Diabetes and Hearing Loss Among Underserved Populations

Hyperglycemia-induced oxidative stress exacerbates mitochondrial apoptosis damage to cochlear stria vascularis pericytes via the ROS-mediated Bcl-2/CytC/AIF pathway

OBJECTIVES

Diabetes is closely linked to hearing loss, yet the exact mechanisms remain unclear. Cochlear stria vascularis and pericytes (PCs) are crucial for hearing. This study investigates whether high glucose induces apoptosis in the cochlear stria vascularis and pericytes via elevated ROS levels due to oxidative stress, impacting hearing loss.

METHODS

We established a type II diabetes model in C57BL/6J mice and used auditory brainstem response (ABR), Evans blue staining, HE staining, immunohistochemistry, and immunofluorescence to observe changes in hearing, blood-labyrinth barrier (BLB) permeability, stria vascularis morphology, and apoptosis protein expression. Primary cultured stria vascularis pericytes were subjected to high glucose, and apoptosis levels were assessed using flow cytometry, Annexin V-FITC, Hoechst 33342 staining, Western blot, Mitosox, and JC-1 probes.

RESULTS

Diabetic mice showed decreased hearing thresholds, reduced stria vascularis density, increased oxidative stress, cell apoptosis, and decreased antioxidant levels. High glucose exposure increased apoptosis and ROS content in pericytes, while mitochondrial membrane potential decreased, with AIF and cytochrome C (CytC) released from mitochondria to the cytoplasm. Adding oxidative scavengers reduced AIF and CytC release, decreasing pericyte apoptosis.

DISCUSSION

Hyperglycemia may induce mitochondrial apoptosis of cochlear stria vascularis pericytes through oxidative stress.

Prevalence and Severity of Sensorineural Hearing Loss in Diabetic and Hypertensive Patients: A Comparative Cross-Sectional Study

Background The ability to perceive sound is crucial for effective communication and environmental awareness. This study aimed to assess sensorineural hearing loss (SNHL) in patients with both diabetes mellitus (DM) and hypertension (HTN). Materials and methods A total of 120 participants of both genders were divided into three groups: Group I consisted of diabetic patients (n=40, 22 males and 18 females), Group II included hypertensive individuals (n=40, 16 males and 24 females), and Group III served as controls (n=40, 15 males and 25 females). General ear examinations, including otoscopy, were conducted. Hearing function and the degree, pattern, and configuration of hearing loss were assessed using general ear examinations and pure tone audiometry. Results Normal hearing was observed in 25% of Group I, 26% of Group II, and 85% of Group III. Mild hearing loss was evident in 75% of Group I, 50% of Group II, and 15% of Group III, while moderate hearing loss was observed in 24% of Group II. These differences were statistically significant (P < 0.05). Conclusion Diabetic and hypertensive individuals demonstrated a higher hearing loss prevalence than healthy controls.

How have services for diabetes, eye, hearing and foot health been integrated for adults? Protocol for a scoping review

INTRODUCTION

The global population is ageing, and by 2050, there will be almost 2.1 billion people over the age of 60 years. This ageing population means conditions such as diabetes are on the increase, as well as other conditions associated with ageing (and/or diabetes), including those that cause vision impairment, hearing impairment or foot problems. The aim of this scoping review is to identify the extent of the literature describing integration of services for adults of two or more of diabetes, eye, hearing or foot services.

METHODS AND ANALYSIS

The main database searches are of Medline and Embase, conducted by an information specialist, without language restrictions, for studies published from 1 January 2000 describing the integration of services for two or more of diabetes, eye, hearing and foot health in the private or public sector and at the primary or secondary level of care, primarily targeted to adults aged ≥40 years. A grey literature search will focus on websites of key organisations. Reference lists of all included articles will be reviewed to identify further studies. Screening and data extraction will be undertaken by two reviewers independently and any discrepancies will be resolved by discussion. We will use tables, maps and text to summarise the included studies and findings, including where studies were undertaken, which services tended to be integrated, in which sector and level of the health system, targeting which population groups and whether they were considered effective.

ETHICS AND DISSEMINATION

As our review will be based on published data, ethical approval will not be sought. This review is part of a project in Aotearoa New Zealand that aims to improve access to services for adults with diabetes or eye, hearing or foot conditions. The findings will be published in a peer-reviewed journal and presented at relevant conferences.

The Impact of Diabetes Mellitus on Sensorineural Hearing Loss: A Cross-Sectional Study in Eastern India

Objective Hearing loss as a comorbidity of type 2 diabetes mellitus (type 2 DM) is frequently overlooked by patients and healthcare professionals because of a lack of awareness. This cross-sectional study aims to investigate the impact of DM on sensorineural hearing loss (SNHL) in the population of Eastern India. The primary objectives are to assess the prevalence and severity of SNHL among individuals with DM, explore demographic and clinical factors associated with hearing impairment, and contribute valuable insights to the understanding of this relationship in a specific regional context. Methods An institutional-based cross-sectional study was conducted on 198 patients with type 2 DM. Of these, 46 patients were excluded based on exclusion criteria. All patients underwent detailed demographic and clinical assessments, including glycemic control, DM duration, and associated complications. Pure tone audiometry was used to evaluate hearing thresholds. Otoacoustic emission testing was performed to assess cochlear dysfunction. Results A high prevalence of SNHL (70.4%) was observed among the 152 participants meeting the inclusion criteria. Females exhibited a higher prevalence than males, and most participants experienced mild SNHL. Rural residence, lower socioeconomic status, and poor glycemic control were associated with increased SNHL. Significant associations were found between hearing loss severity and DM duration, glycosylated hemoglobin (HbA1c) levels, and complications. Among complications, a strong association was noted with diabetic neuropathy. No significant association was observed with the presence or absence of otoacoustic-emission. Conclusion This study reveals a substantial impact of DM on SNHL in Eastern India, emphasizing the importance of routine hearing assessments in diabetic populations. The findings contribute to regional understanding and have implications for targeted healthcare interventions and preventive strategies.

Hearing Loss Characteristics of Workers with Hypertension Exposed to Occupational Noise: A Cross-Sectional Study of 270,033 Participants

Objectives

This study investigated the hearing loss characteristics among occupational noise exposure workers with hypertension and the link between hypertension and hearing loss when exposed to occupational noise.

Methods

A total of 267,766 occupational noise-exposed workers were enrolled, including 29,868 workers with hypertension and 240,165 without hypertension. Hypertension was diagnosed according to WHO criteria. Hypertension was classified into four grades based on blood pressure. Assessment of hearing was performed through measurement of an unadulterated tone threshold at different frequencies, which ranged between 250 and 8,000 Hz.

Results

A substantial link was observed to exist between hypertension and the increment in the hearing limit. The increase in the hearing threshold was substantially higher among those having grade 2 hypertension.

Conclusion

The current investigation suggested patients with hypertension exhibit a substantial rise in hearing loss in comparison with patients without hypertension. The rise in hearing loss was significant in patients with grade 2 hypertension. Efficient and practicable measures are required to decrease the hearing loss in workers with hypertension and work-related noise exposure.

Cochlear dysfunction and microvascular complications in patients with type 1 diabetes mellitus

Sensorineural hearing impairment has been associated with DM, and it is probably linked to the same pathophysiological mechanisms as well-established in microvascular diabetes complications. The study of otoacoustic emissions (OAEs) is useful to identify subclinical cochlear dysfunction. Therefore, the aim of this study was to evaluate the association between abnormal OAEs responses, diabetic kidney disease (DKD) and diabetic cardiac autonomic neuropathy (CAN). We performed a cross-sectional study with 37 type 1 DM patients without auditory symptoms, submitted to the study of Distortion Product Otoacoustic Emissions (DPOAEs) and screened for DKD and CAN. The otoacoustic emissions responses were considered abnormal in 27/37 (73%) patients. A correlation was found between abnormal OAEs responses and presence of DKD (r = 0.36, p < 0.05), and 14/16 (88%) patients with a lower amplitude of OAEs in 8 kHz frequency band presented DKD. Abnormal OAEs responses in the 6 kHz frequency band were correlated with the presence (r = 0.41, p = 0.01) and severity of CAN (r = 0.44, p < 0.001). Additionally, 7/9 (78%) patients with abnormal OAE responses in this frequency also presented abnormal CAN scores. Our results suggest that abnormal otoacoustic emissions responses in high frequency bands are associated with diabetes microvascular complications and could be a risk marker for DKD and CAN, presenting low sensitivity and high specificity. Therefore, assuming that hearing impairment is a pre-clinical stage of hearing loss, performing distortion product otoacoustic emissions in T1DM patients with microvascular complications could be useful to identify those who would be benefit with regular audiologic follow up and tighter diabetes control.

Interaction between diabetes mellitus and hypertension on risk of hearing loss in highly endogamous population

AIM

The aim of this study was to determine the prevalence of hearing loss and its association with type 2 diabetes mellitus (T2DM) in a highly endogamous population.

DESIGN

This is a cross-sectional study.

SETTING

The present study is carried out in Ear Nose Throat (ENT) and Endocrinology outpatient clinics of the Hamad General and Rumeilah Hospitals, Hamad Medical Corporation.

SUBJECTS

All subjects aged between 20 and 59 years who visited the Endocrinology and ENT outpatient clinics of the Hamad Medical Corporation with hearing difficulty were included in this study during the period from January 2013 to July 2014.

METHOD

During the study period, prevalence, hearing, audiological test, family history and medical problems associated with hearing impairment in middle aged patients were recorded. Two audiometers Grason Stadler GSI 61 and Madsen Orbiter 922 were used to evaluate the hearing loss.

RESULT

Majority of the hearing loss observed at the age above 45 years old, (44.8% vs 51.7%, p=0.05). The prevalence of hearing impairment was higher in Qataris than in non-Qataris (59.7% vs 46.6%, p<0.001). The consanguineous marriages were observed higher in Hearing loss (32.1%) than in normal hearing (21.8%) (p=0.028). The mean of diabetes onset duration (7.8±4.12years), sleeping disorder (5.81±1.29h), obese subjects (38% vs 27.4%); family history of diabetes (30.6 vs 23.1%) were higher among hearing impairment. The associated risk factors were significantly higher in T2DM with hearing loss, hypoglycemia (32.8% vs 27.4%), retinopathy (313% vs 18.5%), Nephropathy (17.9% vs 9.8%), Neuropathy (17.9% vs 10.2%), macro-vascular disease (11.9% vs 6.2%), diabetic foot ulcer (20.9% vs 12.6%), Tinnitus (68.7% vs 51.3%), and Vertigo (25.4% vs 16.9%) than in normal hearing diabetes. There was a statistically significant differences between hearing impairment and normal hearing among T2DM regarding hearing assessment frequency (p=0.041). There were statistically significant differences between hearing impairment versus normal hearing for vitamin D [18.91±7.65ng/mL vs 22.85±9.00ng/mL; p<0.001], calcium [1.80±0.12ng/mL vs 1.96±0.14mmol/L; p<0.001], magnesium [0.80±0.09mmol/L vs 0.8±0.14mmol/L; p<0.001], phosphorous [1.42±0.30mmol/L vs 1.56±0.26mmol/L; p<0.001], ceatinine [1.42±0.30mmol/L vs 1.56±0.26mmol/L; p<0.001], cholesterol [4.92±1.08mmol/L vs 4.40±1.01mmol/L; p=0.035], LDL [1.92±0.88mmol/L vs 2.09±0.92mmol/L; p=0.024], albumin [43.1±6.10mmol/L vs 39.8±7.93mmol/L; p=0.010], systolic blood pressure [135.8±16.6Hg vs 130.2±12.5Hg; p=0.017] and, diastolic blood pressure [85.1±9.2mmHg vs 83.0±7.9mmHg; p=0.012]. There were highly statistically significant differences between hearing impairment versus normal for both side right and left ear frequency in Db unit (p<0.001). The multivariate stepwise logistic regression analysis revealed that head ache (p<0.001), family history of DM (p<0.001), sleep disturbance (p<0.001), high blood pressure (p=0.006), consanguinity (p=0.010), nationality (p=0.014), age in years (p=0.025), and sheesha smokers (p=0.045) were considered at higher risk as a predictors of hearing loss among diabetic patients.

CONCLUSION

The current study results confirm previous reports that adults with DM and hypertension associated showed greater hearing impairment in highly endogamous population… Diabetic patients with hearing loss were likely to have high blood glucose and other risk factors like hypertension, retinopathy, nephropathy and neuropathy.

A risk-score model for predicting risk of type 2 diabetes mellitus in a rural Chinese adult population: A cohort study with a 6-year follow-up

BACKGROUND

Several prediction tools have been developed to identify people with type 2 diabetes mellitus (T2DM) and to quantify the probability of developing T2DM. However, most of the risk models were constructed based on cross-sectional studies and tea-drinking was not included.

METHODS

A total of 15 768 participants without known T2DM were followed up from 2007-2008 to 2013-2014; 12 654 were randomly assigned to the derivation dataset and 3114 to the validation dataset. We constructed a risk-score model for T2DM by using a Cox proportional-hazards model. Risk scores were calculated by multiplying β by 10 in the derivation cohort and were verified in the validation dataset. The model's accuracy was assessed by the area under the receiver operating characteristic curve (AUC).

RESULTS

Predictors for T2DM risk in the derivation dataset were drinking tea frequently, body mass index ≥28.0 kg/m² , waist to height ratio ≥ 0.5, triglycerides level 1.70 to 2.25 and ≥2.26 mmol/L, and fasting plasma glucose 5.6 to 6.0 and ≥6.1 mmol/L. The corresponding scores were -2, 7, 7, 4, 6, 11, and 25, respectively. The sensitivity, specificity, and AUC (95% confidence interval) for this full model were 69.63%, 75.56%, and 0.791 (0.783-0.799), respectively. The ability of the non-invasive models to predict T2DM was not superior to that of the full model. With the validation dataset, the predictive performance was better for our full model than the Framingham risk-score model (AUC 0.731 vs 0.525, P < .001).

CONCLUSIONS

Our risk-score model has fair efficacy for predicting 6-year risk of T2DM in a rural adult Chinese population.

Características audiológicas de pacientes com diabetes mellitus Tipo 2

RESUMO Objetivos: identificar as características audiológicas de pacientes com diabetes mellitus tipo 2. Métodos: estudo transversal, realizado em unidade de atenção secundária para diabetes em Fortaleza, de abril a julho de 2010. Amostra composta por 152 pacientes diabéticos tipo 2, independente do sexo, entre 36 e 60 anos. Realizou-se audiometria tonal liminar (ATL), emissões otoacústicas evocadas por estímulo transiente (EOAT) e emissões otoacústicas evocadas-produto de distorção (EOAPD). Resultados: associação da idade e do tempo de diagnóstico com a presença de perda auditiva, e do tempo de diagnóstico com a ausência de EOAPD. Observou-se perda auditiva sensorioneural em 63,2% dos pacientes, das quais 71,9% eram bilaterais e 75% simétricas. Aproximadamente, 50% das perdas auditivas apresentaram configuração plana. As EOAT estavam ausentes em 75% dos pacientes e as EOAPD em 78,9%. Houve ausência de emissões otoacústicas na presença de ATL normal, em média, em 32% dos pacientes à direita e 48% à esquerda. Já a presença de emissões otoacústicas na ocorrência de perda auditiva foi observada em, aproximadamente, 30% dos pacientes para EOAT e 14% para EOAPD à direita; e 25% para EOAT e 11% para EOAPD à esquerda. Conclusão: predomínio de perda auditiva sensorioneural bilateral simétrica com configuração plana, e ausência de EOAT e EOAPD. A análise da associação dos resultados da ATL e das emissões otoacústicas sugere prejuízo das células ciliadas externas da cóclea ou possível neuropatia auditiva. Tais achados justificariam o monitoramento da audição destes pacientes, bem como a realização de testes específicos para avaliação do sistema auditivo central.

Toll-like receptor 2 and type 2 diabetes

Innate immunity plays a crucial role in the pathogenesis of type 2 diabetes and related complications. Since the toll-like receptors (TLRs) are central to innate immunity, it appears that they are important participants in the development and pathogenesis of the disease. Previous investigations demonstrated that TLR2 homodimers and TLR2 heterodimers with TLR1 or TLR6 activate innate immunity upon recognition of damage-associated molecular patterns (DAMPs). Several DAMPs are released during type 2 diabetes, so it may be hypothesized that TLR2 is significantly involved in its progression. Here, we review recent data on the important roles and status of TLR2 in type 2 diabetes and related complications.

PSIP1/LEDGF: a new gene likely involved in sensorineural progressive hearing loss

Hereditary Hearing Loss (HHL) is an extremely heterogeneous disorder. Approximately 30 out of 80 known HHL genes are associated with autosomal dominant forms. Here, we identified PSIP1/LEDGF (isoform p75) as a novel strong candidate gene involved in dominant HHL. Using exome sequencing we found a frameshift deletion (c.1554_1555del leading to p.E518Dfs*2) in an Italian pedigree affected by sensorineural mild-to-moderate HHL but also showing a variable eye phenotype (i.e. uveitis, optic neuropathy). This deletion led to a premature stop codon (p.T519X) with truncation of the last 12 amino acids. PSIP1 was recently described as a transcriptional co-activator regulated by miR-135b in vestibular hair cells of the mouse inner ear as well as a possible protector against photoreceptor degeneration. Here, we demonstrate that it is ubiquitously expressed in the mouse inner ear. The PSIP1 mutation is associated with a peculiar audiometric slope toward the high frequencies. These findings indicate that PSIP1 likely plays an important role in HHL.