Diabetes and hearing impairment in Mexican American adults: a population-based study

Hearing Loss and Cardiovascular Disease Risk Profiles: Data from the Hispanic Community Health Study/Study of Latinos

BACKGROUND

 Individual cardiovascular disease (CVD) risk factors (RFs) have been associated with hearing loss (HL). The relationship to aggregate risk is poorly understood and has not been explored in the Hispanic/Latino population.

PURPOSE

 The aim of this study was to characterize the association between aggregate CVD RF burden and hearing among Hispanics/Latinos.

RESEARCH DESIGN

 Cross-sectional examination.

STUDY SAMPLE

 Participants (18-74 years; n = 12,766) in the Hispanic Community Health Study/Study of Latinos.

DATA COLLECTION AND ANALYSIS

 Thresholds (0.5-8 kHz) were obtained, and HL was defined dichotomously as pure-tone average (PTA0.5,1, 2,4) > 25 dB HL. Optimal CVD risk burden was defined as follows: systolic blood pressure (SBP) < 120 mm Hg and diastolic blood pressure (DBP) < 80 mm Hg; total cholesterol < 180 mg/dL; nonsmoking; and no diabetes. Major CVD RFs were diabetes, currently smoking, SBP >160 or DBP > 100 mm Hg (or antihypertensives), and total cholesterol > 240 mg/dL (or statins). Thresholds were estimated by age (18-44 and ≥45 years) and sex using linear regression. The association between CVD risk burden and HL was assessed using multivariable logistic regression. Models were adjusted for age, sex, Hispanic/Latino background, center, education, income, alcohol use, body mass index, and noise exposure.

RESULTS

 In the target population, 53.03% were female and 18.81% and 8.52% had all RFs optimal and ≥2 major RFs, respectively. Elevated BP (SBP 120-139 mm Hg or DBP 80-89 mm Hg) was associated with HL in females < 45 years (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.14-4.16). Diabetes (OR, 1.37; 95% CI, 1.01-1.84) and tobacco smoking (OR, 1.44; 95% CI, 1.03-2.01) were associated with HL in females ≥ 45 years. The odds of HL were higher for females ≥ 45 years with ≥2 RFs versus those with all RFs optimal (OR, 1.99; 95% CI, 1.12-3.53). Elevated BP (SBP 140-159 mm Hg or DBP 90-99 mm Hg), but not aggregate risk burden, was associated with HL in males ≥ 45 years (OR, 1.49; 95% CI, 1.02-2.19). No relationships with major CVD RFs were significant in males < 45 years.

CONCLUSIONS

 HL is associated with elevated BP in females < 45 years, with diabetes and hypertension in males ≥ 45 years, and with diabetes, smoking, and having ≥2 major CVD RFs in females ≥ 45 years. Future studies are needed to examine if these factors are associated with incident HL.

High-Frequency Audiovestibular Dysfunction in Long-Standing Diabetes Mellitus: Insights from a Cross-Sectional Study

This study investigates audiovestibular dysfunction in individuals with long-standing diabetes mellitus (DM). A cross-sectional study was conducted involving 100 patients (DM for ≥ 10 years) at the Department of E.N.T. in Prakash Institute of Medical Sciences and Research, Sangli, Maharashtra. A mean age of 43.09 years among patients, with 64% male and 36% female participants. Hearing loss was the most common complaint, affecting 46% of subjects, followed by vertigo in 23%. Pure tone audiometry revealed that 34% of patients had sensorineural hearing loss, with varying degrees of severity. Vestibular dysfunction was observed in 10% of cases. Correlation analysis indicated a significant positive relationship between the duration of DM and hearing thresholds at various frequencies, as well as with HbA1c levels. This suggests a worsening of hearing with longer DM duration and higher HbA1c levels. The prevalence of hearing impairment was higher at higher frequencies, with vestibular dysfunction also noted in a subset of patients.

Diabetes mellitus and hearing loss

Diabetes mellitus (DM) is a major disease threatening human health and its incidence is increasing year on year. As a chronic complication of DM, hearing loss mostly occurs undetectably. However, the mechanism of this diabetes-related hearing loss (DRHL) remains unclear and there is no effective clinical treatment. Studies of animal or human pathology show that DM causes damage to the blood vessels, spiral ganglion neurons, afferent nerve fibers, the organ of Corti, and the stria vascularis of the inner ear. In recent years, more advances in pathological research have revealed the possible mechanism of DRHL. In addition, a large number of clinical studies suggest that the duration and severity of DM are closely related to the incidence and severity of DRHL. This review focuses on the relationship between DM and hearing loss. The clinical audiological characteristics of diabetic patients, risk factors for DRHL, typical pathology, and potential interventions of DRHL are summarized. This will help reveal the pathogenesis and intervention approaches for DRHL.

Diabetes-induced auditory complications: are they preventable? a comprehensive review of interventions

Diabetes mellitus is a chronic metabolic disorder characterized by elevated blood glucose levels, which, over time, lead to major chronic complications in various organs of the body. A growing body of research suggests that diabetes could also result in degenerative changes in the auditory system. To date, several attempts have been made to prevent and reduce diabetes-induced auditory complications. Such attempts have generally focused on disease modifying as well as other pharmacological treatments involving several herbal and non-herbal agents such as vitamins C and E, rutin, resveratrol, coffee, trigonelline, Dioscorea nipponica, red ginseng, Pterostilbene Bofutsushosan, Daisaikoto, tolrestat, ACE inhibitors (enalapril), Ca antagonists (nimodipine), Lipo-prostaglandin E1, methylprednisolone, dexamethasone, and chlorogenic acid and also other strategies like acupuncture. However, there is no consensus about which are the most effective strategies for preventing and reducing auditory complications in diabetic patients with few side effects and maximum efficacy. This paper provides a comprehensive review of interventions for preventing and treating diabetes-induced auditory complications to help therapists.

Alterations in hearing function of patients with glucose disorders

OBJECTIVE

To study the prevalence of hearing impairment in patients with various glucose disorders.

PATIENTS AND METHODS

A total of 499 individuals were studied, 51 patients with type 1 (TIDM), 188 patients with type 2 diabetes mellitus (T2DM), 39 patients with impaired fasting glucose (IFG), and 221 controls. Measurements were performed, blood was drawn, and a relevant questionnaire was completed. Ηearing function was assessed by pure-tone audiometry (PTA) and distortion product otoacustic emissions (DPOAEs).

RESULTS

Patients with impaired glucose metabolism (IGM: T2DM or IFG) compared to controls had a higher percentage of abnormal PTA and DPOAEs for both the right (70.2 vs. 56.9% and 40.4 vs. 24.2%, respectively, p < 0.001) and the left (74.1 vs. 59.3% and 47.5 vs. 25.4%, respectively, p < 0.001) ear. Patients with TIDM had similar levels for the left ear (54.9 vs. 59.3% and 27.5 vs. 25.4%, respectively, p > 0.05) and lower levels for the right ear (35.3 vs. 56.9% and 13.7 vs. 24.2%, respectively, p < 0.001 and p = 0.044) percentages of abnormal PTA and DPOAEs compared to controls. Logistic regression analysis indicated that independent parameters for abnormal DPOAEs in one or both ears are age, male gender, exposure to noisy environments, and the presence of IGM.

CONCLUSIONS

Hearing impairment was more prevalent in patients with IGM compared to healthy controls, as assessed by PTA and DPOAEs. Age, male gender, and exposure to noise are other factors that can independently affect hearing ability. Physicians should bear in mind possible defects in hearing ability when dealing with such patients.

Metabolic syndrome is associated with hearing loss among a middle-aged and older Chinese population: a cross-sectional study

BACKGROUND

Although the association of metabolic syndrome (MetS) and hearing loss has been evaluated, findings are controversial. This study investigated this association in a Chinese population.

METHODS

A cross-sectional study including a total of 18,824 middle-aged and older participants from the Dongfeng-Tongji Cohort study was conducted. Hearing loss was defined as the pure-tone average (PTA) of frequencies 0.5, 1.0, 2.0, and 4.0 kHz >25 decibels hearing level (dB HL) in the better ear and graded as mild (PTA 26-40 dB HL), moderate (PTA >40 to ≤60 dB HL), and severe (PTA >60 dB HL). MetS was defined according to the International Diabetes Foundation (IDF) criteria of 2005. Association analysis was performed by logistic regression.

RESULTS

After adjustment for potential confounders, participants with MetS showed higher OR of hearing loss (OR, 1.11; 95% CI: 1.03-1.19). The MetS components including central obesity (OR, 1.07; 95% CI: 1.01-1.15) and hyperglycemia (OR, 1.12; 95% CI: 1.04-1.20) were also positively associated with hearing loss. Low HDL-C levels were also associated with higher OR of moderate/severe hearing loss (OR, 1.21; 95% CI: 1.07-1.36).

CONCLUSIONS

The MetS, including its components central obesity, hyperglycemia, and low HDL-C levels were positively associated with hearing loss. Key messages Studies indicated that cardiovascular disease and diabetes might be risk factors of hearing loss. However, few efforts have been made to establish a direct relationship between metabolic syndrome and hearing loss, especially in Chinese population. In the present study, a cross-sectional design using data from the Dongfeng-Tongji Cohort study was conducted to assess the association between metabolic syndrome and hearing loss. The metabolic syndrome, as well as its components central obesity, hyperglycemia, and low HDL-C levels were positively associated with hearing loss.

Impairment of extra-high frequency auditory thresholds in subjects with elevated levels of fasting blood glucose

This study was performed to assess whether there is an association between elevated Fasting Blood Glucose (FBG) and hearing impairment in Bangladeshi population. A total of 142 subjects (72 with elevated FBG; 70 control) were included in the study. The mean auditory thresholds of the control subjects at 1, 4, 8 and 12 kHz frequencies were 6.35 ± 0.35, 10.07 ± 0.91, 27.57 ± 1.82, 51.28 ± 3.01 dB SPL (decibel sound pressure level), respectively and that of the subjects with elevated FBG were 8.33 ± 0.66, 14.37 ± 1.14, 38.96 ± 2.23, and 71.11 ± 2.96 dB, respectively. The auditory thresholds of the subjects with elevated FBG were significantly (p < 0.05) higher than the control subjects at all the above frequencies, although hearing impairment was most evidently observed at an extra-high (12 kHz) frequency. Subjects with a long duration of diabetes (>10 years) showed significantly (p < 0.05) higher level of auditory thresholds at 8 and 12 kHz, but not at 1 and 4 kHz frequencies, compared to subjects with shorter duration of diabetes (≤10 years). In addition, based on the data of odds ratio, more acute impairment of hearing at the extra-high frequency was observed in diabetic subjects of both older (>40 years) and younger (≤40 years) age groups compared to the respective controls. The binary logistic regression analysis showed a 5.79-fold increase in the odds of extra-high frequency hearing impairment in diabetic subjects after adjustment for age, gender and BMI. This study provides conclusive evidence that auditory threshold at an extra-high frequency could be a sensitive marker for hearing impairment in diabetic subjects.

Diabetes mellitus and the incidence of hearing loss: a cohort study

Background

To evaluate the association between diabetes mellitus (DM) and the development of incident hearing loss.

Methods

Prospective cohort study was performed in 253 301 adults with normal hearing tests who participated in a regular health-screening exam between 2002 and 2014. The main exposure was the presence of DM at baseline, defined as a fasting serum glucose ≥ 126 mg/dL, a self-reported history of DM or current use of anti-diabetic medications. Pre-diabetes was defined as a fasting glucose 100-125 mg/dL and no history of DM or anti-diabetic medication use. Incident hearing loss was defined as a pure-tone average of thresholds at 0.5, 1.0 and 2.0 kHz > 25 dB in both right and left ears.

Results

During 1 285 704 person-years of follow-up (median follow-up of four years), 2817 participants developed incident hearing loss. The rate of hearing loss in participants with normal glucose levels, pre-diabetes and DM were 1.8, 3.1 and 9.2 per 1000 person-years, respectively ( P < 0.001). The multivariable-adjusted hazard ratios for incident hearing loss for participants with pre-diabetes and DM compared with those with normal glucose levels were 1.04 (95% confidence interval 0.95-1.14) and 1.36 (1.19-1.56), respectively. In spline regression analyses, the risk of incident hearing loss increased progressively with HbA1c levels above 5%.

Conclusions

In this large cohort study of young and middle-aged men and women, DM was associated with the development of bilateral hearing loss. DM patients have a moderately increased risk of future hearing loss.

Hearing Loss in Type 2 Diabetes in Association with Diabetic Neuropathy

BACKGROUND

Reports assessing hearing abnormalities in diabetes are debated. We aimed to evaluated auditory alterations and their possible associations with vascular and neurological dysfunction in 160 Type 2 diabetes mellitus individuals and 100 age and sex-matched healthy controls.

METHODS

Participants underwent pure tone audiometry (PTA). Associations with demographic, metabolic and neuropathic variables were assessed.

RESULTS

Compared with healthy controls, diabetic patients had higher mean hearing thresholds at each frequency, with statistical significance at 2-8 kHz (p <0.05). Prevalence of hearing loss in diabetics was 67.5% (108/160), including high-frequency (72.22%, 78/108), and low/mid- and high-frequency (27.78%, 30/108). The mild hearing loss was predominant in diabetics with high-frequency impairment (52.56%), while the moderate/severe hearing loss was high in individuals with both low-and high-frequency hearing loss (80.00%). Multiple logistic regression analysis of PTA parameters showed that higher Semmes Weinstein Monofilament (OR 1.24, 95% CI 1.02-1.52), Michigan Neuropathy Screening Instrument score (OR 1.38, 95% CI 1.14-1.68), and vibration perception threshold (OR 1.19, 95% CI 1.05-1.34) were independent risk factors for hearing impairment in diabetics after adjusting for potential covariates.

CONCLUSIONS

These findings suggest that hearing loss is common in T2DM subjects, with predominantly high frequency involved. Diabetic neuropathic factors may explain the underlying mechanism of the association between diabetes and hearing loss.

Hearing thresholds in adult Nigerians with diabetes mellitus: a case-control study

OBJECTIVES

To determine the prevalence, types and severity of hearing loss and associated factors in a hospital population of adult Nigerians with diabetes mellitus.

SUBJECTS AND METHODS

This study was a prospective hospital-based study conducted at the Otorhinolaryngology and Diabetic Clinics of the University of Nigeria Teaching Hospital (UNTH) Ituku-Ozalla, Enugu, for a period of 12 months. Consecutively presenting eligible adult diabetics and their age- and sex-matched healthy controls were recruited. Each case and control participant had clinical and otologic examination, followed by pure tone audiometry. Data were analyzed using descriptive and comparative statistics.

RESULTS

There were 224 patients and 192 control participants. The patients comprised 112 males and 112 females (sex ratio=1:1), whose mean age was 47.6 years (range: 26-80 years). The prevalence of hearing loss was 46.9%. This comprised 43.8% sensorineural and 3.1% conductive hearing losses. The distribution of hearing loss by severity was mild 25.0%, moderate 15.6% and severe 6.3%. The controls comprised 96 males and 96 females whose mean age was 44.6 years (range: 25-79 years). The prevalence of hearing loss was significantly higher overall and by type (sensorineural hearing loss, conductive hearing loss) in cases compared with controls.

CONCLUSION

The prevalence of hearing loss among diabetic adults at UNTH, Enugu, is comparatively high. Hearing loss is predominantly sensorineural and often mild to moderate in severity. Routine audiometric evaluation of all adult diabetics at UNTH is recommended.

Risk Factors for Hearing Impairment among Adults with Diabetes: The Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

AIM

The aim was to examine risk factors for hearing impairment among Hispanic/Latino adults with diabetes.

METHODS

Findings are based on 3384 participants aged 18-76 years with diagnosed or previously undetected diabetes who completed audiometric testing as part of the Hispanic Community Health Study/Study of Latinos. We defined hearing impairment as the pure-tone average (PTA) >25 decibels hearing level [dB HL] of pure-tone thresholds at high frequencies (3000, 4000, 6000, and 8000 Hz) in the worse ear and defined a second hearing impairment outcome with the additional requirement of PTA >25 dB HL of low/mid-frequency (500, 1000, and 2000 Hz) thresholds in the worse ear. We identified independent associations using logistic regression.

RESULTS

Controlling for age and Hispanic/Latino background, prevalence ratios for hearing impairment in the high plus low/mid frequencies were 1.35 (95% CI 1.07, 1.71) for current smoking, 1.64 (1.14, 2.38) for alcohol consumption (≥ 14 drinks/week for men or ≥ 7 drinks/week for women), and 1.29 (1.06, 1.56) for triglycerides ≥ 150 mg/dL. For high-frequency only hearing impairment, the prevalence ratio for estimated glomerular filtration rate 30-59 mL/min/1.73m2 was 1.23 (1.03, 1.47) adjusted for age and sex. People with family income less than $20,000 had almost twice the prevalence of hearing impairment (PR=1.93 (1.34, 2.78)) as people with income over $40,000.

CONCLUSIONS

Current smoking, alcohol consumption, high triglycerides, and chronic kidney disease are potentially preventable correlates of hearing impairment for persons with diabetes. Low income is a marker of increased likelihood of hearing impairment.

Clinical Study to Evaluate the Association Between Sensorineural Hearing Loss and Diabetes Mellitus in Poorly Controlled Patients Whose HbA1c >8

The relationship between sensorineural hearing loss (SNHL) and Diabetes mellitus has been known since more than 150 years. The pathophysiology of diabetes related hearing loss is speculative. Hearing loss is usually, bilateral, gradual onset, affecting higher frequencies. This study aims at knowing the prevalence of SNHL in DM and its relation to age, sex, duration of DM and control of DM. A total of 50 type 2 diabetics of age group 30-65 years were involved in the study. FBS, PPBS, HbA1c of all the subjects were done and later subjected to PTA. The type and severity of hearing loss was noted. Occurrence of SNHL was later compared with age, sex, duration, and control of DM. Sensorineural hearing loss was found in 66 % of type II diabetic patients and 34 % were found normal. Out of 50 diabetes mellitus patients, 33 patients had SNHL. All cases of SNHL detected were of gradual in onset and no one had hearing loss of sudden onset. Normal hearing was found in 34 % of patients, whereas 54 % of patients had mild hearing loss and 12 % of patients had moderate hearing loss. Association of hearing loss of DM patients with sex of the patient is insignificant. However there is significant association between older age group, longer duration and uncontrolled DM with that of SNHL. In subjects with HbA1c more than 8 and duration of diabetes mellitus more than 10 years prevalence of SNHL is more than 85 %, which is statistically significant. Sensorineural hearing loss in diabetes mellitus is gradually progressive involving high frequency thresholds. Hearing threshold increases with increasing age duration of diabetes and also high level of HbA1c greater than 8 %.

Hearing Impairment in Relation to Severity of Diabetes in a Veteran Cohort

OBJECTIVE

Type 2 diabetes is epidemic among veterans, approaching three times the prevalence of the general population. Diabetes leads to devastating complications of vascular and neurologic malfunction and appears to impair auditory function. Hearing loss prevention is a major health-related initiative in the Veterans Health Administration. Thus, this research sought to identify, and quantify with effect sizes, differences in hearing, speech recognition, and hearing-related quality of life (QOL) measures associated with diabetes and to determine whether well-controlled diabetes diminishes the differences.

DESIGN

The authors examined selected cross-sectional data from the baseline (initial) visit of a longitudinal study of Veterans with and without type 2 diabetes designed to assess the possible differences in age-related trajectories of peripheral and central auditory function between the two groups. In addition, the diabetes group was divided into subgroups on the basis of medical diagnosis of diabetes and current glycated hemoglobin (HbA1c) as a metric of disease severity and control. Outcome measures were pure-tone thresholds, word recognition using sentences presented in noise or time-compressed, and an inventory assessing the self-perceived impact of hearing loss on QOL. Data were analyzed from 130 Veterans ages 24 to 73 (mean 48) years with well-controlled (controlled) diabetes, poorly controlled (uncontrolled) diabetes, prediabetes, and no diabetes. Regression was used to identify any group differences in age, noise exposure history, and other sociodemographic factors, and multiple regression was used to model each outcome variable, adjusting for potential confounders. Results were evaluated in relation to diabetes duration, use of insulin (yes, no), and presence of selected diabetes complications (neuropathy and retinopathy).

RESULTS

Compared with nondiabetics, Veterans with uncontrolled diabetes had significant differences in hearing at speech frequencies, including poorer hearing by 3 to 3.5 dB for thresholds at 250 Hz and in a clinical pure-tone average, respectively. Compared with nondiabetic controls, individuals with uncontrolled diabetes also significantly more frequently reported that their hearing adversely impacted QOL on one of the three subscales (ability to adapt). Despite this, although they also had slightly poorer mean scores on both word recognition tasks performed, these differences did not reach statistical significance and all subjects performed well on these tasks. Compared with Veterans with controlled diabetes, those with uncontrolled disease tended to have had diabetes longer, be insulin-dependent, and have a greater prevalence of diabetic retinopathy. Results are generally comparable with the literature with regard to the magnitude of threshold differences and the prevalence of hearing impairment but extend prior work by providing threshold difference and hearing loss prevalence effect sizes by category of diabetes control and by including additional functional measures.

CONCLUSIONS

In a cohort of Veterans with type 2 diabetes and relatively good hearing, significant effects of disease severity were found for hearing thresholds at a subset of frequencies and for one of the three QOL subscales. Significant differences were concentrated among those with poorly controlled diabetes based on current HbA1c. Results provide evidence that the observed hearing dysfunction in type 2 diabetes might be prevented or delayed through tight metabolic control. Findings need to be corroborated using longitudinal assessments.

Risk of developing sudden sensorineural hearing loss in diabetic patients: a population-based cohort study

OBJECTIVES

To explore the risk of development of sudden sensorineural hearing loss (SSHL) among diabetes mellitus patients.

STUDY DESIGN

A retrospective cohort study.

SETTING

Population-based study of Taiwan National Health Insurance Research Database.

PATIENTS

Approximately 26,556 newly diagnosed diabetic patients and 26,556 comparison subjects without diabetes mellitus were selected from claims made during 2000 to 2004.

MAIN OUTCOME MEASURES

The incidence of sudden sensorineural hearing loss (SSHL) at the end of 2009 was determined.

RESULTS

The incidence of SSHL was 1.54-fold higher in the diabetic group compared with the nondiabetic group (1.29 versus 0.78 per 1,000 person-years), and using Cox proportional hazard regressions, the adjusted hazard ratio (HR) was 1.592 (95% confidence interval [CI], 1.295-1.957). The risk of developing SSHL increased substantially to an HR of 2.060 (95% CI, 1.051-4.037), for patients who required triple antidiabetic medication compared with diabetic patients treated with a single antidiabetic drug. An increased risk of developing SSHL, with adjusted HRs of 1.574 (95% CI, 1.091-2.271) and 2.842 (95% CI, 1.880-4.295), was observed in diabetic patients with newly diagnosed comorbidities of retinopathy or retinopathy combined with renal insufficiency, which are both expected to reflect the severity of diabetes.

CONCLUSION

Diabetes mellitus was significantly associated with an increased risk of developing SSHL. Coronary heart disease or retinopathy comorbidities in diabetic patients seemed to be associated with an increased risk of developing SSHL. The risk of developing SSHL increased with the severity of diabetes.

A Single Blinded Randomized Controlled Study of the Effect of Conventional Oral Hypoglycemic Agents Versus Intensive Short-Term Insulin Therapy on Pure Tone Audiometry in Type II Diabetes Mellitus

Neuropathy is frequently a late complication of diabetes mellitus. Auditory neuropathy and microangiopathy of inner ear are the possible causes of hearing loss in diabetics. To study the correlation between glycaemic control and hearing threshold in patients with type 2 diabetes mellitus and to determine the differences of hearing threshold between groups treated with different modality. This single blind randomized controlled study was performed at the Department of Medicine and Department of Otorhinolaryngology, Hospital Universiti Kebangsaan Malaysia (UKM) between 1st May 2003 and 31st September 2004. This study was approved by Research Ethics Committee (code number FF-137). Subjects were randomized into two groups. Group 1 were patients treated with conventional oral hypoglycemic agents. The patients in group 2 were those treated with insulin injection. The subjects were seen 4 weekly for 3 months. Audiometric test were performed in all subjects at each visit. Blood were taken for fasting blood glucose, Hb1Ac, and fructosamine at every visit to determine the glycaemic controls of the subject. They were 11 patients (22 ears) treated with oral hypoglycemic agents and 17 patients treated (34 ears) with subcutaneous insulin. There is no significant difference between mean pure tone threshold before and after treatment at all frequencies in both groups. There is also no significance different in fasting glucose level and fructosamine. However, there is significant difference HbA1c levels between the two groups after treatment (P < 0.05). This study has shown that glycaemic control does not have significant impact on hearing. The hearing threshold is neither affected by insulin treatment nor by the glycaemic control.

Relationship of Type 2 diabetes to the prevalence, incidence and progression of age-related hearing loss

AIMS

Type 2 diabetes and associated microvascular abnormalities are postulated to affect hearing. Our study reports on the relationship between Type 2 diabetes and the prevalence, 5-year incidence and progression of hearing impairment in a representative, older, Australian population.

METHODS

The Blue Mountains Hearing Study is a population-based survey of age-related hearing loss conducted in a defined suburban area, west of Sydney. Hearing loss was defined as the pure-tone average of frequencies 0.5, 1.0, 2.0 and 4.0 kHz > 25 decibels hearing level (dB HL) in the better ear (bilateral hearing loss). Type 2 diabetes was defined from reported physician-diagnosed diabetes or fasting blood glucose > or = 7.0 mmol/l.

RESULTS

Age-related hearing loss was present in 50.0% of diabetic participants (n = 210) compared with 38.2% of non-diabetic participants (n = 1648), odds ratio (OR) 1.55 [95% confidence interval (CI) 1.11-2.17], after adjusting for multiple risk factors. A relationship of diabetes duration with hearing loss was also demonstrated. After 5 years, incident hearing loss occurred in 18.7% of participants with, and 18.0% of those without diabetes, adjusted OR 1.01 (CI 0.54-1.91). Progression of existing hearing loss (> 5 dB HL), however, was significantly greater in participants with newly diagnosed diabetes (69.6%) than in those without diabetes (47.8%) over this period, adjusted OR 2.71 (CI 1.07-6.86).

CONCLUSIONS

Type 2 diabetes was associated with prevalent, but not incident hearing loss in this older population. Accelerated hearing loss progression over 5 years was more than doubled in persons newly diagnosed with diabetes. These data explore further reported links between Type 2 diabetes and age-related hearing loss.

Hearing deficit in a birth cohort of U.S. male commuter air carrier and air taxi pilots

PURPOSE

Long-term exposure to multiple risk factors in aviation may place pilots at excess risk of developing hearing deficits. We examined the incidence and risk factors for hearing deficit in a birth cohort of male commuter and air taxi pilots.

METHODS

The subjects (N = 3019), who were 45-54 yr of age and held Class I medical certificates in 1987, were followed up from 1987 to 1997 through the medical certification system of the Federal Aviation Administration (FAA). In this study, hearing deficit refers to the FAA pathology code 220 (defective hearing, deafness, not elsewhere classified). Poisson regression modeling based on generalized estimation equations was used to assess the associations between pilot characteristics and the risk of developing hearing deficit.

RESULTS

The 10-yr follow-up accumulated a total of 20,671 person-years and 574 incident cases of hearing deficit, yielding an incidence rate of 27.8 per 1000 person-years. Compared with age 45-49 yr, the risk of developing hearing deficit at age 50-54 yr, 55-59 yr, and 60-64 yr increased by 12% [adjusted relative risk (RR) 1.12, 95% confidence interval (CI) 0.98-1.30], 34% (RR 1.34, 95% CI 1.13-1.59), and 79% (RR 1.79, 95% CI 1.20-2.67), respectively.

CONCLUSIONS

Hearing deficit is prevalent among commuter air carrier and air taxi pilots and the risk of hearing deficit increases progressively with pilot age. Effective programs for preventing excess hearing loss in the pilot population are warranted.

Characterization of hearing loss in aged type II diabetics

Presbycusis - age-related hearing loss - is the number one communicative disorder and a significant chronic medical condition of the aged. Little is known about how type II diabetes, another prevalent age-related medical condition, and presbycusis interact. The present investigation aimed to comprehensively characterize the nature of hearing impairment in aged type II diabetics. Hearing tests measuring both peripheral (cochlea) and central (brainstem and cortex) auditory processing were utilized. The majority of differences between the hearing abilities of the aged diabetics and their age-matched controls were found in measures of inner ear function. For example, large differences were found in pure-tone audiograms, wideband noise and speech reception thresholds, and otoacoustic emissions. The greatest deficits tended to be at low frequencies. In addition, there was a strong tendency for diabetes to affect the right ear more than the left. One possible interpretation is that as one develops presbycusis, the right ear advantage is lost, and this decline is accelerated by diabetes. In contrast, auditory processing tests that measure both peripheral and central processing showed fewer declines between the elderly diabetics and the control group. Consequences of elevated blood sugar levels as possible underlying physiological mechanisms for the hearing loss are discussed.

Auditory Impairment in Patients with Type 2 Diabetes Mellitus

BACKGROUND

We assessed the auditory function of 94 patients with type 2 diabetes mellitus and 94 age- and sex-matched healthy subjects.

METHODS

To study the influence of the clinical characteristics of the disease on the auditory function, after a clinical interview with ophthalmological assessment, subjects were evaluated using pure-tone audiometry, speech audiometry, auditory brainstem responses, the Michigan Diabetic Neuropathy Score and albuminuria. The mean age when diabetes was diagnosed was 42.8 +/- 6.5 years (mean +/- SD) and the time elapsed since diabetes diagnosis was 7.2 +/- 5.4 years.

RESULTS

Forty-eight patients (62%) had HbA1c >8%; diabetic retinopathy was evident in 14 patients (14%) and microalbuminuria was identified in 12 patients. Compared to healthy subjects, diabetic patients showed an increase of the perception threshold at 8000 Hz (p <0.01), higher hearing levels to discriminate at least 90% of 10 monosyllables (p <0.01), and longer latencies of wave V, interwave I-V and interwave III-V (p <0.01). Significant correlation was found between the hearing threshold at 8 KHz and patient age, and the former and the time elapsed since the diabetes was diagnosed (p <0.001).

CONCLUSIONS

Patients with type 2 diabetes mellitus can have subclinical hearing loss and impaired auditory brainstem response, independent of peripheral neuropathy, retinopathy or nephropathy.

Pesquisa do nistagmo/vertigem de posição e avaliação eletronistagmográfica em um grupo de indivíduos portadores de diabetes Mellitus tipo I

Introdução: De acordo com a Sociedade Brasileira de Diabetes, estima-se que existam no Brasil cerca de 5 milhões de pessoas com a patologia. No estado do Rio Grande do Sul há, provavelmente, 400.000 pacientes diabéticos23,27. Dentre as alterações que os indivíduos portadores de diabetes Mellitus podem apresentar, estão incluídos os distúrbios vestibulares. Objetivo: O presente trabalho teve por objetivo colaborar nas pesquisas de melhoria na qualidade de vida do paciente diabético e realizar pesquisa do nistagmo/ vertigem de posição e eletronistagmografia, a fim de identificar possíveis alterações. Forma de estudo: Clínico prospectivo. Material e método: 12 indivíduos portadores de diabetes Mellitus tipo I, usuários regulares de insulina, com idades entre 12 e 27 anos e componentes da Associação Riograndense de Apoio aos Diabéticos (ARAD). Para verificar as respostas vestibulares nos indivíduos portadores de diabetes Mellitus tipo I, foram realizados anamnese específica, meatoscopia, timpanometria, pesquisa do nistagmo/ vertigem de posição e eletronistagmografia na amostra selecionada. Resultados: Verificou-se Síndrome Vestibular Periférica Irritativa em 75% dos resultados alterados. Destes, 62,5% se tratavam de sujeitos sem queixa otoneurológica. Conclusões: Observou-se que o efeito do diabetes tipo I, na função vestibular, deve ser avaliado como as demais complicações diabéticas usuais, mesmo em pacientes assintomáticos, pois, com o diagnóstico etiológico precoce, é possível o auxílio na prevenção das complicações desta patologia.