HRT lowers asthma risk in menopausal women

Hormonal replacement therapy (HRT) may help menopausal women avoid late-onset asthma, a recent study has found.

Drawing from the UK’s Optimum Patient Care Database, the researchers constructed a 17-year open cohort including 353,173 women at-risk of asthma aged 46–70 years. The Read Clinical Classification System was used to define HRT use, duration, and subtypes, as well as the outcome variable of asthma onset.

In the study population, 16 percent used any HRT: 9 percent took combined oestrogen and progestogen HRTs, while 7 percent were on oestrogen-only HRTs. Ultimately, over 17 years of follow-up (1,340,423 person-years), 7,614 new asthma cases were reported, yielding an incidence rate of 5.7 cases per 1,000 person-years.

HRT use, regardless of timing and subtype, reduced the risk of late-onset asthma by around 20 percent in menopausal women.

For example, previous use of any HRT led to a 17-percent drop in the likelihood of asthma (adjusted hazard ratio [aHR], 0.83, 95 percent confidence interval [CI], 0.78–0.88), while current use had a 21-percent effect (aHR, 0.79, 95 percent CI, 0.74–0.85).

Subdividing by type did not change the findings. Previous use of oestrogen alone (aHR, 0.89, 95 percent CI, 0.84–0.95) or in combination with progestogen (aHR, 0.82, 95 percent CI, 0.76–0.88) had similar magnitudes of effect, as did current use of both HRT types (oestrogen only: aHR, 0.80, 95 percent CI, 0.73–0.87; oestrogen + progestogen: aHR, 0.78, 95 percent CI, 0.70–0.87).

“Further prospective cohort studies are now required to confirm these findings,” the researchers said. “There is also a need for mechanistic studies to elucidate the specific pathways through which HRT may influence inflammation leading to asthma pathogenesis.”