Dyslipidemia and auditory function

Abstract

The relationship between dyslipidemia and hearing is unclear. This study was conducted to investigate whether elevated serum lipid levels impact auditory function in humans and in guinea pigs. In the human study, a cross-sectional study of 40 volunteers with dyslipidemia was conducted. Pure tone thresholds, distortion product otoacoustic emissions, and lipid profiles were analyzed. When controlled for patient age and sex, we found that elevated triglycerides were associated with reduced hearing. In the guinea pig study, a prospective study of animals fed a high-fat diet for 14 weeks was conducted. Although the high-fat diet led to a dramatic elevation in the average weight and total cholesterol in all animals (from 61 to 589 mg/dl), there were no meaningful changes in distortion product otoacoustic emission magnitudes. These results suggest that whereas chronic dyslipidemia associated with elevated triglycerides may reduce auditory function, short-term dietary changes may not.

FIG. 1

Age- and sex-adjusted audiograms for the human study arm. The 20 patients with the highest triglycerides (very high: 272 ± 7 mg/dl) are compared with the 20 patients with the lower triglycerides (less high: 141 ± 11 mg/dl). Patients with very high triglycerides had slightly worse thresholds than those with less high triglycerides. This effect was more prominent in the high frequencies. Data are not shown below 1,000 Hz because the Occupational Safety and Health Administration correction tables do not include this frequency range. Data are plotted as mean ± SEM.