Occupational noise-induced hearing loss in platinum miners: what do the data tell us?

ABSTRACT

Background: Occupational noise-induced hearing loss (ONIHL) is one of the most common occupational health diseases affecting miners in South Africa. Accurate and appropriate medical data are essential for making valid diagnoses. Objectives: The purpose of this study was to describe the electronic records of a South African platinum mine's audiometry medical surveillance system and their role in early diagnosis of ONIHL. Ear-related conditions of affected miners, occupations, and noise levels were concurrently reviewed, and the characteristics of miners with and without ONIHL were described. Methods: This was an analysis of secondary data from the electronic audiometry and employee occupational records of 305 platinum mine workers for the period 2014 to 2017. Data were analysed using descriptive statistics. Results: Although the audiometry records contained appropriate and relevant data, including annual hearing screening percentage loss of hearing (PLH) shifts, there was evidence of inaccurate and insufficient recording of risk factors for hearing loss in the medical surveillance records. The records indicated that the miners in some occupations were exposed to dangerously high noise levels, exceeding 85 dB(A). Miners as young as 21 years of age were diagnosed with ONIHL. Conclusion: The insufficient and inaccurate data captured in the miners' records has important implications for the mine's efficient implementation of hearing conservation programme (HCP) elements aimed at mitigating ONIHL. The hazardous noise levels recorded call for increased attempts to meet noise level regulations, while the presence of conditions such as pseudohypacusis highlights the need for exploration of more reliable assessment measures: