BOSTON -- A new review of data from the Centers for Disease Control and Prevention showed that a growing number of teenagers have minor hearing loss.

The study, published in the Journal of the American Medical Association Tuesday, revealed that 20 percent of adolescents ages 12-19 have “evidence of at least some kind of hearing loss,” according to study co-author Dr. Josef Shargorodsky.

The study was conducted jointly by researchers at Mass Eye And Ear Infirmary and Brigham and Women’s Hospital. They reviewed CDC data from a national health survey done in 2005-2006.

Similar data gathered between 1988-1994 showed that 15 percent of teens exhibited hearing loss at that time. The new data represents a nearly 25 percent increase in two decades.

“That’s a little bit surprising and a little bit alarming,” said Shargorodsky.

“We really need to start taking a lot more precautions,” said Alexa Curhan, 17, whose parents are also co-authors on the JAMA report. She is keenly aware of the danger posed by loud noises, and even surveyed her high school peers about their exposure to noisy areas like concerts, gunshots and school gymnasiums or sporting events.

“In social situations it can start to get really awkward because you might start not hearing parts of the conversation,” she said. “Or you might be thinking people are talking about something else.”

Minor hearing loss can mean that people miss the sound made by a dripping faucet, or the whisper of a friend.

“If you look at an average classroom, there will be several kids in that class that will probably have some kind of hearing problem,” said Shargorodsky. Undiagnosed hearing loss has been linked, much like an undiagnosed vision problem, to poor performance in school.

This latest review does not find any clear causes of hearing loss. There is little, if any, hard evidence that the use of portable music players such as iPods might be a contributing factor.

Other studies have shown that teenagers are listening to loud music longer than in previous generations, which is a risk factor.

It also found that boys and teenagers who live below the federal poverty line were more likely to lose their hearing.

Perhaps a bigger problem: teenagers who don’t think hearing loss is a problem.

“Teenagers actually consider acne to be a bigger health concern than hearing loss,” said Shargorodsky.

Curhan hopes that will change.

“Thinking about it now in terms of, 'Well, maybe my hearing's not as good as it could be.'” She hopes her friends and other teenagers will “realize that it's not just the situation; it could be their ears.”

Shargorodsky said the first signs of hearing loss can come in everyday life. Turning the television up louder than before could be a signal your hearing is fading. Also, he said many people first realize their hearing has declined while straining to catch a group conversation.