Loud-noise tumor increases risk

Years of repeated exposure to loud noise increases the risk of developing a noncancerous tumor that could cause hearing loss, suggests research from Ohio State University, Columbus.

"It doesn't matter if the noise comes from years of on-the-job exposure or from a source that isn't job-related," according to Colin Edwards, a doctoral student in the School of Public Health.

In the study, people who repeatedly were exposed to loud noise over the span of several years were, on average, one-and-a-half times as likely to develop this type of tumor compared to individuals who were not subjected to such loud decibels. The tumor, called acoustic neuroma, grows slowly and symptoms typically become noticeable around age 50 or older. An acoustic neuroma tumor presses the cranial nerve that is responsible for sensing sound and helping with balance. Symptoms include hearing loss and a constant ringing in the ears, or tinnitus.

The tumor is fairly rare, accounting for only about six to 10% of tumors that develop inside the skull. Depending on the population, anywhere from one to 20 people per 100,000 develop acoustic neuroma each year. Those with the tumor in this study had the most common type--unilateral. About 95% of all cases affect only one ear. The other type, bilateral acoustic neuroma, is inherited and involves both ears.

If the tumor is caught early enough, a physician may be able to remove it surgically. Yet, as the tumor grows larger, it may become attached to the nerves that control facial movement, balance, and hearing, making it far more difficult to remove entirely.

Categories for loud noise include exposure to machines, power tools, and construction sites; motors, including airplanes; high-volume music, especially for those in the entertainment industry; and screaming children, sports events, and restaurants and bars.

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