Hearing impairment common, perhaps preventable, chronic disease among middle-aged adults

In background information in the article, the authors estimate that at least 29 million Americans have a hearing impairment. "Population-based epidemiological prevalence estimates range from 20.6 percent in adults aged 48 to 59 years to 90 percent in adults older than 80 years," the author report. "The severity of this condition has been shown to be associated with a poorer quality of life, communication difficulties, impaired activities of daily living, dementia, and cognitive dysfunction."

Scott D. Nash, M.S., from the University of Wisconsin School of Medicine and Public Health, Madison, and colleagues analyzed data collected as part of the Beaver Dam Offspring Study, an epidemiological study of aging. The study included 3,285 participants ranging in age from 21 to 84 years, with an average age of 49. The researchers evaluated hearing impairment as a pure-tone average greater than 25 decibels hearing level in either ear, and also measured word recognition at different sound levels and with male and female voices. Study participants also provided information about medical history, behaviors and environmental factors.

The prevalence of hearing impairment was 14.1 percent and the average word recognition in quiet was 89.6 percent, but 63.5 percent in competing message environment. "Hearing impairment was more likely in men, in participants with lower education levels, and in those working in noisy occupations or with a history of ear surgery," the authors report. Other factors suggest there may be cardiovascular correlates associated with hearing impairment as based on the word recognition scores, including statin use, a higher hematocrit percentage (a marker of blood viscosity), and intima-media (artery walls) thickness. The authors note that participants in the study also had significantly higher odds of a parental history of hearing impairment and that this is a highly heritable condition.

"Hearing impairment is a common condition in middle-aged adults. Cardiovascular disease risk factors may be important correlates of age-related auditory dysfunction." The authors conclude that if hearing impairment is detected early, it may be a preventable chronic disease."