The Apolipoprotein Allele and Sensorineural Hearing Loss in Older Community-Dwelling Adults in Australia
Julia Z Sarant1, Steven J Bowe2, Mark McEvoy3
1Department of Audiology and Speech Pathology, The University of Melbourne, Melbourne, Victoria, Australia.
Objectives:
Previous research has investigated whether the apolipoprotein E (APOE) ε4 allele, which is associated with an increased risk of cognitive decline, is also associated with hearing loss in older people. Results of the very limited research to date are conflicting, and sample sizes for all but one study were small. The present study aimed to investigate whether there is an association between the APOE ε4 allele and hearing loss in a large, population-based sample of community-dwelling older adults.
Design:
Cross-sectional audiometric data on hearing levels and APOE genotypes for 2006 participants (aged 55 to 85 years) of the Hunter Community Study were analyzed using multiple linear regression to examine the association between APOE ε4 carrier status and the 4-frequency pure-tone average (0.5 to 4 kHz) in the better hearing ear, and also across individual frequencies in the better ear.
Results:
Observed and expected APOE allele frequency distributions did not differ significantly overall from established general population allele frequency distributions. Unadjusted modeling using better ear pure-tone average showed a statistically significant association between APOE ε4 allele status (0, 1, 2 copies) and reduced hearing loss, but when the model was adjusted for age, this was no longer statistically significant. Across individual hearing frequencies, unadjusted regression modeling showed APOE ε4 status was significantly associated with a reduction in mean hearing thresholds at 1 and 2 kHz, but again this effect was no longer statistically significant after adjusting for age.
Conclusions:
The results of this study did not provide any evidence of a statistically significant association between APOE ε4 allele status and hearing loss for older adults. Further investigation of the effect of homozygous carrier status on hearing thresholds is required.
