Excellent article by Melinda Wenner, frequent contributor to Scientific American
on cell phones and brain tumors.
Posted by Cindy Sage to firstname.lastname@example.org
Does radio frequency radiation pose a cancer risk? Researchers in the largest study to date won”t say
by Melinda Wenner
illustration by Errol F. Richardson
Published in the September 2008 issue.
Daniel Shattuck calls himself a soldier, and you might assume as much from his shaved head and six-foot, 210-pound frame. But he”s never been in the armed forces. Instead, Shattuck has been reluctantly drafted to fight against something in his own body: a malignant brain tumour. “To me, it”s a war,” he says. “I”m at war with this thing every day.”
Although Shattuck doesn”t know for sure what caused his tumour “” he”s asked his doctor “a thousand times” but says he”s never received a clear answer “” he certainly has a theory: he worked as an operator and then as a technician for a phone company for thirteen years, and regularly used a cellphone for a good ten of them. Three of his former co-workers also have malignant brain tumours, and he suspects their cellphone use, too, is to blame.
Shattuck isn”t alone in worrying about the effects of the devices. In May, speculation swirled that Massachusetts senator Edward Kennedy”s brain cancer was linked to habitual cellphone use. Picking up on the rumours, cnn”s Larry King Live devoted a show to the subject. On it, the neurosurgeon who treated US attorney Johnnie Cochran”s brain tumour in 2005 said he would not rule out a link between cellphones and cancer. An issue that won”t go away had resurfaced, and concern over cellphones causing or contributing to brain tumours went mainstream again.
The wireless industry adamantly denies the association. “The overwhelming majority of studies that have been published in scientific journals around the globe show that wireless phones do not pose a health risk,” says a spokesperson for the ctia, a heavyweight international organization that represents the trillion-dollar wireless industry. Many scientists agree: the literature shows little evidence of a problem.
But what if the published science doesn”t reflect what”s really happening out there? And what if there has been a concerted effort to shield us from the evidence that does exist? Accounts from a handful of well-respected scientists suggest that since the mid-1990s wireless companies have been doing their best to bury worrying findings, discredit researchers who publish them, and design experiments that virtually guarantee the desired results. “Biological effects are undoubtedly there, no question, and it”s a canard to suggest that they”re not,” says Abe Liboff, a research professor at Florida Atlantic University, and co-editor of the journal Electromagnetic Biology and Medicine. The cellphone industry, he insists, “will use any excuse to avoid the truth.”
Even so, a new possibility is emerging. Although cellphones appear to be safe when used sporadically, individuals who use them frequently for more than a decade may be vulnerable. Eight population-based studies published since 1999 indicate that heavy users are twice as likely to develop certain types of brain tumours as infrequent users. Citing recall bias and memory loss on the subjects” parts, critics reject such suggestions. Still, since cancer often takes decades to develop, other scientists wonder whether these findings are the first faint whispers of a public health crisis. After all, with an estimated three billion users around the world, cellphones have become ubiquitous.
In 1995, Jerry Phillips, a biochemist at the Pettis Veterans Affairs Medical Center in Loma Linda, California, received a call from the head of his biomedical research group. He and his co-workers were doing contract work for Motorola and the US Department of Energy on the effects of electromagnetic radiation, and Motorola, he says, needed a favour: higher-ups had learned of a study just published by University of Washington scientists Henry Lai and N. P. Singh showing that radio frequency fields similar to those emitted by cellphones damaged rats” brain cells, breaking their dna structures after just two hours of exposure. The company, Phillips says, wanted to discredit the study.
To Motorola, it didn”t make sense that a cellphone could break dna. The ionizing radiation of X-rays and atomic bombs has enough energy to knock around electrons and cause genetic damage. But the radiation emitted by cellphones is non-ionizing, similar to radar, and thought to be too weak to do genetic harm. That is, while cellphone radiation fits within the microwave spectrum, it emits too little energy to significantly heat tissue. So how could cellphones, Motorola”s reasoning went, possibly affect or harm the brain?
Nonetheless, Lai”s research suggested they could, and his paper worried Motorola. Phillips recalls that the company asked him to “find ways to put a spin on it that was favourable to them and less favourable to Henry and N. P.” He declined, but did agree to provide Motorola with comments on the study, and to conduct a similar trial if they were interested.
They were. Phillips designed a comparable experiment to investigate how radiation emitted by cellphones affected dna in cells. He tested two slightly different radiation frequencies and exposure times, and found that in both cases the radiation did affect the cells” dna, albeit in significantly different ways: sometimes it increased the base level of dna damage typically seen in cells, and sometimes it lowered it. He wrote a report and sent it to Motorola with a note saying he wanted to publish the results and, if the company would fund him, design studies to further investigate his findings. A few days later, Mays Swicord, the director of electromagnetic research at Motorola, called him.
“He started questioning a lot of the results, pointing to what he called “inconsistencies in data,”” Phillips recalls. “I pointed out that it”s not unusual to see, with a single chemical agent, results go in one direction for one time period, and in the opposite direction for another.” Phillips went on to explain to Swicord that long or heavy exposure to a toxin can initiate a cell”s repair mechanisms, immediately fixing the damage. A shorter or lighter exposure might cause damage, but not enough to trigger the same repair mechanisms. In this manner, paradoxically, the lighter dose might be more dangerous.
Swicord, who has a background in bioelectromagnetics, wasn”t convinced. “He suggested that I consider not publishing anything and that I do more work,” Phillips says. “And I said no. I know when the project is done. I”ve been doing research for twenty-five years.”
Their argument went on for weeks. Eventually, says Phillips, the head of his research group, Ross Adey, phoned him. Apparently under a lot of pressure, and worried that his group might lose Motorola”s financial support if he didn”t cooperate, Adey, says Phillips, “told me that if I didn”t give Motorola what they wanted, it could be detrimental to my career.” Phillips wouldn”t back down. “This isn”t about the group. It isn”t about money,” he told Adey. “It”s about science.”
Phillips refused to work on any further Motorola-funded projects, and in 1998, in the peer-reviewed journal Bioelectrochemistry and Bioenergetics, he published his dna study, which would be one of his last. That same year, the Department of Energy stopped funding the group”s work on electromagnetic radiation effects. Phillips left Loma Linda and moved to Colorado Springs. Today he”s the director of the Science/ Health Science Learning Center at the University of Colorado.
Lai, the soft-spoken University of Washington scientist who published the study that inspired Phillips” research, has also felt outside pressure. In a 1994 Motorola memo “” obtained and published by the New York””based Microwave News “” a corporate communications employee discussed how the company could discredit Lai”s findings. The memo concludes, “I think that we have sufficiently war-gamed the Lai-Singh issue, assuming the Scientific Advisory Group and ctia have done their homework.”
Shortly thereafter, an anonymous call was made to the National Institutes of Health, the agency funding Lai”s work. The person charged that Lai was performing experiments outside the scope of his grant. The nih looked into the allegation but told Lai to continue his research. Then, he says, the scientific advisory group created by ctia to manage $25 million (US) in industry-donated research money sent a letter to the president of the University of Washington demanding that Lai and Singh both be fired. Lai wasn”t, but soon after, all non-industry funding for related research dried up in the US. Like Phillips, he left the field.
Swicord, now semi-retired, admitted in an interview that he asked Phillips to collect more data, but insisted that Motorola eventually encouraged him to publish his findings. Similarly, the Motorola spokesperson acknowledged the “war game” memo, but told me that the company and the wireless industry in general have “demonstrated a strong commitment to high- quality research in the area of the safety of radio waves.”
The industry has indeed funded a number of trials on the potential effects of cellphone radiation, but the results of those studies differ markedly from those funded by the government or other public agencies. In short, industry-funded research tends to show no cause for concern; the findings of other studies suggest a need for precaution.
In a paper published last year in Environmental Health Perspectives, Swiss researchers reported that of the studies published between 1995 and 2005, which investigated whether controlled exposure to radio frequency radiation affected humans, 82 percent of those funded by public agencies, and 71 percent of those funded by a combination of industry and public money, reported that there were effects; only 33 percent of the solely industry-funded studies did. The authors point out that scientists funded by public agencies may have an interest in finding a response in order to secure additional funding, but Lai doesn”t buy this argument. Having shifted his research focus to finding cancer cures, he still follows the literature on cellphones, and has done his own analysis of 336 published papers. Industry-funded studies, he says, are roughly twice as likely as government-funded ones to conclude that cellphones are harmless. Phillips is also convinced that the industry either cherry-picks its data or designs studies to show nothing. “A lot of the studies that are done right now are done purely as PR tools for the industry,” he says.
Recent epidemiological (population-based) studies comparing the cellphone habits of people with brain tumours to healthy individuals suggest that the frequency “” and length “” of use may indeed play a role in tumour development. “There”s no indication, for people who use their phones for less than ten years, of an association between mobile phone use and these particular cancers,” says Lawrie Challis, former chairman of the UK”s Mobile Telecommunications and Health Research Programme. But “knowing what happens in the short term tells you nothing about what happens in the long term.”
Indeed, of thirteen epidemiological studies published since 1999 on cellphone use for more than ten years, eight suggest a two- to threefold risk increase.
Just the same, it”s hard to publish convincing results from studies like these. For one thing, cellphones have only been popular for a decade or so, making it difficult to find enough subjects who”ve used them for long periods of time. Add to this the fact that brain tumours are rare, and it becomes almost impossible to produce data that show definitive statistics. Of the eight epidemiological studies that suggest a positive association, for instance, only three are large enough to be considered “statistically significant.”
One way to circumvent these problems and acquire enough reliable data is to pool results from multiple trials. This is the idea behind Interphone, the largest study of its kind to date, coordinated by the International Agency for Research on Cancer in Lyons, France. Led by Canadian scientist Elisabeth Cardis, the project has analyzed some 6,400 tumours in thirteen countries. Here, too, however, mystery abounds. While results from some of the individual countries have been published, the pooled results “” scheduled for release in 2006 “” have not; Cardis says, “The interpretation isn”t clear.” In the January/ February issue of Microwave News, editor Louis Slesin writes, “The code of silence about Interphone must end. Public health demands it.”
Early this year, Siegal Sadetzki, a scientist at the Chaim Sheba Medical Center in Israel, and a participant in the Interphone study, published her country”s arm of the findings. Their report suggests that heavy cellphone users have a 50 percent increased risk of developing parotid gland tumours near the side of the head against which they hold their phones. “Significant risk is shown, and we should take this into consideration, because this technology is really, really, really prevalent,” she says.
While Sadetzki advocates caution (noting “usually it takes a long time to develop solid cancers; ten years is really only the minimum”), others maintain that a two- or threefold increase actually does not represent a large overall risk. Malignant brain tumours are rare “” about one in 14,000 North Americans is diagnosed with one each year “” and even a doubling of the risk for individuals who use cellphones for a decade means only about one in 7,000 people. But what about those who use cellphones for thirty years, or kids who start using them when they”re eight? No one knows.
Clearly, epidemiological studies in which scientists monitor the health and cellphone habits of large groups of people over extended periods of time are required. Properly constructed, such studies would solve problems of memory loss, recall bias, and other research-related challenges.
If the debate over whether cellphones are harmful is controversial, how they might be is even more so. Because cellphone radiation can”t knock around electrons enough to cause dna damage or heat tissue, its biological effects are probably due to something heat independent or “non-thermal.” However, no one knows yet how the radiation could do this, and many dispute that it does. Of the approximately 400 laboratory studies that have investigated whether exposure to radio frequency radiation affects dna in cells and/or animals, only about half report any effects.
Leif Salford, chair of neurosurgery at Lund University in Sweden, has repeatedly shown that exposure to two hours of cellphone radiation opens the bloodbrain barrier and causes brain-cell damage in rats. Other studies have shown that radiation affects biological pathways important for metabolism and stress responses. But what does this have to do with cancer? Although cellphone radiation, unlike uranium or plutonium, may not be powerful enough to cause tumours directly, it might, as Jerry Phillips suggests, indirectly lead to cancer by preventing dna repair mechanisms from working properly, and by producing free radicals, highly reactive molecules that can interact with dna in cancer-causing ways.
It may also be that cellphones don”t seed new tumours, but instead promote or accelerate the growth of existing ones. In other words, cellphone radiation could be what is called a “tumour promoter,” which would require less energy than tumour initiation. (Also, as people are already being bombarded by dozens of known environmental carcinogens, something that helps cancers grow is potentially a big problem.) In the first study Phillips conducted for Motorola, he used a chemical to make a tiny tumour and then looked at how radio frequency fields influenced its growth. “It did appear that these fields could affect already initiated tumours,” he says. According to University of Massachusetts Amherst toxicologist Edward Calabrese, animals and cells respond differently and inconsistently to low-level toxic exposures, so varied findings are not surprising. At low levels, he says, the way a body reacts to exposures can be counterintuitive, just as in Phillips” experiment, where low exposures appeared to cause more damage than higher ones.
Probing these issues requires funding, but outside of the Interphone study interest seems to be flagging. The US government, which didn”t participate in Interphone, has not announced any plans to fund epidemiological studies. The National Toxicology Program has provided $22 million (US) for a series of trials to be performed at the Illinois Institute of Technology, but these animal studies will investigate only whether healthy rats and mice exposed to cellphone radiation develop brain cancer “” and they may not, if cellphones are only tumour promoters.
This is certainly not the first time a ubiquitous product has become a potential public health threat, and the big question is, how will it all play out? The cellphone industry could follow in the steps of Big Tobacco and continue to cast doubt on legitimate studies. Or it could adopt the science-minded approach of the automobile industry, which has responded to obvious public health dangers by engineering new technologies “” the airbag, for instance “” that minimize risk and attract the public”s support.
In this era of Hollywood celebrities weighing in on international affairs, perhaps a media luminary like Larry King will call for long-term epidemiological research on the effects of habitual cellphone use. Or maybe good soldier Daniel Shattuck will discover the truth and broadcast it broadly; maybe he”ll find a less hesitant doctor.Leave a reply →