French Interphone Group Sees Brain Tumor Increase
The French Interphone results are out and they are not reassuring.
The French study team, which includes Elisabeth Cardis, who is in charge of the overall Interphone project, has found high rates of brain tumors (gliomas) among heavy cell phone users. It's not a significant result, statistically speaking, but what is noteworthy is that this excess was apparent regardless of the way a heavy user was defined. As the researchers themselves put it: There is a "general tendency" for a greater glioma risk for "long-term users, heavy users [and] users with the largest numbers of telephones."
For example, those who owned more than one cell phone had twice the risk of getting a glioma, as did those who had used a cell phone for the longest period of time (over about four years). Those who were on a cell phone for the longest total amount of time (260 hours or more) had 80% more gliomas, about the same increase as those whose average cell phone call lasted the longest (over five-and-a half minutes). And those who had made the most phone calls (over 5,100) had about 50% more gliomas. In each category, the heaviest user had the highest risk.
There was no elevated risk for the two other types of brain tumors under study, meningiomas and acoustic neuromas.
If the French results hold up, it would indicate that cell phone-induced brain tumors can develop more quickly than current hypotheses suggest. Combined analyses of the Interphone data from five European countries —Denmark, Finland, Norway, Sweden, U.K.— point to a latency of ten years or more for both acoustic neuroma and gliomas. And while a second team led by Sweden's Lennart Hardell and Kjell Hansson Mild have reported a ten-year latency, some of their earlier papers have pointed to shorter latencies (see for instance this 2003 paper).
The new study couldn't shed any light on ten-year tumor risks because the French took to cell phones relatively late. The researchers note that in 1995, five years before the Interphone project began, only 12% of the French population had a mobile phone. As a result, the study included only four individuals with any of the three types of brain tumors among the 350 cases and 455 controls who had used a cell phone for more than ten years. (By comparison, close to 70% of the French population has a cell phone today.)
To be sure, the French Interphone study is limited by the small number of people in the high exposure groups, but it provides yet another "slight hint" —the phrase (euphemism?) used last week by Lawrie Challis— that we may have a major public health problem brewing. Challis, the head of the U.K. mobile phone health research program, was referring to the current state of knowledge upon the release of his latest progress report.
The French team is delaying drawing any conclusions until the release of the complete Interphone results with the combined data from the 13 participating countries. That paper is already years late. The rest of us have no choice but to wait along with them, but this continuing series of "hints" is getting harder and harder to ignore.
The French paper was posted on the Internet on September 10 and will be published in an upcoming issue of the Revue d'Épidémiolgie et de Santé Publique [Epidemiology and Public Health]. The paper is in French with an abstract in both French and English.