Effect of statins on hearing function and subjective tinnitus in hyperlipidemic patients

Lipids and Statin Medication With Sensorineural Hearing Loss: A Mendelian Randomization Study

BACKGROUND

Recent insights suggest that lipids and statin medication play a role in the development of sensorineural hearing loss (SNHL), yet the exact role remains controversial. This research applied Mendelian randomization (MR) to assess whether lipids and statin medication are associated with an increased risk of SNHL.

METHODS

A two-sample MR was used in this study. Genetic instruments were constructed from variants associated with risk factors. Data for lipids and statin medication were obtained from the IEU OpenGWAS project, and for SNHL from the Finngen research project, which comprises 32,487 individuals with SNHL and 331,736 control individuals.

RESULTS

Genetically predicted higher levels of triglycerides were associated with an increased risk of SNHL. The use of genetically predicted atorvastatin was associated with a lower risk of SNHL. Rosuvastatin has demonstrated potential in treating SNHL, yet further investigations are warranted to elucidate its relationship with SNHL. Insufficient evidence was available to suggest that the genetically predicted level of high-density lipoprotein cholesterol or low-density lipoprotein cholesterol or the use of simvastatin were associated with SNHL.

CONCLUSIONS

The study provides genetic evidence suggesting that increased levels of triglycerides in the blood could be a risk factor for SNHL and that the use of certain statin medications, including atorvastatin and rosuvastatin, could reduce the risk of SNHL. These results align with findings from previous observational studies that have linked hyperlipidemia with the risk of SNHL.

LEVEL OF EVIDENCE

According to the Oxford Centre for Evidence-Based Medicine 2011 levels of Evidence, the study has a third level of Evidence Laryngoscope, 2024.

Association of periodontitis with tinnitus: A population-based cohort study in Taiwan

AIM

Tinnitus, ringing in the ears, is speculated to be driven by inflammation. This study examined whether periodontitis is a risk factor for tinnitus using Taiwan's National Health Insurance Research Database.

MATERIALS AND METHODS

Among the 79,456 patients who visited for dental concerns, 11,055 patients who were diagnosed with periodontitis and underwent periodontal treatment between 2000 and 2015 were enrolled in Group 1. After matching for sex, age, and index year, 11,055 patients with periodontitis who received no treatment were enrolled in Group 2. Similarly, 11,055 participants without periodontitis were included as controls.

RESULTS

At the end of the follow-up, 412 and 404 participants in the two periodontitis groups and 321 participants in the control group had tinnitus. Cumulative risk for tinnitus in Group 1 or 2 was significantly greater than in the control group. More periodontitis patients than controls developed tinnitus (adjusted hazard ratios were 1.71 (95% confidence interval [CI]: 1.49-1.97, p < .001) and 1.64 (95% CI: 1.37-1.86, p < .001) in Groups 1 and 2, respectively). The risks were not significantly different between Groups 1 and 2. Similar findings were obtained after excluding data for the first 1 or 5 years.

CONCLUSIONS

The study findings indicate that periodontitis is associated with tinnitus.

Association between statin medication and hearing impairment in a national health screening cohort

This study aimed to investigate the association of previous stain use with hearing impairment in an adult population. Data from the ≥ 40-year-old population in the Korean National Health Insurance Service Health Screening Cohort were used. The hearing impairment group was classified based on the national registry of hearing-impaired persons. Control participants were randomly selected and matched for age, sex, income, and region of residence. The number of days of statin prescription during the 2 years before the diagnosis of hearing impairment was compared between the hearing impairment group and the control group using conditional logistic regression analysis. Additional analyses were conducted according to age and sex. The number of days of previous statin use was not different between the hearing impairment group and the control group (adjusted odds ratio [aOR] = 0.94, 95% confidence interval (CI) = 0.86-1.02, P = 0.118). According to age, in the ≥ 70-year-old group, those with hearing impairment had 11% lower rates of previous statin use than those in the control group (aOR = 0.89, 95% CI = 0.80-0.99, P = 0.039). According to sex, in the male group, 12% lower rates of previous statin use were observed among those with hearing impairment than among those in the control group (aOR = 0.88, 95% CI = 0.79-0.99, P = 0.037). Previous statin use might have an effect on reducing the prevalence of hearing impairment in elderly individuals and men.

Association Between Sudden Sensorineural Hearing Loss and History of Statin Use: A Nested Case-Control Study

OBJECTIVE

The effect of statin on sudden sensorineural hearing loss (SSNHL) remains unclear. Thus, this study aimed to investigate the association between prior statin use and SSNHL.

STUDY DESIGN

A nested case-control study.

SETTING

Participants aged ≥40 years were enrolled from the 2002-2015 Korean National Health Insurance Service-Health Screening Cohort.

METHODS

A total of 5876 patients with SSNHL were matched with 23,504 control participants for age, sex, income, and region of residence. History of statin use for 2 years before SSNHL onset was investigated between the groups. The odds ratios (ORs) of the length of statin use for SSNHL stratified by age, sex, income, and region of residence were analyzed with conditional logistic regression. Dyslipidemia, total cholesterol, blood pressure, blood glucose, hemoglobin, obesity, smoking, alcohol consumption, and Charlson Comorbidity Index score were adjusted. The adjusted variables were subjected to subgroup analyses.

RESULTS

The SSNHL group had a longer duration of statin use than the control group (mean [SD], 81.9 [197.7] days vs 72.7 [188.0] days; P = .001). However, statin use was not associated with SSNHL after adjusting for the confounders (adjusted OR, 1.04; 95% CI, 0.98-1.11; P = .245). There was a positive correlation between statin use and SSNHL in the crude model (crude OR, 1.10; 95% CI, 1.04-1.16; P = .001). However, there was no association between statin use and SSNHL in all subgroup analyses.

CONCLUSION

Previous statin use was not associated with SSNHL.

Evidence Supporting the Hypothesis That Inflammation-Induced Vasospasm Is Involved in the Pathogenesis of Acquired Sensorineural Hearing Loss

Sensorineural hearing loss is mainly acquired and affects an estimated 1.3 billion humans worldwide. It is related to aging, noise, infection, ototoxic drugs, and genetic defects. It is essential to identify reversible and preventable causes to be able to reduce the burden of this disease. Inflammation is involved in most causes and leads to tissue injury through vasospasm-associated ischemia. Vasospasm is reversible. This review summarized evidence linking inflammation-induced vasospasm to several forms of acquired sensorineural hearing loss. The link between vasospasm and sensorineural hearing loss is directly evident in subarachnoid haemorrhage, which involves the release of vasoconstriction-inducing cytokines like interleukin-1, endothelin-1, and tumour necrosis factor. These proinflammatory cytokines can also be released in response to infection, autoimmune disease, and acute or chronically increased inflammation in the ageing organism as in presbyacusis or in noise-induced cochlear injury. Evidence of vasospasm and hearing loss has also been discovered in bacterial meningitis and brain injury. Resolution of inflammation-induced vasospasm has been associated with improvement of hearing in autoimmune diseases involving overproduction of interleukin-1 from inflammasomes. There is mainly indirect evidence for vasospasm-associated sensorineural hearing loss in most forms of systemic or injury- or infection-induced local vascular inflammation. This opens up avenues in prevention and treatment of vascular and systemic inflammation as well as vasospasm itself as a way to prevent and treat most forms of acquired sensorineural hearing loss. Future research needs to investigate interventions antagonising vasospasm and vasospasm-inducing proinflammatory cytokines and their production in randomised controlled trials of prevention and treatment of acquired sensorineural hearing loss. Prime candidates for interventions are hereby inflammasome inhibitors and vasospasm-reducing drugs like nitric oxide donors, rho-kinase inhibitors, and magnesium which have the potential to reduce sensorineural hearing loss in meningitis, exposure to noise, brain injury, arteriosclerosis, and advanced age-related and autoimmune disease-related inflammation.