2016-12-15 16:39:11
Americans’ Hearing Loss Decreases Even as Headphone Use Rises

As concern rises over the effect of continuous use of headphones and earbuds on hearing, a new paper by federal researchers has found something unexpected. The prevalence of hearing loss in Americans of working age has declined.

The paper, published on Thursday in the journal JAMA Otolaryngology — Head & Neck Surgery, used data from the National Health and Nutrition Survey, which periodically administers health tests to a representative sample of the population. The investigators, led by Howard J. Hoffman, the director of the epidemiology and statistics program at the National Institute on Deafness and Other Communication Disorders, compared data collected between 1999 and 2004 to data from 2011 and 2012, the most recent available.

Hearing loss in this study meant that a person could not hear, in at least one ear, a sound about as loud as rustling leaves.

The researchers reported that while 15.9 percent of the population studied in the earlier period had problems hearing, just 14.1 percent of the more recent group had hearing loss. The good news is part of a continuing trend — Americans’ hearing has gotten steadily better since 1959.

Most surprising to Mr. Hoffman, a statistician, was that even though the total population of 20- to 69-year-olds grew by 20 million over the time period studied — and the greatest growth was in the oldest people, a group most likely to have hearing problems — the total number of people with hearing loss fell, from 28 million to 27.7 million.

Hearing experts who were not associated with the study said they were utterly convinced by the results.

“It’s a fantastic paper,” said Brian Figos, an audiologist with Lantos Technologies of Wakefield, Mass., which develops custom earpieces to protect ears from noise. “I totally believe them.”

“Initially, I was surprised,” said Dr. Debara Tucci, a professor of otolaryngology at Duke. “But then I thought about all the reasons why hearing loss might be declining.”

It is a long list including the closing of noisy factories, reduced use of medications like some antibiotics that can cause hearing loss, immunizations to prevent childhood illnesses like measles that can affect hearing, and better health in general in the population.

In her region, Dr. Tucci said, many patients used to work in noisy textile factories, most of which are now closed.

“I used to see a huge amount of noise-induced hearing loss,” she said. “I don’t see that so much anymore.”

Mr. Hoffman said — and others agreed — that although years of exposure to very loud noise can damage hearing, concerns that loud music being played through headphones is diminishing the hearing of a generation are as yet unproven.

If there were a headphone connection, it might have shown up as an increase in hearing loss among people in their 20s, because the issue of people wearing headphones for extended periods of time has been around for more than decade. But people in their 20s had no more hearing loss than people that age a decade ago.

“We are going to keep studying this,” Mr. Hoffman said.

The study found that men — at all ages — were more likely to have hearing problems than women, and that the greatest risk factor for hearing loss was age.

While the new data is gratifying, Mr. Hoffman cautioned that hearing loss remains a problem. “This doesn’t mean we have prevented hearing loss,” he stressed. “It just means it is delayed.”

Still, other researchers said the declining prevalence of hearing loss was part of a broad health trend internationally, with almost every major disease and disability on the wane and occurring later in life.

The hearing loss data, said James Vaupel, director, Max Planck Institute for Demographic Research in Rostock, Germany, “is consistent with other research showing a delay in aging.”

“The evidence suggests that 70 is the new 60,” Dr. Vaupel said, “with health and mortality of 70-year-olds today being similar to the health and mortality trends of 50-year-olds half a century ago.”