Noise level in different places of Dhaka Metropolitan City (DMC) and noise-induced hearing loss (NIHL) in Dhaka City dwellers.

ABSTRACT

A cross sectional, exploratory study was designed at "National Center for Hearing and Speech for Children" (NCHSC), Dhaka, Bangladesh, from May 2001 to June 2002, with a view to determine the average noise level in different places of Dhaka Metropolitan City (DMC), and also aiming at evaluating the extent of Noise-induced Hearing Loss (NIHL) in different groups of city dwellers and finally a base line information. A total of 32 places in DMC were selected randomly. The highest noise level recorded 104 dB at Sayedabad bus terminal and the lowest 68 dB in Banani and Baridhara residential area. In silent zone of DMC, average noise level was 79 dB, in residential zone 72 dB, in commercial zone 90 dB, and in mixed zone average noise level was recorded at 91 dB. Measured noise levels were more than acceptable and permissible levels in all places of DMC. A total of 312 persons aged between 15-45 years (mean age- 24.64 years) were enrolled for the study as per inclusion criteria. Gender-wise male were 211(67.62%) and female were 101(32.57%). Profession-wise Automobile drivers were 57(18.26 %), Garment workers 58(18.55 %), City dwellers 72(23.07%), Students 72(23.07%), Traffic polices 12(3.85%), Hawkers and Road side shopkeepers were 41(13.1%). Definite noise notch (>25dB) at 4KHz observed in 33(10.58%) audiogram of persons under study. Automobile drivers, Traffic polices, Road side hawkers and Shop keepers, Garment workers are mostly affected were 17.54%, 16.4%, 12.09% and 12.06% respectively. A total of 201 persons (64.42%) were not aware of their hearing impairment, 244(78%) of the person had poor level of knowledge regarding bad effects of noise on health and about protective means available. Amongst persons (33) found to have NIHL did not use any protective device.