HEARING LOSS, ITS PERCEPTIONS PREVENTIVE PRACTICE AMONG MACHINISTS EXPOSED TO NOISE POLLUTION IN IBADAN NORTH LOCAL GOVERNMENT AREA

Abstract

Abstract In Nigeria, there is dearth of information on the prevalence of hearing loss among machinists. Their perceptions anti practices relating to noise pollution have not been fully investigated. The objective of this study was to determine the prevalence of hearing loss among machinists and to document their perceptions and preventive practices regarding noisy work environment in Ibadan North Local Government Area. A comparative cross-sectional study design was adopted. Participants from worksites were selected based on the size of the workforce in each site. Using simple random sampling process a loud of 336 participants were selected from resaw, grinding and automobile services. A similar process was used to recruit 286 participants (mainly traders) who work 500-1000 meters away from each of the three sites as controls. A validated semi-structured questionnaire was used to interview the participants. Noise Levels were measured using a sound level meter at the worksites and the control areas, Otoscopic examinations were performed on consenting participants before audiometry. Pure-tone audiometry tests at the frequency of 500, 1000, 2000 and 4000Hertz were conducted on 27 resaw workers, 23 grinders and 18 auto mechanics using Kamplex Audiometer at the Ear, Nose and throat clinic of the University College Hospital. lbadan. Similar tests were conducted on 15, L4 and 12 persons that served as respective controls. Data were analysed using descriptive and inferential statistics. Majority (93.6%) of the machinists (exposure group) were males while 58% of their controls were also males. Mean age of machinists was 40.6±13.5 and controls (32.8±11.1). The significant difference in age was controlled for using logistic regression. Average not levels measured in A-weighted decibels; dB(A) at worker's position for the machinists were: resaw (100.5dB(A)1, grinders [96.7dB(A)], auto mechanics [60.3dB(A)] while their respective control worksites recorded less than 70 dB( A) (P<0.05).The prevalence of hearing loss in the better car at ≥41dB among machinists was 26.5% (Mean Heari ng Threshold (MHT) 35.1±12.7) while that of the control was 2.4% (MHT 20.2±8.9) (P<0.05). Hearing loss among specific exposure groups were: resaw (29.6%). grinders (34.8%) while each of their control groups recorded 0% (P<0.05). Auto mechanics recorded 11.1% hearing loss and their control (8.3%). Few machinist(17.2%) knew that noise affects hearing ability compared to 13.4% of control. About 7.7% of machinists knew that noise affects blood pressure compared to 5.2% of their control. Approximately 65.0% or machinists agreed they would stick to their job than hake to a noiseless one with lower wage as they believed that noise is not harmful. Furthermore, 94.5% of machinists reported not using ear protectors during work hours and 88.2% or them have never gone for hearing function check-up. An appreciable proportion of machinists suffer from noise -induced hearing loss while majority have no knowledge about the consequences of noisy work environment. The need to initiate hearing conservation programmes including health education interventions is recommended to ameliorate the situation.