Electric Blankets Don't Cause Cancer, You Fool

Nathan Rodriguez
JOUR 801 – Perlmutter
Data Virus Analysis – 25 September 2006
A. Describe What the Essential Alleged Facts of the Story Are
Although it was tempting to use a subject investigated by the Discovery Channel’s Mythbusters (do goldfish have 3-second memories; does a duck’s quack not echo?), the subject studied is whether there is any validity to the assertion that electric blankets cause cancer.
This story gained prominence in the 1990s through mainstream media outlets, and unnamed “researchers” were usually cited in the allegations. When televised, the stories rarely offered details, and were typically used to fill a ten-second spot before the commercial break. The original and most popular claim first gained traction in 1990 after a study in the American Journal of Epidemiology (hereafter AJE) claimed “electric blankets…were weakly associated with childhood cancer.” The revised version of the tale is that electric blankets cause breast cancer.
B. Build Your Case That the Item is Indeed False
In examining the claim that electric blankets cause cancer, one must first analyze the content of the claim. The fact that the study claims electric blankets were “weakly associated” would imply additional testing is necessary. Indeed, the very next sentence urges this, saying it “warrants further evaluation.” This “further evaluation” has resulted in a near-consensus that human usage of electric blankets does not cause cancer.
In June 1996, the AJE released another study showing “no evidence to support the hypothesis that there is a relation between brain cancer occurrence in children … and exposure from the use of electric blankets.”
Also in 1996, the CA Cancer Journal of Clinicians reported in its review of the literature that “Results have been largely negative. Electric blanket use was not associated with excess risk except in one childhood cancer study where risk of brain cancer was increased in relation to maternal use during pregnancy. In no instance was there persuasive evidence that risk might increase with greater frequency or duration of use.”
In 1998, a large study performed by the National Cancer Institute indicated that a causal relationship between childhood cancer and electric blanket use was “unlikely.” A British study reported by The Lancet in December 1999 also shows “provides no evidence that exposure…increases risks for childhood leukemia, cancers of the central nervous system, or any other childhood cancer.”
With respect to breast cancer risk, in Fall 1998, The Archives of Environment Health reported “there was no increase in breast cancer risk associated with an electric blanket.” This study confirmed additional findings by AJE in September of that year, indicating “these data do not support the hypothesis that electric blanket use increases breast cancer risk.” In July 2000, AJE released another study, and again the “results did not support an association between breast cancer risk and exposure to EMFs from electric blankets.” Finally in August 2002, AJE released another study showing “no link between endometrial cancer and electric blanket usage,” as if to pre-empt a future variation of the claim involving cancer of the uterus.
C. Try to Ascertain the Origins of the Tale
In 1998, the New York Times offered a piece on “Common Myths” regarding the dangers of household appliances. In it, they state that the claim of electric blankets causing cancer stemmed from a single study in 1990 that showed a mild correlation to childhood cancer. As previously discussed, the CA Cancer Journal for Clinicians also performed a thorough review of the literature, and concurred that the 1990 study was the only evidence for the claim.
Subsequent revisions of the electric blanket rumor involve breast cancer. While dozens of television stations reported in 2000 that Yale researchers had debunked the link between electric blankets and cancer, many local news programs had propagated the myth throughout the mid-90s, citing (anonymous) “researchers” and using anecdotal evidence to support their assertion. They would have been better served adhering to the notion that “extraordinary claims require extraordinary evidence.”
Chicago’s WBBM Channel 2 News at Noon reported in August 1996 that “Consumer Reports says that pregnant moms should not use electric blankets.” In December 1997, WLS-TV said “electric blankets may pose risks for pregnant women according to researchers.” WCAU-TV reported in December 1999 that “Tap water and electric blankets may have contributed to a cancer cluster in Toms River, New Jersey.” Finally, WBTV News in May 2000 offers an anecdote as scientifically meaningful as a “four out of five dentists recommend” label: “Researchers say there is a link between EMF and depression…One doctor says he has stopped using electric blankets.”
D. Describe What “Theory” (Belief Systems) the Story Supports
The story that electric blankets cause cancer fits within at least three major theories related to mass communications: Narrative Theory, Source Status Theories, and Cultivation Analysis. Narrative Theory posits that human beings live their life according to the stories they believe, in this case meaning that once a certain percentage of the population “heard,” “read,” or “saw” that electric blankets may cause cancer, they accepted it as fact and stopped using the blankets altogether. Source Status Theory means humans are influenced by the perceived credibility of the source providing the information. When local news networks are quoting sources such as Consumer Reports, it adds a veneer of infallibility to a source (news network) that already has enough credibility to initially draw in viewers. Cultivation Analysis dovetails nicely with this, holding that TV creates a worldview that is shared by those that watch it: most people tend to believe that the stories presented on the news are factual, and follow accordingly.