Researchers provide new insights into hearing loss
Between one-quarter and one-third of individuals older than 65 experience age related hearing loss. Today, researchers are gaining new perspectives into risk factors that may help prevent or delay the onset of impaired hearing.
Some studies in recent years have investigated the possibility of a connection between osteoporosis and hearing loss. Osteoporosis effects mineral density of bones throughout the body, including the small bones of the ear, such as the cochlea and ossicles. Although a handful of studies in recent years have produced mixed findings on the matter, researchers from Gyeongsang National University Hospital in South Korea may have elucidated some of the finer connections between osteoporosis and hearing loss. The study which included 4,861 participants discovered that bone mineral density of the lumbar spine was not significantly associated with hearing loss, however, there was a significant association with bone mineral density of the femoral neck. Specifically, loss of bone mineral density in the femoral neck was associated with a 1.7-fold increased risk of hearing loss. The research team anticipated these results in their hypothesis- that femoral bone would be a better predictor of hearing loss; similar to the ossicles of the ear, the femoral neck is comprised of a relatively high amount of cortical bone.
Hormone replacement therapy (HRT) is commonly used to treat the troublesome vasomotor symptoms of menopause and to reduce the risk of osteoporosis. Robert Frisnia, PhD, a professor and chair of the department of medical engineering at the University of South Florida has been studying the effects of hormone replacement on hearing loss for over a decade. The data he has collected suggests that estrogen alone may in fact be protective for hearing, while combination therapy could play detrimental role. In his latest study, published in Aging Cell, they administered either combination HRT or estrogen alone to aging mice to investigate specific molecular changes that resulted from the treatments. Additionally, he included a group of mice that received progesterone alone- a treatment which until then, had yet to be isolated to determine its effects on hearing. The results were consistent with his hypothesis; the mice who received combination HRT experienced the most negative effects on hearing loss. Another significant finding was that these effects were not reversible. “We were hoping that when we discontinued the HRT with the animals, there might be some recovery of hearing in the combination group. There wasn’t any recovery at all,” said Frisnia. The mice treated with estrogen, however, demonstrated positive impacts on hearing.
Frisnia suggests that these new findings may offer new possibilities for the prevention of hearing loss in patients who receive ototoxic medications, such as cancer patients who receive chemotherapy. On the other hand, these results raise concerns about the widespread use of combination HRT. “If a woman has no history of any type of cancer and she has very severe menopausal symptoms, then she might want to go ahead and take it,” Frisina says. “But it’s important for OB/GYNs and the patients to know that it might hurt their hearing as well, so that they can put that into the equation. If they already have hearing loss or they have a family history of breast or ovarian cancer, they might not want to do it.”
By: Jake Brassard
For the full article, visit: https://www.todaysgeriatricmedicine.com/archive/SO19p20.shtml