Haemoglobin A1c and hearing impairment: longitudinal analysis using a large occupational health check-up data of Japan

Sensorineural hearing loss among type 2 diabetic patients and its association with peripheral neuropathy: a cross-sectional study from a lower middle-income country

INTRODUCTION

Despite potential links between diabetes and sensorineural hearing loss (SNHL), routine hearing assessments for diabetic patients are not standard practice. Our study aimed to investigate the prevalence of SNHL and its association with diabetes-related factors among patients with type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

This cross-sectional study was conducted at the Diabetes Clinic, Jinnah Postgraduate Medical Centre, Karachi, Pakistan, from May to September 2021. A total of 396 patients fulfilling the inclusion criteria participated after informed consent. Data collection involved a sociodemographic profile, Michigan Neuropathy Screening Instrument examination followed by pure-tone audiometry and laboratory tests including haemoglobin A1C (HbA1c). HL was defined using better ear four-frequency pure-tone average of ≥26 dB HL and graded as per WHO criteria. Statistical analyses were performed using SPSS. χ2, independent t-test and multinomial logistic regression analyses were applied. P<0.05 at 95% CI was considered significant.

RESULTS

Our study revealed a high prevalence of SNHL among patients with T2DM. Mild HL was seen in 55.8%, while 18.7% suffered from moderate HL. Common audiological symptoms included difficulty understanding speech in noisy surroundings (44.2%), balance problems (42.9%), sentence repetition (35.9%), tinnitus (32.3%) and differentiating consonants (31.1%). Hearing impairment predominantly affected low (0.25-0.5 kHz) and high (4-8 kHz) frequencies with a significant difference at 4 kHz among both sexes (t (394)=2.8, p=0.004). Peripheral neuropathy was significantly associated with SNHL on multinomial logistic regression after adjusting with age, sex, body mass index and the presence of any comorbidities. Diabetes duration, HbA1c or family history of diabetes was found unrelated to SNHL severity.

CONCLUSIONS

The study highlights the substantial prevalence of SNHL among patients with T2DM and emphasises the importance of targeted audiological care as part of a holistic approach to diabetes management. Addressing HL early may significantly improve communication and overall quality of life.

Cardiometabolic diseases according to the type and degree of hearing loss in noise-exposed workers

Background

This study aimed to determine the association between cardiometabolic diseases, including metabolic syndrome, hypertension, and diabetes, and the type and degree of hearing loss in noise-exposed workers.

Methods

A total of 237,028 workers underwent air conduction pure tone audiometry in 2015 to assess their health and diagnose cardiometabolic diseases. The study defined metabolic syndrome, hypertension, and diabetes using blood pressure, fasting blood sugar, cholesterol, and triglyceride levels. Mid-frequency hearing loss was defined as ≥ 30 dB at 2,000 Hz, whereas high-frequency hearing loss was ≥ 40 dB at 4,000 Hz. The average air conduction hearing thresholds at these frequencies were used to determine hearing loss degrees.

Results

The odds ratio (OR) of combined exposure to noise and night-shift work in all cardiometabolic diseases was higher than that of noise exposure alone. The risk of cardiometabolic diseases was dose-response, with higher hearing loss causing higher ORs. The ORs of hypertension compared with the normal group were 1.147 (1.098-1.198), 1.196 (1.127-1.270), and 1.212 (1.124-1.306), and those of diabetes were 1.177 (1.119-1.239), 1.234 (1.154-1.319), and 1.346 (1.241-1.459) for mild, moderate, and moderate-severe hearing loss, respectively.

Conclusions

Workers who are exposed to noise tend to demonstrate high risks of hearing loss and cardiometabolic diseases; thus, bio-monitoring of cardiometabolic diseases, as well as auditory observation, is necessary.

Association of TyG index with hypertension in Chinese adults: the China Health Examination Collaborative Study (CHEC Study)

BACKGROUND AND OBJECTIVES

We aimed to investigate the association of triglyceride-glucose (TyG) index with hypertension and compare the discriminative power of the TyG index, lipid, glycemic parameters for hypertension using the China Health Examination Collaborative study (CHEC Study).

METHODS AND STUDY DESIGN

Data were collected at Ningbo Mingzhou Hospital and Beijing physical examination center from the CHEC Study during 2014 and 2021. Participants with ≥2 medical check-up times were included. The TyG index is the logarithmized product of fasting triglyceride and glucose. Generalised estimation equation (GEE) model was used to evaluate the association between the TyG index, lipid parameters, glycemic parameters and hypertension. Receiver operating characteristic (ROC) analysis was performed to explore the predictive ability of TyG index on hypertension at different years of medical check-up.

RESULTS

112,902 participants with an average age of 42.8 years were recruited in the study, 36,839 participants developed hypertension over the 8-year period. GEE model analysis showed that the ORs with 95% CI of hypertension were 3.35 (3.15-3.57), 1.86 (1.76-1.95), 1.67 (1.58-1.78), 1.45 (1.33-1.58), 1.24 (1.19-1.29), 0.92 (0.86-0.99), and 1.90 (1.83-1.97) in the highest versus lowest quintiles of TyG index, TG/HDL-C ratio, TG, TC, LDL-C, HDL-C and FPG in model 2. The area under the ROC curve of the overall years of medical check-up was signifi-cantly higher than a particular year in predicting hypertension (AUC: 0.883, p < 0.05).

CONCLUSIONS

TyG index is associated with hypertension and shows the superior discriminative ability for hypertension compared with lipid and glycemic parameters.

Sex-Linked Biology and Gender-Related Research Is Essential to Advancing Hearing Health

There is robust evidence that sex (biological) and gender (behavioral/social) differences influence hearing loss risk and outcomes. These differences are noted for animals and humans-in the occurrence of hearing loss, hearing loss progression, and response to interventions. Nevertheless, many studies have not reported or disaggregated data by sex or gender. This article describes the influence of sex-linked biology (specifically sex-linked hormones) and gender on hearing and hearing interventions, including the role of sex-linked biology and gender in modifying the association between risk factors and hearing loss, and the effects of hearing loss on quality of life and functioning. Most prevalence studies indicate that hearing loss begins earlier and is more common and severe among men than women. Intrinsic sex-linked biological differences in the auditory system may account, in part, for the predominance of hearing loss in males. Sex- and gender-related differences in the effects of noise exposure or cardiovascular disease on the auditory system may help explain some of these differences in the prevalence of hearing loss. Further still, differences in hearing aid use and uptake, and the effects of hearing loss on health may also vary by sex and gender. Recognizing that sex-linked biology and gender are key determinants of hearing health, the present review concludes by emphasizing the importance of a well-developed research platform that proactively measures and assesses sex- and gender-related differences in hearing, including in understudied populations. Such research focus is necessary to advance the field of hearing science and benefit all members of society.

Estimated Glomerular Filtration Rate and Hearing Impairment in Japan: A Longitudinal Analysis Using Large-Scale Occupational Health Check-Up Data

Several longitudinal studies have examined associations between renal dysfunction and hearing impairment. Here, we explored the longitudinal association between estimated glomerular filtration rate (eGFR) and hearing impairment among the working-age population in Japan. Participants were 88,425 males and 38,722 females aged 20-59 years, without hearing impairment at baseline (2013), who attended Japanese occupational annual health check-ups from 2013 to 2020 fiscal year. eGFR was categorized into four groups (eGFR upper half of ≥90, lower half of ≥90 (reference), 60-89, and <60 mL/min/1.73 m²). Low- and high-frequency hearing impairment were assessed using data from pure-tone audiometric testing. A Cox proportional hazards model was applied to estimate hazard ratio (HR) values for hearing impairment. Low eGFR did not increase the risk of low- or high-frequency hearing impairment. For males, multivariable-adjusted HR of high-frequency hearing impairment was 1.16 (95% confidence interval, 1.01-1.34) for the upper half of the ≥90 mL/min/1.73 m²; however, this positive association between high eGFR and high-frequency hearing impairment did not appear to be robust in a number of sensitivity analyses. We conclude that, among the Japanese working-age population, eGFR was not generally associated with hearing impairment in people of either sex.

Relationship between ideal cardiovascular health metrics and hearing loss: A 10-year retrospective cohort study

OBJECTIVE

The role of ideal cardiovascular health (CVH) metrics in developing hearing loss remains uncertain. Thus, our objective was to analyse the connection between hearing loss and ideal CVH metrics in a 10-year retrospective cohort.

STUDY DESIGN

Retrospective cohort study.

SETTING

A health management centre in Taiwan.

PARTICIPANTS

Participants who underwent the first annual health check-up between 2000 and 2006 and with a follow-up check-up more than ten years later.

MAIN OUTCOME MEASURES

Hearing thresholds were measured at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. Individuals with a best ear pure-tone audiometry four-frequency average of >25 dB HL were defined as having hearing loss. The ideal CVH metrics were classified into 7 categories based on the American Heart Association's definition. The associations of hearing loss with the sum of the ideal CVH metrics and each ideal CVH metric were examined by multiple logistic regression analysis.

RESULTS

The present study consisted of 6974 participants. The 10-year follow-up showed that the odds ratio (OR) of hearing loss was .74 for participants with 5-7 ideal CVH metrics (95% CI, .59-.93, p = .01) compared with those with 0-2 ideal CVH metrics. Among the CVH metrics, participants with an ideal smoking status might have reduced odds of developing hearing loss; the OR was .72 (95% CI, .58-.89, p = .003).

CONCLUSIONS

Participants with an increased number of ideal CVH metrics and better performance on the smoking metric had a significantly protective effect regarding hearing loss development.

Association between serum uric acid and obesity in Chinese adults: a 9-year longitudinal data analysis

OBJECTIVES

Hyperuricaemia has been reported to be significantly associated with risk of obesity. However, previous studies on the association between serum uric acid (SUA) and body mass index (BMI) yielded conflicting results. The present study examined the relationship between SUA and obesity among Chinese adults.

METHODS

Data were collected at Guangdong Second Provincial General Hospital in Guangzhou City, China, between January 2010 and December 2018. Participants with ≥2 medical check-up times were included in our analyses. Physical examinations and laboratory measurement variables were obtained from the medical check-up system. The high SUA level group was classified as participants with hyperuricaemia, and obesity was defined as BMI ≥28 kg/m². Logistic regression model was performed for data at baseline. For all participants, generalised estimation equation (GEE) model was used to assess the association between SUA and obesity, where the data were repeatedly measured over the 9-year study period. Subgroup analyses were performed by gender and age group. We calculated the cut-off values for SUA of obesity using the receiver operating characteristic curves (ROC) technique.

RESULTS

A total of 15 959 participants (10 023 men and 5936 women) were included in this study, with an average age of 37.38 years (SD: 13.27) and average SUA of 367.05 μmol/L (SD: 97.97) at baseline, respectively. Finally, 1078 participants developed obesity over the 9-year period. The prevalence of obesity was approximately 14.2% for high SUA level. In logistic regression analysis at baseline, we observed a positive association between SUA and risk of obesity: OR=1.84 (95% CI: 1.77 to 1.90) for per-SD increase in SUA. Considering repeated measures over 9 year for all participants in the GEE model, the per-SD OR was 1.85 (95% CI: 1.77 to 1.91) for SUA and the increased risk of obesity were greater for men (OR=1.45) and elderly participants (OR=1.01). In subgroup analyses by gender and age, we observed significant associations between SUA and obesity with higher risk in women (OR=2.35) and young participants (OR=1.87) when compared with men (OR=1.70) and elderly participants (OR=1.48). The SUA cut-off points for risk of obesity using ROC curves were approximately consistent with the international standard.

CONCLUSIONS

Our study observed higher SUA level was associated with increased risk of obesity. More high-quality research is needed to further support these findings.

The Association Between Glycolyzed Hemoglobin A1c and Hearing Loss in Diabetic Patients

Purpose

Our study aimed to determine the correlation between glycated hemoglobin (HbA1c) levels and the audiometric parameters in diabetic patients.

Methods

We included 724 patients (376 male, 348 female) in our outpatient clinic and created four groups by reference to the HbA1c values. The first group was 192 patients with an HbA1c value < 4.5, 176 patients with an HbA1c value between 4.5 - 5 as Group 2, 177 patients with an HbA1c value between 5 - 6 as Group 3, and 179 patients that had an HbA1c value greater than 6 as Group 4. The correlations between HbA1c values and median pure tone thresholds at 250, 500, 1,000, 2,000, 4,000, and 8,000 Hz, the speech recognition thresholds, and the speech discrimination scores were compared.

Results

The median speech recognition thresholds, speech discrimination scores, and the median pure-tone thresholds at 250, 500, 1,000, 2,000, 4,000, and 8,000 MHz in the left ear significantly differed in the fourth group (p < 0.001). Pure-tone thresholds at 500 Hz, 4,000 Hz, speech discrimination scores, and recognition thresholds in the right ear had a significant positive correlation in the fourth group (p < 0.001).

Conclusion

According to HbA1c levels, the severity of diabetes can affect high to all frequencies of hearing functions negatively. The follow-up of patients with higher levels of HbA1c should undergo audiological tests more regularly.

Low-Normal Platelets and Decreasing Platelets Are Risk Factors for Hearing Impairment Development

OBJECTIVE

Identification of undefined risk factors will be crucial for the development of therapeutic strategies in hearing impairment. Platelets are likely to affect the development of sudden sensorineural hearing loss, which is a primary risk factor for permanent hearing impairment. This implies that abnormal platelets might contribute to long-term hearing loss. This study investigated the role of platelets in the development of hearing impairment over a 5-year period.

METHODS

This study was a retrospective cohort study and consisted of a population-based survey, which was performed for 1,897 participants in 2014 to 2019. To evaluate the effect of platelet level on hearing ability, the subjects were divided into two groups: a high-normal platelet group (25 ∼ 40 × 10⁴ cells/μL) and a low-normal platelet group (15 ∼ 25 × 10⁴ cells/μL). Subjects were defined as having hearing impairment when pure tone audiometry was over 25 dB HL in either ear (tested in 2017 and 2019). Incidence of hearing impairment was analyzed.

RESULTS

Incidence of hearing impairment at low frequencies was significantly higher in the low-normal platelet group than in the high-normal group year over year. Low-normal platelet count associated with low-frequency hearing impairment (LFHI) incidence (odds ratio [OR], 2.34; 95% confidence interval [CI], 1.15-4.76). In the low-normal platelet group, subjects whose counts declined from baseline developed more LFHI than those whose counts increased over time. Further, decreasing platelets appeared to be an independent risk factor contributing to the incidence of LFHI (OR, 2.10; 95%CI, 1.09-4.06) in the low-normal platelet group.

CONCLUSION

Both a low-normal platelet and a declining platelet count were independently associated with the incidence of LFHI.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:E1287-E1295, 2021.

Association between hypertension, dyslipidemia, and diabetes and prevalence of hearing impairment in Japan

Epidemiological information regarding the relationship between hypertension, dyslipidemia, and/or diabetes and hearing impairment (HI) has been controversial. The present cross-sectional study investigated this issue in Japan. The subjects were 371 men and 639 women aged 36‒84 years. Hypertension was defined as systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg, or current use of antihypertensive medication. Dyslipidemia was defined as a serum low-density lipoprotein cholesterol concentration ≥140 mg/dL, high-density lipoprotein cholesterol concentration <40 mg/dL, triglyceride concentration ≥150 mg/dL, or current use of cholesterol-lowering medication. Diabetes was defined as a fasting plasma glucose level ≥126 mg/dL, hemoglobin A1c level ≥6.5%, or current use of diabetic medication. HI was defined as present when subjects did not respond to a pure-tone average of >25 dB HL in the better hearing ear. Adjustments were made for age, smoking, alcohol consumption, body mass index, household income, and education. The prevalence of HI was 31.5% in men and 20.8% in women. In men, hypertension, but not dyslipidemia or diabetes, was independently positively associated with HI: the adjusted prevalence ratio (PR) was 1.52 (95% CI: 1.07‒2.16). Having at least two cardiovascular risk factors among hypertension, dyslipidemia, and diabetes was independently positively related to HI: the adjusted PR was 1.82 (95% CI: 1.11‒2.99, P for trend = 0.02). Such positive associations were not found in women. Hypertension and having at least two cardiovascular risk factors may be positively associated with HI in men only.

Obesity and risk of hearing loss: A prospective cohort study

BACKGROUND & AIMS

The existing yet limited prospective studies reported conflicting results about obesity and hearing loss. We investigated the prospective association between obesity and hearing loss in a large-scale Japanese working population, as well as the association between metabolic phenotype and hearing loss.

METHODS

The study included 48,549 employees aged 20-64 years and free of hearing loss at baseline. Pure-tone audiometric testing was performed annually to identify hearing loss at 1 and 4 kHz. Cox proportional hazards regression was used to investigate the risk of hearing loss associated with body mass index (BMI) and metabolic phenotype (based on a BMI of ≥25.0/<25.0 kg/m² and presence/absence of ≥2 components of metabolic syndrome, except waist circumference). Baseline and updated information were obtained from annual health checkups.

RESULTS

With a median follow-up of 7 years, 1595 and 3625 individuals developed unilateral hearing loss at 1 and 4 kHz, respectively. The adjusted hazard ratios (HR) for hearing loss at 1 kHz were 1.21 (1.08, 1.36) and 1.66 (1.33, 2.08) for those with BMI 25.0-29.9 kg/m² and BMI ≥30.0 kg/m², respectively, compared to individuals with BMI <25.0 kg/m². For hearing loss at 4 kHz, the corresponding HRs were 1.14 (1.05, 1.23) and 1.29 (1.09, 1.52). Compared with metabolically healthy non-obese individuals, the adjusted HRs for hearing loss at 1 kHz were 1.19 (1.03, 1.39), 1.27 (1.01, 1.61), and 1.48 (1.25, 1.76) for unhealthy non-obese, healthy obese, and unhealthy obese individuals, respectively. For hearing loss at 4 kHz, the corresponding HRs were 1.13 (1.04, 1.25), 1.21 (1.04, 1.41), and 1.26 (1.12, 1.41).

CONCLUSIONS

Overweight and obesity are associated with an increased risk of hearing loss, and metabolically unhealthy obesity may confer additional risk.