Hearing Loss May Be Modifiable Risk Factor for Dementia

Approximately one-third of dementia cases may be attributed to audiometric-measured hearing loss among older adults, according to the findings of a study published in JAMA Otolaryngology-Head & Neck Surgery.

Researchers conducted a prospective cohort study as part of the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS) to assess the population attributable fraction of incident dementia associated with hearing loss in older adults. ARIC, a longitudinal cohort study of 15,792 adults between the ages of 45 and 64 years from 4 US communities, includes up to 8 years of follow-up. For this analysis, the researchers included data from ARIC visit 5 (2011-2013) through visit 7 (2018-2019), as well as hearing data from all participants at visit 6 (2016-2017).

All participants without baseline dementia were included, and participants without hearing and covariate data were excluded. Incident all-cause dementia was identified using a standardized algorithm, and pure tone air-conduction audiometry was used for hearing testing. Cox proportional hazards regression models and population attributable fractions (PAF) were employed for statistical analysis.

A total of 2946 participants were included in the study (mean age, 74.9 years; women, 59.4%; Black, 21.6%). Overall, 66.1% had clinically significant hearing loss on audiometry, with 27% demonstrating moderate or greater hearing loss; 37.2% self-reported hearing loss. About half (55.9%) of those with moderate or greater hearing loss on audiometry used hearing aids. During a median follow-up time of 6.6 years (Interquartile range [IQR], 6.0-6.9), 8% of the participants developed incident dementia.

The PAF of 8-year incident dementia from mild or greater audiometric hearing loss was 32.0% (95% CI, 11.0%-46.5%); PAFs from mild and moderate or greater hearing loss were similar (16.2% vs 16.6%), while self-reported hearing loss was not associated with an increased risk for dementia.

A greater proportion of dementia was attributable to any measured hearing loss among participants aged 75 years and older (30.5% [95% CI, –5.8% to 53.1%]) vs those younger than age 75 years (22.0% [95% CI, –7.8% to 39.8%]), primarily due to larger PAFs among those 75 years and older who had moderate or greater hearing loss. The PAF for any hearing loss was slightly higher in women vs men participants (30.8% vs 24.0%) and in White vs Black participants (27.8% vs 22.9%).

PAFs among those with hearing loss who did not use hearing aids were more modest; among participants with any hearing loss, the PAF from no hearing aid use was 12.9% (95% CI, –13.4% to 31.8%).

Similar results to the primary analysis were observed in the sensitivity analysis.

Study strengths include longitudinal PAFs for a large population; limitations include potential survivor bias.

“This cohort study suggests that treating hearing loss might delay dementia for a large number of older adults. Public health interventions targeting clinically significant audiometric hearing loss might have broad benefits for dementia prevention,” the researchers concluded.

Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.