One in Five Americans Age 12 and Older Experiences Hearing Loss Severe Enough to Hinder Communication

The new research, published in the Archives of Internal Medicine, examined data from the National Health and Nutritional Examination Surveys, or NHNES, which has collected health information from thousands of Americans since 1971. The researchers looked specifically at people age 12 and older -- men and women of all races -- whose hearing had been tested during NHANES exams.

"Hearing loss is inevitable in many ways, and a lot of people view it as inconsequential, which is where there is a big mistake," said Dr. Frank Lin, assistant professor in the department of otolaryngology at Johns Hopkins School of Medicine and lead author of the study. "Hearing loss has a great impact on cognitive abilities and can progressively lead to social isolation and loneliness," he told ABCNews.com.

"When people can't communicate effectively, the brain actually has to reallocate resources to help with hearing, and that may affect dementia and other cognitive impairment," said Lin.

And with an older population that's living longer, hearing loss could become a serious impediment to social intercourse.

"Helen Keller once said, 'Blindness separates us from things, but deafness separates us from people,'" said Dr. Rob Jackler, chairman of the American Academy Otolaryngology Hearing committee and a professor at Stanford University School of Medicine. "It is central to what a human being is, and as you become older, hearing clarity diminishes, and it is a reason older people withdraw from life and become depressed."

While hearing loss nearly doubles with every age decade, women and blacks were significantly less likely to suffer from substantial hearing loss at any age than were men, whites and Hispanics.

Experts said estrogen and melanin in darker skin could both have protective effects on the ear, which may explain the lower rates of hearing loss in such populations.

"This certainly suggests that there can be some genetic-based hearing loss along with environmentally based loss," said Jackler.

But hearing loss has a large environmental component too.

"Seeds of older-age hearing loss may be planted by excessive noises in the younger years, so we really need to pay attention to amplified music through ear phones, because it will move the life curve of hearing loss along quicker," said Jackler.

That ringing or hollow sound in one's ear after listening to a steady stream of loud noise is known as a temporary threshold shift. That shift is a "red flag" for causing potential permanent damage, said Jackler, especially if the ringing lasts more than a few hours. Impulse noise is even worse than the temporary threshold, though.

"Shooting guns or having a firework go off near your ear is even more dangerous," said Jackler. "The ear has a defense mechanism that mitigates slightly continuous sounds. There are little muscles that tighten to resist sound, which allows for a minor degree of protection, but impulse noises get in before the ear has time to defend itself."

As in-ear headphones become a staple of the American wardrobe, experts worry that the constant blaring of music directly into the ears could do long-term damage.

"You don't see the effects of true hearing loss for several years," said Lin. "It's hard to say how much the ears will be affected from iPods and such. It's certainly not going to help your hearing, but we just don't know how much it's going to hurt it."