Long-term exposure to electric fields. A cross-sectional epidemiologic investigation of occupationally exposed workers in high-voltage substations.

Abstract

In the present epidemiologic study, 53 workers with a long-term (> 5 yr) exposure to the electric field of 400 kV substations were examined and compared with a matched reference group of 53 nonexposed workers from the same power companies. Matching variables included age, geographic location and employment time. The possibility of persistent, chronic health effects in the exposed group as a consequence of exposure was investigated. The investigation included the nervous system (neurasthenic symptoms, psychological tests and EEC), the cardiovascular system (symptoms, blood pressure and ECG), and the blood (Hb, red blood cells, reticulocytes, white blood cells including differential count, thrombocytes and sedimentation rate). Fertility was also assessed. There were no differences between the exposed and reference groups as a consequence of the long-term exposure to the electric fields. The groups differed in that the exposed group had consistently better results on the psychological performance tests; a fewer number of children, especially boys and somewhat higher education. The differences in test results were due to the higher education among the exposed. The difference in number of children was apparently related to factors other than exposure since it was present 10-15 yr before the work in 400 kV substations began.