Common Menopause Therapy Now Linked to a Chronic Lung Disease

Millions of women take hormone therapy to ease the discomfort of menopause, from hot flashes to sleep trouble. A large new study following nearly 97,000 postmenopausal women suggests that choice may carry a lung-related tradeoff most doctors and patients have never considered: a higher risk of a chronic lung condition called bronchiectasis.

Bronchiectasis happens when the airways in the lungs become permanently widened and scarred, often after repeated infections or inflammation. It leads to a persistent cough, mucus buildup, and, over time, more frequent lung infections. Roughly 400,000 people in the United States live with it, and for reasons doctors don’t fully understand, it shows up in women nearly twice as often as in men, especially after age 50.

Researchers who analyzed health records from the Women’s Health Initiative, a major long-running study of postmenopausal women, found that women who used hormone therapy had a 19% higher risk of developing bronchiectasis compared to those who never used it. The findings were published in Chronic Obstructive Pulmonary Diseases: Journal of the COPD Foundation. At the same time, women who had more years between their first period and menopause, meaning a longer stretch of natural reproductive hormone exposure, had a lower risk of the disease. But that protective effect only showed up in women who never used hormone therapy. Among women who did use it, the benefit of a longer reproductive lifespan disappeared entirely.

How Researchers Studied Hormone Therapy and Bronchiectasis Risk

Scientists pulled data from the Women’s Health Initiative, a study that enrolled more than 161,000 postmenopausal women across the United States between 1993 and 1998. For this analysis, researchers narrowed the group to 96,996 women with usable Medicare insurance records who were 65 or older when they enrolled in Medicare and had complete information about their reproductive history. Most participants were White (87.9%), with 7% identifying as Black or African American and 3.4% as Hispanic or Latina. The typical participant was 63 years old at the start of the study.

Researchers tracked these women through their Medicare claims looking for a first-time diagnosis of bronchiectasis, using standard medical billing codes. They excluded anyone whose lung disease was tied to known separate causes, like cystic fibrosis, so the findings would reflect bronchiectasis that develops later in life for other reasons. Over about 16 years of follow-up, 2,586 women, or 2.7% of the group, developed bronchiectasis.

From there, the team compared bronchiectasis risk across three reproductive measurements: age at first period, age at menopause, and the total number of years between the two, called reproductive lifespan. Those comparisons adjusted for other factors that could skew the results, including race, body weight, smoking history, whether a woman had her ovaries surgically removed, birth control pill use, and other health conditions.

What the Numbers Show About Hormone Therapy and Bronchiectasis Risk

Women with the shortest reproductive lifespans, under 30 years, had the highest rates of bronchiectasis. Those with the longest reproductive lifespans, 40 years or more, had a 12% lower overall risk than the shortest group. When researchers separated out hormone therapy users from non-users, the pattern got sharper. Among women who never used hormone therapy, those with the longest reproductive lifespans had a 22% lower risk of bronchiectasis than those with the shortest. Among hormone therapy users, that protective pattern mostly vanished.

A similar story played out when researchers looked at age at menopause alone. Women who reached menopause later in life, at 50 or beyond, had a lower risk of bronchiectasis than women who went through early menopause, before age 40. That link held up clearly among women who never used hormone therapy, but not among those who did. Age at first period mattered too: women who started their periods at 12 or older had roughly 15% lower risk than those who started earlier, and this difference was also strongest in women who never took hormones.

Across the study’s main statistical models, hormone therapy use itself was associated with a 19% higher risk of bronchiectasis, no matter how long a woman’s reproductive years lasted or when she went through menopause.

Why Hormone Therapy May Raise Bronchiectasis Risk

One question runs through the results: if longer natural exposure to reproductive hormones appears protective, why would taking replacement hormones after menopause raise risk instead of lowering it? The paper’s authors offer a couple of possible explanations, while carefully noting these are educated guesses rather than proven mechanisms.

One possibility is what scientists call reverse causality: women with the greatest drop in estrogen after menopause, who may already have been more prone to bronchiectasis, could also have been more likely to seek out hormone therapy in the first place. In other words, the hormone therapy might be a marker of who was already vulnerable, not the actual cause of the added risk.

Another possibility is that estrogen isn’t purely protective for the lungs. The study authors point to research on cystic fibrosis showing that estrogen can interfere with the lungs’ ability to clear mucus and may even help certain bacteria become more aggressive once they’re in the airways. If that is happening here too, then the real story might not be about hormones directly but about some underlying biological or genetic trait that separately controls both how long a woman’s reproductive years last and how vulnerable her lungs are.

This same research team also pointed out that their results echo an earlier study of more than a million women in South Korea, which found that shorter reproductive lifespans and hormone therapy use for five years or more were both linked to higher bronchiectasis risk. Seeing a similar pattern show up in a very different population in the United States adds weight to the idea that this isn’t a fluke tied to one country’s health system.

None of this means women should panic about hormone therapy or stop a treatment their doctor recommended. But it does point to lung health deserving a place in the conversation about the risks and benefits of hormone therapy, a conversation that up to now has mostly centered on heart disease, cancer, and bone health. A chronic lung disease that develops slowly over years, and now appears linked to a treatment millions of women take to feel better in the short term, is exactly the kind of tradeoff patients deserve to know about as researchers work to pin down the connection.

Disclaimer: This article summarizes the findings of a single observational study and is intended for general informational purposes only. Because the research shows an association rather than cause and effect, it cannot prove that hormone therapy causes or worsens bronchiectasis. It is not medical advice and should not be used to start, stop, or change any treatment. Women with questions about hormone therapy or lung health should consult a qualified healthcare provider about their individual circumstances.