A recently published article in the Journal of the American Geriatrics Society has revealed that women with osteoporosis (a disease which causes bones to become fragile and more likely to break) and the stage before osteoporosis [osteopenia, or low bone density (LBD)[i]] are at a heightened risk of hearing loss.[ii]
Previous works of academic literature have made observations of elevated osteoporosis and LBD incidence among those with hearing loss, but until now, research on the issue of whether bone conditions ‘influence’ the risk of hearing loss has been scarce.
As part of the Conservation of Hearing Study (CHEARS), which has been set up to identify potentially modifiable risk factors that may contribute to hearing loss, researchers at Boston’s Brigham and Women’s Hospital (the 2nd largest teaching hospital of Harvard Medical School) analysed health data pertaining to 144,000 female registered nurses.
This data was sourced from the Nurses’ Health Study (NHS) and NHS II, which are large, ongoing prospective cohorts, first established in 1976 and 1989, respectively.
Over the course of 34-years of follow-up, participants completed self-reported questionnaires biennially and underwent audiometric assessments to ascertain audiometric thresholds.
So, did the investigators discover a longitudinal relationship between osteoporosis, or LBD, and subsequent development of hearing loss?
Results were not definitively conclusive. The most common osteoporosis-related fractures are vertebral fractures and hip fractures. In respect of the former, this was associated with a risk of ‘moderate or worse hearing loss’ up to 40% higher. By contrast, the latter did not appear to be correlated with increases in ‘moderate or worse hearing loss’.
Lead author and Instructor in Medicine, Sharon Curhan MD, explained that:
‘The differing findings between these skeletal sites may reflect differences in the composition and metabolism of the bones in the spine and the hip. These findings could provide new insight into the changes in the bone that surrounds the middle and inner ear that may contribute to hearing loss’.[iii]
Whilst the underlying mechanism, potentially connecting bone conditions with sensorineural hearing impairment, is still unclear, it is theorised that:
‘… abnormal bone remodelling and changes in the pathways involved in maintaining bone homeostasis may influence the integrity of the bone that protects the nerves and structures involved in hearing or alter ion and fluid metabolism in the cochlea, the main structure involved in hearing’.
By developing on these initial findings, the extent to which osteoporosis and LBD poses a risk to human hearing will be better understood.
Depending upon the outcomes of consequent studies, it may be the case that entries of osteoporosis and/or LBD in medical records can provide an adequate defence to the causation element of noise-induced sensorineural hearing loss (NIHL) claims.
[ii] Curhan SG et al., Osteoporosis, bisphosphonate use, and risk of moderate or worse hearing loss in women. J Am Geriatr Soc. 2021 May 24. <https://agsjournals.onlinelibrary.wiley.com/doi/full/10.1111/jgs.17275> accessed 9 June 2021.
[iii] ‘Study Finds Women with Osteoporosis and Low Bone Density Are at Increased Risk of Hearing Loss’ (24 May 2021 Brigham and Women’s Hospital) <https://www.brighamandwomens.org/about-bwh/newsroom/research-briefs-detail?id=3897> accessed 9 June 2021.