Study Sparks Debate on Electromagnetic Fields, Cancer Risk

The debate over the risk of cancer resulting from exposure to electrical transmission lines and appliances escalates today with the publication of a controversial new study by UC Berkeley particle physicist David Jackson.

Jackson attempts to rebut earlier studies showing a link between exposure to such electromagnetic fields (EMF) and an increased risk of leukemia and brain tumors in children, and certain other tumors in adults, by comparing the long-term growth of electrical power use with trends in cancer incidence.

He concludes in the prestigious Proceedings of the National Academy of Sciences that the incidence of the cancers in question has not changed despite a 2,500% increase in electricity use since 1940.

But critics charge that his study is supported by a raft of misleading or false assumptions that invalidate its conclusions.

“Intuitively, it sounds logical to look at such data,” said epidemiologist David Savitz of the University of North Carolina. “But there are so many things going on over that period--new drugs, new treatments, new causes of cancer--that it really doesn’t tell us anything.”

“This is a fatuous piece of work,” said cancer epidemiologist Richard Stevens of the Batelle-Pacific Northwest Laboratories. “It’s irritating because, at first blush, it makes intuitive sense to say that, if something is a cause of cancer, cancer rates should go up when its use increases. But based on this data, you couldn’t even show any significant effect of smoking on cancer, much less a more subtle effect like this one.”

“No epidemiologist I know would make this argument,” said Louis Slesin, editor of Microwave News, a newsletter that has provided steady coverage of the controversy over EMF. “This proves only that particle physicists should stick to particle physics.”

Jackson counters: “It takes a physicist to know how to deal with the power data. . . . We’re looking at historic facts, and I am as competent as anyone to deal with that.”

Jackson’s approach is seemingly straightforward. Electric power use has grown from none in 1881 to the point where it is ubiquitous today. In particular, he argues, residential consumption per capita has increased by a factor of 25 since 1940 and exposure to electric fields should have increased proportionately.

That is his first mistake, critics say. “There is no evidence that use of electric power is a good indicator of exposure,” Savitz said. In fact, as population bases have shifted from cities to the suburbs, experts say, exposure has probably been reduced because people live farther from power lines.

Furthermore, noted Stevens, house wiring has changed dramatically in the last 50 years and new wiring methods dramatically reduce stray EMF.

Jackson compares electric power consumption to cancer incidence. He concedes that data collected before 1970 is unreliable and focuses primarily on the last 20 years. The incidence of cancer has gone up over this period, he noted in a telephone interview, “but all of the increase is due to four common forms of cancer--lung, breast, prostate and colon--all of which have causes unrelated to electromagnetic fields. When you take them away, you’re left with only a quarter of a percent increase per year. In particular, if you look at the graph for childhood leukemia, it’s as flat as a pancake.”

But Jackson is wrong on all counts, experts said. “We do not have any idea why those four have been increasing so dramatically,” Stevens said, “and there is a good biological rationale” by which EMF could increase the risk for both breast and prostate cancer.

Furthermore, experts said, the fact that the incidence of a particular form of cancer does not change is largely meaningless. They cite, for example, bladder cancer. A variety of direct evidence indicates that smoking increases the risk of bladder cancer threefold.

“But if you look at bladder cancer incidence since 1930, there has been absolutely no increase in the United States despite the tremendous increases in smoking,” Stevens said. “Mostly, we don’t understand it. There has been less occupational exposure, but that only accounts for a small part of it. Something else has improved dramatically, and we don’t know what.”

The critics who castigated Jackson do not necessarily believe that EMF causes cancer.

“I am not claiming that there are effects,” Stevens said. “I am not an advocate. But I am not neutral on whether (the link between EMF and cancer) should be studied. This definitely should be studied.”