Effect of age and duration of driving on hearing status of Indian agricultural tractor drivers

Tractor noise is critical occupational hazard which is the major cause of hearing impairment among Indian agricultural farm workers. The study aimed to show the effect of age and driving exposure on hearing impairment of drivers. Ninety healthy male subjects of similar age, height, and weight were selected and divided into four groups, i.e. 21–30, 31–40, 41–50, and 51–60 years. The audiometric testing was conducted of both the ears at 10 different frequencies, i.e. 0.125, 0.25, 0.5, 1, 1.5, 2, 3, 4, 6, and 8 kHz. The hearing threshold levels of office workers at audiometric test frequencies did not exceed 25 dB(A) to cause hearing handicap. However, it exceeded 25 dB(A) for tractor drivers and was higher for higher age group tractor drivers. Whereas, it did not exceeded 25 dB(A) at the audiometric test frequencies for the office workers except at 51–60 years of age group. Also, with the increase in age group and increase of driving experience, the mean hearing threshold levels of tractor drivers increase. It was concluded that the occupational hazards of tractor driving significantly increased the hearing threshold levels and the risk is even higher for the tractor drivers with ≥15 years of driving experience. Also, the mean hearing threshold levels for tractor drivers increase with increase in driving experience.