Abstract
Sensorineural hearing loss and type 2 diabetes are two frequent health issues that arise with ageing. Although both type 2 diabetes and gestational diabetes have been linked to hearing loss, a direct causal relationship has proven challenging to demonstrate. The intricate connection between gestational diabetes and sensorineural hearing loss will be outlined in the following article. To assess the hearing status in Gestational Diabetes Mellitus Patients. It was a one-year observational study. A total of 66 patients participated in the study in which 33 patients belonged to the Gestational Diabetes Mellitus group and other 33 patients belonged to control group. Gestational Diabetes Mellitus group was selected according to the DIPSI criteria. ENT and PTA evaluation were performed on all 66 participants. In the present study, the mean female age is 26 years. Hearing loss was statistically significant when the relationship between hearing loss and gestational diabetes mellitus was evaluated. It was determined that more than 50% of the patients have hearing impairment after a mean value was calculated that took into consideration the duration of pregnancy, DIPSI score, and that of hearing loss independently. From the observations in the study, we can conclude that there is a need for continual assessment of hearing status in patients with Gestational Diabetes Mellitus. Sensorineural hearing loss and type 2 diabetes are two frequent health issues that arise with ageing. Although both type 2 diabetes and gestational diabetes have been linked to hearing loss, a direct causal relationship has proven challenging to demonstrate. The intricate connection between gestational diabetes and sensorineural hearing loss will be outlined in the following article.
Keywords: DIPSI, Diabetes mellitus, Gestational diabetes, Hearing loss, Pure tone audiometry, Sensory neural hearing loss
Introduction
The survey of WHO in 2018 brings out the information that out of 6.1% of world’s population having disabling hearing loss, hearing loss disability is 4th highest. In retrospective analysis it is observed that patients with diabetes mellitus are likely to suffer from auditory dysfunction like bilateral sensorineural hearing loss (SNHL).
The incidence of hearing loss in Diabetes Mellitus ranges from 0 to 80%, according to recent studies. The hearing loss associated with diabetes mellitus is often bilateral SNHL, with a focus on high frequency tones and a slow onset and progression. In a diabetic patient, Edgar et.al discovered high frequency SNHL for the first time in 1915 [1].
Gestational diabetes mellitus is characterised by carbohydrate intolerance and is defined as glucose intolerance identified at or beyond the achievement of 20 full weeks of gestation. Complications from gestational diabetes mellitus can resemble those from pre-existing diabetes mellitus. Because the inner ear doesn't store energy and is sensitive to blood glucose levels, cochlear dysfunction may result from gestational diabetes mellitus [2]. Minor changes in blood glucose can alter inner ear function and cause symptoms including vertigo, hearing loss, and tinnitus. One of the more recurring morphological features of diabetes mellitus is widespread basal membrane thickness, which can also occur with vascular endothelium and is known as diabetic microangiopathy [3]. Skin capillaries, skeletal muscles, the retina, renal glomeruli, and the renal medulla show it off the most.
Although its pathophysiology is still unknown, hyperglycaemia is undoubtedly a factor. Angiopathy can affect the cochlea directly by impairing transport via thicker capillary walls and indirectly by decreasing blood flow in vascular routes or by causing secondary 8th cranial nerve atrophy [4].There are just two researches on the cited topic that revealed a high frequency SNHL in pregnant diabetes mellitus, despite the fact that diabetes mellitus frequently causes issues with hearing.
Therefore, further data are needed to prove that patients with gestational diabetes mellitus have auditory involvement when utilising traditional pure tone audiometry.
Therefore, the goal of the current study is to evaluate the hearing status of women who have gestational diabetes mellitus.
Objective
To assess the audiological status in patients with gestational diabetes mellitus.
Methodology
A one-year observational study was performed on 66 patients which included 33 cases and 33 controls between the age of 18–40 years, who were willing to undergo ENT and PTA evaluation between January and December 2021.
Ethical Clearance—Obtained from the Institutional Ethical Committee JNMC Ref: MDC/DOME/61 dated on 25/01/2021.
Inclusion Criteria
All patients in the age group of 18 to 40 years:
Diagnosed case of Gestational diabetes mellitus patients who are willing to undergo PTA.
The case and control group will consist of patients with a normal state of health, free from all signs or symptoms of ear disease and from obstructing wax in the ear canal, and with no history of exposure to noise, potentially ototoxic drugs other than drugs used for gestational diabetes mellitus or familial hearing loss those will attend ENT OPD.
Exclusion Criteria
Patients who suffered from prior diabetes mellitus.
Patients suffering from external, middle and inner ear disorders.
Traumatic head injury.
Metabolic diseases Metabolic disorders such as hyperlipidemias and renal disorders.
Hypertension.
Exposure to noise
The use of ototoxic medication different from that used in the treatment of gestational diabetes mellitus.
Bell’s palsy
Informed consent was obtained from all the participants in this study.
Methodology
In this study we are observing the hearing statusin patients with Gestational diabetes mellitus and non-diabetic pregnant patients.
Procedure
GDM was diagnosed using a DIPSI criteria and the cut off values were more than 140 mg/dl after 2 h of oral glucose (75 g).
After taking informed consent from the patient, their details and a through clinical history will be obtained for duration of hearing loss, duration of gestational diabetes mellitus and drugs taken for it will be assessed.
All patients will be clinically examined including general physical examination, careful examination of the ear, nose and throat and OBGY examination.
Otoscopic examination and tuning fork tests will be performed.
Hearing assessment will be done with MAICOTM MA53 audiometer.
The hearing threshold for pure tone audiometer will be determined in a sound treating room at frequencies ranging from125 to 8000 Hz for air conduction and 250–4000 Hz for bone conduction.
Statistical Methods Used
Data was analyzed using following statistical methods.
Diagrammatic representation.
Mean ± standard deviation.
Chi square test.
Kolmogorov Smirnov test for normalcy of the parameters.
Karl Pearson’s correlation coefficient method to check the correlation.
Results
In the total of 66 patients in this study an age between 18 and 40 years is included in the study. The median age of gestational diabetes mellitus patients was 26 years, with an upswing primarily in the 25–29 age group as shown in Fig. 1 and Table 1.
Fig. 1.
Age distribution
Table 1.
Age distribution
| Cases | Control | P value | Inference | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| MEA | SD | MIN | MAX | MEA | SD | MIN | MAX | |||
| Age | 26.4 | 4.30 | 20 | 37 | 24.7 | 2.99 | 18 | 30 | 0.06 | NS |
In this study 33 cases were included and around 15 patients had normal hearing and the hearing loss was sensory neural in this case group and bilateral SNHL was seen around 17 patients and unilateral SNHL was seen in just 1 patient whereas, in the control group 29 patients had normal hearing and only 4 had unilateral and 1 had bilateral SNHL (Tables 2 and 3) (Fig. 2).
Table 2.
Comparison of hearing loss on both sides
| Type of hearing loss | Cases | Control | ||
|---|---|---|---|---|
| Number | % | Number | % | |
| Normal | 15 | 45.45 | 29 | 85.29 |
| Left SNHL | 1 | 3.03 | 1 | 2.94 |
| Right SNHL | 0 | 0.00 | 3 | 8.82 |
| B/l SNHL | 17 | 51.52 | 1 | 2.94 |
| Total | 33 | 100.00 | 34 | 100.00 |
Table 3.
Frequency distribution of hearing loss
| Frequency | Cases | Control | ||
|---|---|---|---|---|
| Number | % | Number | % | |
| Normal | 15 | 45.45 | 34 | 100.00 |
| High frequency | 18 | 54.55 | 0 | 0.00 |
| Total | 33 | 100.00 | 34 | 100.00 |
Fig. 2.
Type of hearing loss
The Relevance of hearing loss and Gestational Diabetes Mellitus was calculated and compared to controls, the case group has more prevalence of hearing loss and comparison was carried between right and left ear which showed statistically significant hearing loss in the left ear and less significance in the right ear (Tables 2 and 3) (Fig. 3).
Fig. 3.
Correlation of hearing loss in cases and controls
In the case group of 66 patients, 49 patients had normal hearing and 18 patients had SNHL for high frequency i.e., more than 2000 Hz (Fig. 4).
Fig. 4.
Frequency distribution of hearing loss
Discussions
Results of the study showed that there is statistically significant hearing loss associated with Gestational Diabetes Mellitus.
All continuous variables are presented as the mean ± SD and compared using independent t test. Categorical data are shown as percentages and compared using the Chi square test.
Hearing loss is a major health problem affecting the quality of life and performance at workplace. Gestational diabetes frequently precedes type 2 diabetes. Two large meta-analyses on type 2 diabetes development following gestational diabetes report a risk ratio of 7.43 and cumulative incidence rates of up to 70 per cent.
In another study done by Guoju et al. [5] concluded that advancing maternal age is a known risk factor for Gestational Diabetes Mellitus (28–30) and this discrepancy may be attributed to the differences in participants.
In the total of 66 patients in this study, the age between 18 and 40 years is included in the study and a peak of age distribution is seen in the age group around 25–29 (42.4%) years and this is due to the significant relationship between the age and gestational diabetes mellitus. Likewise, a study conducted by Zargar et al. [6], In which they concluded that the age above 25 years was an important risk factor for gestational diabetes mellitus [6].
Out of the 33 GDM patients,15 (45.5%) of them had normal hearing and 18(54.52%) was noted to have Bilateral sensory neural hearing loss (SNHL), all of them had hearing loss confined to high frequency 1 of the patients were found to have unilateral SNHL and none of the patients had conductive hearing loss.
In our present study 17 (51.52%) patients, were found to have bilateral mild SNHL.There was significant hearing loss noted in patients with GDM with the p value of < 0.001. The hearing loss among the right and left ear were P < 0.1709 and P < 0.0067 respectively which showed no significance.
In study conducted by Selcuk et al. [3], high frequency loss was seen in 20 out of 21 GDM patients, 1 ear had both low and high-frequency hearing loss and 12 ears with speech frequency involvement.
In study done by Ozel et al. [4], hearing threshold for all frequencies and speech recognition scores were significantly lower in patients with diabetes mellitus than in control participants [4].
A similar study done by kwatra et al. [7], showed a statistically significant elevation in the mean values of hearing thresholds at frequencies 0.5, 2 and 4 kHz for the study group when compared with the corresponding values for the control group. Most of them had hearing loss of mild degree and had right sided high-frequency hearing loss. In a study done by Biurrun et al. [8], Cases of mild sensory neural hearing loss, mostly at high frequencies with no associated auditory complaints were observed.
In this present study, it is found that there is no positive correlation between advancing age and hearing loss, with the P value of 0.0610. However, in a study conducted by Guoju et al. [5], it’s implied that GDM occurs at an older age and may worsen with age. Study also revealed a tendency towards increased early onset of GDM. In our study most cases of SNHL were detected in age group 25–29years (42.42%), which was statistically not significant (p-value 0.0610). However, we did not observe any association between age and SNHL in the study.
Selcuk et al. [3], concluded their findings that the auditory system requires high glucose levels because of the high energy utilization of its complex signal processing activity [2]. Hearing loss in the context of type 2 diabetes may result from micro angiopathic processes that follow glycoprotein deposition caused by hyper glycaemia in small blood vessels, which affects neurological function. Another study by Kwatra et al. [7] showed correlation between GDM and hearing loss with P value < 0.005.
Framingham trial demonstrated the link between pregnant women's blood glucose levels and hearing loss. In 1997, a study examining the central and peripheral auditory pathways in type 2 GDM revealed that cochlear receptors were the primary target of the study, with central pathways showing no impact [9].
In a study conducted Cayony et al. [10], mild hearing loss was seen in patients.
The hearing loss was common in type 2 DM. Most diabetic patients had mostly bilateral mild to moderate sensorineural hearing loss affecting hearing thresholds in higher frequencies than the healthy controls as assessed by pure tone audiometry [11].
Hearing loss is an often overlooked comorbidity in type 2 diabetes, highlighting the need for regular hearing evaluations and appropriate management. Maintaining strict control of blood glucose levels and hypertension is crucial to reducing the impact of diabetes on hearing function [12].
In a study conducted by Andrea et al. [13], Pregnancy-related changes to hearing tests were observed in 14 out of 15 investigations, with a higher risk in high-risk pregnancies.Some organizations reported a shift in threshold at low frequencies, similar to that of Meniere's illness. They attributed this change to water and salt retention, which is common during pregnancy, particularly in the third trimester.
It can be concluded with this available evidence that for normal inner ear function there should be a good balance between insulin and blood glucose levels [14].
Conclusions
From the observations in the study, we can conclude that Gestational Diabetes Mellitus may lead to hearing impairment similar to what is seen in type II diabetes mellitus as suggested by significant changes seen when the AC hearing threshold values were compared with controls. However, a larger sample size and more similar studies are required to study the cause and effect.
Author Contributions
All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Dr. Shilpa D.Mallapur, Dr. Basavaraj P.Belaldavar, Dr. Yeshita V.Pujar, Dr.Prashant H.Patil, Dr.Neema k. The first draft of manuscript was written by Dr. Shilpa D.Mallapur. Review and guidance were provided by Dr Basavaraj P.Belaldavar and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.
Funding
Nil.
Declarations
Conflict of interest
Nil.
Ethics Approval and Consent to Participate
The study was approved by the institutional ethical committee vide letter no.MDC/DOME/61.
Footnotes
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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