MedWire News: Postmenopausal women who take estrogen-only hormone replacement therapy (HRT) may face an increased risk for developing asthma, study results suggest.
Isabelle Romieu (Instituto Nacional de Salud Publica, Cuernavaca, Mexico) and team studied data on 57,664 postmenopausal French women who participated in the E3N study, part of the European Prospective Investigation into Cancer and Nutrition (EPIC).
All the women completed questionnaires about their use of HRT and the development of asthma symptoms every 2 years between 1990 and 2002.
Overall, 35.7% of the participants had never used HRT, while the remainder had used some form of HRT since experiencing the menopause.
In total, 569 women developed asthma during 495,448 person-years of follow-up.
The researchers found that women who had ever used HRT were 1.20 times more likely to have developed asthma over the study period that those who had never used HRT.
Further analysis revealed that only the use of estrogen-alone HRT was associated with a significantly increased risk for asthma, at a hazard ratio (HR) of 1.54, after accounting for potential confounding factors such as body mass index, parity, use of oral contraceptives, and type of menopause (natural/surgical/unknown).
This risk was particularly elevated in never smokers (HR=1.80) and women who reported suffering from allergic disease before asthma onset (HR=1.86), the researchers note in the journal Thorax.
Romieu and team conclude: “Our study shows an association between the use of estrogen alone as menopausal hormone therapy and asthma onset in a large cohort of postmenopausal women. This effect might be linked to an increase in airway inflammation mediated by different pathways, such as inflammatory cytokine release or stimulation of nitric oxide synthesis.”
They add: “The increase in asthma risk associated with hormone therapy must be judged in the light of all other health effects of hormone therapy use, including its beneficial effect on the quality of life of menopausal women.”
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