The link: In 1993, a man suing the manufacturer of his wife's mobile phone claimed on Larry King Live that the device was responsible for her brain cancer. The broadcast provoked a public outcry, a rash of similar lawsuits, and millions of dollars poured into studying whether radio waves emitted by cell phones could be harmful.
The reality: The largest study to date, published last spring, could neither confirm nor dismiss a connection between cell phones and cancer. Scientists tracked nearly 13,000 adults for a decade and found a slightly higher rate of one of four cancers—gliomas, a particularly aggressive variety of brain cancer—among frequent cell users. But cell users overall had a lower rate of the cancers than never-users. Participants gave their own estimates of how much time they spent talking, which may have muddied the results. Researchers have now embarked on an even larger study in Europe.
Antiperspirant and Deodorant
The link: A decade ago, an E-mail warning women that using antiperspirant could cause breast cancer went viral. Since then, some research has suggested that aluminum in antiperspirants and preservatives called parabens in both antiperspirants and deodorants mimic the hormone estrogen, which in high amounts can increase a woman's breast cancer risk.
The reality: There is no evidence that antiperspirants or deodorants cause cancer. Although a 2004 study heightened concern when researchers found parabens in breast cancer tissue samples, suggesting the chemicals may have caused the tumors, the investigators did not check for the presence of parabens in healthy tissue. Evidence suggests that 99 percent of us are exposed to parabens from numerous sources, including various cosmetics and foods, according to the American Cancer Society. Little evidence indicates they may be harmful. The organization says more study is needed to be certain that there is no risk. A 2002 study of hundreds of women with and without breast cancer, found no sign the antiperspirants or deodorants upped cancer risk.
The link: Women got a shock in 1995 when "Dressed to Kill," written by a husband and wife team of medical anthropologists, alleged that those who regularly wore bras had a much higher risk of cancer than women who didn't wear them. They theorized that bras promote the buildup of cancer-causing toxins in the breast.
The reality: Experts stress that a link between bras and breast cancer has never been proven. Considerable evidence points to other variables affecting a woman's risk of breast cancer, such as weight, age, and family history. Women who don't wear bras tend to weigh less or have less dense breast tissue, both of which reduce breast cancer risk. Those factors alone, according to the American Cancer Society, "would probably contribute to any perceived difference in risk."
The link: In 2008 researchers from the World Health Organization's International Agency for Research on Cancer (IARC) revived concern of a hair dye-cancer connection after finding a pattern of bladder cancer in male hairdressers and barbers. They found too little evidence to say whether people who used the products every so often at home were also at risk.
The reality: The IARC finding was based on studies conducted at different times, so any increased risk could result from heavy exposure to chemicals that were discontinued decades ago after scientists discovered they caused cancer in rodents. It's unclear whether the chemicals used in current dyes cause cancer, according to the National Cancer Institute. Most evidence, however, does not support a link.
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