Hearing loss does raise the risk of dementia, with studies showing that even mild cases can double the chances and severe ones can increase it up to five times. This link shows up in people of all ages, but it starts as early as midlife and grows stronger over time.
Researchers have tracked this connection for years. One long-term study followed 639 adults for nearly 12 years and found mild hearing loss doubled dementia risk, moderate loss tripled it, and severe loss made it five times higher. Brain scans in these people also showed faster shrinking in key areas tied to thinking skills. For more details, see this study summary at https://www.audiologymaine.com/hidden-risks-of-untreated-hearing-loss.
Experts point to a few reasons why hearing loss harms the brain. First, it creates extra work for the brain, called cognitive load, as it strains to make sense of fuzzy sounds. This pulls resources away from memory and problem-solving. Second, less sound input might starve the brain of stimulation, leading to changes in its structure. Third, people with hearing trouble often pull back from talks and events, causing isolation that feeds into dementia on its own. A recent analysis from the National Health and Aging Trends Study showed moderate to severe hearing loss raised dementia odds by nearly twofold, but social isolation changed how strong that link was. Check the full paper here: https://academic.oup.com/psychsocgerontology/advance-article/doi/10.1093/geronb/gbaf276/8413483.
The risk starts young. Midlife hearing loss, around age 45 and up, tops the list of changeable factors for dementia, linked to about 7 to 8 percent of cases worldwide. The Lancet Commission, a top group on dementia, updated this in their latest report, estimating hearing loss boosts risk by 32 percent overall. Even in younger and middle-aged adults, untreated loss ties to drops in memory, speed, and flexibility. Details from that review are at https://pmc.ncbi.nlm.nih.gov/articles/PMC12729490/.
Good news comes from treatment. People who use hearing aids often see lower dementia risk. One breakdown of new research noted untreated loss raised risk by 71 percent, but those with aids showed no big jump. Another study found aids might cut dementia cases by up to 7 percent if used widely in midlife. A video explaining this links hearing aids to better brain health: https://www.youtube.com/watch?v=Q1X2pQDSTto.
These patterns hold across big reviews. Meta-analyses put the added dementia risk from hearing loss at 30 to 50 percent, with stronger ties in older adults. More on the numbers and brain pathways is in this overview: https://pmc.ncbi.nlm.nih.gov/articles/PMC12697576/.
Sources
https://academic.oup.com/psychsocgerontology/advance-article/doi/10.1093/geronb/gbaf276/8413483
https://www.youtube.com/watch?v=Q1X2pQDSTto
https://www.audiologymaine.com/hidden-risks-of-untreated-hearing-loss
https://pmc.ncbi.nlm.nih.gov/articles/PMC12729490/
https://pmc.ncbi.nlm.nih.gov/articles/PMC12697576/
https://www.mensjournal.com/health-fitness/study-finds-midlife-hearing-loss-significantly-raises-dementia-risk-but-this-tool-can-help
https://www.memphishearingaid.com/blog/treating-hearing-loss-may-delay-dementia/
