Calm Down. Cell Phones (Probably) Don’t Cause Cancer.

Following breathless headlines last week reporting that a new federal study concluded cell phones caused cancer in laboratory rats, health reporters are now lining up to poke holes in the findings and assure us that, yes, cell phones are safe. Probably.

Ars Technica’s Beth Mole writes: “The study, which was not properly peer reviewed—despite what some outlets have reported—is chock full of red flags: small sample sizes, partially reported results, control oddities, statistical stretches, and a slim conclusion.”

So how did this study grab headlines? First, the authors are researchers at the National Toxicology Program (NTP), which years back received millions of dollars from the government to set up this experiment, the largest animal study to date on the subject. In carefully designed and expensive setups, researchers exposed more than 2,000 rats and mice to wireless frequencies using two common signal modulations: Code Division Multiple Access (CDMA) and Global System for Mobile Communications (GSM). In batches of 90, rats got full-body exposure to 900MHz frequencies of both types of signal modulations. Mice received the same treatment, but at 1900MHz frequencies. Exposure came in 10 minute stretches over 18 hours, with a total of nine hours a day, seven days a week. In humans, that would equate to a lot of phone time.

After collecting two years’ worth of data, the researchers are now reporting the results from the rats. In short, the researchers report “low incidence” of brain and heart cancers (malignant gliomas in the brain and schwannomas in the heart) in male rats compared to controls. Female rats showed no increased incidence of cancers at all. The mouse data has yet to be released.

Scientific American’s John Boice reports:

The NTP animal experiment is the best yet conducted, but has serious limitations. The comprehensive reviews by scientists from the National Institutes of Health, attached to the report, are informative with one concluding: “I am unable to accept the authors’ conclusions”.

Consistency (or replication) is the key to interpreting findings. In these data, the results were not internally consistent in that the significant excesses occurred only in male rats and not in the females. Further, it appears that there were no similar effects in mice of either sex. Thus the findings are not replicated in studies conducted by the authors.

David H. Gorski, a surgical oncologist and fervent critic of pseudoscience in medicine directly compared the fears of cell phone-induced cancer to the hysteria surrounding anti-vaccinations. “[F]rom a biological standpoint, a strong link between cell phone use and brain cancer (or any other cancer) is not very plausible at all; in fact, it’s highly implausible,” he writes.