Postmenopausal women who use hormone therapy are at a higher risk for developing asthma, but not chronic obstructive pulmonary disease (COPD), according to an article in The Archives of Internal Medicine.
Because the incidence of asthma changes depending on a person's age, researchers suspect that reproductive hormone therapy may influence the development of the disease, which affects 5 percent to 8 percent of the United States population. Studies also suggest that incidence of COPD, the fourth leading cause of death in the United States, may also be influenced by sex hormones.
R. Graham Barr, of Brigham & Women's Hospital, and colleagues evaluated whether postmenopausal women using hormone therapy were at an increased risk for newly diagnosed asthma or COPD.
The researchers used data from the Nurse's Health Study, which enrolled 121,700 married female registered nurses, aged 30 to 55 years old in 1976.
The researchers found that current use of estrogen alone was associated with increased risk (2.29 times higher) of asthma compared with women who never used hormones. Women who used estrogen plus progestin had a similar increased rate of newly diagnosed asthma. However, the rates of newly diagnosed COPD among hormone users and non-hormone users were similar.
"Postmenopausal hormone use was associated with an increased rate of newly diagnosed asthma but not newly diagnosed COPD," the authors write. "Female reproductive hormones may contribute to the onset of asthma among adult women, but do not appear to hasten the development of COPD."
In other research, a small pilot study funded by the National Institutes of Health suggests that women who undergo HRT may run the risk of diminished hearing. Depending on the measure, HRT recipients on average did anywhere from 10 to 30 percent worse on hearing tests than women who had not received HRT, says Robert D. Frisina, professor of Otolaryngology at the University of Rochester Medical Center. Frisina and colleagues presented the research this week at the annual meeting of the Association for Research in Otolaryngology.
The scientists used three tests to compare the hearing of 32 women between the ages of 60 and 86 who had had hormone therapy to 32 other women who had not. While the HRT group performed more poorly across the board, it was in complex settings - such as the ability to decipher a sentence while listening to someone amid a loud backdrop, like the cacophony at a cocktail party - that the HRT group fared worst.
"It's important to alert women that there could be another significant side effect of hormone-replacement therapy," says Frisina. "We know these findings clearly apply to the 64 women we studied. What we can't say, from such a small number of people, is the extent to which they apply to everyone. A much larger study needs to be done.
"These results are very surprising. We thought hormones would help women hear better, because of the presence of estrogen receptors in the ear. This is the opposite of what we were expecting."
The HRT group performed most poorly on a test aimed at measuring not just how well the ear actually detects a sound, but also how well the brain processes that information. A large portion of age-related hearing loss, called presbycusis, involves the brain's faltering ability to process information. It's not much different from the work your computer does when billions of electronic signals registering as "0s" and "1s" flow in from the Internet - the computer takes those signals and makes words and graphics which we grasp quickly.
Our brains do similar work, filtering out unneeded information and prioritizing and organizing other information in a way we can understand. It's this sophisticated system that decreases as we get older, the team has found - and it's this ability that is most diminished in women who have received HRT compared to women who have not. Women in the HRT group on average performed this task 30 percent less effectively than other women.
"This would be most noticeable in situations where there is a lot going on, where there's a lot of background noise," says Frisina. "The most obvious situation is a party where a lot of people are talking, and you're trying to listen to one particular person. It's as if the aging process, when it comes to their ability to hear, was accelerated in these women.
"Our findings raise concerns. Women should talk to their doctors before making any decisions. And certainly, the findings call for more extensive studies."