Objective:

To evaluate the association between severity of hearing loss and risk of incident dementia in participants of the Atherosclerosis Risk in Communities (ARIC) study.

Background:

According to the Lancet Commission, hearing loss carries the highest population attributable risk for dementia. The impact of varying degrees of hearing loss on dementia risk requires further investigation.

Design/Methods:

We conducted a Cox proportional hazards survival analysis on 2,578 participants from the ARIC study, with covariates—including hearing loss, cognitive status, and other risk factors—measured at visit 6 (2016–2017). Incident dementia diagnosis was the outcome with a maximum follow-up period of 3 years. Audiometry-derived hearing loss was the exposure and categorized as none (<25 dB hearing level [HL]), mild (≥25 to <40 dB HL), or moderate/severe (≥40 dB HL).

Results:

We included 2,578 individuals at baseline (mean age 79.1±4.5 years, 58.2% female, 18.4% Black). There were 152 dementia cases during the study period. In a Cox model adjusted for age, sex, race, education, APOE genotype, diabetes, hypertension, previous stroke and cognitive decline, moderate/severe hearing loss was associated with a higher risk of dementia (HR 1.64, 95% CI 1.03-2.62, p=0.038), while mild hearing loss was not (HR 1.17, 95% CI 0.75-1.83, p=0.492). Other significant predictors of dementia included advanced age (HR 1.09, 95% CI 1.06-1.13, p<0.001), APOE ε4 carrier status (HR 1.64, 95% CI 1.25-2.15, p<0.001), diabetes (HR 1.54, 95% CI 1.10-2.15, p=0.011), and cognitive decline (HR 2.71, 95% CI 1.91-3.83, p<0.001). There was no interaction between hearing loss and sex, race, or age (all p>0.5).

Conclusions:

Moderate to severe hearing loss is an independent predictor of dementia risk. Given the projected rise in dementia cases, understanding the optimal timing for screening and intervening on hearing loss is paramount. Concurrently, ensuring equitable access to hearing aids for at-risk populations may produce a meaningful impact on the burden of dementia.