INCIDENCE OF CANCER AMONG WORKERS IN NORWEGIAN HYDROELECTRIC POWER COMPANIES

OBJECTIVES - The goal of this study was to examine whether exposure to electric or magnetic fields is related to cancer. METHODS - The study cohort consisted of 5088 men who had worked for at least one year bet ween 1920 and 1991 for any of eight participating companies which prod uce and distribute hydroelectric power in Norway. The occupational exp osure of these workers included extremely low-frequency electromagneti c fields. Incident cancer cases identified from the Cancer Registry of Norway were analyzed on the basis of the standardized incidence ratio with the Norwegian male population as reference. RESULTS - The incide nce of cancer was close to unity for the cohort. The standardized inci dence ratio for lymphoma was below unity, whereas those for leukemia a nd brain tumors were similar to those expected. Calculated cumulative exposure to electric or magnetic fields was not associated with the in cidence of leukemia or brain tumors, but an excess of malignant melano ma was shown for the highest category of magnetic field exposure. An a nalysis of combined possible exposure to oils containing polychlorinat ed biphenyls and exposures to magnetic fields or possible exposure to electric sparks gave standardized incidence ratios of 265 and 280, res pectively, for the higher exposure category. CONCLUSIONS - These resul ts do not support the assumption of a possible association between exp osure to electromagnetic fields and leukemia and brain tumors. The pos sible association between exposure to polychlorinated biphenyls or mag netic fields and risk of malignant melanoma should be further evaluate d in future studies.