The Association between Impaired Fasting Glucose and Noise‐induced Hearing Loss

Abstract

The Association between Impaired FastingGlucose and Noise-induced Hearing Loss: Tae-Won Jang, et al. Department of Occupational and Environmental Medicine, Hangang Sacred Heart Hospital, Hallym University College of Medicine, Korea-Objectives: This study was performed to determine whether there is an association between impaired fasting glucose and noise-induced hearing loss. Methods: The study subjects were workers in one automobile manufacturing company. The data were obtained from results of health examinations during 2005 and 2009. The factors analyzed were age, smoking and alcohol history, work duration, environmental noise level, hearing thresholds, blood pressure, serum creatinine, initial hearing threshold and fasting glucose. Results:The hearing thresholds at 4,000 Hz frequencies for both ears were significantly higher in 2009 than those in 2005. The changes in the hearing thresholds of the subjects with an impaired fasting glucose (100-125 mg/dl) and diabetes (≥126 mg/dl) were greater than those of the normal (<100 mg/dl) group. After adjusting for variables such as age, smoking and alcohol history, environmental noise, hypertension and serum creatinine, fasting glucose was found to be a significant variable. Impaired fasting glucose (100-125 mg/dl) was significant (β=1.339, p=0.002) for the right ear, whereas it was not significant (β=0.639, p=0.121) for the left ear. Conclusions: Impaired fasting glucose, as well as diabetes, might be risk factors for hearing loss in individuals with exposure to certain noise levels. The results of this study suggest that impaired fasting glucose should be considered a risk factor for hearing loss. (J Occup Health 2011; 53: 274-279)

Association of hearing impairment with insulin resistance, β–cell dysfunction and impaired fasting glucose before onset of diabetes

“…In a previous study of workers in an automobile manufacturing company, those with IFG had greater incremental change of hearing thresholds than those with normal fasting glucose levels during a 4‐year follow‐up period, suggesting that workers with IFG were more susceptible to noise‐induced hearing loss. In that study, only the 4000 Hz threshold was measured in the workers exposed to occupational noise . A cross‐sectional study using a veteran cohort reported that pre‐diabetes, which was defined as subjects with < 38.8 mmol/mol, showed a tendency to have higher pure‐tone average of thresholds at low to high‐frequency compared to subjects with normal glucose levels, however, no difference remained after adjustment for age.…”

Increased Inner Ear Susceptibility to Noise Injury in Mice With Streptozotocin-Induced Diabetes

“…Another survey observed significant interactions between firearm noise exposure and hearing loss in diabetic patients at 3 kHz (36). Automobile company workers with high fasting blood glucose levels showed significantly higher hearing thresholds at 4 kHz than workers with normal fasting glucose levels (14). These studies and ours suggest that patients with diabetes are potentially more susceptible to noise-induced hearing loss.…”

“…Recently, using a large population-based dataset, Bainbridge, Hoffman, and Cowie concluded that diabetes is an independent risk factor for hearing loss (12). In addition, interactions between noise exposure and diabetes were reported (13,14). …”

Atherogenic Risk Factors and Hearing Thresholds

“…However, studies exploring the direct association between atherogenic risk factors and hearing loss show inconsistent findings: dyslipidemia in terms of elevated levels of total cholesterol, low-density lipoprotein (LDL), triglycerides (TG) and low levels of high-density lipoprotein (HDL) have shown mainly adverse effects on hearing ability [Gates et al, 1993;Suzuki et al, 2000;Shargorodsky et al, 2010] but a gainful effect of high total cholesterol level has also been reported [Jones and Davis, 2000]. A relation between hearing ability and diabetes-related measures has been reported in several studies [Austin et al, 2009;Jang et al, 2011;Akinpelu et al, 2014], which is also the case for smoking [Fransen et al, 2008;Shargorodsky et al, 2010] and high BMI [Fransen et al, 2008;Lalwani et al, 2013]. Other studies, however, have shown conflicting results for these factors [Gates et al, 1993;Shargorodsky et al, 2010].…”