Assessing Risk Factors Pre-Disposing Individuals to Noise Induced Hearing Loss

Noise induced hearing loss (NIHL) has the highest prevalence of all occupational diseases in the manufacturing sector accounting for one out of every nine recordable illnesses. Currently, after accounting for known risk factors, a large amount of unexplained variance remains in statistical models of NIHL. The purpose of this study was to determine the underlying factors pre-disposing people to NIHL as well as the association between early and future occupational hearing loss. The ecological model of health behavior provided the theoretical framework for this study. The key research questions were: which demographic factors (age, gender, and race) are associated with accelerated occupational NIHL; is there an association between hearing loss early in an individual’s work history and accelerated occupational NIHL later in their career; and in a multivariate adjusted model, which demographic, lifestyle, and occupational factors are associated with NIHL and are there significant interactions between the factors. A total of 4,894 subjects were followed for up to 13 years with 708 (14.5%) of them developing hearing impairment. Increasing age and being of White race were associated with an increased risk of developing hearing impairment. The sex of the worker and the annualized change in noise notch over the worker’s first five years were found to interact with regard to the risk of developing hearing impairment. The observed relationship between early occupational hearing loss and risk of hearing impairment will allow companies to incorporate criteria that trigger additional education and, possibly, re-assignment of at-risk employees to jobs within their company with lower noise exposure. Through this type of policy, the societal burden of hearing loss can be reduced