European Journal of Cardiovascular Medicine

Hearing loss is strongly associated with physical, emotional and cognitive disability, with a profound impact on social communication, quality of life, and medical and non-medical costs. The World Health Organization (WHO) estimates that over 360 million people, approximately 5% of the world’s population, has disabling hearing loss and the number of cases of hearing impairment is increasing because of population ageing. Established causes of hearing loss include genetic predisposition, vascular causes, infections, ototoxic drugs and longstanding exposure to excessive noise, but the determinants of most cases of ageing-related hearing loss are uncertain. Since sensorineural hearing loss cannot be restored, identification of preventable causes of hearing loss is a major clinical and public health goal. Sensorineural hearing loss (SNHL) is a type of hearing loss in which the cause lies in the inner ear (cochlea and associated structures), vestibulocochlear nerve (cranial nerve VIII), or central auditory processing centres of the brain. Diabetes Mellitus is one of the most important metabolic diseases which affects several organ systems in the body and risk factor for hearing loss, neuropathy, retinopathy, and nephropathy Diabetes mellitus (DM) is a syndrome of chronic hyperglycemia due to relative insulin deficiency or resistance. As diabetes is caused by a glucose/insulin pathology, it can have a direct effect on the sensory and support cells of the cochlea. Macro- and micro-vascular insults that lead to reduced blood flow, oxygen exchange, and ion transport are primary complications of hypertension and diabetes that affect the ear. Microangiopathy of the cochlear arteries, neuropathy of the auditory nerve, and changes in inner ear glucose levels are the three primary explanations for the aetiology of sensorineural hearing loss in diabetes patients. The inner ear angiopathy causes deafness by reducing the transfer of nutrients through thicker capillary walls or reducing blood flow through restricted vasculature. Hearing loss is one of the commonly occurring diseases in diabetes patients that could affect their quality of life and lead to hearing disabilities, so the present study aims to assess the presence and severity of hearing loss among patients with type 1 diabetes.

Study Design: A cross-sectional study conducted at a teaching hospital department of ENT & General Medicine  Rama Medical College, Hospital & Research Centre, Hapur from December 2024 to May 2025 for a period of 6 months. A total of 100 patients were randomly selected for study and informed consent was taken.

Inclusion Criteria

1. Any patient with Diabetes Mellitus with and above age of 35 years.
2. Any patient who has complained of hearing loss and requires an assessment of hearing loss.
3. Willingness to participate in the study

Criteria for Exclusion

1. Anyone who refuses to participate in the study
2. Patients with a history of ear infections or procedures in the middle ear
3. People who have conductive hearing loss.
4. Patients who are using any ototoxic drugs and also people who had a history of usage of ototoxic drugs in the past or having noise exposure at work.

Procedure for the Study

All patients with hearing loss and Type I Diabetes Mellitus who visit the ENT & General Medicine OPD will be asked to give their informed consent to participate in the study. Demographic data including age, sex, occupation, smoking, alcoholism and diabetes history, hypertension history and treatment history were recorded. Haemoglobin levels, FBS/ppBS levels, and HbA1c levels are all standard investigations done. Examination of the ear nose and throat, including tuning fork tests [rinne, Weber and absolute bone conduction] was done PTA is used to evaluate hearing loss in these patients. They are exposed to pure tones that can be increased or decreased in intensity in 5 dB steps in this manner. Tones of 125Hz, 250, 500, 1000, 2000, 4000, and 8000 Hz, air conduction thresholds and bone conduction thresholds are evaluated. The average audiometric hearing threshold at 500, 1000, 2000, and 4000 Hz for both air and bone conduction was determined; this was taken to be the pure-tone average for both air and bone conduction. This was categorized following the American Speech Language-Hearing Association (ASHA), hearing impairment was classified; as normal hearing = − 10-15 dB hearing threshold level (HL), slight hearing loss = 16-25dBHL, mild hearing loss = 26- 40 dB HL, moderate hearing loss = 41-55 dB HL, moderately severe hearing loss = 56-70 dB HL, severe hearing loss = 71-90 dBHL and profound hearing loss = + 91 dbhl.

Table 1: Shows The Age-Wise Distribution of Hearing Loss

Table 2: Shows The Gender-Wise Distribution of Hearing Loss

Table 3: Type of hearing loss

Table 4: Shows diabetes duration

Table 5: Severity of hearing loss in right ear

Table 6: Severity of hearing loss in left ear

Table 7: Shows glycemic control among diabetes patients

In this large cohort study, participants with DM were at an increased risk of incident hearing loss. The association of DM with hearing loss was evident even after adjusting for multiple potential confounders, including demographic characteristics, occupational noise exposure, lifestyle risk factors and other metabolic abnormalities. In the present study, 61 % of patients were in the age group 45-65 years and male preponderance is seen. This is comparable to studies to studies by Cullen and Cinnamond et al, ^[1] Al-Rubeaan K2 et al and Pemmaiah KD, ^[3] et al. In the present study, 70% of patients had SNHL of which 63% of the patients had moderate to moderately severe hearing loss. FRIEDMAN, ^[4] incurred an average of 55% hearing loss in diabetic patients. In Rajendran S, ^[5] study, 73.3% had SNHL among diabetics when compared to controls 6.7% which is highly significant. In a study by Kakarlapudi V, ^[6] et al, in patients with diabetes and SNHL average pure tones in the right ear was 53db in the left ear and 52 db in the right ear comparable to the present study. This study found that hearing loss in diabetics coincided with higher frequencies yielding to moderate degree of hearing loss. In the present study,63% have a diabetes duration of >15 years which is comparable to Lin,^[7] et al and Gupta S, ^[8] et al In a study by Sunkum AJ, ^[9] et al, diabetic patients have a poorer hearing threshold and significant high-frequency loss correlated with an increase in age. Glycemic control is an important factor, HBA1c levels were positively corelated to the degree of hearing loss, as par with studies with Al-Rubeaan K^[2]  and Pemmaiah KD, ^[3] et al.In a study by Misra V,^[10] et al concluded that the age of the patient and degree of glycemic control had positive correlation with hearing loss.

More than 60% of diabetic patients in this study aged between 30-60 years, had hearing loss of varying degrees with 50% of them having moderate to severe degree hearing loss. In our study there was a correlation between Hba1c levels and SNHL. Early glycemic control, can be considered as a modifiable risk factor. Early detection and treatment of diabetes and strict glycemic control prevent SNHL. Diabetic patients are at increased risk of hearing impairment, although they may frequently have other confounding comorbidities. As the severity, course, and consequences of SHNL can be influenced by the medical treatment of diabetes, Audiometry should be considered as a routine test for diabetic patients by healthcare workers.

1. Cullen JR, Cinnamond MJ. Hearing loss in diabetics. J Laryngol Otol. 1993 Mar;107(3):179-82. doi: 10.1017/s0022215100122571. PMID: 8509689.
2. Al-Rubeaan K, AlMomani M, AlGethami AK, Darandari J, Alsalhi A, AlNaqeeb D, Almogbel E, Almasaari FH, Youssef AM. Hearing loss among patients with diabetes mellitus: a cross-sectional study. Ann Saudi Med. 2021 MayJun;41(3):171-178. doi: 10.5144/0256-4947.2021.171. Epub 2021 Jun 1. PMID: 34085541; PMCID: PMC8176373.
3. Pemmaiah KD, Srinivas DR. Hearing loss in Diabetes Mellitus. International Journal of Collaborative Research on Internal Medicine & Public Health. 2011; 3(10):725-731.
4. Friedman SA, Schulman RH, Weiss S. Hearing and diabetic neuropathy. Archives of Internal Medicine. 1975 Apr 1;135(4):573-6.
5. Rajendran S, Anandhalakshmi, Mythili B, Viswanatha Rao Evaluation of the incidence of sensorineural hearing loss in patients with type 2 diabetes mellitus Int J Biol Med Res. 2011; 2(4): 982 – 987
6. Kakarlapudi V, Sawyer R, Staecker H. The effect of diabetes on sensorineural hearing loss. Otol Neurotol. 2003 May;24(3):382-6. doi: 10.1097/00129492-200305000-00006. PMID: 12806288.
7. Lin Chung Er Bi Yan HouTou Jing Waikezazhi Auditory brainstem response and distortion product otoacoustic emission have been used in the clinical detection of hearing loss in diabetic patients. 21(19): 875-9, October 2007.
8. Gupta S, Eavey RD, Wang M, Curhan SG, Curhan GC. Type 2 diabetes and the risk of incident hearing loss. Diabetologia. 2019 Feb;62(2):281-285. doi: 10.1007/s00125-018-4766-0. Epub 2018 Nov 6. PMID: 30402776; PMCID: PMC6494103.
9. Sunkum AJ, Pingile S. A clinical study of audiological profile in diabetes mellitus patients. Eur Arch Otorhinolaryngol. 2013 Mar;270(3):875-9. doi: 10.1007/s00405-012-2063-y. Epub 2012 Jun 14. PMID: 22695875.
10. Misra V, Agarwal CG, Bhatia N, Shukla GK. Sensorineural deafness in patients of type 2 diabetes mellitus in Uttar pradesh: a pilot study. Indian J Otolaryngol Head Neck Surg. 2013 Dec;65(Suppl 3):532-6. doi: 10.1007/s12070-011- 0442-0. Epub 2012 Jan 6. PMID: 24427709; PMCID: PMC3889349.