WEDNESDAY, March 2 (HealthDay News) -- Hearing loss affects nearly two-thirds of older Americans, but blacks are much less likely than whites to have hearing problems, a new study shows.

It involved an analysis of data on 717 people aged 70 and older who took part in the 2005-06 National Health and Nutrition Examination Survey. About 63 percent of them had hearing loss that ranged from mild to severe.

Participants who were older or male were more likely to have hearing loss or more severe hearing loss than those who were younger or female. The study also found that 64 percent of whites had hearing loss, compared with 43 percent of blacks.

After accounting for a number of factors such as age and previous noise exposure, the researchers concluded that blacks were two-thirds less likely than whites to have hearing loss.

It's not clear why the risk was so much lower in blacks, but some research has suggested that pigment produced by cells in the skin and inner ear may protect the inner ear by absorbing free radicals, said study leader Dr. Frank Lin, an assistant professor in the otology division at Johns Hopkins School of Medicine and a core faculty member at Hopkins' Center of Aging and Health.

Despite the high number of older Americans with hearing loss, only a fifth use hearing aids, the study found. Among those with mild hearing loss, just 3 percent use hearing aids.

The study was published online Feb. 28 in the Journal of Gerontology: Medical Sciences.

More information

The U.S. National Institute on Aging has more about hearing loss.