Adults who experience hearing loss may face a higher risk of dementia and perhaps Alzheimer's disease than those who don't suffer hearing loss, new research suggests.
And the greater the loss, the greater the risk, the study suggested.
"This work suggests that there is a strong predictive association between hearing loss as an adult and the likelihood of developing cognitive decline with aging," said the study lead author, Dr. Luigi Ferrucci, chief of the U.S. National Institute on Aging's Longitudinal Studies Section, as well as the director of the Baltimore Longitudinal Study of Aging.
Ferrucci and his colleagues report their findings in the February issue of the journal Archives of Neurology.
The authors noted that by the middle of the century, about 100 million men and women worldwide (about one in 85) will be affected by dementia.
The researchers' investigation into the potential association between hearing loss and dementia focused on 639 men and women between the ages of 36 and 90, none of whom had dementia at the start of the study in 1990.
Cognitive and hearing tests were conducted over a four-year period, followed by patient tracking through 2008 (for an average of about 12 years) to monitor for signs of dementia and/or Alzheimer's.
The researchers noted that 125 study participants were diagnosed with "mild" hearing loss, while another 53 had "moderate" loss, and six had "severe" loss.
Ultimately, 58 patients were diagnosed with dementia, of whom 37 had Alzheimer's disease.