People with hearing loss who do not use hearing aids may have a higher risk of dementia than either those who do use them or individuals who do not have hearing loss, researchers report today.
Authors of an observational study published in today’s edition of The Lancet Public Health have called for greater public awareness of the potential protective effects of hearing aids against dementia.
They found a 1.7% risk of dementia in people with hearing loss who are not using hearing aids, compared to 1.2% among those without hearing loss or who are experiencing hearing loss but using hearing aids.
The Lancet Commission on dementia prevention, intervention and care, published in 2020, suggested that hearing loss may be linked to about 8% of worldwide dementia cases, which meant that addressing hearing impairment could reduce the global burden of dementia.
Researchers at Shandong University, China, analysed data from 437,704 people who were part of the UK Biobank database, which collected information on hearing loss and use of hearing aids via self-reported questionnaires, while dementia diagnoses were determined using hospital records and death register data.
The average age of study participant at recruitment was 56 years old, and the average follow-up time was 12 years.
About three-quarters of the participants (325,882) had no hearing loss, while the remaining one-quarter (111,822) had some level of hearing loss, of whom 11.7% (13,092) used hearing aids.
After controlling for other factors, the authors suggests that, compared to participants with normal hearing, people with hearing loss not using hearing aids had a 42% increased risk of all-cause dementia, while no increased risk was found in people with hearing loss who used hearing aids.
This is approximately equivalent to a 1.7% risk of dementia in people with hearing loss who are not using hearing aids, compared to 1.2% among those without hearing loss or who are experiencing hearing loss but using hearing aids.
Corresponding author Professor Dongshan Zhu, of Shandong University, said: “Close to four-fifths of people experiencing hearing loss do not use hearing aids in the UK.
“Hearing loss may begin early in one’s 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 the early introduction of hearing aids when someone starts to experience hearing impairment.
“A group effort from across society is necessary, including raising awareness of hearing loss and the potential links with dementia, increasing accessibility to hearing aids by reducing cost, and more support for primary care workers to screen for hearing impairment, raise awareness, and deliver treatment such as fitting hearing aids.”
The researchers also analysed how other factors, including loneliness, social isolation and depressive symptoms, could impact the association between hearing loss and dementia, finding that less than 8% of the association between hearing aid use and decreased dementia risk could be removed by improving psychosocial problems.
The authors say this indicates the association between hearing aid use and protection from increased dementia is likely mostly due to direct effects from hearing aids rather than the investigated indirect causes.
Study author Dr Fan Jiang, also of Shandong University, said: “The underlying pathways which may link hearing aid use and reduced dementia risk are unclear. Further research is needed to establish a causal relationship and the presence of underlying pathways.”
Jiang F, Mishra SR, Shrestra N et al. Association between hearing aid use and all-cause and cause-specific dementia: an analysis of the UK Biobank cohort. Lancet Public Health 14 April 2023
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