Nearly one in three cases of incident dementia could be attributable to audiometric hearing loss, much larger than previously estimated, American researchers have claimed in a new study.
Writing in JAMA Otolaryngology–Head & Neck Surgery on 17 April 2025, they said treating hearing loss might delay dementia for many older adults.
The researchers set out to determine what fraction of new cases of dementia could be attributed to hearing loss (HL) in a community-based population of 2,946 older adults.
“In this cohort study of a large, community-based sample of black and white adults 65 years and older in the US, up to 32% of incident dementia over eight years could be attributed to clinically significant audiometric hearing loss (HL) through calculating the population attributable fraction (PAF),” they said.
The PAF from any HL (32%) was “substantially larger than previous US estimates of 2%-19%”, they said. It was also higher than that reported in the 2020 Lancet Commission on Dementia Prevention (8% for objectively measured HL) and the 2024 Lancet Commission on Dementia Prevention (responsible for 7% of dementia cases globally).
“In this large cohort of community-dwelling older adults with a mean age of 75 years, nearly one in three incident dementia cases could be attributed to clinically significant hearing loss,” the Johns Hopkins researchers concluded.
Self-reported HL was not associated with increased dementia risk. They found self-reported HL underestimated clinically significant HL and did not capture the preventive potential of addressing HL on dementia risk.
PAFs from HL were generally larger for older, female, and white populations compared to younger, male, and black populations.
The prospective cohort study was part of the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS). ARIC is the subsample that showed benefit from HL treatment in the ACHIEVE study.
Accounting for both the relative risk and prevalence of HL, the population attributable fraction (PAF) is the maximum proportion of dementia that can be attributed to HL in a population of exposed and unexposed individuals.
Community-dwelling older adults aged 66 to 90 years without dementia at baseline who underwent a hearing assessment at ARIC-NCS visit six (2016-2017) were included in the analysis. Data analysis took place between June 2022 and July 2024.
The population attributable fractions of dementia from both audiometric and self-reported hearing loss were calculated in the same participants, which quantified the maximum proportion of dementia risk in the population that can be attributed to hearing loss.
Researchers found 1,947 participants (66.1%) had audiometric hearing loss, and 1,097 (37.2%) had self-reported hearing loss. Of those with objectively measured moderate or greater HL, 445 (55.9%) used hearing aids.
The population attributable fraction of dementia from any audiometric hearing loss was 32% and it was similar by hearing loss severity (mild HL: 16.2%, moderate or greater HL: 16.6%).
The median follow-up time was 6.6 years, during which time 239 participants (8%) developed incident dementia.
Hearing aid use
While their analysis showed “only a modest association between hearing aid use and decreased risk of dementia”, they said this could be indicative of a longer follow-up needed to detect a benefit to overt cognitive impairment.
“Given the presumed underlying causal relationship between HL and dementia (ie, peripheral HL increasing cognitive load, inducing structural and functional brain changes, and decreasing social engagement), our findings reinforce the importance of investigating the preventive potential of HL intervention to prevent dementia,” they wrote,
“In the ACHIEVE randomised clinical trial participants recruited from ARIC, hearing intervention versus control decreased the rate of 3-year cognitive decline by 48% ; no effect on risk of incident cognitive impairment was observed, although the trial was not powered for this outcome.”
They said a recent meta-analysis found hearing aid use in adults with audiometric HL was associated with a 29% decrease in risk for any cognitive decline relative to those not using hearing aids.
The researchers said future research quantifying population attributable fractions should carefully consider which measures are used to define hearing loss, as self-reporting may underestimate hearing-associated dementia risk.
“Future studies should prioritise objective measures of hearing over subjective measures to quantify its preventative potential on dementia risk, especially among groups known to underestimate their audiometric HL with self-report,” they wrote.
“Interventions for sensory health in late life might be associated with a broad benefit for cognitive health.”
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