Dementia and hearing-aid use: a two-way street

Abstract

Objectives: Hearing-aid use may reduce risk of dementia, but cognitive impairment makes hearing-aid use more challenging. These two causal pathways may both manifest as an association between reduced hearing-aid use and incident dementia. This study examined the effects of each pathway separately, through a unique combination of longitudinal data regarding hearing, general health, dementia diagnoses and continuity of HA use. Methods: Longitudinal health records data from 380,794 Veterans who obtained hearing aids from the US Veterans Affairs healthcare system were analysed. Analysis 1 (n=72,180) used logistic regression to model the likelihood of a dementia diagnosis at 3 year 6 months (3y6m) to 5 years post hearing-aid fitting for patients previously free of dementia and mild cognitive impairment (MCI). Analysis 2 (n=350,918) modelled the likelihood of being a persistent hearing aid user at 3y2m after fitting, contrasting subgroups with differing levels of cognitive function at the time of fitting. Models controlled for relevant predictors available in the dataset. Results: In analysis 1, the adjusted OR for incident dementia was 0.73 (ci 0.66-0.81) for persistent (vs. non persistent) hearing-aid users. In analysis 2, the adjusted OR for hearing-aid use persistence was 0.46 (ci 0.43-0.48) in those with pre-existing dementia (vs. those remaining free of MCI and dementia). Conclusion: The results indicate substantial effects from both causal pathways. Research studying protective effects of hearing-aid use against dementia needs to account for this. Clinically, hearing devices and hearing care processes must be accessible and usable for all, regardless of their level of cognitive function.