Hearing Loss, Hearing Aids, and Cognition.

Importance: Most observational studies examining the association between hearing loss (HL) and cognitive impairment used subjective measures of hearing and addressed only one dimension of cognition, and very few investigated the potential benefit of hearing aids (HAs). Objective: To evaluate objectively measured HL and several dimensions of cognition and estimate the association with HA use. Design, Setting, and Participants: A cross-sectional analysis of the CONSTANCES cohort study, which recruited participants from January 1, 2012, to December 31, 2020, was conducted. Participants were a representative sample of adults (age, 45-69 years) with audiometric data and cognitive evaluation from 21 preventive health centers in France. Data analysis was conducted from April 1 to September 15, 2023. Exposure: The main exposure was HL, which was defined by a pure-tone average in the best ear higher than 20 dB hearing level for mild loss and 35 dB hearing level for disabling loss. Secondary exposure was self-reported HA use. Main Outcomes and Measures: Cognition was evaluated at study inclusion by a standardized battery of 5 cognitive tests conducted by trained neuropsychologists. A global cognitive score was computed from principal component analysis and global cognitive impairment was defined as having a score less than or equal to the 25th percentile of the distribution. Results: The study population included 62 072 participants with audiometric data (mean [SD] age, 57.4 [7] years; 52% women). Overall, 38% (n = 23 768) had mild HL, 10% (n = 6012) had disabling HL, and 3% (n = 1668) were HA users. In multivariable analyses, mild HL (odds ratio [OR], 1.10; 95% CI, 1.05-1.15) and disabling HL (OR, 1.24; 95% CI, 1.16-1.33) were associated with greater global cognitive impairment. The odds of cognitive impairment did not differ significantly between all participants with HA use and participants with disabling HL without HAs (OR, 0.94; 95% CI, 0.83-1.07), except among participants with depression (OR, 0.62; 95% CI, 0.44-0.88). Conclusions and Relevance: In this cohort study, an association between the severity of HL and global cognitive impairment was found. The use of HAs was not associated with significantly lower odds of cognitive impairment. The findings suggest that it may be useful to monitor cognitive function in middle-aged individuals with HL.