P212 Cortisol blood level in chronic noise exposed workers

Abstract

Introduction Cortisol is a hormone produced by adrenal glands under the control of pituitary gland which helps the organism to cope with different types of stress. One of these possible stressors might be occupational noise exposure. Our research studied the possible influence of noise exposure on cortisol blood level (CBL) and if noise induced hearing loss (NIHL) may play a role in this relationship. Material and method 118 workers from a silicon carbide facility were initially included of whom 67 completed the study. For each job site noise exposure was assessed and a cumulative exposure was calculated for every subject (number of years spent in the same job x noise level). A complete physical examination, a pre exposure audio-metric test and two blood samples taken at the same time one week interval (one pre noise exposure – afternoon shift; the other post noise exposure – morning shift) were performed. T Test was used to make statistical analysis. Results Mean age = 42.2±6.29 years. Mean exposure time = 16.16±5.41 years. Mean noise level = 84.88±3.71 dB. Mean cumulative exposure = 1,377±470.9 dB-years. Normal hearing (NH) = 33 subjects (49.25%). NIHL = 34 subjects (50.75%). CBL pre exposure = 126.87 µg/l and post exposure = 114.92 µg/l (p = 0.204). CBL in NH subgroup: pre exposure = 110.04±63.35 µg/l, post exposure = 129.44±66.1 µg/l (p = 0.194). CBL in NIHL subgroup: pre exposure = 143.19±59.77 µg/l, post exposure = 100.82±47.24 µg/l (p = 0.000). CBL pre exposure: NH subjects = 110.04±63.35 µg/l, NIHL = 143.19±59.77 µg/l (p = 0.031). CBL post exposure: NH = 129.44±66.1 µg/l, NIHL = 100.82±47.24 µg/l (p = 0.045). Conclusions There was no significant difference in CBL measured pre and post noise exposure in the entire group. However, we found a statistical significant difference in CBL in NIHL subgroup (lower level post exposure). This subgroup also had significant higher values pre exposure and lower post exposure compared to NH subgroup. These findings have to confirmed by more in depth research.