High-quality evidence – with caveats
Several experts offered perspective on the analysis in a statement from the U.K.-based nonprofit Science Media Centre, which was not involved with the conduct of this study. Charles Marshall, MRCP, PhD, with Queen Mary University of London, said that the study provides “high-quality evidence” that those with hearing loss who use hearing aids are at lower risk for dementia than are those with hearing loss who do not use hearing aids.
“This raises the possibility that a proportion of dementia cases could be prevented by using hearing aids to correct hearing loss. However, the observational nature of this study makes it difficult to be sure that hearing aids are actually causing the reduced risk of dementia,” Dr. Marshall added.
“Hearing aids produce slightly distorted sound, and the brain has to adapt to this in order for hearing aids to be helpful,” he said. “People who are at risk of developing dementia in the future may have early changes in their brain that impair this adaptation, and this may lead to them choosing to not use hearing aids. This would confound the association, creating the appearance that hearing aids were reducing dementia risk, when actually their use was just identifying people with relatively healthy brains,” Dr. Marshall added.
Tara Spires-Jones, PhD, with the University of Edinburgh, said this “well-conducted” study confirms previous similar studies showing an association between hearing loss and dementia risk.
Echoing Dr. Marshall, Dr. Spires-Jones noted that this type of study cannot prove conclusively that hearing loss causes dementia.
“For example,” she said, “it is possible that people who are already in the very early stages of disease are less likely to seek help for hearing loss. However, on balance, this study and the rest of the data in the field indicate that keeping your brain healthy and engaged reduces dementia risk.”
Dr. Spires-Jones said that she agrees with the investigators that it’s “important to help people with hearing loss to get effective hearing aids to help keep their brains engaged through allowing richer social interactions.”
This study was funded by the National Natural Science Foundation of China and Shandong Province, Taishan Scholars Project, China Medical Board, and China Postdoctoral Science Foundation. Dr. Zhu, Dr. Livingston, Dr. Costafreda, Dr. Marshall, and Dr. Spires-Jones have no relevant disclosures.
A version of this article originally appeared on Medscape.com.