Assessment Of Noise Induced Hearing Impairment In A Cement Factory

ABSTRACT

TITLE: ASSESSMENT OF NOISE-INDUCED HEARING IMPAIRMENT IN A CEMENT FACTORY AT TEMA. GHANA. OBJECTIVE: GENERAL:- To assess the prevalence of occupational noise-induced hearing impairment in a cement factory. SPECIFIC: (1) To measure the noise levels at different sections in the factory (2) To compare the prevalence of hearing impairment among workers of different age-groups. (3) To compare the prevalence of hearing impairment among workers with different lengths of exposure. (4) To determine whether the speech frequency range of those workers with hearing impairment is affected. DESIGN: Cross sectional study SETTING: Cement factory with a captured population of 308 workers. PARTICIPANTS: One hundred workers were selected at random from three hundred and eight workers. The selected workers were interviewed to discover other risk factors contributing to hearing loss. A recent auroscopic examination report was examined to rule out any ongoing ear infection. The workers then underwent audiometric assessment with a wide range qualitone Model WRB 6097 Diagnostic Audiometer calibrated according to American National Standard Institute (ANSI) 1969 standard. MAIN OUTCOME MEASURES: Noise levels at different locations in the factory were measured and prevalence of Noise-induced hearing loss assessed. RESULTS: The worst areas of toxic noise was the production section where noise levels ranged between 80 dBA and 108 dBA(decibels -Aweighted). Even though noise levels in the engineering section was below the threshold limit value, most of the workers from this section carry out maintenance work for long hours in the production section. Forty-two (42%) out of the 100 workers selected showed definite noise-induced hearing impairment, whilst 15 (15%) workers were strongly suspected of having noise-induced hearing impairment, 38 workers (38%) had good hearing acuity whilst 5 (5%) had excellent hearing acuity. Out of 42 workers who were forty years of age and below, 10 workers (23.8%) showed noise-induced hearing impairment, whilst out of 58 workers who were above forty years of age, 32 workers (55.2%) showed hearing impairment. Hearing normally declines with age.