Oct. 11, 2006 Older adults with vision loss may be more likely to also have hearing loss, and the opposite appears true as well, according to a report in the October issue of Archives of Ophthalmology, one of the JAMA/Archives journals.
In 1994, 18 percent of U.S. adults older than 70 reported impaired vision, 33 percent reported hearing problems and 9 percent reported both, according to background information in the article. Because more adults are living longer and the number of older adults is increasing, the burden associated with such age-related sensory impairments may be increasing.
Ee-Munn Chia, M.B.B.S., University of Sydney, Australia, and colleagues examined the association between age-related hearing and vision loss in 1,911 adults who were part of the Blue Mountains Eye Study, which enrolled older adults from the Blue Mountains region west of Sydney. Five years after the original study, between 1997 and 1999, participants (then age 55 to 98, average age 69.8) underwent a medical interview along with vision and hearing examinations.
Among the participants, 178 (9.3 percent) had visual impairment (worse than 20/40 vision) without contacts or glasses and 56 (2.9 percent) had best-corrected visual impairment, meaning that their best vision while wearing glasses or contacts was worse than 20/40. In addition, 766 (40 percent) had hearing impairment, including 599 with mild impairment, 141 with moderate impairment and 26 with marked impairment. Hearing loss occurred in 116 patients (65.2 percent) of those who were visually impaired. For each additional line on the eye chart that an individual could not read, his or her odds of having hearing impairment increased by 18 percent if the reduction was in best-corrected vision or 13 percent in uncorrected vision. When the researchers looked specifically at the two most common causes of age-related vision impairment, cataracts and age-related macular degeneration, they found that both were independently associated with hearing loss.
It is possible that both vision and hearing loss are regular consequences of aging, which could explain why they often occur in the same individual. In addition, common risk factors could predispose older adults to both conditions. "Each condition has been postulated to result from somewhat similar genetic, environmental and lifestyle factors," the authors write. "Exposure to oxidative stress [when cells receive too much oxygen], cigarette smoking and atherosclerosis [hardening of the arteries] and its risk factors have been linked respectively to age-related macular degeneration, cataract and hearing loss. Another common risk factor for cataract and visual and hearing impairments is diabetes."
"Irrespective of the cause of sensory impairment, these two impairments were found to have a cumulative effect on function and well-being, significantly affecting both physical and mental domains," they conclude. "Further studies are needed to understand the relationship between visual and hearing impairments in older persons and to determine whether intervention to improve these impairments could delay biologic aging."
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