CORONARY HEART-DISEASES - ASSESSMENT OF RISK ASSOCIATED WITH WORK EXPOSURE TO ULTRALOW-FREQUENCY MAGNETIC-FIELDS

The present analysis was stimulated by previous findings on the possib le influence of natural ultralow-frequency (ULF; 0.001-10 Hz) geomagne tic field variations on the cardiovascular system and indications of a n effect of man-made ULF magnetic fields on the rate of myocardial inf arction. In the present study, we considered the occupational health h azards of the strongest ULF magnetic fields in densely populated urban areas. Measurements of ULF magnetic field fluctuations produced by tr ains powered by DC electricity were performed by means of a computer-b ased, highly sensitive, three-component magnetometer. We found that th e magnitude of magnetic field pulses inside the driver's cab of electr ic locomotives (ELs) could be greater than or equal to 280 mu T in the horizontal component perpendicular to the rails and up to approximate ly 130 mu T in the vertical component, and, in the driver's compartmen t of electric motor unit (EMU) trains, they were approximately 50 and 35 mu T, respectively. We have investigated the relationships between the occupational exposure to ULF magnetic field fluctuations produced by electric trains and cardiovascular diseases (CVDs) among railroad w orkers in the former Soviet Union. We have analyzed medical statistica l data for a period of 3 years for approximately 45,000 railroad worke rs and 4,000 engine drivers. We have also analyzed 3 years of morbidit y data for three subgroups of engine drivers (similar to 4,000 in each group) operating different types of trains. We find that EL drivers h ave a twofold increase in risk (2.00 +/- 0.27) of coronary heart disea ses (CHDs) compared with EMU drivers. Because our analysis of major CV Ds shows that the examined subpopulations of drivers can be considered to have had equal exposure to all known risk factors, the elevated CH D risk among EL drivers could be attributed to the increased occupatio nal exposure to ULF magnetic fields. (C) 1996 Wiley-Liss, Inc.