According to a recent study by French and Mexican researchers, the risk of developing post-menopausal asthma can increase substantially in women who use estrogen-only hormone replacement therapy (HRT).

Experts are of the opinion that though HRT effectively combats menopausal symptoms, like severe hot flushes and vaginal dryness, its risks cannot be overlooked.

Corroborating the findings of earlier studies, which suggest that some female hormones are associated with asthma, the new study – published in the British Medical Journal Thorax - was based on a twelve-year-long comprehensive observation of nearly 58,000 women in France.

The researchers, from the Gustave Roussy Institute in France and the Instituto Nacional de Salud Publica in Mexico, revealed that women who use one or the other form of HRT face an almost 21 percent increased risk of asthma, vis-à-vis their non-HRT-using counterparts. Furthermore, the risk of asthma was even more notable in women who use estrogen alone.

In a commentary accompanying the study, Leanne Metcalf, director of research at the Asthma UK advocacy group, said: “There is now a large body of evidence suggesting a link between female hormones, including the use of HRT, the development of asthma and its severity. However this is the first large-scale and long-term study to suggest that it is estrogen-only HRT which significantly increases the risk.”