One in five American teenagers now suffers from some type of hearing loss, an increase of 31% since the mid-'90s, new research shows.
Most cases of hearing loss are slight, affecting only one ear and involving mostly high-frequency sounds, according to a study in today's Journal of the American Medical Association. Many teens may not even notice the hearing change. About one in 20 have "mild or worsening" hearing loss, which can make them struggle to follow conversations or teachers at school.
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"It's very concerning," says study author Josef Shargorodsky, an otolaryngology/head and neck surgery resident at the Massachusetts Eye and Ear Infirmary in Boston.
Other studies show that even a small hearing loss can harm a child's school performance, language development and social interactions, he says.
Parents may have trouble spotting the change as well, given that teens often tune their parents out, says Shargorodsky, whose research was conducted at the Channing Laboratory at Brigham and Women's Hospital, also in Boston.
Parents may notice other changes — such as an unexplained drop in grades — that could signal hearing loss, he says.
Because hearing loss is cumulative, these teens are at high risk for significant hearing problems as adults, says Brian Fligor, director of diagnostic audiology at Children's Hospital Boston, who wasn't involved in the study. Instead of developing noticeable hearing problems at age 50 or 60, these teens may have trouble hearing beginning at age 40.
Researchers based their findings on records of and interviews with nearly 4,700 kids ages 12-19, led by the Centers for Disease Control and Prevention.
They found no link between hearing loss and ear infections. Kids who reported being exposed to loud noise for at least five hours a week were no more likely to have hearing problems than others, says Shargorodsky, although he notes that teens usually aren't very good at accurately keeping track of their noise exposure.
Children living below the poverty level were much more likely to have hearing loss, possibly because poor kids have worse health in general, Fligor says.
Shargorodsky says his research doesn't explain why hearing loss is becoming more common. But doctors say the study points out the need to do more to protect children's hearing.
"Kids are growing up in a noisier world," Fligor notes.
An Australian study of kids with "mild to moderate" hearing loss found that using a portable music player, such as an iPod, was linked to 70% increased risk of hearing loss. And in a study of New York college students, Fligor found that more than half were listening to an MP3 player above the recommended exposure levels, which are 90 minutes a day at 80% of the maximum volume.
But iPods and rock concerts aren't the only source of noise in a child's world. Kids are also at risk if they fail to protect their ears when mowing the lawn, hunting with a rifle or attending noisy events, such as NASCAR races, Fligor says. Kids can protect their hearing by wearing headphones or inexpensive foam earplugs, Fligor says.
Other health trends also may be harming kids' hearing. Both high blood pressure and obesity can increase the risk of hearing problems, Fligor says. The number of children with diabetes has increased significantly in recent years, and a third of children are now overweight.
"What is scary is that these kids are setting themselves up for earlier hearing decline," says Mark Brown, an Austin otolaryngologist who treats a lot of children. "We will see the consequences of this down the road."
Originally published on USA today: http://www.usatoday.com/news/health/2010-08-18-hearing18_st_N.htm