Certain cancer treatments, antibiotics and infectious diseases including COVID-19 are among key risk factors for adult-onset hearing loss, a review of 72 studies shows.
Other significant risk factors were occupational noise exposure, medical conditions such as diabetes and heart disease, lifestyle factors, biological responses and age progression.
The review by Australian researchers published in Preventive Medicine, March 2024, said risk factors associated with hearing loss (HL) could influence development of the condition.
Epidemiologist Professor Bamini Gopinath, Cochlear Chair of Hearing and Health at Macquarie University Hearing, and colleagues said adult-onset HL was often dismissed as an inevitable consequence of ageing and remained a neglected health issue that warranted increased attention.
“Age remains the single biggest determinant in adult-onset hearing loss, but these results remind us that there are other important risk factors that we need to be alert to, and to modify what we can,” she told the university’s news, The Lighthouse.
The systematic review of research from 42 countries synthesised epidemiological evidence from 2010 to 2023 to generate pooled incidences for risk factors.
Ototoxicity was a significant risk factor, mainly from cancer treatments and antibiotics which could be toxic to the ear. Incidence was markedly high for radiotherapy, chemotherapy and the combination, especially for radiotherapy on head and neck cancers.
Half undergoing cancer treatment developed hearing loss
Pooled proportional incidence – combining data from multiple studies to estimate overall incidence – was 52% for radiotherapy, 45% for chemotherapy, and 55% for the combination – meaning half of those who underwent these cancer treatments developed hearing loss.
“Some people reported hearing loss during their treatment but for others it developed later,” Gopinath told The Lighthouse, adding that the team was surprised by the strength of the influence of cancer medication on hearing.
Reviewers said radiation may harm auditory system components and damage the cochlea from oxidative stress and inflammation, adding the high incidence emphasised the need to explore less destructive therapies, monitor hearing function during treatment and consider aural rehabilitation with hearing devices.
Ototoxicity from other medications such as antibiotics demonstrated a high pooled proportional incidence of 50% for treatment of tuberculosis. HL was linked to the antibacterial class, aminoglycosides, used in drug-resistant TB, particularly long-term amikacin which was linked to an escalated risk of severe hearing loss.
Eight of 10 studies focused on antibiotics for TB while others identified ototoxicity from tobramycin and teprotumumab to treat cystic fibrosis and Graves’ Disease respectively.
COVID-19 linked to HL, tinnitus, vertigo
Infectious diseases or viral infections such as HIV, measles and rubella were known risk factors, they said. Some viral infections harmed structures in the inner ear or triggered an inflammatory response that damaged hearing.
Researchers said emerging research suggested some people with COVID-19 experience audio-vestibular symptoms such as tinnitus, vertigo and sudden sensorineural hearing loss, with pooled incidence for HL from four studies in high-risk populations being 28%.
“Given the moderate incidence levels of HL, it is imperative to promptly and appropriately manage infectious diseases to minimise this risk,” the researchers wrote.
Noise-induced HL also had a 28% incidence of hearing loss for military and other occupations. Mainly due to enduring or recurrent exposure to high-decibel sounds, it was largely preventable, highlighting the need for occupational noise management, reviewers wrote. Repeated exposure led to hair-cell destruction in the cochlea, culminating in sensorineural HL and often tinnitus.
Pooled proportional incidence of HL in relation to age progression was also 28%.
Reviewers said medical conditions including diabetes, heart disease and hypertension were associated with an elevated risk of HL. Pooled proportional incidences were 3.8% for lifestyle factors (smoking and obesity), 2.5% for health conditions (metabolic syndrome, diabetes, pregnancy, atherosclerosis) and 15.6% for biological responses (inflammation, blood pressure, low platelet count). Risk was low for fibromyalgia, spinal cord injury and vitiligo (1.6%).
They said their findings, combined with the epidemiological evidence, enhanced understanding of HL pathogenesis and highlighted areas for intervention, paving the way for more effective prevention and management of adult-onset HL in an ageing global population.
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