Bras, deodorant, and mouthwash—just a few of the everyday products that have been linked to cancer at some point during the past several decades. Preposterous? Not at the time, and new suspects have been added to the list. In honor of World Cancer Day, we reveal the real story behind ordinary household items that have come under scrutiny.
The link: Calorie watchers scored a win when diet sodas were introduced in the early 1950s. Then lab studies suggested that the sweetener cyclamate caused bladder cancer in rats, and the U.S. Food and Drug Administration banned its use. Then saccharin, the replacement of choice, was also shown to cause tumors in rats. Although saccharin was never banned, all products containing the sweetener were required to carry a cancer warning on their packaging.
The reality: No evidence has since emerged that either cyclamate, which is used in other countries, or saccharin causes cancer in humans, according to the National Cancer Institute. Although cyclamate is still banned, saccharin was taken off the government's list of possible carcinogens in 2000, the same year in which saccharin products shed the warning label. The sweetener aspartame has come under suspicion, but scientists have found no increased risk of cancer in humans.
The link: A handful of studies since the late '70s have tied mouthwash that contains ethanol to oral cancer. Investigators theorize that it may make oral tissues more vulnerable to known carcinogens, such as those in cigarettes.
The reality: The evidence against mouthwash is weak, according to the American Dental Association. Studies don't show, for example, that brands with higher alcohol content present a greater risk than those with lesser amounts. Mouthwash is safe when used as directed, says the ADA, which, depending on the product, may mean swishing once or twice daily and not swallowing. People who smoke, have a family history of oral cancer, or have other risk factors may want to choose alcohol-free brands to be on the safe side, the ADA says.
The link: Could these cholesterol-lowering drugs raise the risk of cancer? A 2007 study inspired this belief when researchers investigating the side effects of certain statins—lovastatin, simvastatin, pravastatin, fluvastatin, and atorvastatin—found that participants taking high doses were more likely to be diagnosed with various cancers, including those of the breast, colon, and prostate.
The reality: A 2008 review of 15 clinical trials involving statins cast doubt on the initial results; low LDL cholesterol levels, the reviewers found, were associated with cancer, whether or not participants were taking statins, suggesting that cholesterol levels, not the drugs, were to blame. "This study should reassure those taking statins that they are not increasing their risk of cancer by trying to reduce their risk of cardiovascular disease," senior author Richard Karas of Boston's Tufts University School of Medicine said in a statement. A separate review of research involving roughly 170,000 participants found no link between statins and cancer.
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 in 2010, 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.
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.