Author : S. Thaher, Ghania
The Medical Journal of Basrah University,
Volume 29, Issue 1, Pages 63-69
Background: Noise Induced Hearing Loss (NIHL) is irreversible sensorineural deafness in one or both ears which develops gradually due to chronic exposure to injurious noise in employement.
Objective: To study the extent of hearing loss among steel factory workers as a result of their exposure to noise and to formulate an educational program for wearing a protective devices during the work.
Methods: The study involved 121 subjects aged between 20-59 years. Fifty eight were working in Basrah steel factory as a case group and 63 were working in Basrah medical college as a control group, so (242 ears) were tested for pure tone using air conduction test audiometer. Each group was subdivided into two subgroups according to their ages.The ages of the first subgroup were ranging from 20 to 39 years and the ages of the second subgroup were 40-59 years.
Results: In the subgroup 20-39 years, 93.8% of the workers had bilateral hearing loss, while only 17.3% from the control group had hearing loss, there is a significant difference between the two groups regarding hearing loss (P<0.001) and its severity (P<0.001).
In the subgroup 40-59 years, all workers had bilateral hearing loss and only 40% of the control group had bilateral hearng loss.There is a significant difference regarding hearing loss (P<0.001) and its sevrity (P=0.001) between the two groups.
Comparing the two age groups (20-39 years & 40-59 years), in the workers there is no significant difference in hearing loss (P=0.429), but there is a significant difference regarding severity of hearing loss (P<0.001). While in the control group, there is no significant difference in hearing loss but a significant difference in severity of hearing loss(P=0.093 and P= 0.006 ) respectively.