Hearing loss, lack of hearing aid use associated with increased risk for dementia
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Key takeaways:
- Hearing loss was tied to a higher dementia risk, particularly among those who did not use an aid.
- If confirmed, the findings suggest hearing aids could help combat dementia onset in adults with hearing loss.
Hearing loss was linked to a higher risk for dementia, and this risk was greater among people who did not use a hearing aid than those who did, a recent study in JAMA Otolaryngology – Head and Neck Surgery found.
Previous studies on the relationship between hearing loss and dementia “are cross-sectional, precluding conclusions on temporality and causality,” according to Manuella Lech Cantuaria, PhD, an assistant professor at the University of Southern Denmark, and colleagues.
“The few longitudinal studies produced results ranging from no or weak associations to very strong associations between [hearing loss] and dementia,” they wrote.
The researchers further cited a lack of research on how hearing aids — which are now available over the counter following an FDA ruling in 2022 — may impact dementia risk.
To learn more, Cantuaria and colleagues conducted a population-based cohort study in Southern Denmark between January 2003 to December 2017. The cohort consisted of 573,088 people (mean age, 60 years; 52% women) aged 50 years and older. Among them, 23,023 were diagnosed with dementia.
Compared with no hearing loss, Cantuaria and colleagues reported that hearing loss was linked to a 7% increased risk for dementia (HR = 1.07; 95% CI, 1.04-1.11). The increased dementia risk was associated with severe hearing loss in both a person’s better ear (HR = 1.2; 95% CI, 1.09-1.32) and worse ear (HR = 1.13; 95% CI, 1.06-1.2).
The risk for dementia was even higher among those with hearing loss who were not using hearing aids (1.2; 95% CI, 1.13-1.27) vs. those with hearing loss who did use hearing aids (HR = 1.06; 95% CI, 1.01-1.1), the researchers reported.
The finding is consistent with previous research and “suggests that hearing aid use could be a tool in preventing or delaying dementia onset,” Cantuaria and colleagues wrote.
The researchers highlighted several limitations to the study, which included outcome and exposure misclassifications. They also noted that the increased risk for dementia was lower than risks found in previous studies, “highlighting the need for more high-quality longitudinal studies so that the clinical relevance of this association can be determined.”
Although clinical relevance is still unclear, Cantuaria and colleagues concluded that the study findings highlight the need “for a better understanding of the association between [hearing loss] and dementia as a critical step for the development of prevention strategies.”
Perspective
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This is an interesting article which brings up several points that regular readers of health literature should be aware of. It reports a roughly seven percent increase in dementia in people who have hearing loss, and up to 20% increase if the hearing loss was considered severe. A second finding is that those who use hearing aids were able to decrease that risk by 14%. While the results are interesting, there are several limitations that need to be pointed out before useful conclusions.. First, it is an observational study with all the accompanying limitations and biases. For example, the hearing loss group is 12 years older, more likely to be retired, and less educated. All of these are risk factors for dementia regardless of your ability to hear well. Secondly, because it is a non-randomized study, there are most certainly unknown differences between the groups, called residual confounding. That in itself makes it impossible to determine any type of causation. With regards to hearing aid use, it is even more problematic because the authors make no attempt to account for possible reasons why people wouldn’t use hearing aids. This again makes causal inference impossible. Hearing aids are wonderful devices for people to hear better, and hearing loss is an issue which all physicians should be aware of in terms of impact on quality of life. But connections between hearing loss, hearing aids, and dementia is not possible from an observational study such as this.
Perspective
Back to TopHearing loss in older adults is known to be a risk factor for major neurocognitive disorders such as dementia. This study is a retrospective cohort study, meaning that it looks at outcomes following an intervention being put in place. This study does not make a definitive link to the extent of hearing loss and dementia but does suggest a reduction in risk with the use of hearing aids. There is a need for a longitudinal study following longer time intervals and screening for cognitive impairment using a standardized and validated instrument such as the Montreal Cognitive Assessment, or MoCA. Multiple forms of this assessment exist so that the examinee does not take the same test repeatedly and have the ability to learn the correct answers, thus ensuring the screening is accurate.
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