Quotes of the Day

That's what the latest analysis of national health data on adolescents shows. Between 1988-94 and 2005-06, the percentage of teens with hearing loss jumped by about a third, from 15% of 12-to-19-year-olds to 19.5%. And the reason may not be the ubiquitous earphones that snake from nearly every teen's ears during most hours of the day.

A team headed by Dr. Josef Shargorodsky, an ear, nose and throat specialist at Channing Laboratory at Brigham and Women's Hospital and Massachusetts General Hospital, drew raw numbers from data collected by the government's National Health and Nutrition Examination Survey, conducted over a six-year period in the 1990s and a two-year period more recently. Adjusting for factors such as age, race and exposure to infections that can damage delicate auditory nerves and affect hearing, they found just the kind of slow but significant rise in hearing loss that experts had been predicting in an era in which kids spend more time attached to earphones than ever before. But according to the survey, in which adolescents were asked about their exposure to loud noises, there was not a significant rise in this exposure in the two time periods. So music, say the authors, may not be the only thing that can be damaging kids ears. Diet and nutrition, as well as exposure to toxins, might be factors. Living in poverty is also associated with greater risk of hearing loss among youngsters, as children in lower-income families may not be getting adequate nutrition to support proper development of the auditory system.

It's this wealth of other possibilities which makes the investigators, who published their findings in the Journal of the American Medical Association, reluctant to blame listening devices for the problem. But whatever the causes, the hearing-loss trend is troubling. Difficulty in hearing among youngsters has been linked to slower language development, poorer performance in school and lower self-esteem. And because social skills are dependent on language, previous studies have found that even slight hearing loss in elementary and high school students can result in progressively lower scores on communication tests and greater anxiety.

Further research is needed to pinpoint the primary factors behind the rise in hearing loss, but while Shargorodsky is not ready to point the finger at iPods and their ilk, he's not exonerating them either. He notes that the adolescents in the surveys were asked only one question about their exposure to loud sounds, and that the question did not specifically mention earphones or other personal listening devices. Teens are notoriously inaccurate at reporting their exposure to potentially damaging decibels, he says, and may not even consider music piped in through earbuds as a source of danger. "We don't have a great grasp on noise exposure," Shargorodsky says. "But we hope to find better ways to ask the question and identify other factors that might be involved in the rise in hearing loss."

• Alice Park
• "Can you hear me now?" If you're a teen, the answer may increasingly be no