Noise induced hearing loss among sawmill workers in a Sub-Saharan African country

Abstract Background: Noise Induced Hearing Loss (NIHL) is a permanent sensorineural hearing loss (HL) which affects the quality of life of exposed individuals. This study was done to determine the prevalence of NIHL among sawmill workers at the Timber market and petty traders in Accra, Ghana, and to assess the difference in actual and self-reported HL among the sawmill workers. Methods: This was a comparative study of NIHL among sawmill workers at the Agbogbloshie Timber Market of Accra and petty traders whose work environment was situated remotely from the sawmill. Data was analysed using SPSS version 20.0. Demographic characteristics and pure tone audiometric testing of study participants were analysed and presented as mean ± standard deviation, counts and percentages. Independent T-test was used in comparing pure tone hearing thresholds of sawmill workers and petty traders at various frequencies. Results: A total of 120 sawmill workers and 120 petty traders were studied. Sixty-four (53.3%) of the petty traders were females and all the sawmill workers were males. The mean ages for the sawmill workers and petty traders were 41.5 ± 11.8 and 32.5 ± 10.4 years. The prevalence of NIHL among the sawmill workers was 37.5% in the right ear and 43.3% in the left ear. Among the petty traders, the prevalence of NIHL was 12.5% in the right ear and 8.3% in the left ear. There was a statistically significant difference in NIHL between the sawmill workers and the petty traders (p-value = 0.0001). The prevalence of HL in the better ear for the sawmill workers and petty traders was 16.7% and 1.7% respectively. Sixty-nine (57.5%) sawmill workers self-reported HL compared to actual HL of 39 (32.5%) which showed a statistically significant difference (p-value = 0.011). Conclusions: The prevalence of NIHL among the sawmill workers and the petty traders for right and left ears was 37.5% and 43.3% and 12.5% and 8.3% respectively. There was a significant difference between actual and self-reported HL among the sawmill workers.