Older adults with severe hearing loss are more likely to have dementia, according to a study by researchers at the Johns Hopkins Bloomberg School of Public Health, but cases of dementia were lower among study participants who used hearing aids. .
What did we learn?
Previous studies have also observed a link between hearing loss and dementia. A study published in 2012 found that, compared to those with normal hearing, those with mild hearing loss had twice the risk of developing dementia, those with moderate hearing loss had three times the risk, and those with hearing loss severe have five times the risk of developing dementia. In fact, hearing loss has been estimated to account for 8% of dementia cases worldwide – more than any other potentially modifiable dementia risk factor, according to the Lancet Commission for the prevention, intervention and care of dementia.
But the researchers for this last study, the results of which were published in a research letter in the peer-reviewed journal JAMA on Jan. 10, they say past studies were limited because they were “vulnerable to selection bias” — using self-reported data that didn’t provide an accurate look at hearing loss and dementia. on a national scale.
“This study used an objective, audiometric measure of hearing rather than relying on subjective, self-reported hearing loss. We also used data that have a greater representation of older adults in the United States,” Alison Huang, lead author of the study and a senior research associate at the Johns Hopkins Cochlear Center for Hearing and Public Health, said in an email to Yahoo News.
The study, funded by the National Institute on Aging, analyzed a national data set from the National Study of Health and Aging Trends, which has been ongoing since 2011.
“The National Health and Aging Trends Study collects data through home visits, which make it easier for more vulnerable populations, such as adults over 90 and older adults with disabilities, to participate compared to a clinic-based study, which captures only people. who have the ability and means to get to clinics,” said Huang.
The analysis of this study covered 2,413 individuals, about half of whom were over 80 years old, and “showed a clear association between the severity of hearing loss and dementia.” according to a press release from Johns Hopkins. Among participants with “moderate/severe hearing loss,” the prevalence of dementia was 61% higher than among participants with normal hearing.
The good news?
The good news is that there may be a potential side benefit to hearing aids. The study found that among 853 participants with moderate to severe hearing loss, “the use of hearing aids was associated with a 32% lower prevalence of dementia.”
“We are encouraged by seeing an association between hearing aid use and lower prevalence of dementia, which creates support for public health action to improve access to hearing,” Huang told Yahoo! News.
He added that more work is needed from randomized trials to definitively test the effect of hearing aids on cognition and dementia. The ACHIEVE (Aging and Cognitive Health Evaluation in Elders) trial, also funded by the National Institute on Aging, is testing the effect of hearing loss treatment on cognition and dementia, and the outcomes of that process will be available later this year, Huang said.
About one-third of older adults have hearing loss, with the likelihood of developing hearing loss increasing with age, according to the National Institute on Aging.
Dr. Frank Lin, one of the leaders of the ACHIEVE process, he proposed several possible reasons for the connection between hearing loss and cognitive decline. Hearing loss “can make the brain work harder”, straining to listen at the expense of memory systems; Hearing loss can also cause the brain to “shrink faster.” Another possible reason is that hearing loss can cause people to be more socially isolated, which damages brain health.
“If you can’t hear very well, you can’t get out as much,” Lin said, “so the brain is less engaged and active.”