One in five U.S. teens shows some level of hearing loss, an increase of about 30 per cent over roughly 15 years, according to a study slated for publication Wednesday.

The study, which appears in the Aug. 18 issue of the Journal of the American Medical Association, compared data from two nationally representative surveys that measured teenagers' hearing in 1988-1994 and 2005-2006.

While the majority of hearing loss was slight, researchers found the prevalence of mild to severe hearing loss -- 25 decibels or greater -- jumped to 5.3 per cent from 3.5 per cent.

Teenage girls demonstrated less hearing loss than their male peers in 2005-2006.

"It's important to get that information out there so physicians are aware of this and teachers are aware of this, that this problem is so common and people are affected by it," says researcher Dr. Josef Shargorodsky of Brigham and Women's Hospital in Boston.

The study examined 2,928 participants between the ages of 12 and 19 in 1988-1994 and 1,771 in 2005-2006.

Hearing loss affects tens of millions of people of all ages in the U.S. While common, adolescent hearing loss isn't well understood, and may compromise social, communication and learning skills, researchers explain in the article.

Some risk factors linked to hearing loss -- such as exposure to loud music and sounds -- seem particularly relevant for teens.

Shargorodsky said the study did not determine what factors have contributed to the spike in hearing loss among young people, though researchers did look at factors such as participants' economic and ethnic backgrounds, history of ear infections and noise exposure.

"This study did not show that it's noise exposure that's driving this change in hearing loss," Shargorodsky told CTV News Channel Tuesday afternoon.

"Now the caveat to that is we asked the participants about whether or not they were exposed to loud noise, and teenagers are just not very good at reporting that. They just don't consider hearing loss to be a significant problem. And they don't consider a noise to be loud that other people might consider to be loud."

Boston student Alexa Curhan says she's exposed to loud noises every day.

"I realized how loud even the lunchroom is and when I'm going home, listening to my music, or if we're going to concerts or even sports events," she said. "Even at our school the sports games are really loud."

While many teens say they don't care about the possible side effects of loud music, experts say they should.

"In most cases, if we can ascertain a hearing loss and it is something permanent, usually it is music," audiologist Marshall Chasin told CTV News.

Hearing loss caused by an infection or fluid in the ear is not always permanent, Shargorosdsky said.

"But if it's nerve damage and it really is damage from loud music exposure over a long period of time, if that's really what this is, then it might actually be irreversible and it might actually only get worse," he said.

With files from CTV medical specialist Avis Favaro