The Effects of Chronic Industrial Noise Exposure on Urinary Cortisol, Fatigue, and Irritability : A Controlled Field Experiment

The measurement of cortisol in saliva provides the basic scientist as well as the clinician with a reliable tool for investigations of hypothalamus-pituitary-adrenal axis activity. Since saliva samples can be obtained stress-free and independent from medically trained personnel this method may be well suited for use in psychobiological studies. This overview intends to give a comprehensive introduction to the method of salivary cortisol assessment and to briefly discuss its application in different scientific disciplines.

The role of noise exposure in the etiology of high blood pressure is unclear. A cross-sectional study of occupational noise exposure and high blood pressure was conducted in March 1981-August 1982 in a group of blue-collar workers from a noisy (greater than or equal to 89 dBA) and a less noisy plant (less than 81 dBA). There were 197 randomly sampled men from the noisier plant and 169 from the comparison factory. Clinical examinations, audiograms and a psychologic inventory were conducted. Body mass index, alcohol intake, and family history of hypertension were comparable for the two groups. There was no difference in mean systolic or diastolic blood pressure between workers in the two plants. There was, however, a strong relationship between severe noise-induced hearing loss (greater than or equal to 65 dBA loss at 3, 4, or 6 k Hz) and high blood pressure (greater than or equal to 90 mmHg diastolic or taking blood pressure medication) in the 56+ age group in both plants after adjusting for risk factors (p less than 0.02). Multiple regression analysis revealed that in the noisier plant, body mass index, severe noise-induced hearing loss, and noisy hobbies explained a significant amount of the variation in diastolic pressure (p less than 0.05) R2 = 0.19. This suggests that there may be a population at increased risk for hearing loss and high blood pressure.