ABSTRACT
Noise-induced hearing loss is a major health risk worldwide. Also, noise is one of the commonest physical stressors to which industrial workers are exposed. The objective of this study was to find out whether chronic exposure of workers to loud occupational noise during the daytime would cause changes in their cardiovascular system, stress hormone levels and their hearing thresholds. Thirty eight male marble and granite workers were interviewed, using questionnaires, as regards their medical and occupational history, use of hearing protection and they underwent clinical and laboratory examinations including measurement of blood pressure, ECG and pure-tone audiometry. We assessed noise-induced alterations in physiological stress by measuring serum and urinary levels of cortisol, catecholamines and the lipid profile. In the study areas, the noise levels ranged from 90 to 105 dBA. Results were analyzed and compared with the data of 20 normal persons matched in age, sex and socioeconomic status. Compared to the control group, the exposed workers showed statistically significant noise-induced hearing loss. Noise exposure produced physiological stress responses in workers in the form of significant increase in the serum and urinary cortisol levels after exposure to noise. Also, the exposed group displayed greater serum lipid responses and higher catecholamines levels than their controls. urthermore, blood pressure was significantly higher and ECG changes were more significant among the exposed than the control group. The present data suggest that chronic noise exposure might potentially lead to endocrine dysfunctions. Thus, we can say that workers exposed to loud occupational noise react to the stress and show, in addition to the NIHL, changes in the ECG and development of hypertension which may be attributed to the exposure to noise