Although I don’t think very many women in the UK are taking estrogen-only HRT, a new study has shown they may be at increased risk of developing asthma after the menopause according to a new study released in February, 2010 and published in the British Medical Journal.

It involved almost 58,000 women in France over a 12 year period and adds to a growing body of evidence suggesting a link between some female hormones and asthma. French and Mexican researchers found that compared with women who had never used any form of HRT, those who did use it were 21 percent more likely to develop asthma, but the risk was most significant in those using estrogen alone.

Among these women, the overall risk of asthma was 54 percent higher than for women who had never used any form of HRT, the scientists from the Gustave Roussy Institute in France and the Instituto Nacional de Salud Publica in Mexico wrote in a study in the British Medical Journal’s Thorax publication.

“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,” Leanne Metcalf, director of research at the advocacy group Asthma UK, said in a commentary on the study.”However this is the first large-scale and long-term study to suggest that it is estrogen-only HRT which significantly increases the risk.”

Experts say asthma is more common in young women after they have started having periods, and hospital admissions for asthma are more common among women than men. Hormones play a part too, as the severity of asthma also varies throughout the menstrual cycle and during pregnancy, but the incidence tends, in general, to fall after menopause.