Introduction: Noise-induced hearing loss is a serious health issue that affects people
all over the world. Occupational noise-induced hearing loss (ONIHL) is one of the
commonest occupational diseases. Several factors have been revealed to produce
hearing loss including diabetes mellitus (DM). Aim of Work: To study the relation
between type II DM and ONIHL. Materials and Methods: A total of 1292 workers
from 3 companies, occupationally exposed to noise, were categorized into normal and
hearing impairment groups by pure tone audiometry (PTA). The studied group was
subjected to a specially designed detailed questionnaire about noise exposure at work
and hearing problems. Blood pressure, fasting blood sugar, serum urea, creatinine,
and glycated hemoglobin (HbA1c) were measured. Body mass index was calculated.
Results: DM was more frequent among workers with NIHL (13.2%) than those without
(4.8%). Diabetic workers tended to be significantly older than the non-diabetics (50.6
±7.2 compared with 40.9 ± 9.6 years, p < 0.001), they also spend longer time exposed
to noise at work (9.2 ± 6.6 years compared with 6.6 ± 5.7 years, p= 0.002). Both
systolic and diastolic blood pressures were significantly higher among diabetic than
non-diabetic workers. Diabetic workers had a higher loss of hearing levels at all studied
frequencies. By multiple logistic regression analysis, diabetes mellitus, noise exposure
years, and age were significant predictors of NIHL. Glycated hemoglobin (HbA1c)
had a significant positive correlation with the overall hearing loss. Conclusion and
Recommendations: Diabetes mellitus increase the risk of developing noise induced
hearing loss among workers exposed to noise at the workplace. Diabetic workers in
noisy occupations should undergo frequent audiological assessments, should have
easier access to healthcare facilities and their blood glucose levels checked regularly
including HbA1c testing.