Friday, February 19, 2010

Hormone Replacement Therapy With Estrogen Alone Increases Risk for Asthma Onset After Menopause

From Medscape Medical News
Fran Lowry

February 17, 2010 — Hormone replacement therapy (HRT) with estrogen has been linked to an increased risk for the development of asthma after menopause, according to new research published online February 7 in Thorax.

"Epidemiological studies have suggested that female hormones might play a role in asthma and that menopausal hormone therapy (MHT or ...HRT) might increase the risk of asthma in postmenopausal women," write Isabelle Romieu, MD, of the Instituto Nacional de Salud Publica, Cuernavaca, Morelos, Mexico, and colleagues. "The mechanisms underlying the link between hormonal factors and asthma risk are still not clearly understood. Knowing whether MHT affects this risk and if so, whether different preparations have a similar effect would provide a useful insight into the mechanisms by which the hormonal milieu acts on the airways."

The aim of the study was to learn more about the association between different types of hormone therapy and the risk for asthma onset after menopause.

The investigators used data from the E3N study, which is the French component of the European Prospective Investigation into Cancer and Nutrition (EPIC). The study observed a cohort of 98,995 French women born between 1925 and 1950 for more than 10 years, from 1990 to 2002.

The women completed a self-administered questionnaire every 2 years about their medical history, menopausal status, and various lifestyle characteristics. They were considered incident cases of asthma if they stated that they had never had an asthma attack before menopause and had a medical diagnosis of asthma after menopause.

Among 57,664 women who were free of asthma at the start of menopause and who had information about their use of HRT, there were 569 incident cases during 1990 and 2002, which corresponded to an incidence of 1.15/1000 per year, the study authors report.

An increased risk for asthma onset was associated with hormone use. After adjustment for age, smoking, body mass index, oral contraceptive use, parity, and total caloric intake, the hazard ratio (HR) of asthma onset among women who had ever used HRT was 1.21 (95% confidence interval [CI], 1.00 - 1.46) vs never-users.

In women who had recently used HRT, the HR of asthma onset was 1.20 (95% CI, 0.98 - 1.46), and among past users, it was 1.16 (95% CI, 0.86 - 1.57).

However, the increased risk for asthma was significant only in women who used estrogen alone, the study authors report. Compared with never-users, the HR for estrogen-only users was 1.54 (95% CI, 1.13 - 2.09). This risk increased in never-smokers (HR, 1.80; 95% CI, 1.15 - 2.80) and in women who reported allergic disease before asthma onset (HR, 1.86; 95% CI, 1.18 - 2.93).

A small increase in the risk for asthma was observed with combination estrogen-progestagen use in women who never smoked and who had prior allergic disease, the study authors write.

Use of combination hormone therapy with estrogen plus progestagen was also associated with a small increase in the risk for asthma in these 2 subgroups.

The study authors note that they did not measure pulmonary function; therefore, some women may have had chronic obstructive pulmonary disease vs asthma. Results of their study could also be biased if respondents who used hormone replacement "systematically" reported more asthma attacks or were diagnosed with asthma more often because of more frequent visits to the clinician.

This association between the unopposed estrogen and asthma onset needs to be evaluated in light of the beneficial effects of the therapy on the quality of life of menopausal women, the study authors conclude.


Thorax. Published online February 7, 2010.

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