By Janet Raloff, for Science News' Science & the Public Blog
Several government bodies around the world suggest that anyone who uses a cell phone (and these days, who doesn’t) would be well advised to keep a little distance between that phone and their body. And when people need to make a call, they should minimize radiation exposures by phoning only where reception is really good.
In justifying these and other precautions at a Senate Appropriations subcommittee hearing on Monday, several scientists observed that recent studies have begun linking heavy use of cell phones over a prolonged period with an increased risk of cancer. Especially in the head, and on the same side that people normally hold their phones.
Of course, if such a link were robust, cell phones would be sold with little warning labels, much as cigarettes are today. That link is not robust. On the other hand, they argued, it’s also not going away. Quite the contrary.
For instance, Olga Naidenko, a senior scientist with the Environmental Working Group, a research/advocacy organization based in Washington, D.C., led a team that just completed a 10-month analysis of 200 peer-reviewed studies on cell-phone safety.
“We found that the studies amassed during the first two decades of cell-phone use produced conflicting results and few definitive conclusions on cell-phone safety,” Naidenko said. “But, the latest research, in which scientists are for the first time able to study people who have used cell phones for many years, suggests the potential for serious safety issues.”
She and others at the hearing argued that in light of the accumulating—though still far from strong—indications of health risks, people would be wise to adopt the precautionary principle. Israeli physician and cell-phone researcher Siegal Sadetzki put it succinctly: “Better safe than sorry.”
People can and should adopt simple practices that reduce their exposure to cell-phone radiation, said this researcher from the Gertner Institute (affiliated with the Sackler School of Medicine at Tel-Aviv University). Nearly all of the researchers and scientists who spoke at the hearing similarly advocated a precautionary approach.
The lone holdout: Linda Erdreich, who spoke at the behest of CTIA-The Wireless Association®. This international group represents, among others, cell-phone makers and wireless-service providers. Erdreich, a consulting epidemiologist, saw no reason to take precautionary measures, she said, because her reading of the scientific literature suggests wireless phones pose no harm.
“The currently available scientific evidence about the effects of radiation emitted by mobile phones is contradictory,” admits Dariusz Leszczynski of Finland’s Radiation and Nuclear Safety Authority, in Helsinki. “There are both studies showing effects and some studies showing no effect.”
Rather than view this uncertainty as reason for complacency, he says, it makes more sense to consider as “premature” any interpretation that cell phones are safe. In fact, Leszczynski contends, “Current [cell phone] safety standards are not supported by science because of the very limited research on human volunteers and on children.” Rather, he says, “This uncertainty calls not only for precautionary measures but also for further research.”
His agency has issued two cell-phone advisories suggesting what such precautions might include — like limiting children’s use of cell phones. And texting, when possible, instead of actually talking on a cell phone (to keep that phone away from direct contact with the body).
Last year, Sadetzki’s team reported finding a 50 to 60 percent increased risk among certain Israeli adults of parotid-gland tumors (mostly benign tumors of the salivary gland). The affected group: heavy users of cell phones who did not listen to their calls via a hands-free device (such as a wired earphone or wireless ear piece). Writing in the American Journal of Epidemiology, she and her colleagues noted: “A positive dose-response trend was found for these measurements. Based on the largest number of benign PGT patients reported to date, our results suggest an association between cellular phone use and PGTs.”
At the hearing, Sadetzki said her group’s findings were consistent with research by others linking cell phone use for 10 or more years to tumors in the brain and to acoustic neuroma (a benign tumor affecting the nerve that connects the ear to the brain).
In the July International Journal of Oncology, Lennart Hardell and Michael Carlberg of Orebro University Hospital in Sweden reported an update of their cell-phone studies looking at brain-cancer risk. Here, phone habits were analyzed for some 3,600 people, both individuals with cancer and healthy controls. And people who had developed astrocytoma—a type of brain cancer—were five times as likely to be heavy cell-phone users who got their first mobile phone during their teen years, at least a decade earlier. Cordless home phones did not show a similar link.
It may not be surprising that some of these links to cell phone use are only now emerging, Sadetzki said at the hearing, because there can be long latency periods separating exposures to carcinogens and the development of tumors. For instance, she pointed out that the first reports of brain tumors linked to radiation from the atomic-bomb blasts in Hiroshima and Nagasaki didn’t show up until a half-century after the bombings.
“Since widespread cell-phone use began only in the mid-‘90s,” she notes, “the followup period in most published studies is only about 10 years.”
Cell-phone technology “is here to stay,” she acknowledges, so “the question that needs to be answered is not whether we should use cell phones, but how.”
For instance, she noted that the French health ministry has warned against excessive cell-phone use by children because their bodies may still be undergoing developmental changes that render them especially susceptible to radiofrequency emissions. Moreover, cell-phone radiation penetrates their brains proportionately more deeply than it does in adults. The Israeli health ministry recommends that cell-phone users employ speakers, earphones or hands-free technologies and limit use of these phones where reception is weak.
Naidenko has yet another recommendation: “Buy low-radiation phones.” Identifying which emit the lowest radiation can be difficult, she acknowledged. That’s why her group developed a free, interactive online guide that provides manufacturer-stated radiation-emissions values for more than 1,200 different phones.