Association of Dyslipidemia With Sudden Sensorineural Hearing Loss: A Retrospective Study

Abstract

Background: Blood lipid levels have been widely studied in patients with sudden sensorineural hearing loss (SSNHL), but it has been unclear whether dyslipidemia associates with SSNHL. Whether there is a simple and feasible blood lipid index to predict the onset of SSNHL remains to be found.Methods: This study reviewed 100 SSNHL patients and 100 healthy subjects who received relevant clinical examination in our hospital from June 1, 2015 to June 1, 2019. The demographic, clinical characteristics, lipid levels and lipid metabolism indexes of the two groups were compared.Results: In this study, 100 patients (64 men [64%]; 36 women [36%]; mean [SD] age, 38.47 [14.36] years) were included in the SSNHL group, and 100 healthy people(60 men [60%]; 40 women [40%]; mean [SD] age, 36.52 [9.86] years) served as the control group. No significant differences between the SSNHL group and the control group in age, sex, BMI, smoking habits and alcohol drinking patterns were observed. Meanwhile, it can be seen the mean (SD) concentrations of total cholesterol (TC) (194.59 [38.22] vs 176.83 [23.55] mg/dL; MD, 17.76 mg/dL; 95% CI, 26.64-46.72 mg/dL), the mean (SD) concentrations of low density lipoprotein cholesterol (LDL-C) (116.99 [33.59] vs 96.91 [22.01] mg/dL; MD, 20.08 mg/dL; 95% CI, 32.43-48.26 mg/dL) and apolipoprotein (apo) B (89.82 [21.38] vs 81.16 [16.17] mg/dL; MD, 8.66 mg/dL; 95% CI, 12.03-23.21 mg/dL) were significantly higher than the control group. In addition, it was also observed that the median [IQR] concentrations of high density lipoprotein cholesterol (HDL-C) (1.51 [1.33-1.76] vs 1.56 [1.40-1.84] mg/dL) and the median [IQR] concentrations of apolipoprotein (apo) AI (118.50 [103.00-141.25] vs 133.00 [115.25-1.52.75] mg/dL) were lower than those in the control group. In terms of lipid metabolism indexes, the median [IQR] value of TC/HDL-C (3.31 [2.68-3.85] vs 2.72 [2.42-3.37]), the mean (SD) value of apo B/apo AI (0.76 [0.26] vs 0.63 [0.18]; MD, 0.13; 95% CI, 0.20-0.32) and the median [IQR] value of atherogenic index (ATH index) (1.61 [0.97-2.50] vs 1.01 [0.73-1.75]) were significantly higher than the control group, while the mean (SD) value of atherogenic index of plasma (AIP) (-0.24 [0.28] vs -0.25 [0.21]; MD, 0.01; 95% CI, -0.06-0.08) showed no difference between the two groups.Conclusions: There were significant differences in blood lipid levels and lipid metabolism between the SSNHL group and the control group. LDL-C, apo AI and apo B were important independent predictors of SSNHL.

Potential diagnostic biomarkers for early detection of idiopathic sensorineural hearing loss in type 2 diabetes mellitus patients

“…This condition will affect the flow of oxygenfilled blood to the auditory organ. 22 The results of the analysis of the study comparing 250 patients with SSNHL with 250 without SSNHL found that LDL-C and apo B levels (p≤0.05) were significantly higher in the case group than in the control group. However, this study did not find a significant difference (p>0.05) in other types of lipid profiles such as apo AI and HDL-C (23).…”

“…The apo AI and HDL-C concentrations were assessed as protective factors against sudden sensorineural hearing loss. 22 Low-density lipoprotein cholesterol (LDL-C) is a lipoprotein particle that carries cholesterol to tissue cells in the periphery. Before LDL-C particles enter the blood vessel wall through endothelial cells, LDL-C will be oxidized in the subendothelial tissue into oxidized LDL-C (ox-LDL-C).…”

“…This condition causes stiffness of the arterial walls. 22 If this condition persists for a long time, LDL-C will help the formation of atherosclerotic plaques, which are closely related to the incidence of thrombotic and cardiovascular diseases, including sensorineural hearing loss. This process occurs because, in the walls of blood vessels, Ox-LDL-C will be engulfed by macrophages, then converted into xanthoma cells.…”

“…The fusion and proliferation of xanthoma cells will form the lipid core of the atherosclerotic plaque. 22,24 Excess cholesterol concentration, in addition to affecting the flow of blood vessels in the organs of hearing, cholesterol also plays a role in the destruction of the structure and activity of the outer hair cells (OHC), which is an important structure in the hearing process. The apolipoprotein of LDL-C is Apo B, a protein particle expressed on the surface of LDL-C. Apo B particles play an important role in recognizing and binding LDL-C particles with their receptors in peripheral tissue cells.…”

“…This protein particle becomes the main structural component of HDL-C. A decrease of apo AI concentration will reflect a reduction in the function of HDL-C to increase cholesterol metabolism and export cholesterol. 22 In addition, if a person has dyslipidemia, there will be an increase in LDL-C concentration, which interferes with the release of nitric oxide. Nitric oxide is a powerful vasodilator that plays an important role in maintaining the blood supply to the organs of hearing.…”