Ann Occup Environ Med.  2019 ;31(1):e11. 10.35371/aoem.2019.31.e11.

The effect of diabetes on 4-year changes of hearing thresholds in male workers exposed to noise in a single company: a longitudinal study

• Kim DY
• Kim AR
• Sung JH
• Lee CR
• Lee J

• KMID: 2466055
• DOI: http://doi.org/10.35371/aoem.2019.31.e11

Abstract

BACKGROUND
Recently, several studies have assessed the association between diabetes and hearing impairment. However, the effect of diabetes on hearing impairment is not well known in diabetic patients exposed to noise, a typical cause of hearing impairment. The aim of this study is to longitudinally analyze the effect of diabetes on hearing impairment in workers exposed to similar noise levels from 2013 to 2017 who had experienced little change in their working conditions.
METHODS
The study subjects included 2,087 male workers exposed to noise in a single company and who underwent health examinations at the same hospital in Ulsan city in 2013 and 2017. Hearing impairment was defined that a pure-tone average of pure-tone audiometry (PTA) thresholds at 1,000, 2,000, 3,000, and 4,000 Hz was 25 dB and over in both ears. Statistical analyses were conducted using χ2 tests, ANOVA, and Cox proportional hazard models. We analyzed covariates that might affect hearing impairment, including age; working period; levels of total cholesterol, triglyceride, and serum creatinine; smoking and alcohol history; and noise level.
RESULTS
The average PTA thresholds and their average changes between 2013 and 2017 were significant in the diabetes mellitus (DM) group than those in the normal and impaired fasting glucose group. Among the subjects with the same status of fasting glucose group in 2013 and 2017, the adjusted hazard ratios for incident hearing impairment among those in the DM group compared to normal group were 3.35 (95% confidence interval [CI], 1.54-7.29) in the left ear and 5.66 (95% CI, 2.01-15.98) in the right ear.
CONCLUSIONS
This study suggested that the risk of hearing impairment in the DM group was significantly higher than that in the normal group in both ears, even when exposed to similar noise levels.

Keyword

Diabetes mellitus; Blood glucose; Hearing impairment; Noise; Workers

MeSH Terms

Audiometry, Pure-Tone
Blood Glucose
Cholesterol
Creatinine
Diabetes Mellitus
Ear
Fasting
Glucose
Hearing Loss
Hearing*
Humans
Longitudinal Studies*
Male*
Noise*
Proportional Hazards Models
Smoke
Smoking
Triglycerides
Ulsan
Blood Glucose
Cholesterol
Creatinine
Glucose
Smoke