Hearing loss more prevalent than thought
■ Data show a significant number of middle-age adults are hearing impaired, and nearly one in five Americans 12 and older is affected.
- WITH THIS STORY:
- » External links
Though hearing loss is most commonly reported in the elderly, there is a significant percentage of impairment among middle-aged adults, according to a study led by Johns Hopkins researchers.
To help identify and treat these individuals, primary care physicians should ask adult patients if they have trouble hearing or understanding others when they are in a busy setting, such as a crowded restaurant, said lead study author Frank R. Lin, MD, PhD.
He encourages doctors to refer patients who have difficulty hearing to a specialist for testing.
Nearly one in five Americans 12 and older (48 million people) has hearing loss in at least one ear, according to the study in the Nov. 14 issue of Archives of Internal Medicine. That figure is up from previous estimates that hearing impairment affects 21 million to 29 million people.
The increase is due largely to the diverse population researchers analyzed, Dr. Lin said. He said previous research focused on particular age groups or regions of the U.S.
The Archives study shows that impairment is most common among people 80 and older, 89% of whom have hearing loss. About one in four people in their 50s has hearing impairment compared with about one in eight people in their 40s.
"A lot of people don't recognize they have hearing loss. It creeps up on you, and you learn to ignore it," said Dr. Lin, assistant professor in the Division of Otology, Neurotology and Skull Base Surgery at the Johns Hopkins University School of Medicine in Baltimore. He also is assistant professor in the Dept. of Epidemiology at the university's Bloomberg School of Public Health.
Impact of hearing loss
If left untreated, hearing impairment has been related to cognitive decline, dementia and poor physical functioning, Dr. Lin said.
"Those are all hugely important health and function outcomes for middle-age and older adults," he said. "It's important for primary care physicians to recognize that hearing loss is not an inconsequential part of aging."
Researchers examined data on more than 7,000 people 12 and older whose hearing was tested during the 2001-08 National Health and Nutrition Examination Surveys. The surveys assess the health and functional status of the noninstitutionalized U.S. population.
Air conduction pure-tone audiometry was administered to participants in a sound-attenuating booth during the surveys. A person was considered to have hearing loss if he or she could not hear sounds of 25 decibels or less in speech frequencies.
At that level of impairment, a person can hear people talk but typically has trouble hearing them clearly, Dr. Lin said.
Researchers found about 30 million people (13% of the population) have hearing loss in both ears.
The prevalence of overall hearing impairment increases with age, nearly doubling in each studied age group. Impairment was less common in women than in men. The condition occurred less frequently among blacks than in white people. Dr. Lin said the female hormone estrogen and the melanin pigment in darker skin could have a protective effect on the inner ear.