patients with LPP or among patients without scarring alopecia. It’s probably not that hormone replacement causes FFA but rather the FFA disease itself predisposes to symptoms requiring hormone replacement therapy or early menopause. Women with FFA are at risk for early menopause and some may elect to start HRT. In alopecia areata, it does not seem that hormone replacement therapy impacts alopecia areata in any way that we currently know.

Clearly, more studies are needed.

It’s turning out that mast cells have a key role in many hair loss conditions. If mast cells play a key role in asthma and hormone replacement has the potential to affect asthma the question then arises as to whether hormone replacement therapy has the potential impact mast cells in patients with autoimmune hair loss. For now, it does not seem there is all that much of a link but more studies are needed.

Reference

Hansen et al.   Backer V. Hormone replacement therapy and development of new asthma. CHEST. Published online March 25, 2021. doi:10.1016/j.chest.2021.01.054