A Norwegian study shows that men have a greater risk of developing hearing loss than women and that male-dominated positions are more at risk than others. The results can be used to fight hearing damage in these high-risk jobs.

What job you have has something to say about your hearing. Those are the findings of a study from the Norwegian Institute of Public Health, who have investigated the hearing of almost 50,000 Norwegian builders, workshop workers, wood workers and machine and motor repairers.

"For a large proportion this is because these are the nosiest work places. We saw that the damage was caused by the work itself, as we looked at self-reported subjection to noise in the workplace. This indicates, that work-related factors can have an effect, such as vibrations, the use of solvents and work-related illness,” explains Bo Engdahl, department head at the Norwegian Institute of Public Health.

Non-work related factors such as noise outside work, ear infection and hearing impairment did not explain why some groups were more at risk than others. The study did however show that factors such as education and income did play a role in the occurrence of workplace injuries, which suggests that at least some injuries are the result of social inequalities.

 
The results can be used as prevention 
 
The most at-risk groups had an average hearing loss of around 10dB compared to the normal level at that age, with around double as many invalidating hearing injuries. This work-related hearing loss is in addition to the normal hearing loss that comes with age.
”The consequences can be difficulty in understanding speech and other audio signals, especially when there is background noise or poor acoustics as well as difficulty understanding speech via radio, TV, telephone and other sound sources, if it is of a low quality,” says Bo Engdahl.

Hearing impairment was most noticeable in the older employees, which could be a result of long-term exposure to noise. The explanation could also be that noise in the workplace has been reduced and that employees have become better at protecting themselves from noise, for example by using ear protectors.

The researchers also found only minor damage in women. The explanation for this could partly be that the positions which are most often connected to hearing impairment are male-dominated.

"The results can be useful in evaluating which positions have the highest risk of hearing impairment and which areas should be studied further with a view to prevention,” Engdahl says.

Source: Engdahl B, Tambs K. Type of occupation and the risk of hearing loss. Results from the Nord-Trøndelag Hearing Loss Study. Scand J of Work, Environment & Health (Published online in advance of print 2009)