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TODAY Tuesday 20 January 1998 Each weekday. Conn Nugent on what's new in the world, on the site. |
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TODAY Tuesday 20 January 1998 Each weekday. Conn Nugent on what's new in the world, on the site. |
TODAY IN THE WORLD: Electromagnetic Sleuthing
Most of us are happy enough to bury an environmental health scare. The world has enough worries. It was a relief when a National Academy of Sciences panel reported in 1996 that there was no demonstrable link between proximity to high electromagnetic fields (like power lines) and the incidence of childhood cancers. A limited finding, but it seemed to address the most poignant of EMF anxieties and it certainly seemed to license the jettisoning of further concern about EMF in general. Federal research funds for the study of the health effects of electromagnetic fields are no longer available and the Electric Power Research Institute is winding up its own research program. Anti-regulatory think tanks now cite the worries about EMF as a prime example of environmentalist hysteria at odds with "sound science." The zapping of America has been interred in the burial ground of baseless fears.
Exhume the corpse. There's new evidence that electromagnetic fields do affect health, but in oblique ways through unsuspected channels.
This new evidence is summarized by Janet Raloff in the 10 January issue of Science News. Anyone who follows Janet Raloff's work knows her to be the personification of sobriety, professionally immune to bandwagons. When she says that new studies demonstrate "a hitherto unrecognized responsiveness of cells, tissues, and animals" to the presence of electromagnetic fields, you sit up and check your preconceptions.
Raloff closely describes many of these recent experiments. In one of them, Wolfgang Loescher exposed female rats to varying strengths of EMF. He then injected all of the rats with a uniform dose of a chemical that causes breast cancer. After three months, the rats with the higher EMF exposures showed a higher number of cancerous tumors, and the tumors were up to twice as large as those of the unexposed rats. The exposed rats, Loescher found, had produced less melatonin, a hormone known to suppress breast cancer growth. And the exposed rats also exhibited weakened immune systems. "Loescher focused on the immune system's T cells," Raloff writes, "a class of white blood cells whose role is to attack and destroy tumors and foreign substances. T cells from animals raised for 3 months in 500- or 1,000-mG fields proved only half as likely as those from unexposed rats to proliferate when exposed to a foreign substance." The so-called Melatonin Hypothesis -- that EMFs foster the growth of malignancies by reducing the release of melatonin by the brain -- appears to have gained new respectability.
Other experiments widened the scope of the hypothesis. Test-tube studies indicate that EMF exposures also seemed to make affected cells less sensitive to the melatonin that arrived. "Estrogen-receptors" were altered and suppressed. And overnight exposures of men and women to high EMFs elevated estrogen levels in the women and reduced testosterone in the men -- tendencies linked to breast, testicular, and prostate cancers.
The counter-intuitive kicker to all this is that the most influential variable may not be the magnitude of a field. Loescher found that very high exposures had as little impact as very low exposures. "Only those [fields] across a relatively narrow range consistently foster tumors and other negative health effects," Raloff reports. There are new data that seem to indicate that pulsating exposures may do more harm than steady ones.
There may not be any major funding for this line of inquiry under the heading of "electromagnetic fields," but there's a relatively ample budget for federally-supported research under the heading of "endocrine disrupters." The hunt is on.
TODAY ON THE SITE
For the latest and best summary of what's happening in the weird world of hormones, check into the excellent work of Carolyn Strange in the endocrine disrupters feature of our In The Trenches section. You're also encouraged to wander off the grounds and visit the excellent site maintained by the authors of "Our Stolen Future."
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To access more "Today" columns, click "Archives" below.