Epidemiological and clinical study of subjects occupationally exposed to noise

The role of occupational exposure to noise as a cardiovascular risk factor has not been established sufficiently. The present study investigated the blood pressure (BP) and electrocardiographic (ECG) changes in subjects exposed to different degrees of noise. The first group, comprising 105 males with a mean working life of 20.9 years, was occupationally exposed to mean 93 db(A). The second group, comprising 311 subjects, with a mean working life of 20.2 years, was occupationally exposed to a lower level of noise (15% on average). A control group included 150 clerical workers with a mean working life of 19.7 years not exposed to noise at work. The prevalence of hypertension in differences are statistically significant ( p <0.02). The prevalence of orthostatic hypotension was significantly higher in the noise-exposed groups than in the controls (p<0.05). The incidence of electrocardiographic abnormalities in the three groups was 21.9%, 10.9%, and 7.9%, respectively, ( p <0.01). These data demonstrate that subjects occupationally exposed to noise are at higher risk for developing certain cardiovascular disorders. The noise-related risk correlates with the intensity of noise and the duration of exposure.