Dyslipidemia and cochlear function

Abstract

Problem: The relationship between dyslipidemia and hearing is unclear. This study was conducted to investigate whether elevated serum lipid levels impact cochlear function. Methods: Two animal models (human and guinea pig) were used. In the human model, a cross-sectional study of 40 volunteers with dyslipidemia was conducted. Total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), triglycerides, pure tone thresholds, and distortion product otoacoustic emissions (DPOAEs) were measured. In the guinea pig model, a prospective study over 14 weeks was conducted. A control group of 7 males were fed a normal diet. The experimental groups of 9 males and 8 females were fed a high fat diet. Weight, total cholesterol, and DPOAE magnitude were measured for each group. Results: For the human study, multiple linear regression analysis was performed in order to identify an effect of triglycerides, HDL, or LDL on pure tone thresholds and DPOAEs. When controlled for patient age, there was no statistically significant effect of any of the independent variables on cochlear function. For the guinea pig study, the paired students’ t test was performed in order to identify an effect of diet on DPOAEs. While the high fat diet led to a dramatic elevation in the average total cholesterol in all animals (from 61 to 589 mg/dL), there were no meaningful changes in DPOAE magnitudes. This was similar for the males as well as the females. Conclusion: These results suggest that dyslipidemia has no significant effect on cochlear function. Significance: Assessment of a patient’s lipid levels when determining a possible cause of his or her hearing loss may not be warranted. Support: None reported.