Occupational noise and age: A longitudinal study of hearing sensitivity as a function of noise exposure and age in South African gold mine workers

• Published in: South African journal of communication disorders Vol. 67; no. 2; pp. 1 - 7
• Main Authors: Swanepoel, De Wet, Strauss, Susan, Becker, Piet, Grobler, Leoni M., Eloff, Zahan
• Format: Journal Article
• Language: English
• Published: South Africa AOSIS 17-03-2020; African Online Scientific Information Systems (Pty) Ltd t/a AOSIS
• Subjects: Adult; Age Factors; Age-related hearing loss; Audiometry - statistics & numerical data; Cardiovascular diseases; Case-Control Studies; Cholesterol; Coronary heart disease; Diseases; Female; Gold; Hearing loss; Hearing Loss, Noise-Induced - epidemiology; Hearing Loss, Noise-Induced - etiology; Heart diseases; Humans; Longitudinal Studies; Male; Middle Aged; Miners - statistics & numerical data; Mining; Noise control; Noise exposure; Noise, Occupational - adverse effects; Noise-induced hearing loss; Occupational Diseases - epidemiology; Occupational Diseases - etiology; Occupational noise exposure; Original Research; Regression analysis; Retrospective Studies; South Africa - epidemiology; Time; Tinnitus; South Africa; Mining; Occupational noise exposure; Noise exposure; Age-related hearing loss; Noise-induced hearing loss
• ISSN: 0379-8046; 2225-4765; 2225-4765
• DOI: 10.4102/sajcd.v67i2.687

Background: A relationship exists between occupational noise exposure and age, which remains poorly understood.Objectives: The aim of this study was to establish the relationship between hearing loss and age over time.Method: Audiological data from 2583 mine workers in South Africa were utilised. Data were received from a non-noise exposed group (NNEG) (n = 951) and a noise exposed group (NEG) (≥85 dBA) (n = 1632). Data comprised a low-frequency average (LFA512) (average of audiological thresholds for 0.5 kHz, 1 kHz and 2 kHz) and high-frequency average (HFA346) (average of audiological thresholds for 3 kHz, 4 kHz and 6 kHz). Data were compared by using mixed-effects regression analysis.Results: Base threshold values were higher for the NEG than for the NNEG across frequencies. All year-to-year increases in mean hearing thresholds were statistically significant (p Conclusion: Age and occupational noise exposure influence hearing thresholds over time. The continued increase in hearing thresholds of the NEG above that of the NNEG can be related to ineffective noise management programmes and/or the fact that early noise exposure leads to a higher burden of hearing loss over time – even after noise exposure had stopped.