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Abstract
Objective To test the hypothesis that incipient Alzheimer disease (AD) may adversely affect hearing and that hearing loss may adversely affect cognition, we evaluated whether genetic variants that increase AD risk also increase problem hearing and genetic variants that increase hearing impairment risk do not influence cognition.
Methods UK Biobank participants without dementia ≥56 years of age with Caucasian genetic ancestry completed a Digit Triplets Test of speech-in-noise hearing (n = 80,074), self-reported problem hearing and hearing with background noise (n = 244,915), and completed brief cognitive assessments. A genetic risk score for AD (AD-GRS) was calculated as a weighted sum of 23 previously identified AD-related polymorphisms. A genetic risk score for hearing (hearing-GRS) was calculated using 3 previously identified polymorphisms related to hearing impairment. Using age-, sex-, and genetic ancestry–adjusted logistic and linear regression models, we evaluated whether the AD-GRS predicted poor hearing and whether the hearing-GRS predicted worse cognition.
Results Poor speech-in-noise hearing (>-5.5-dB speech reception threshold; prevalence 14%) was associated with lower cognitive scores (ß = −1.28; 95% confidence interval [CI] −1.54 to −1.03). Higher AD-GRS was significantly associated with poor speech-in-noise hearing (odds ratio [OR] 1.06; 95% CI 1.01–1.11) and self-reported problems hearing with background noise (OR 1.03; 95% CI 1.00–1.05). Hearing-GRS was not significantly associated with cognitive scores (ß = −0.05; 95% CI −0.17 to 0.07).
Conclusions Genetic risk for AD also influences speech-in-noise hearing. We failed to find evidence that genetic risk for hearing impairment affects cognition. AD disease processes or a that shared etiology may cause speech-in-noise difficulty before dementia onset.
Glossary
- AD=
- Alzheimer disease;
- CI=
- confidence interval;
- DTT=
- Digit Triplet Test;
- GERA=
- Genetic Epidemiology Research on Adult Health and Aging;
- GRS=
- genetic risk score;
- ICD-9=
- International Classification of Diseases, 9th revision;
- IGAP=
- International Genomics of Alzheimer's Project;
- MR=
- mendelian randomization;
- OR=
- odds ratio;
- PC=
- principal component;
- SE=
- standard error;
- SNP=
- single nucleotide polymorphism;
- SRT=
- speech reception threshold
Footnotes
Go to Neurology.org/N for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
- Received November 11, 2019.
- Accepted in final form May 12, 2020.
- © 2020 American Academy of Neurology
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