Noise-Induced Hearing Loss in Laundry Workers in Lagos

Abstract

The noise levels and the effects of occupational noise exposure were determined in the students' hostels, administrative offices and the laundry department of Lagos University Teaching Hospital (LUTH). All 40 test subjects and 54 control had comprehensive otological screening and fulfilled other inclusion criteria. The subjects had pure tone audiometric assessments by means of a standard calibrated diagnostic audiometer. Noise levels determined using a standard sound level meter averaged 45dB(A) in the administrative offices and students' hostels and 100.5dB(A) in the laundry department. The prevalence of noise-induced hearing loss, NIHL, among the control group was 9.3% and 65% in the laundry department. The results show a significant threshold shift at all test frequencies in the laundry workers compared with control. When considered by duration of exposure, laundry workers showed significant NIHL in the first decade of exposure (Pure Tone Average, PTA, 29.7), that did not seem to worsen in the second decade of exposure (PTA 26.4) only to show a more severe loss in the third decade (PTA 30.6). None of the laundry workers used hearing protective devices although the establishment provided these for them. Considering the fact that NIHL is preventable but irreversible once it is established, there is need for employee education concerning the continuing use of protective hearing devices. We also suggest pre-employment and regular on-the-job audiometric assessments to enable appropriate placement of workers susceptible to noise. Where possible, actual reduction of industrial noise by use of silencers or modification of the machines used should be encouraged. These measures will protect the general health of the employees while also reducing the economic loss suffered by employers as a result of NIHL and general ill health.


Key Words: Noise, Hearing Loss, Protective Device, Laundry


Nigerian Medical Practitioner Vol.44(1) 2003: 3-6