NIOSH study identifies occupations with highest rate of hearing loss and tinnitus

Most employers are aware that occupational noise has the potential to cause permanent hearing loss in exposed workers. Less well known, and less studied, is the link between occupational noise exposure and tinnitus. A new study from the National Institute for Occupational Safety and Health (NIOSH) looks at both conditions, teasing out their individual prevalence, how often they occur together, and how they are connected to occupational noise exposure.

Tinnitus: Do you hear what I hear?

Noise-induced hearing loss is the most widely known and well understood effect of occupational noise exposure, but other effects, like increased stress and cardiovascular issues, are less well defined.

Tinnitus, or “ringing in the ears,” is another condition known to be connected to noise exposure but without much detail. It’s different from hearing loss, although the two conditions sometimes occur together.

Rather than diminished hearing, tinnitus is sound that is perceived in one or both ears even when the environment has no source of sound. It can disrupt sleep and concentration, increasing fatigue, reducing alertness, and degrading performance—all factors that can lead to accidents, both on and off the job.

The NIOSH study is the first to look at occupationally induced tinnitus. Before this study was published, there were no reliable estimates of how common tinnitus was in the workplace.

NIOSH’s findings

NIOSH used the 2007 National Health Interview Survey (NHIS)—which includes detailed self-reported information from workers on hearing difficulty, tinnitus, and exposures to occupational noise—to generate its estimates. According to the NHIS data, the incidence of hearing difficulty among workers who had never been exposed to occupational noise was 7 percent.
In that same group, 5 percent reported tinnitus, and 2 percent reported having both conditions. Among workers who had at any point in their working life been exposed to occupational noise, the incidence of both conditions was much higher: 23 percent reported hearing difficulty, 15 percent reported tinnitus, and 9 percent reported both.

Highest risk industries

The risk of tinnitus varies by industry. Workers were at increased risk if they had ever held jobs in:

  • Agriculture, forestry, fishing, and hunting.These workers had a significantly increased risk of hearing difficulty, tinnitus, and their co-occurrence.
  • Manufacturing. These workers also had significantly higher risk for hearing difficulty, tinnitus, and the co-occurrence.
  • Life, physical and social sciences, and personal care and service occupations.These workers were at significantly higher risk of hearing difficulty.
  • Architecture and engineering. These workers had a significantly increased risk of tinnitus.

One set of workers was at a reduced risk. Workers in sales and related occupations had significantly lower chance of developing hearing difficulty, tinnitus or both.

Prevention and treatment of tinnitus

Tinnitus has more than one possible cause. For example, more than 200 medications are known to have tinnitus as a side effect. Exposure to bomb blasts is another cause, making tinnitus one of the most common service-related disabilities among combat veterans.

But work-related tinnitus is most commonly caused by the same exposure that causes hearing loss: occupational noise. So if you are working to prevent noise-induced hearing loss, you are also doing what you need to do to prevent noise-induced tinnitus.
What you might not be doing is sending workers who suffer from tinnitus for treatment. Effective treatment is available for the condition and includes:

  • Hearing aids. These can help improve overall hearing and make tinnitus less noticeable.
  • Wearable sound generators. Like hearing aids, these small electronic devices are inserted in the ear. They mask tinnitus with a soft, pleasant sound chosen by the wearer.
  • Tabletop sound generators. Tabletop generators can be used at home to assist in relaxation or sleep.
  • Acoustic neural stimulation. Stimulation delivers a broadband acoustic signal embedded in music to desensitize sufferers and can reduce or eliminate tinnitus.
  • Cochlear implants. These are used to treat people who are suffering from both tinnitus and severe hearing loss. The implants bypass the damaged inner ear, directly stimulating the auditory nerve. They can mask tinnitus and stimulate change in the neural circuits.
  • Don’t let workers think that no help is available if they suffer from tinnitus. They can seek treatment, and their quality of life and job performance will likely improve if they do.

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