The Apolipoprotein Allele and Sensorineural Hearing Loss in Older Community-Dwelling Adults in Australia

Hearing Loss and Cognitive Impairment: Epidemiology, Common Pathophysiological Findings, and Treatment Considerations

In recent years, there has been increasing research interest in the correlation between hearing impairment and cognitive decline, two conditions that have demonstrated a strong association. Hearing loss appears as a risk factor for cognitive impairment, especially among certain populations, notably nursing home residents. Furthermore, hearing loss has been identified as a modifiable age-related condition linked to dementia, and it has been estimated that midlife hearing loss, if eliminated, might decrease the risk of dementia in the general population. Several mechanisms have been suggested to explain the pathologic connections between hearing loss and dementia; however, clear evidence is missing, and the common pathophysiological basis is still unclear. In this review, we discussed current knowledge about the relationship between hearing loss and dementia, and future perspectives in terms of the effects of hearing rehabilitation for early prevention of cognitive decline.

Sex differences in the association between the APOEε4 allele and hearing impairment: A longitudinal memory clinic study

BACKGROUND

The APOEε4 allele and hearing impairment are risk factors for dementia. Cross-sectional studies have shown controversial findings regarding the relationship between APOEε4 and hearing impairment. These may be explained by reported sex differences in the association between APOEε4 and some Alzheimer's disease biomarkers. We aimed to investigate APOEε4 and hearing impairment in a longitudinal setting considering the modifying effects of sex on APOEε4.

METHODS

In total, 1810 subjects with APOE genotype at Ilsan Hospital memory clinics were linked to the longitudinal National Health Insurance Service database with International Statistical Classification of Diseases and Related Health Problems 10th revision (ICD-10) diagnosis codes of hearing impairment. After excluding cases with prevalent hearing impairment and incomplete records, 1092 subjects were analyzed for the period January 2004-July 2019. We used Cox proportional hazard models with or without adjustment for education, hypertension, diabetes, and cognitive function. Effect modification was analyzed by sex stratification and by adding APOEε4 by sex interaction terms.

RESULTS

Hearing impairment did not differ between APOEε4 carriers and non-carriers. Sex-stratification analysis with an unadjusted model showed men with APOEε4 developed more hearing impairment than men without (HR 1.90, 95% CI 1.20-3.01), but women did not. The results remained similar in covariate-adjusted models. The interaction between APOEε4 and sex was also significant regardless of adjustment.

CONCLUSIONS

Our longitudinal analyses suggested male memory clinic visitors with APOEε4 allele were more likely to develop hearing impairment than those without the genotype. This group may benefit more from regular monitoring and preventive measures for hearing impairment.