Risk factors for sudden deafness: a case-control study

Atrial Fibrillation Is Not Associated With Sudden Sensorineural Hearing Loss

OBJECTIVES

The aim of this study is to assess the association between atrial fibrillation (AF) and sudden sensorineural hearing loss (SSNHL).

METHODS

This study was conducted by searching the longitudinal health insurance database of the Taiwan National Health Insurance Program for relevant information from January 1, 2000, to December 31, 2011. Patients with AF were matched with non-AF controls with a 1:1 strategy according to propensity scores. Multiple logistic regression analyses were performed to determine the risk of SSNHL.

RESULTS

In total, 14 698 patients with AF were matched with the same number of non-AF patients as controls. After propensity score matching, the use of antiplatelet or anticoagulation medications and the occurrence of SSNHL were found to have a significant difference between AF and non-AF patients. The occurrence of SSNHL was found to be higher in men, those of 45 to 74 years old, and patients with hypertension in both AF and non-AF groups. Multiple logistic regression analyses revealed that male gender, age between 45 and 74 years, hyperlipidemia, and hypertension are risk factors for SSNHL. The use of aspirin was found to reduce the rate of SSNHL (odds ratio [OR]: 0.67, 95% CI: 0.49-0.94, P = .019), but AF was not found to be a risk factor for SSNHL (OR: 0.89, 95% CI: 0.64-1.23, P = .467).

CONCLUSION

The association between AF and SSNHL is not significant.

Cardiovascular Risk Factors, Cerebral Small Vessel Disease, and Subsequent Risk of Stroke in Patients with Idiopathic Sudden Sensorineural Hearing Loss: Systematic Review and Meta-Analyses of the Current Literature

Vascular involvement in the pathophysiology of idiopathic sudden sensorineural hearing loss (iSSNHL) has been previously proposed. The objective of this study was to perform a systematic review of the current literature and conduct meta-analyses to evaluate associations between cardiovascular risk factors, cerebral small vessel disease, and subsequent stroke after presentation with iSSNHL. Three systematic literature reviews and meta-analyses were conducted using PubMed, Embase, and CINAHL. All studies investigating associations between iSSNHL and the cardiovascular risk factors: body mass index (BMI), diabetes mellitus, hyperlipidemia, hypertension, medical history of myocardial infarction (MI), smoking, the degree of white matter hyperintensities, and incidence of stroke were included. Adhering to the PRISMA guidelines, two independent reviewers reviewed the articles and assessed risk of bias. The cardiovascular risk factors of abnormal BMI, diabetes, hypertension, total cholesterol, low-density lipoprotein cholesterol, and a medical history of MI were significantly associated with iSSNHL. The adjusted hazard ratio of a higher degree of white matter hyperintensities was 0.70 (95% CI 0.44, 1.12). Patients with iSSNHL showed a higher risk of stroke compared to controls, with hazard ratios ranging from 1.22 up to 4.08. Several cardiovascular risk factors are more frequently present in patients with iSSNHL than in the general population. The degree of white matter hyperintensities does not appear to be increased in patients with iSSNHL, while the risk of stroke following ISSNHL is increased. Prospective studies with larger study populations are needed to confirm the associations between generalized cardiovascular disease and iSSNHL and to assess whether these patients benefit from cardiovascular risk management to prevent future cardiovascular and cerebrovascular disease.

Etiological analysis of patients with sudden sensorineural hearing loss: a prospective case-control study

Sudden sensorineural hearing loss (SSNHL) is a multifactorial emergency disease. Until now, the etiology of SSNHL is still unknown. Previous studies regarding the etiology of SSNHL are clinical studies depending on clinical data collection and analysis. Due to the insufficient sample size or various selective bias in clinical studies, the results of these studies may be inaccurate. This prospective case-control study aimed at exploring the possible etiology and risk factors of SSNHL. We enrolled 255 SSNHL patients and 255 sex-, age- and residence-matched non-SSNHL subjects in the control group. Our study shows that there was no significant difference in the prevalence of comorbidities including hypertension and diabetes, as well as the incidence of smoking and drinking habits between the case and control groups (P > 0.05). In addition, the peripheral blood white blood cell count, neutrophil count, platelet-to-lymphocyte ratio (PLR) and fibrinogen level of the case group were significantly higher than those in the control group (P < 0.05). These findings suggest smoking, drinking, hypertension and diabetes may not be related to the onset of SSNHL. However, hypercoagulable state and inner ear vascular microthrombosis related to an elevated fibrinogen level might be the risk factors of the disease. In addition, inflammation play an important role of SSNHL onset.Trial Registration: Chinese Clinical Trial Registry. Registration number: ChiCTR2100048991.

Comorbidities and laboratory changes of sudden sensorineural hearing loss: a review

Sudden sensorineural hearing loss (SSNHL) is defined as an abrupt hearing loss of more than 30 dB in three contiguous frequencies within 72 h. It is an emergency disease requiring immediate diagnosis and treatment. The incidence of SSNHL in Western countries' population is estimated between 5 and 20 per 1,00,000 inhabitants. The etiology of SSNHL remains unknown. Due to the uncertainty of the cause of SSNHL, at present, no specific treatment targets the cause of SSNHL, resulting in poor efficacy. Previous studies have reported that some comorbidities are risk factors for SSNHL, and some laboratory results may provide some clues for the etiology of SSNHL. Atherosclerosis, microthrombosis, inflammation, and the immune system may be the main etiological factors for SSNHL. This study confirms that SSNHL is a multifactorial disease. Some comorbidities, such as virus infections, are suggested to be the causes of SSNHL. In summary, by analyzing the etiology of SSNHL, more targeting treatments should be used to achieve a better effect.

Is Idiopathic Sudden Sensorineural Hearing Loss Seasonal?

OBJECTIVE

To investigate the circannual rhythm (seasonal incidence) of idiopathic sudden sensorineural hearing loss (ISSNHL).

METHODS

Data were retrieved from the medical files of an original cohort of all consecutive patients with ISSNHL in a tertiary medical center between 2012 and 2020. A systematic literature search of "MEDLINE" via "PubMed," "Embase," and "Web of Science" on comparable published cases was performed. A Google Trends analysis of the term [sudden hearing loss] and related terms between 2014 and 2020 was also performed.

RESULTS

Most of the published series (9/12) reported the highest ISSNHL incidence in the spring and the lowest in the winter (8/12). In our local series, the incidence during the winter was significantly lower than that for the other seasons by a factor of 0.69 (95% confidence interval, 0.65-0.77; p = 0.041; r = 0.36). Google Trends data showed no significant correlation between the calendric month and the incidence of ISSNHL in any of the analyzed countries ( p = 0.873, r2 = 0.029).

CONCLUSION

The ISSNHL incidence was lowest during the winter season in our cohort and reported for other cohorts worldwide. Google Trends-based model analysis did not determine any circannual rhythm.

Association of Acute Upper Respiratory Tract Infections with Sudden Sensorineural Hearing Loss: A Case-Crossover, Nationwide, Population-Based Cohort Study

The etiology of sudden sensorineural hearing loss (SSNHL) has been unclear until now. Understanding its potential etiology is crucial for the development of preventive medicine. In this study, we investigated the association between acute upper respiratory tract infections (URIs) and SSNHL risk. We conducted a case-crossover study by using the longitudinal health insurance database derived from the National Health Insurance Research Database in Taiwan. Individual acute URI between the case and control periods was reviewed. Multivariable conditional logistic regression models were used to estimate the adjusted odds ratios (aORs) of SSNHL risk associated with acute URIs after adjustments for potential confounders. In total, 1131 patients with SSNHL between 2010 and 2013 fulfilled our inclusion criteria and were included. The aOR (95% confidence interval [CI]) for SSNHL was 1.57 (1.20-2.05) in relation to acute URIs one month before the index date. Moreover, the aORs (95% CIs) of the female and young to middle-aged (≤65 years) populations were 1.63 (1.13-2.36) and 1.76 (1.29-2.40), respectively. In addition, the association between SSNHL and acute URIs was decreased over time. The aOR for SSNHL was 1.25 (1.01-1.56) in relation to acute URIs three months before the index date. Acute URIs increase SSNHL risk and are a potential risk factor for SSNHL. The establishment of a feasible health policy for the prevention of acute URIs is crucial for SSNHL prevention, particularly in female, and young to middle-aged populations.

Antidepressants and risk of sudden sensorineural hearing loss: a population-based cohort study

BACKGROUND

Increasing numbers of animal studies have found that sudden sensorineural hearing loss (SSNHL) is related to the mechanism of serotonergic modulation. However, the relationship between antidepressants and SSNHL is unclear in humans. Therefore, this study aimed to evaluate the association between antidepressant use and risk of SSNHL.

METHODS

Data from 218 466 antidepressant users and 1 116 518 nonusers were obtained from the Taiwan Longitudinal Health Insurance Database. We used propensity-score matching (PSM) and inverse-probability treatment weighting (IPTW) to eliminate any bias. Each patient was tracked for 5 years to ascertain whether or not they were diagnosed with SSNHL. Cox proportional-hazard regression analyses were performed to calculate the SSNHL risk.

RESULTS

The adjusted hazard ratio (aHR) of SSNHL for antidepressant users was 1.36 compared with nonusers in the full cohort study. The aHR for antidepressant users was 1.44 and 1.49 compared with the nonusers in the IPTW and PSM cohorts, respectively. All classes of antidepressants consistently increased the SSNHL risk. Additionally, patients receiving four classes of antidepressants were associated with a much higher SSNHL risk (aHR, 2.05) and those receiving one or two classes of antidepressants had a relatively lower SSNHL risk.

CONCLUSION

Antidepressants increased SSNHL risk, regardless of their class. Furthermore, patients who took a higher number of antidepressant classes showed an increased risk of developing SSNHL than those who took a lower number of antidepressant classes. Therefore, physicians should estimate the risks and benefits of antidepressant use and avoid prescribing antidepressants concurrently.

Association between Sudden Sensorineural Hearing Loss and Preexisting Thyroid Diseases: A Nationwide Case-Control Study in Taiwan

Background: Little evidence is available about the risk of sudden sensorineural hearing loss (SSNHL) in patients with thyroid diseases. We assessed whether a diagnosis of thyroid disease, particularly hyperthyroidism or hypothyroidism, is associated with SSNHL risk in an Asian population. Material and Methods: This case-control study was conducted with population-based data from Taiwan’s National Health Insurance Research Database from January 2000 to December 2013. The case group comprised 3331 adult patients with newly diagnosed SSNHL, and four controls without SSNHL for each case matched by sex, age, monthly income, and urbanization level of residence. Underlying Thyroid diseases were retrospectively evaluated in the case and control groups. Multivariate logistic regression analyses were used to explore relations between thyroid diseases and SSNHL. Results: Of the 3331 cases, 5.7% had preexisting thyroid diseases, whereas only 4.0% of the 13,324 controls had the same condition. After adjustment for sex, age, monthly income, urbanization level of residence, history of hypertension, diabetes mellitus, chronic otitis media, and hyperlipidemia, associations were identified between a history of either hypothyroidism (adjusted odds ratio [AOR], 1.54; 95% CI, 1.02–2.32; p = 0.042) or hyperthyroidism (AOR, 1.41; 95% CI, 1.07–1.85; p = 0.015) and an elevated risk of SSNHL. In subgroup analysis, the correlation between hypothyroidism and increased SSNHL risk remained significant only for patients aged over 50 years (AOR, 1.61; 95% CI, 1.01–2.57; p = 0.045), and that between hyperthyroidism and SSNHL was significant only for female patients (AOR, 1.48; 95% CI, 1.09–2.01; p = 0.012). Treatment for hypothyroidism and hyperthyroidism did not alter the association in subgroup analyses. Conclusion: Preexisting hypothyroidism and hyperthyroidism appear associated with SSNHL susceptibility in Taiwan. Physicians should be wary of this elevated risk of SSNHL among patients with previously diagnosed thyroid dysfunction, especially women and patients aged more than 50 years.

Association between Uncoupling Protein 2 Gene Ala55val Polymorphism and Sudden Sensorineural Hearing Loss

OBJECTIVES

The pathology of sudden sensorineural hearing loss, which is known as sudden deafness (SD), remains unknown. The purpose of this study was to investigate the association between mitochondrial uncoupling protein 2 (UCP2) polymorphism and SD risk.

MATERIALS AND METHODS

We compared 83 patients suffering from SD and 2048 controls who participated in the Longitudinal Study of Aging at the National Institute for Longevity Sciences. Multiple logistic regression was used to calculate the odds ratios (ORs) for SD with a polymorphism of the UCP2 (rs660339) gene.

RESULTS

Under the additive model of inheritance, UCP2 polymorphisms showed significant association with a SD risk. The OR was 1.468 (95% confidence interval, 1.056-2.040) with an adjustment for any past history, such as diabetes, dyslipidemia, or hypertension, and for age and sex.

CONCLUSION

Our results imply that the UCP2 (rs660339) polymorphism has a significant association with the risk of developing SD.

Increased incidence in hospitalised patients with sudden sensorineural hearing loss: a 14-year nationwide population-based study

Objective: To conduct a 14-year nationwide study on the epidemiologic incidence in patients with sudden sensorineural hearing loss (SSNHL). Design: Retrospective cross-sectional design. Study sample: Data of patients hospitalised with the diagnosis of SSNHL from 2000 to 2013, extracted from the Taiwan National Health Insurance Research Database. Results: In total, 31,258 patients were included. The mean age was 50.30 ± 16.70 years. Males (53.5%) were more commonly diagnosed with SSNHL than females (46.5%). The patients most commonly presented with SSNHL were in the age group of 45-64 years. The crude incidence of SSNHL from 2000 to 2013 was 9.76 per 100,000 people per year. The annual incidence rate shows a steady increased from 5.15 in 2000 to 13.97 per 100,000 people in 2013 with a statistical significance (p < 0.001). Conclusion: This 14-year nationwide study indicated an increased incidence rate of SSNHL. This necessitates the development of additional treatment modalities to enhance the prognosis and the clarification of the underlying mechanism of this enigmatic disease.

A Trend in Sudden Sensorineural Hearing Loss: Data from a Population-Based Study

This is the first study reporting on the incidence and clinical aspects of sudden sensorineural hearing loss (SSNHL) in South Korea. Using Health Insurance Review and Assessment Service data from 2011 to 2015, the monthly incidence of unilateral SSNHL and incidence according to patients’ sex, age, and month of diagnosis were investigated. The monthly incidence of unilateral SSNHL increased over the 5-year study period, with a mean annual incidence of 17.76 cases/ 100,000 of the population. The incidence increased with age, with most patients presenting in their 60s. There was a slight female preponderance, with a male-to-female ratio of 1: 1.35. Most new patients were diagnosed in October, and the fewest in January. In conclusion, this large-scale study indicates that unilateral SSNHL has a higher incidence among the elderly, women, and in autumn (i.e., along with colder weather).

Evaluation of Compliance for Treatment of Sudden Hearing Loss: A CHEER Network Study

OBJECTIVE

The objective of this study is to describe the presentation and management of sudden sensorineural hearing loss for patients seen in academic and community-based practices within the context of the American Academy of Otolaryngology-Head and Neck Surgery Foundation's "Clinical Practice Guideline: Sudden Hearing Loss." The intention is to use these findings to guide implementation strategies and quality improvement initiatives and as pilot data for the development of clinical research initiatives.

STUDY DESIGN

A cross-sectional study of patients with sudden hearing loss.

SETTING

Patients were recruited from practices within the Creating Healthcare Excellence through Education and Research (CHEER) network. The CHEER network is an National Institutes of Health-funded network of 30 otolaryngology sites across the country, half of which are community based and half of which are academic practices.

SUBJECTS AND METHODS

A total of 173 patients were recruited. Data were gathered via custom questionnaires collected by study site coordinators and entered into a secure online platform. Descriptive analyses and correlation statistics were run with SAS 9.3.1.

RESULTS

Of the 13 guideline statements in the American Academy of Otolaryngology-Head and Neck Surgery Foundation's clinical practice guideline on sudden hearing loss, 11 statements were evaluable through this study. Compliance for otolaryngologists was >95% for key action statements (KASs) 1, 3, and 6; 90% to 95% for KASs 5 and 10; and <90% for KASs 7 and 13. Compliance was <45% for nonotolaryngologists for KASs 3 and 5-7.

CONCLUSIONS

There is opportunity for nonotolaryngologists to improve for statements 3 and 5-7. Otolaryngologists are compliant with many of the KASs overall, but there is significant room for improvement.

Factors Prognostic of Season-Associated Sudden Sensorineural Hearing Loss: A Retrospective Observational Study

Background and Objectives

This study examined whether the prognosis of sudden deafness was dependent on the time of onset and evaluated the factors affecting prognosis during each period.

Subjects and Methods

Patients who developed sudden hearing loss from January 2005 to December 2015 were evaluated retrospectively. Meteorological data were obtained from the official website of the Korea Meteorological Administration. Factors prognostic of hearing recovery rate were analyzed.

Results

The hearing recovery rate of the 318 patients who developed sudden deafness did not differ significantly by month. Mean temperature and daily temperature range at onset of sudden deafness were not associated with recovery rate.

Conclusions

The recovery rate in patients with sudden deafness did not differ markedly by season.

Sudden Sensorineural Hearing Loss after Rapid Reduction of Blood Pressure in Malignant Hypertension

Although circulatory impairment of the cochlea would be intuitively a possible cause of sudden sensorineural hearing loss (SSHL), definite proof is lacking. A 46-year-old man developed bilateral SSHL immediately after rapid reduction of the blood pressure in malignant hypertension. Vertigo and left-sided hearing impairment and tinnitus resolved spontaneously a few hours after onset. The right-sided hearing loss and tinnitus persisted, and the hearing loss improved only 17 dB after 3 months of treatment. This case may provide an in vivo human model of SSHL caused by ischemia. Bilateral involvement is possible in SSHL if the circulatory disturbance is systemic. In addition, a poorer prognosis is anticipated on the side with the more severe initial attack.

Sudden-Onset Sensorineural Hearing Loss after Immunization: A Case-Centered Analysis

OBJECTIVE

Case reports of sudden sensorineural hearing loss (SSHL) following vaccines have led to concerns that vaccines may rarely cause hearing loss. Because of this concern, we analyzed for an association between SSHL and vaccinations.

STUDY DESIGN

We used a case-centered method, equivalent to a case control design using immunization dates from all matched members of the population to calculate exposure to vaccines, rather than sampling.

SETTING

Kaiser Permanente Northern California (KPNC), 2007 to 2013.

SUBJECTS AND METHODS

We searched KPNC databases from 2007 to 2013 for all first-time diagnoses of SSHL. We used the date of any hearing- or ear-related visit in the 60 days prior to the first SSHL diagnosis as the onset date. Using only SSHL cases immunized in the prior 9 months, we compared the vaccine exposure in several risk intervals prior to onset with the exposure to the same vaccine during the same time period in all KPNC membership, matched to sex and age.

RESULTS

During the study period, >20 million vaccines were administered at KPNC. In all risk intervals prior to onset of SSHL, we found no evidence of increased risk of immunization compared with matched controls. The odds ratios for vaccination 1 week prior to SSHL were 0.965 (95% confidence interval, 0.61-1.50) for trivalent inactivated influenza vaccine (TIV); 0.842 (0.39-1.62) for tetanus, reduced diphtheria, and reduced acellular pertussis; and 0.454 (0.08-1.53) for zoster vaccine.

CONCLUSION

A large-scale analysis applying a case-centered method did not detect any association between SSHL and previous receipt of TIV or other vaccines.

Prognostic predictors of sudden sensorineural hearing loss in defibrinogenation therapy

CONCLUSIONS

Defibrinogenation therapy rather than corticosteroids therapy should be chosen for patients specifically with profound hearing loss and with initial high fibrinogen.

OBJECTIVES

Corticosteroids therapy is the standard treatment for sudden sensorineural hearing loss (SSNHL) and prognostic factors by this therapy were reported. Defibrinogenation therapy is one of the treatment options for SSNHL. Aims of this study were to identify prognostic factors and correlative markers with hearing improvement in treating SSNHL by defibrinogenation therapy.

METHODS

During the early phase of the study, consecutive 61 patients were treated by defibrinogenation therapy with batroxobin (50 units), whereas corticosteroids (500 mg/day of hydrocortisone tapered by 9 days) were used for consecutive 64 patients during the late phase. Blood data that could predict a complete recovery were identified. Coagulation/fibrinolysis markers correlated with hearing improvement by defibrinogenation therapy were investigated.

RESULTS

Although there were no overall differences in hearing improvement between the two therapies, recovery rate in profound hearing loss patients was better in defibrinogenation therapy. In patients who showed complete recovery, serum fibrinogen level before treatment was significantly higher in the defibrinogenation group than the corticosteroid group. Responses of several fibrinolysis markers to defibrinogenation therapy evaluated by post-/pre-values were negatively correlated with hearing improvement.

Gallstone is correlated with an increased risk of idiopathic sudden sensorineural hearing loss: a retrospective cohort study

OBJECTIVES

This study aims to test the hypothesis that gallstone disease (GSD) is a risk factor for the development of idiopathic sudden sensorineural hearing loss (ISSNHL). Research has shown risks of cardiovascular and cerebrovascular events in patients with GSD; however, well-conducted English studies on the association between GSD and the development of ISSNHL are lacking.

DESIGN AND SETTING

Retrospective cohort study using the Taiwan Longitudinal Health Insurance Database.

PARTICIPANTS

We compared 26,449 patients diagnosed with GSD between 1 January 2001 and 31 December 2007, with 52,898 age-matched, gender-matched and comorbidities propensity scores-matched controls.

OUTCOME MEASURED

We followed each patient until the end of 2011 and evaluated the incidence of ISSNHL for at least 4 years after the initial GSD diagnosis.

RESULTS

The incidence of ISSNHL was 1.42 times higher in the GS cohort than in the non-GS cohort (9.27 vs 6.52/10,000 person-years). Using Cox proportional hazard regressions, the adjusted HR was 1.44 (95% CI 1.19 to 1.74). In the cohort of patients with GSD who needed a cholecystectomy, 37 patients suffered from ISSNHL. Among those patients, 31 (83.7%) patients sustained ISSNHL before cholecystectomy and 6 (16.2%) patients sustained ISSNHL after cholecystectomy.

CONCLUSIONS

A diagnosis of GSD may be an independent risk for ISSNHL. This finding suggests that an underlying vascular and inflammatory mechanism may contribute to the development of ISSNHL. Physicians may want to counsel patients with GSD to seek medical attention if they have hearing impairments, because patients may be at an increased risk of developing ISSNHL.

Impact of mean platelet volume on the occurrence and severity of sudden sensorineural hearing loss

Objective:

We aimed to determine: (1) whether mean platelet volume was elevated in patients with sudden sensorineural hearing loss, compared with healthy controls; and (2) whether mean platelet volume level was related to hearing loss severity.

Materials and methods:

The study included 31 patients with sudden sensorineural hearing loss and 31 age- and sex-matched, healthy controls. Peripheral venous blood samples were taken from subjects and mean platelet volume and levels of glucose, total cholesterol, high-density lipoprotein, low-density lipoprotein and triglyceride were measured.

Results:

Mean platelet volume was significantly greater in the sudden sensorineural hearing loss group compared with the control group. However, there was no significant correlation between mean platelet volume level and hearing loss severity.

Conclusion:

Mean platelet volume, a determinant of platelet activation, is elevated in patients with sudden sensorineural hearing loss. To our knowledge, this is the first report investigating mean platelet volume levels in such patients. Our findings indirectly support the hypothesis of vascular impairment as a pathogenetic factor in sudden sensorineural hearing loss.

Sudden sensorineural hearing loss associated with chronic periodontitis: a population-based study

OBJECTIVE

Although plenty of researchers have reported systemic effects originating from chronic periodontitis (CP) on potentially distal inflammatory processes, such as those leading to coronary heart disease, cerebrovascular disease, and cancer, no study has reported the association between CP and sudden sensorineural hearing loss (SSNHL). The present study explored the association between CP and SSNHL using a large, population-based dataset in Taiwan.

STUDY DESIGN

A case-control study.

SETTING

Taiwan.

PATIENTS

We used administrative claims data from the Taiwan National Health Insurance program to identify 2,436 subjects with SSNHL and to randomly select 7,308 controls.

MAIN OUTCOME MEASURES

A conditional logistic regression analysis was conducted to calculate the odds ratio (OR) for having been previously diagnosed with CP between cases and controls.

RESULTS

In total, 1,663 (17.1%) of the 9,744 sampled subjects had received a CP diagnosis before the index date; 520 (21.4%) were cases and 1143 (15.6%) were controls. The χ2 test suggested that there was a significant difference in the prevalence of previous SSNHL between cases and controls (p < 0.001). The conditional logistic regression revealed after adjusting for hypertension, diabetes, hyperlipidemia, renal disease, coronary heart disease, obesity, and stroke, the OR of having previously received a CP diagnosis among cases was 1.44 (95% CI = 1.29∼1.63) that of controls.

CONCLUSION

This study found that SSNHL was significantly associated with a previous diagnosis of CP. Further prospective studies are warranted to confirm our findings and clarify the underlying pathomechanism.

Healthy diets, healthy hearing: National Health and Nutrition Examination Survey, 1999-2002

OBJECTIVE

A significant relationship between dietary nutrient intake and susceptibility to acquired hearing loss is emerging. Variability in the outcomes across studies is likely related to differences in the specific metrics used to quantify nutrient intake and hearing status. Most studies have used single nutrient analysis. Although this analysis is valuable, interactions between nutrients are increasingly recognized and could modify modeling of single nutrient effects. Therefore, we examined the potential relationship between diet and hearing using a metric of overall dietary quality.

DESIGN

This cross-sectional analysis was based on healthy eating index data and audiological thresholds.

STUDY SAMPLE

Data for adults between the ages of 20 to 69 years of age were drawn from the National Health and Nutrition Examination Survey, 1999-2002.

RESULTS

Controlling for age, race/ethnicity, sex, education, diabetes, and noise exposure, we found a significant negative relationship (Wald F = 6.54, df = 4, 29; p ≤ 0.05) between dietary quality and thresholds at higher frequencies, where higher dietary quality was associated with lower hearing thresholds. There was no statistically significant relationship between dietary quality and threshold sensitivity at lower frequencies.

CONCLUSIONS

The current findings support an association between healthier eating and better high frequency thresholds in adults.

Correlations of inflammatory biomarkers with the onset and prognosis of idiopathic sudden sensorineural hearing loss

HYPOTHESIS

We investigated whether inflammatory biomarkers and stress are involved in the pathophysiology of idiopathic sensorineural hearing loss (ISHL).

STUDY DESIGN

Individual cohort study.

SETTING

Two tertiary centers.

PATIENTS

Forty-three ISHL and 10 non-ISHL patients seen in our ENT departments from 2004 to 2010 within a week from the onset of new symptoms and without steroid administration before visiting our departments.

INTERVENTION

Multiple audiologic evaluations, blood tests including leukocyte counts, natural killer cell activity (NKCA), interleukin 6 (IL-6), tumor necrosis factor, high-sensitivity CRP (hCRP), and the General Health Questionnaire were used to evaluate the systemic stress and inflammatory response.

MAIN OUTCOME MEASURES

Correlations between biomarkers and ISHL severity and prognosis were evaluated by statistical analysis.

RESULTS

In the ISHL patients, a neutrophil count above the reference range was associated with severe hearing loss and poor prognosis, and was accompanied by low NKCA and high IL-6. In the non-ISHL patients, these associations were not present. The abnormal neutrophil count was independent of preexisting vascular diseases. The abnormal counts responded to treatment and decreased into the reference range.

CONCLUSION

Neutrophil counts above the reference range of a facility will be a useful indicator of poor prognosis of ISHL. Synchronism of different types of NF-κB activation pathways could be required to cause severe ISHL. An NKCA decrease, an acute neutrophil count increase, and an IL-6 increase can induce NF-κB activation in the cochlea and cause severe ISHL. Further epidemiologic surveys should be conducted to evaluate whether stressful life events increase the risk of severe ISHL onset.

Increased risk of getting sudden sensorineural hearing loss in patients with chronic kidney disease: a population-based cohort study

OBJECTIVES/HYPOTHESIS

To examine the risk of getting Sudden Sensorineural Hearing Loss (SSHL) among patients with chronic kidney disease (CKD).

STUDY DESIGN

A retrospective cohort study.

METHODS

Population-based representative insurance claims data were used to examine the risk of getting SSHL among patients with chronic kidney disease. Data extracted from the Taiwan National Health Insurance Research Database yielded 37,421 patients with newly diagnosed renal insufficiency and 37,421 subjects without renal insufficiency from between 2000 and 2004.

RESULTS

The incidence of SSHL at the end of 2009 was determined. The incidence of SSHL was 1.57 times higher in the CKD-carrying group compared to the incidence in the non-CKD group (10.24 vs. 6.52 per 10,000 person-years), with adjusted hazard ratio (HR) of 1.46 (95% CI = 1.194-1.787) using Cox proportional hazard regressions. Age was an independent risk factor of getting SSHL, with adjusted HRs of 2.01, 3.178, and 2.285 for age ranges of 35 ≈ 49, 50 ≈ 64 and ≥ 65 compared with age range of 0 ≈ 35. Diabetes Mellitus was another independent risk factor with HR of 1.31 (95% CI = 1.003-1.711).

CONCLUSIONS

Present results suggested a significant association between CKD and increased risk of getting SSHL. Comorbidity of diabetes in patients with CKD appeared to be associated with increased risk of getting SSHL, especially for the patients who are 35 years of age and older.

Polymorphisms in genes involved in inflammatory pathways in patients with sudden sensorineural hearing loss

Although the etiology of idiopathic sudden sensorineural hearing loss (SSNHL) remains unclear, the pathologically increased permeability of blood vessels, elucidated by gadolinium-enhanced magnetic resonance imaging (MRI), suggests the involvement of inflammation. Because SSNHL is considered a multifactorial disease, possibly caused by interactions between genetic factors and environmental factors, the authors investigated the associations of polymorphisms of inflammatory mediator genes with susceptibility to SSNHL. The authors compared 72 patients affected by SSNHL and 2010 adults (1010 men and 1000 women; mean age 59.2 years; range 40-79) who participated in the National Institute for Longevity Sciences Longitudinal Study of Aging. Multiple logistic regression was used to obtain odds ratios (ORs) for SSNHL in subjects with polymorphisms in the genes IL-6 C - 572G, IL-4R G1902A, IL-10 A - 592C, TNFα C - 863A, TNFRSF1B G593A, VEGF C936T, VEGF C - 2578A, and VEGF G - 1154A, with adjustment for age, gender, and any history of hypertension, diabetes, or dyslipidemia. The per-allele OR for the risk of SSNHL in subjects bearing IL-6 C - 572G was 1.480 (95% confidence interval [CI], 1.037-2.111) in model 1 (no adjustment), 1.463 (CI, 1.022-2.094) in model 2 (adjusted for age and gender), and 1.460 (CI, 1.016-2.097) in model 3 (adjusted for age, gender, and a history of hypertension, diabetes, or dyslipidemia). Under the dominant model of inheritance, the ORs were 1.734 (CI, 1.080-2.783) in model 1, 1.690 (CI, 1.050-2.721) in model 2, and 1.669 (CI, 1.035-2.692) in model 3. The remaining seven polymorphisms failed to show any associations with the risk of SSNHL. These data need to be confirmed on larger series of patients. In conclusion, the IL-6 C - 572G polymorphism is associated with a risk of SSNHL. Because permeability of blood vessels in the inner ear is frequently increased in patients with SSNHL, inflammation of the inner ear might be involved.

Systematic review and meta-analysis of the risk factors for sudden sensorineural hearing loss in adults

OBJECTIVES/HYPOTHESIS

To review the medical literature evidence of potential risk factors for sudden sensorineural hearing loss (SSNHL) in the adult general population.

STUDY DESIGN

Systematic review of prospective and retrospective studies; meta-analysis of case-controlled studies.

METHODS

Three researchers independently reviewed MEDLINE (January 1, 1950-November 30, 2010), Embase (January 1, 1980-November 30, 2010), and Evidence-Based Medicine Reviews databases in addition to conducting a manual reference search. Randomized controlled trials, prospective cohort studies, consecutive/nonconsecutive case series, and retrospective reviews in which a clear definition of SSNHL was stated were included in the study. Researchers individually extracted data regarding patient information and the presumed risk factors. Discrepancies were resolved by mutual consensus.

RESULTS

Twenty-two articles met the inclusion criteria. Cardiovascular risk factors (smoking, increased alcohol consumption) appeared to be associated with a higher risk of developing SSNHL. A low level of serum folate may also be implicated as a risk factor. Factor V Leiden and MTHFR gene polymorphisms were found to occur more frequently in patients with SSNHL in several studies, suggesting these inherited prothrombophilic mutations could be independent risk factors of SSNHL.

CONCLUSIONS

Acquired and inherited cardiovascular risk factors appeared to be associated with an increased risk of developing SSNHL.

Multivariate analysis of hearing outcomes in patients with idiopathic sudden sensorineural hearing loss

CONCLUSIONS

Contralateral hearing loss is significantly correlated with poor hearing outcomes in patients with idiopathic sudden sensorineural hearing loss (ISSNHL).

BACKGROUND

The hearing outcome in patients with ISSNHL was analyzed using multiple variables.

METHODS

A retrospective chart review was conducted using 89 patients with ISSNHL. Patients within 40 dB HL of average hearing levels and/or patients whose hearing loss was restricted to low frequencies were excluded. The influence of pre-existing conditions on hearing outcome was analyzed using a polytomous universal model. Pre-existing conditions analyzed included hyperglycemia, hypercholesterolemia, hypertension, and contralateral hearing loss. In addition, the severity of hearing loss, age group, and the existence of vertigo were analyzed concomitantly.

RESULTS

Hearing recovery was significantly reduced in patients with a past history of contralateral hearing loss.

Metabolic disorders prevalence in sudden deafness

OBJECTIVES

The aim of the present study was to establish the frequency of metabolic disorders among patients with sudden deafness and to compare this frequency with data from population surveys.

INTRODUCTION

No consensus has been reached regarding the prevalence of metabolic disorders among sudden deafness patients or their influence as associated risk factors.

METHODS

This cross-sectional study enrolled all sudden deafness patients treated in the Otolaryngology Department of the University of São Paulo between January 1996 and December 2006. Patients were subjected to laboratory exams including glucose and cholesterol levels, low-density lipoprotein cholesterol fraction, triglycerides, free T4 and TSH.

RESULTS

The sample comprised 166 patients. We observed normal glucose levels in 101 (81.5%) patients and hyperglycemia in 23 (18.5%) patients, which is significantly different (p < 0.0001) compared to the diabetes mellitus prevalence (7.6%) in the Brazilian population. Cholesterol levels were normal in 78 patients (49.7%) and abnormal in 79 (50.3%) patients, which is significantly different compared to the Brazilian population (p = 0.0093). However, no differences were observed in low-density lipoprotein cholesterol fraction (p = 0.1087) or triglyceride levels (p = 0.1474) between sudden hearing loss patients and the Brazilian population. Normal levels of thyroid hormones were observed in 116 patients (78.4%), and abnormal levels were observed in 32 (21.6%) patients. Compared with the prevalence of thyroid disorders in the general population (10%), statistical analysis revealed a significant difference (p = 0.0132) between these two groups.

DISCUSSION

Among sudden deafness patients, we observed frequencies of hyperglycemia and thyroid disorders that were more than twice those of the general population.

CONCLUSIONS

Hyperglycemia and thyroid disorders are much more frequent in patients with sudden deafness than in the general population and should be considered as important associated risk factors.

Thirty-year trends in sudden deafness from four nationwide epidemiological surveys in Japan

CONCLUSIONS

The estimated annual number of patients with sudden deafness treated in Japan has increased during the last 30 years, especially in the elderly population. Hypertension and diabetes mellitus could contribute to the etiology of this disorder.

OBJECTIVES

To investigate the epidemiological trends of sudden deafness in Japan over the past 30 years by analyzing data from national surveys.

MATERIALS AND METHODS

Nationwide epidemiological surveys on sudden deafness were conducted four times by the Research Committee of the Ministry of Health and Welfare in Japan. The first, second, third, and fourth surveys were performed in 1972, 1987, 1993, and 2001, respectively.

RESULTS

The estimated annual numbers of patients with sudden deafness treated in Japan were 4000 in 1972; 16,700 in 1987; 24,000 in 1993, and 35,000 in 2001. The average ages of patients at onset were 39.1, 45.4, 49.3, and 51.3 years, respectively. Thus, both the number of patients and the average age of patients with sudden deafness have increased during the past 30 years. Patients with sudden deafness in the fourth survey exhibited hypertension and diabetes mellitus more frequently than did patients in the first survey; this trend was particularly noticeable among elderly patients.

Sudden Sensorineural Hearing Loss: Evidence from Taiwan

OBJECTIVE

This study uses 5-year population data to determine the incidence rate of sudden sensorineural hearing loss (SSNHL) in Taiwan, taking into consideration the age and gender of patients, as well as seasonal variations.

STUDY DESIGN

A retrospective cross-sectional study.

METHOD

The data used is from the Taiwan National Health Insurance Research Database covering the period from 1998 to 2002. A total of 9,267 sample patients were identified from the database by a principal diagnosis of unspecified sudden hearing loss (ICD-9-CM code 3882). The autoregressive integrated moving average (ARIMA) method was also carried out in order to identify any variations in the monthly incidence rates of SSNHL.

RESULTS

We find that for the period under examination, gender-specific incidence rates per 100,000 of the population were 8.85 for males, and 7.79 for females, and that there was an increase in age-specific SSNHL incidence with age. The ARIMA test for seasonality was found to be significant for the whole sample. Of all the seasons in Taiwan, the highest SSNHL incidence rates were found in autumn.

CONCLUSIONS

Our finding of significant variations in the monthly incidence of SSNHL provides valuable information for otolaryngologists and public health officials, creating an awareness of periods of a potential increased risk of SSNHL.

The effects of weather on the incidence of sudden sensorineural hearing loss: a 5-year population-based study

OBJECTIVE

This study utilizes 5-year population data to examine the association between weather conditions and the incidence of sudden sensorineural hearing loss (SSNHL) in Taiwan with a specific focus on ambient temperature, relative humidity, atmospheric pressure, rainfall and total hours of sunshine.

METHOD

The data, covering the period from 1998 to 2002, is sourced from the Taiwan National Health Insurance Research Database (NHIRD), with a total of 8712 first-time admissions being identified from the database by a principal diagnosis of unspecified sudden hearing loss (ICD-9-CM code 3882). After controlling for time trend effects, this study adopted the autoregressive integrated moving average regression method as a means of evaluating the effects of climatic and monthly factors on SSNHL incidence rates.

RESULTS

Although significant associations were found between ambient temperature, relative humidity and the SSNHL incidence rates for the total population, after adjusting for seasonality, months and trends, the significant relationship between SSNHL incidence rates and the climatic parameters disappeared.

CONCLUSIONS

This study has demonstrated that after adjusting for seasonality, months and trends, there is no significant relationship between monthly SSNHL incidence rates and weather conditions. Therefore, the theory that weather is a triggering factor in SSNHL pathogenesis is not supported by this study.

Japanese and Western diet and risk of idiopathic sudden deafness: a case-control study using pooled controls

BACKGROUND

One of the proposed aetiological mechanisms for idiopathic sudden deafness is vascular disease. However, it is not known whether traditional cardiovascular risk factors, such as particular dietary factors, are associated with this condition.

METHODS

A case-control study using pooled controls was conducted in Japan to investigate the relationship between idiopathic sudden deafness and diet. An m:n matched-pairs method was used to obtain age-, gender- and residential district-matched controls from a nationwide database of pooled controls. Food intake was assessed from a self-administered usual food frequency questionnaire that asked about intake of 35 foods (including four drinks). Participants were classified according to the frequency of intake of Western foods and the frequency of intake of traditional Japanese foods. Subgroup analyses were performed using audiometric subtypes of idiopathic sudden deafness.

RESULTS

Data were obtained for 164 cases and 20,313 controls. An increased risk of sudden deafness was observed among participants who frequently consumed Western foods (OR = 1.82, 95% CI : 1.14--2.89), and a decreased risk of this condition was observed among participants who frequently consumed Japanese foods (OR = 0.52, 95% CI : 0.33--0.82). A direct association of sudden deafness with Western food intake was evident for flat-type hearing loss.

CONCLUSIONS

This study suggests that a largely Western diet might be a risk factor for idiopathic sudden deafness, a traditional Japanese diet might be a preventive factor for this condition, or both. These findings are consistent with the hypothesis that vascular factors are an important cause of idiopathic sudden deafness, although the possibility of residual confounding by unmeasured confounders such as socioeconomic status cannot be ruled out.

Clinicoepidemiologic features of sudden deafness diagnosed and treated at university hospitals in Japan

Nationwide epidemiologic surveys were done 3 times by the Research Committee of the Ministry of Health and Welfare in Japan to investigate the number of patients and clinical manifestations of idiopathic sudden sensorineural hearing loss (sudden deafness). The first, second, and third surveys were carried out during the 1970s, 1980s, and 1990s, respectively. For each patient, we have compiled data regarding age, sex, onset day, presence or absence of vertigo, and hearing ability, including initial and final audiograms, in a computer in the Nagoya University Computer Center. Regarding patients who visited university hospitals, complete data were collected for 421 subjects (age: 40.2+/-15.4 years, female: 203, male: 218) between July 1973 and June 1974, for 813 subjects (age: 45.1+/-15.4 years, female: 407, male: 406) in 1987, and for 1112 subjects (age: 49.1+/-16.0 years, female: 591, male: 521) in 1993. The number of patients with sudden deafness treated in university hospitals in Japan has increased, especially in the elderly population. This increase is associated with population increase and age-adjusted incidence rates per 100,000 in the elderly population. The initial and final hearing levels in the first survey were worse than those in the second and third surveys; there was no significant difference in hearing between the second and third surveys. The hearing levels were worse in children and elderly patients than in the other age groups.