Listen: Hearing aids could help fend off dementia

Dementia and hearing loss are common conditions among older adults. The Lancet Commission on dementia prevention, intervention, and care, published in 2020, suggested that hearing loss may be linked to around 8% of worldwide dementia cases,^[1] therefore, addressing hearing impairment could be a crucial way to reduce the global burden of dementia.

Evidence is building that hearing loss may be the strongest modifiable risk factor for dementia in midlife, but the effectiveness of hearing aid use in reducing real-world dementia risk has remained low. clear. Our study provides the best evidence to date to suggest that hearing aids could be a minimally invasive and cost-effective treatment to mitigate the potential impact of hearing loss on dementia, says corresponding author Prof. Dongshan Zhu, Shandong University (China).

The researchers looked at data from 437,704 people who were part of the UK Biobank database. Information on the presence of hearing loss and hearing aid use was collected via self-report questionnaires, and dementia diagnoses were determined using hospital records and death registry data. The mean age of study participants at enrollment was 56 years and the mean follow-up time was 12 years.

Approximately three quarters of participants (325,882/437,704) had no hearing loss and the remaining quarter (111,822) had some level of hearing loss. Among those with hearing loss, 11.7% (13,092/111,822) used hearing aids.

After controlling for other factors, the study suggests that, compared to participants with normal hearing, people with hearing loss who don’t use hearing aids had a 42 percent higher risk of dementia from all causes, while no increased risk was found. in people with hearing loss which hearing aids used.

This is roughly equivalent to a dementia risk of 1.7% in people with hearing loss who do not use hearing aids, compared with 1.2% among those without hearing loss or who have hearing loss but do use hearing aids.

Almost four fifths of people with hearing loss do not use hearing aids in the UK.^[2] Hearing loss can begin in the early 40s, and there is evidence that gradual cognitive decline before a dementia diagnosis can last 20 to 25 years. Our findings highlight the urgent need for early introduction of hearing aids when someone begins to suffer from hearing impairment. A concerted effort from across society is needed, including raising awareness of hearing loss and potential links to dementia, increasing accessibility to hearing aids by reducing costs, and increasing support for caregivers primary focus for hearing-impaired screening, awareness-raising, and the provision of care such as fitting hearing aids, says Dongshan Zhu.

The researchers also looked at how other factors, including loneliness, social isolation and depressive symptoms, might influence the association between hearing loss and dementia. Analysis from the study suggests that less than 8% of the association between hearing aid use and decreased dementia risk could be removed by ameliorating psychosocial problems. The authors say this indicates that the association between hearing aid use and protection from increased dementia is likely due primarily to the direct effects of hearing aids rather than the indirect causes studied.

The underlying pathways that may link hearing aid use and dementia risk reduction are unclear. More research is needed to establish a causal relationship and the presence of underlying pathways, says study author Dr. Fan Jiang, Shandong University (China).

The authors acknowledge some limitations to the study, including that self-report is at risk of bias, and that because this study is observational, the association between hearing loss and dementia could be due to reverse causation through neurodegeneration. or other shared mechanisms. Also, while many cofactors were accounted for, there may be unmeasured factors, such as those who used hearing aids potentially took even better care of their health than those who didn’t. Finally, the majority of UK Biobank participants are white, and very few participants were born deaf or experienced hearing loss before acquiring spoken language, which may limit the generalizability of the results to other ethnicities and people with hearing limited use of sign language.

Writing in a linked commentary, Prof Gill Livingston and Dr Sergi Costafreda, University College London, who were not involved in this research, said: With the addition of the work of Jiang and colleagues, the evidence that hearing aids are a powerful tool to reduce the risk of dementia in people with hearing loss is best possible without randomized controlled trials, which may not be practically possible or ethical because people with hearing loss should not be prevented from using effective treatments. Dementia is not only a disease that affects the individual and their family, it can also be costly. However, using hearing aids to prevent dementia has proven to be cost effective and cost effective. In the United States, hearing aids have become available for over-the-counter purchase, thus making them more affordable. The evidence is compelling that treating hearing loss is a promising way to reduce the risk of dementia. Now is the time to increase awareness and detection of hearing loss, as well as the acceptability and usability of hearing aids.

References:

1. Dementia prevention, intervention and care: 2020 report Hand Commission of Prof Gill Livingston, MD; Jonathan Huntley, PhD; Andrew Sommerlad, PhD; Prof David Ames, MD; Prof. Clive Ballard, MD; Prof Sube Banerjee, MD; Prof Carol Brayne, MD; Prof. Alistair Burns, MD; Prof Jiska Cohen-Mansfield, PhD; Prof. Claudia Cooper, PhD; Sergi G. Costafreda, PhD; Amit Dias, MD; Prof Nick Fox, MD; Prof. Laura N Gitlin, PhD; Prof. Robert Howard, MD; Prof. Helen C Kales, MD; Prof Mika Kivimki, FMedSci; Prof. Eric B Larson, MD; Prof. Adesola Ogunniyi, MBChB; Vasiliki Orgeta, PhD; Prof. Karen Ritchie, PhD; Prof Kenneth Rockwood, MD; Prof Elizabeth L Sampson, MD; Quincy Samus, PhD; Prof Lon S Schneider, MD; Prof Geir Selbk, MD; Prof Linda Teri, PhD and Naaheed Mukadam, PhD, July 30, 2020, The Lancet.
   DOI: 10.1016/S0140-6736(20)30367-6
2. Correlates of Hearing Aid Use in UK Adults: Self-Reported Hearing Difficulties, Social Participation, Living Situation, Health, and Demographics by Chelsea S Sawyer, Christopher J Armitage, Kevin J Munro, Gurjit Singh and Piers D Dawes, September/October 2019, Ear and Hearing.
   DOI: 10.1097/AUD.000000000000695

Reference: Association between hearing aid use and all-cause and cause-specific dementia: A UK Biobank cohort analysis by Fan Jiang, PhD; Shiva Raj Mishra, PhD; Nipun Shrestha, PhD; Prof. Akihiko Ozaki, PhD; Prof Salim S Virani, PhD; Tess Brilliant, PhD; Prof. Hannah Kuper, ScD; Prof Chengchao Zhou, PhD and Prof Dongshan Zhu, PhD, April 13, 2023, The Lancet Public Health.
DOI: 10.1016/S2468-2667(23)00048-8

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. See article for a complete list of author affiliations.