In 2011, the World Health Organization's International Agency for Research on Cancer published the Interphone Study, which was conducted to figure out if mobile-phone use increases the risk of brain tumours. The researchers interviewed participants over five years using a very detailed questionnaire. While the majority of the roughly 14,000 respondents showed no increased risk of brain cancer or benign brain tumors over the course of 10 years, the results differed slightly for the heaviest 10% of callers. The study suggests that users with the highest number of total recalled hours spent on phone calls may have had a slightly higher rate of glioma, a cancerous tumor that develops on the brain or spine. What’s more, the glioma was more likely to show up in the temporal lobe, right by the ear. And, both glioma and meningioma, an often benign brain tumor, were more likely to show up on the same side of the brain that people usually used their phone on. The study also indicated another type of tumor, one that develops on the nerve connecting the ear to the brain, was more likely to occur on the same side of the head where a cell phone was usually used.
While this information would typically help prove correlation, inconsistencies led scientists to believe the possible connection was due to reporting bias. For instance, a woman with a brain tumor on her left lobe might believe she used her cell phone more often on her left side, whether or not she actually did. It should also be noted that the study participants were only estimating the duration they spent on phone calls and not exact call times.
This is a fiercely debated topic, yet it can be difficult to find people in the scientific community willing to speak on the record about it because, as one official told me, “scientific studies take time” and “governments don’t speculate.” The World Health Organization offers equally vague answers on its website. “Because many cancers are not detectable until many years after the interactions that led to the tumour, and since mobile phones were not widely used until the early 1990s, epidemiological studies at present can only assess those cancers that become evident within shorter time periods,” writes E. van Deventer, team leader of their Radiation Programme in the Department of Public Health, Environmental and Social Determinants of Health. Okay, now we’re getting somewhere — cell-phone-related studies need more time.
“However, results of animal studies consistently show no increased cancer risk for long-term exposure to radio-frequency fields,” says Deventer. So, then there’s no real connection between cancer and cell-phone use? “Based largely on these data, IARC has classified radio frequency electromagnetic fields as possibly carcinogenic to humans (Group 2B), a category used when a causal association is considered credible, but when chance, bias, or confounding cannot be ruled out with reasonable confidence,” he writes. It’s important to note that Group 2B means the jury is still out on the substances. As a point of reference, caffeic acid found in coffee is also listed in the 2B category. Still, we’re left wondering: Do cell phones cause cancer or not?
“I would certainly not argue that all of the evidence is 100% convincing [in proving a connection between cell phone use and cancer]," says Carpenter. "But, I think if you read those reports coming elsewhere, they don’t deny that’s there’s evidence for harm. They often say, 'Well, it’s not conclusive.' What do they mean by 'conclusive'? One-hundred-percent proof? That’s not the appropriate standard.” So, while many scientists are pretty sure talking on your cell phone won’t cause cancer, they can’t say that without a shadow of a doubt. That’s why they continue to study cell-phone use. But, it will be a while before we have any definitive answers.
A very recent study conducted by the Mobile Telecommunications and Health Research (MTHR) program out of the U.K. found no health risks associated with cell phone use in an 11-year period. Like the Interphone Study, the MTHR report relied heavily on participant memory, which can be flawed. Still, the report was exhaustive, testing not only the effect of cell phones, but also the effect of cell towers on both on human health and fetal health. While the report is confident that cell phones won’t make you sick, it recommended a follow-up study to see if any symptoms pop up beyond a 10-year period.
That study, called COSMOS, is currently tracking 290,000 mobile users over an extended period of time and hopes to resolve uncertainties related to long-term use. While more research is needed — and underway — the best, current studies we have don't show a substantial risk. Until better data is in, it's not unreasonable to take some precautions, like texting instead of calling when you can. But, really, when was the last time you used your cell to actually call a friend, anyway?