One out of every eight Americans has hearing loss in both ears, according to a new study - and as many as one in five are hard of hearing on at least one side.

Researchers found that hearing problems were more common in men than in women and in whites than in blacks. As expected, they also increased with age.

The prevalence of hearing loss “was pretty shocking,” said Dr. Frank Lin, from the Johns Hopkins School of Medicine in Baltimore, who worked on the study.

“There’s a common perception that hearing loss is a more inconsequential part of the aging process,” he added. But, “It’s not just inconsequential. Hearing loss actually does have a significant health impact on people’s lives.”

Lin’s own recent research has suggested that bad hearing may be tied to declines in thinking and memory as people age, for example (see Reuters Health story of February 14, 2011).

The new nationwide estimates are based on hearing exams that were given to about 7,500 people age 12 and up between 2001 and 2008.

Participants’ hearing was tested at a range of different noise levels in a sound-proof booth. The definition of hearing loss was not being able to hear sounds softer than 25 decibels. (According to the National Institutes of Health, a whisper is about 20 decibels.)

“This is the level of hearing loss at which you’re going to begin noticing you have trouble communicating in situations with background noise,” Lin explained.

While less than one percent of people age 29 and younger had hearing loss in both ears, close to 80 percent of the oldest group, age 80 and above, had significant hearing problems.

The number of participants with hearing loss in at least one ear ranged from two percent of teenagers to 89 percent of the most elderly, according to findings published in the Archives of Internal Medicine.

In middle-aged and older adults, rates of hearing loss tended to be highest in white and Hispanic study participants and in men.

Based on the findings, the researchers calculated that 30 million Americans age 12 and older, or about one in eight, are hard of hearing in both ears.

“We’ve known that (hearing loss) is a big problem, and I think this highlights just how big a problem it is,” said Dr. Josef Shargorodsky, an ear, nose and throat doctor and researcher with Harvard Medical School in Boston who wasn’t involved in the new study.

“It’s a little bit startling just how many people have hearing loss in this country,” he told Reuters Health.

Researchers said that genetics, poor nutrition, exposure to loud noises and certain medications have all been tied to an increased risk of hearing loss. But the biggest cause, Lin and Shargorodsky agreed, is simply old-age.

“Very much like you develop white hair over time… you develop damage to your ears over time,” Lin told Reuters Health.

Many people with hearing problems might not even know it, he said, because it often comes on so slowly. And partly because of that, most hearing problems are untreated, even though there are treatments - such as hearing aids - that have very little risk of side effects, Lin added.

Still, the idea of screening everyone for hearing loss is controversial, Shargorodsky said, partly because almost all older adults would test positive - and then, “where do you go from there?” he said.

But Lin is not in doubt.

“Anybody who thinks they may have hearing loss… it’s definitely worth getting evaluated, and you should definitely consider treating it.”

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SOURCE:  Archives of Internal Medicine, online November 14, 2011