According to a study by researchers at the Johns Hopkins Bloomberg School of Public Health, older people with severe hearing loss are more likely to have dementia, but incidences of dementia were lower among participants in the study. study who used hearing aids.
What have we learned?
Previous studies have also observed a link between hearing loss and dementia. A study published in 2012 found that compared to people with normal hearing, people with mild hearing loss were twice as likely to develop dementia, those with moderate hearing loss three times as likely, and those with severe hearing loss five times more likely to develop dementia. develop dementia. In fact, hearing loss is estimated to account for 8% of dementia cases worldwide, more than any other potentially modifiable risk factor for dementia, according to the Lancet Commission on Prevention, Intervention and Care in Dementia. dementia.
But the researchers of this latest study, the results of which were published in a research letter in the peer-reviewed journal JAMA on January 10, say earlier studies were limited because they were “vulnerable to selection bias” – in using self-reported data that may not have provided an accurate snapshot of hearing loss and dementia nationwide.
“This study used an objective audiometric measurement of hearing rather than relying on subjective, self-reported hearing loss. We also used data that has a greater representation of older adults in the United States,” said Alison Huang, lead author of the study and senior research associate at the Cochlear Center for Hearing and Public Health, in an email to Yahoo News.
The study, funded by the National Institute on Aging, analyzed a national dataset from the National Health and Aging Trends Study, which has been ongoing since 2011.
“The National Health and Aging Trends Study collects data through home visits, making it easier for more vulnerable populations, such as adults over 90 and older adults with disabilities, to participate. , compared to a clinic study, which only captures people who have the ability and means to come to clinics,” Huang said.
The study’s analysis involved 2,413 people, about half of whom were over the age of 80, 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 secondary benefit to hearing aids. The study found that among 853 participants with moderate to severe hearing loss, “hearing aid use was associated with a 32% lower prevalence of dementia.”
“We are encouraged to see an association between hearing aid use and lower prevalence of dementia, which strengthens support for public health action to improve access to hearing care,” Huang said. at Yahoo News.
She 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 of Aging, is testing the effect of hearing loss treatment on cognition and dementia, and results from this trial will be available more later this year, Huang said.
According to the National Institute on Aging, approximately one-third of older adults have hearing loss, with the risk of developing hearing loss increasing with age.
Dr. Frank Lin, one of the leaders of the ACHIEVE trial, offered several possible reasons for the link between hearing loss and cognitive decline. Hearing loss “can make the brain work harder,” straining to hear 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 become more socially isolated, which negatively affects brain health.
“If you can’t hear very well, you might not get out as much,” Lin said, “so the brain is less engaged and active.”