Hormone Replacement Therapy Can Increase Asthma Risk: Study

A new study suggests that hormone replacement therapy (HRT) can increase the risk of women developing asthma after menopause. While HRT has long been suspected of increasing the risk of asthma, researchers found that the greatest increase in risk came from the use of estrogen-only HRT therapy.

The study, conducted by French and Mexican researchers, was published in the latest issue of the medical journal Thorax on February 8. The study represents over a decade of research on more than 57,000 women. While both estrogen-only and combination HRTs were found to increase asthma risk, researchers said the only significant increase was that associated with estrogen-only pills.

Hormone replacement therapy involves the use of hormones and progestins to artificially boost hormone levels in women undergoing menopause due to surgery or in postmenopausal women, to provide relief from symptoms such as hot flashes, irregular menstruation or weight gain.

Researchers studied 57,664 French women to look at the use of HRT and asthma symptom onset every two years between 1990 and 2002. The researchers found that HRT use in general increased the risk of asthma by 21%. However, the use of estrogen-only HRT pills more than doubled that risk, increasing the likelihood of postmenopausal women developing asthma by 54%. Estrogen-pill users who had never smoked or had some other allergy before being diagnosed with asthma faced the highest risks; 80% and 86% higher than other women, respectively.

Some researchers involved with the project suggested that the results could be linked to an airway inflammation caused by female hormones. They also said that the results should be weighed with both the other risks and benefits of HRT.

In 2002 the National Institutes of Health released the results of studies that found women receiving HRT were at higher risk of breast cancer, strokes and heart attacks. The studies, part of the Women’s Health Initiative, sparked a large number of the hormone replacement therapy breast cancer lawsuits currently pending throughout the country.

There are currently about 9,000 lawsuits against Prempro, one of the leading HRTs in the U.S.. The drug was originally distributed by Wyeth, which was acquired by Pfizer last year. All of the lawsuits claim that inadequate warnings were provided about the risk of invasive breast cancer from the HRT drugs and that the drug makers intentionally hid the cancer risk from women.