More on leukemia and electrical workers.

Three years ago, Washington State epidemiologist Samuel Milham Jr. reported a provocative study linking death from leukemia with employment in professions that suggested possible exposures to high electric and magnetic fields (SN: 8/21/82, p. 123). Two additional suggestions of such a link now appear in the April 6 LANCET.

The first involves a study of 546 men in New Zealand who were identified as leukemia patients between 1979 and 1983. Each was matched, based on age and year of cancer registration, with four other men from that nation's cancer registry. The study found a significant excess of leukemias among those electrical workers who had been employed as electronic equipment assemblers (4 cases where only 0.5 cases would have been expected) and radio and television repairers (7 cases where only 1.5 cases were expected). The number of cases involved was too small to permit an investigation of risks for specific leukemia types, according to N.E. Pearce and his colleagues at the Department of Community Health, Wellington Clinical School and National Health Statistics Centre in Wellington, New Zealand. However, they conclude, the findings do suggest that electrical workers are at increased risk of developing the cancer.

The second report is by Milham, who works with the Department of Social and Health Services in Olympia, Wash. Responding to an amateur radio operator's request, he investigated what proportion of male members of the American Radio Relay League--amateur radio operators--died from leukemia. Focusing on deaths occurring between 1971 and 1983, he obtained death certificates for 95 percent of the 296 deceased Washington members and 86 percent of the 1,642 deceased California members. Of the total of 24 leukemias identified in this way, 16 were of the myeloid class (originating in a type of white blood cells called granulocytes)--nearly triple the 5.7 deaths that would have been expected from these leukemias.

Acknowledging that this excess might be attributable to chance, Milham does point out that three other recent studies in the United States and United Kingdom have "revealed a tendency toward a relative increase in the acute myelogenous type of leukemia in electrical workers." In his study, 11 of the 16 myeloids were of the acute form--almost a tripling of the 3.8 cases that would have been expected.