To determine whether baseline hearing loss increases cognitive decline and risk for all-cause dementia in a population of elderly individuals.
Longitudinal cohort study.
Men and women aged 65 years or older without dementia at baseline.
All subjects completed the Modified Mini-Mental Status Exam (3MS-R) at baseline and over 3 triennial follow-up visits. Hearing loss (HL) at baseline was based on observation of hearing difficulties during testing or interview. Incident dementia was determined by clinical assessment and expert consensus.
Main Outcome Measure(s)
Dementia and 3MS-R score.
At baseline, 4,463 subjects were without dementia, 836 of whom had HL. Of those with HL, 16.3% developed dementia, compared with 12.1% of those without HL (p < 0.001). Mean time to dementia was 10.3 years in the HL group versus 11.9 years for non-HL (log rank test p < 0.001). In Cox regression analyses controlling for sex, presence of APOE- ɛ4 allele, education, and baseline age, and cardiovascular risk factors, HL was an independent predictor of developing dementia (hazard ratio = 1.27, p = 0.026 [95% CI, 1.03–1.56]). Linear mixed models controlling for similar covariates showed HL was associated with faster decline on the 3MS-R, at a rate of 0.26 points/year worse than those without HL.
Elderly individuals with HL have an increased rate of developing dementia and more rapid decline on 3MS-R scores than their nonhearing impaired counterparts. These findings suggest that hearing impairment may be a marker for cognitive dysfunction in adults age 65 years and older.