Occupationally-acquired noise-induced hearing loss: a senseless workplace hazard

Occupational noise-induced hearing loss (ONIHL) describes an acquired hearing deficiency directly attributable to excessive workplace noise exposure. Data suggest that excessive noise attributes to approximately 37% of all adult causes of hearing loss and remains a significant contributor to employment-related morbidity internationally. Typically insidiously-acquired, often without frank progressive symptomatology, regional medical agencies continue to struggle with this potentially debilitating condition. The aim of the study was to provide a synopsis of the current understanding of ONIHL, its impact on individual workers and the wider international community, and to identify barriers to more uniform adoption of personal hearing protection.

A review of the contemporary literature was performed using defined keyword searches and OVID, PubMed, and Google Scholar as primary electronic search engines.

A number of published works were identified, describing aspects of the relationship between workplace-related noise exposure and subsequent development of employee hearing impairment, which demonstrate an overwhelming gender imbalance, with up to 97% of affected individuals being male. Industry-specific associations (e.g., mining, manufacturing and heavy construction) were well documented, as were links to toxin-specific exposures, in the recognized development of hearing loss. However, evidence of integration of appraisal of the topically-current area of genetic susceptibility was often lacking. Much discordance still exists among international agencies in the prescriptive regulation and enforcement of "safe" exposure limits.

Despite a high level of public awareness regarding the importance of hearing preservation and increasingly stringent international occupational health, safety and welfare requirements mandating provision of safer work environments, ONIHL continues to be a significant occupational hazard. ONIHL is permanent and may cause significant disability, for which there currently exists no cure, but is largely overtly-preventable. The impact of ONIHL on the global transition toward dominant communication-rich white-collar employment roles is difficult to quantitate, but is likely to be substantive upon the afflicted individual. In the mainstream setting, exposure-avoidance strategies aimed to reduce the incidence of ONIHL remain the focus of public health and occupational medicine approaches.