Conductive Hearing Loss is Associated With Dementia in the All of Us Research Program

Sensorineural hearing loss (SNHL) has been associated with cognitive impairment and dementia. However, because SNHL contains a neural component, it is difficult to completely exclude reverse causation whereby dementia causes worse SNHL. Conductive hearing loss (CHL), a purely peripheral phenomenon, would not have this mechanistic connection. We investigate the association between CHL and dementia in a large national cohort.

Cross-sectional study of ≥ 18-year-old (n = 338,048) voluntary participants from the NIH All of Us Research Program. The exposure was bilateral CHL defined by ICD-10 code (H90.0). The outcome was dementia defined by ICD-10 codes (F03, G30-32). The odds of dementia in subjects with and without CHL were assessed with multivariable regression, controlling for potentially confounding variables (age, sex, ethnicity, race, education, and smoking history), as well as surgical and medical interventions for CHL.

The mean (SD, range) age was 54 years (±17). 62.9% (n = 212,623) of participants identified as female. The cohort included 393 (0.1%) individuals with CHL. 1.9% (n = 6597) had dementia. After controlling for covariates, the odds of dementia were 2.05 times (95% CI 1.18-3.32; p = 0.006) higher for those with CHL compared to those without CHL. The odds were variably reduced when surgical interventions (stapedectomy, tympanoplasty, mastoidectomy, myringoplasty) (OR = 2.03, CI 1.17-3.29; p = 0.007) or hearing devices (hearing aids, implants) (OR = 1.98, CI 1.13-3.21; p = 0.010) were added to the fully adjusted multivariable model.

In the All of Us Research Program, CHL was strongly associated with dementia and treatment of CHL, both surgically and non-surgically, minimally reduced the odds of dementia.