Women with osteoporosis, low bone density, or a previous vertebral fracture show significant increases in the risk of hearing loss compared to those without osteoporosis, according to a new study with more than 3 decades of follow-up.
The use of bisphosphonate therapy did not alter the risk, the researchers found.
“To the best of our knowledge, this is the first large longitudinal study to evaluate the relations of bone density, bisphosphonate use, fractures, and risk of hearing loss,” reported Sharon Curhan, MD, and colleagues in research published online in the Journal of the American Geriatric Society.
“In this large nationwide longitudinal study of nearly 144,000 women with up to 34 years of follow-up, we found that osteoporosis or low bone density was independently associated with higher risk of incident moderate or worse hearing loss,” the authors wrote.
“The magnitude of the elevated risk was similar among women who did and did not use bisphosphonates,” they added.
Participants were from the nurses’ health study and NHS II
With recent research suggesting a potential link between bisphosphonate use and prevention of noise-induced hearing loss in mice, Dr. Curhan, of the Channing Division of Network Medicine at Brigham and Women’s Hospital, Boston, and colleagues turned to the large longitudinal cohorts of the Nurses’ Health Study (NHS), conducted from 1982 to 2016, and the Nurses’ Health Study II (NHS II), from 1995 to 2017.
In total, the primary analysis included 60,821 women in the NHS and 83,078 in the NHS II.
Women in the NHS were aged 36-61 years at baseline and 70-95 years at the end of follow-up, while in the NHS II, women were aged 31-48 years at baseline and 53-70 years at the end of follow-up.
After multivariate adjustment for key factors including age, race/ethnicity, oral hormone use, and a variety of other factors, women in the NHS with osteoporosis had an increased risk of moderate or worse hearing loss, as self-reported every 2 years, compared to those without osteoporosis (relative risk, 1.14; 95% confidence interval, 1.09-1.19).
And in the NHS II, which also included data on low bone density, the risk of self-reported hearing loss was higher among those with osteoporosis or low bone density (RR, 1.30; 95% CI, 1.21-1.40).
No significant differences were observed in hearing loss risk based on whether women were treated with bisphosphonates, with the mean duration of use of the medication being 5.8 years in the NHS and 3.4 years in the NHS II.
Those who sustained a vertebral fracture also had a higher risk of hearing loss in both studies (NHS: RR, 1.31; NHS II: RR, 1.39).
However, the increased risk of hearing loss was not observed with hip fracture.
“Our findings of up to a 40% higher risk among women with vertebral fracture, but not hip fracture, were intriguing and merit further study,” the authors noted.
“The discordant findings between these skeletal sites may reflect differences in composition and metabolism of bones in the spine and hip and could provide insight into the pathophysiological changes in the ear that may lead to hearing loss,” they added.
Audiometric subanalysis
In an analysis of a subcohort of 3,749 women looking at audiometric thresholds for a more precise measure of hearing loss, women with osteoporosis or low bone density continued to show significantly worse hearing loss when treated with bisphosphonates compared to those without osteoporosis or low bone density.
However, there were no significant hearing loss differences among those with osteoporosis who did not take bisphosphonates versus those without osteoporosis.
The authors speculate that the use of bisphosphonates could have been indicative of more severe osteoporosis, hence the poorer audiometric thresholds.
In an interview, Dr. Curhan said the details of bisphosphonate use, such as type and duration, and their role in hearing loss should be further evaluated.
“Possibly, a potential influence of bisphosphonates on the relation of osteoporosis and hearing loss in humans may depend on the type, dose, and timing of bisphosphonate administration,” she observed. “This is an important question for further study.”
Mechanisms: Bone loss may extend to ear structures
In terms of the mechanisms linking osteoporosis itself to hearing loss, the authors noted that bone loss, in addition to compromising more prominent skeletal sites, could logically extend to bone-related structures in the ear.
“Bone mass at peripheral sites is correlated with bone mass at central sites, such as hip and spine, with correlation coefficients between 0.6 and 0.7,” they explained. “Plausibly, systemic bone demineralization could involve the temporal bone, the otic capsule, and the middle ear ossicles.”
They noted that hearing loss has been linked to other pathologic bone disorders, including otosclerosis and Paget disease.
Furthermore, imbalances in bone formation and resorption in osteoporosis may lead to alterations in ionic metabolism, which can lead to hearing loss.
Looking ahead, Dr. Curhan and colleagues plan to further examine whether calcium and vitamin D, which are associated with the prevention of osteoporosis, have a role in preventing hearing loss.
In the meantime, the findings underscore that clinicians treating patients with osteoporosis should routinely check patients’ hearing, Dr. Curhan said.
“Undetected and untreated hearing loss can adversely impact social interactions, physical and mental well-being, and daily life,” she said.
“Early detection of hearing loss offers greater opportunity for successful management and to learn strategies for rehabilitation and prevention of further progression.”
The study received support from the National Institutes of Health.
A version of this article first appeared on Medscape.com.