By 2050, dementia is predicted to affect 150 million people worldwide. Research has shown an association between hearing loss and dementia.
The 2020 Lancet Commission reported that 12 modifiable risk factors account for around 40% of worldwide dementia cases, making addressing preventable risk factors crucial for the prevention of dementia. Worldwide, hearing loss (≥20 dB) affects 10% of people aged 40–69 years, 30% in people aged over 65 years and 70–90% in people aged 85 years or older.
Research has shown an association between hearing loss and dementia, indicating hearing loss might be a potential modifiable risk factor for dementia. Addressing hearing loss, such as through the use of hearing aids in middle-aged or older age people might be a potential way to reduce the risk of dementia.
Knowledge gaps still exist in the association of hearing aid use and the risk of dementia. Although studies have reported that hearing aid use is associated with improved cognitive function, the effectiveness of hearing aid use on reducing the risk of dementia in a real-world context remains unclear.
In a new study in the United Kingdom, researchers aimed to assess whether hearing aid use was associated with decreased risk of dementia (all-cause dementia, Alzheimer’s disease, vascular dementia, and non-Alzheimer’s disease non-vascular dementia) in people with hearing loss, using people without hearing loss as reference. Researchers also examined the effect of loneliness, isolation, depressed mood, and the interaction of socioeconomic status, smoking and morbidity status.
The health records of 437,000 people were used in the analyses. Here is what was found:
- People with hearing loss but without hearing aids had an increased risk of dementia compared with participants without hearing loss.
- Researchers found no increased risk in people with hearing loss with hearing aids.
- The positive association of hearing aid use was observed in all-cause dementia and cause-specific dementia subtypes (Alzheimer’s disease, vascular dementia, and non-Alzheimer’s disease non-vascular dementia).
- The attributable risk proportion of dementia for hearing loss was estimated to be 29·6%.
- Of the total association between hearing aid use and all-cause dementia, the risk proportions were lessened by 1·5% by reducing social isolation, 2·3% by reducing loneliness, and 7·1% by reducing depressed mood.
In people with hearing loss, hearing aid use is associated with a risk of dementia of a similar level to that of people without hearing loss. If, as the research suggests, up to 8% of dementia cases could be prevented with proper hearing loss management, the research findings highlight the urgent need to take measures to address hearing loss to improve cognitive decline.
Well-designed clinical trials are needed to assess the effect of hearing aid use in dementia risk and to qualify the role of types of hearing aids and length of hearing aid use for the prevention of dementia in different types of hearing impairment.
Hearing loss might begin early in one’s 40s, and the prodromal phase of dementia (the early stage when cognitive symptoms are present) also lasts for 20–25 years. The research findings highlight the urgent need to take measures to address hearing loss across the life course to improve cognitive decline. Public health strategies are necessary to raise awareness of hearing loss and the potential harm of untreated hearing impairment, increase accessibility to hearing aids by reducing cost, encouraging screening, and delivering potential interventions such as fitting hearing aids.
Read the full article in The Lancet