How often has your clock radio awakened you with the distressing news that something you eat, drink, breathe or do has just been shown in a new study to be a serious health hazard? And how often did it turn out to be a false alarm, unsupported by subsequent research?
The American Council on Science and Health, based in New York, recently updated and expanded its popular report, "Facts Versus Fears," reviewing what it considers the greatest unfounded health scares of the last five decades. Although controversy continues to rage about potential risks associated with some of these "scares," including Agent Orange and hormones in beef, most -- including those that resulted in serious economic damage and changes in public policy -- have been soundly discounted by subsequent studies.
The following review of some of the most prominent scares in recent decades serves as a cautionary tale that should help you realize why it is unwise to leap before you look more closely at what any new study actually means.
ALAR In 1989, the popular television show "60 Minutes," the Natural Resources Defense Council and the actress Meryl Streep denounced this chemical used to regulate the ripening of apples as "the most potent cancer-causing agent in our food supply" and said it was a cause of childhood cancer.
The accusation was based on a 1973 study in which a byproduct of Alar caused tumors in mice. The dosage used in the study was eight times greater than the so-called maximum tolerated dose, the amount above which tissue damage occurs even from innocent substances because of the high concentration.
Subsequent tests by the National Cancer Institute and the Environmental Protection Agency failed to show that Alar caused cancer. Only when mice were given extremely high doses, equivalent to 133,000 to 266,000 times the amount a preschool child might consume in a day in apples and apple juice, did any tumors result.
Still, millions of alarmed parents panicked and dumped untold gallons of apple juice and bushels of apples, the apple industry lost about $375 million, the Department of Agriculture lost another $15 million, countless children were given far less nutritious drinks in place of apple juice and Alar was taken off the market by its manufacturer.
Coffee and Pancreatic Cancer
In 1981 in The New England Journal of Medicine, Harvard researchers published an "unexpected" finding linking pancreatic cancer to coffee consumption. Just two cups of coffee a day doubled the risk and five cups tripled it, said the researchers, who estimated that coffee accounted for more than half the cases of this nearly universally fatal cancer.
But the study was designed to look not at coffee but at alcohol and smoking as factors in this cancer, and other researchers who had been studying huge numbers of people had found no such link to coffee. Nor did animal studies disclose any association between coffee and pancreatic cancer. Five years later, the Harvard group repeated its study and failed to confirm its own findings.
In "Facts Versus Fears," the council stated, "This brief scare illustrates the danger of putting too much credence in a single study without analyzing any possible biases or confounding factors."
Electric Blankets
Everyone in modern societies is exposed to electromagnetic fields (EMF's) -- at home, at work and everywhere that electricity is in use. A 1979 report hinted at a possible relationship between childhood cancer and living near high-current residential power lines, and subsequently, electric blankets were singled out as possible risks, because of their nightlong proximity to the body.
In 1990, a study found a modest increase in cancers in children whose mothers had used electric blankets during pregnancy and a lesser increase in children who had used such blankets.
This prompted a warning label on all electric blankets and a redesign of the product that reduced EMF exposure to the background level produced by household wiring.
But subsequent studies have not borne out the 1990 finding, and this year a large National Cancer Institute study concluded that a causal relationship between childhood brain tumors and EMF's from appliances, including electric blankets, was unlikely. Other studies that examined several adult cancers also found no relationship to the use of electric blankets.
Cellular Phones
Like electric blankets, cell phones create EMF's. In 1990, a woman who had used a cell phone extensively for two years developed a brain tumor just behind her right ear, where she typically placed the phone's antenna.
Her husband filed suit against the manufacturer, saying that the phone's EMF's had caused his wife's cancer. In 1993 he appeared on the CNN program "Larry King Live" to proclaim his assertion, which prompted three lawsuits from other cell phone users making similar claims.
In response, the industry paid for independent safety studies, which have yet to clearly link cell phones to cancer. Although it is not possible to prove that EMF's are safe, there is still no convincing evidence of harm from the kind of EMF's that cell phones emit.
While the incidence of brain tumors has risen slightly in recent years, there has been no disproportionate increase in tumors near the ears, despite a meteoric rise in cell phone use.
As the council points out in its report, by far the most serious hazard associated with these phones is their use while driving. Last year a study reported in The New England Journal of Medicine showed that drivers who use cell phones are four times as likely as nonusers to have an accident.
Asbestos in Schools
Asbestos that is contained in a solid substance is harmless. But when it becomes crumbly, airborne and inhaled, it can lodge in body tissues, where it can sometimes cause cancer. Asbestos insulation to protect against fire was required in schools until 1973, when the Environmental Protection Agency banned its use to reduce children's exposure. The 1980's produced two Congressional acts requiring schools to inspect for asbestos hazards and clean them up. Despite the fact that in most schools asbestos levels were extremely low (less than the amount that in 10 years of exposure might cause one additional death in 100,000 over a lifetime -- one-third the risk of being struck by lightning), by 1990 some $6 billion had been spent on asbestos abatement in schools.
Many experts believe that asbestos removal, which increased airborne asbestos, created a far greater hazard to the children, who might have benefited far more had this money been spent on enhancing their education.
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