Review of environmental factors affecting hearing.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing laboratory and field literature without systematic methodology.
PubMed 7044773 · doi:10.1289/ehp.8244119
What was done
This paper reviewed literature on non-genetic causes of sensorineural hearing loss, focusing on laboratory and field evidence concerning continuous noise, impulse noise, ototoxic medications (specifically aminoglycosides), viral and bacterial infections, aging, and synergistic interactions among these exposures.
What was found
The review reported that risk of hearing loss emerges at continuous noise levels above 75–80 dBA, scaling with intensity, duration, and exposure frequency. Impulse noise risk increases at peak sound pressure levels above 145–155 dB SPL. Synergistic organ of Corti injury occurs between certain steady-state noises and acoustic impulses, as well as between noise and aminoglycoside antibiotics. Aminoglycosides were reported to cause hearing loss in up to 55% of the estimated one million individuals receiving them for tuberculosis or severe gram-negative infections. Following rubella vaccination and Rhogam, cytomegalovirus was noted as likely the most frequent cause of congenital deafness. Aging combined with lifestyle and environmental exposures leads to moderate-to-severe hearing loss in most older adults.
Why it matters
It outlines foundational exposure thresholds for acoustic injury and highlights the combined risks of ototoxic drug administration and environmental noise.
Limits
The abstract describes a broad narrative synthesis rather than a systematic review; it does not detail search methods, study counts, inclusion criteria, or quantitative risk estimates beyond general thresholds and single-point drug incidence estimates.
Cited by
- context Certain tribes in Africa not exposed to modern noise environments maintain normal hearing thresholds into their 80s.