Mobile phones may present a cancer risk after all.
Epidemiologists at the Karolinska Institute in Stockholm have found that the phones can increase the incidence of acoustic neuromas, benign tumors of the auditory nerve. The nerve is exposed to radiation during the normal use of a cell phone. Those who used mobile phones for at least ten years, had close to twice the risk of developing acoustic neuromas, according to a team led by Prof. Anders Ahlbom, the deputy director of the Karolinska’s Institute of Environmental Medicine.
For those acoustic neuromas that were on the same side of the head as the phone was used, the risk was even higher —approximately a fourfold increase compared to controls, a statistically significant finding.
“These are strong data,” Ahlbom told Microwave News in a telephone interview. “Just how strong will be determined in the upcoming post-publication assessment,” he added. The new study, which appears in the November issue of Epidemiology, is part of the 13-nation Interphone study coordinated by the International Agency for Research on Cancer (IARC) in Lyon, France.
These findings will be formally announced at a press conference in Stockholm today, Wednesday, October 13.
Acoustic neuromas account for less than 10% of all brain tumors. Approximately 1 in 100,000 people develop this type of cancer. All the Interphone study teams, including Ahlbom’s, will also report on the risk of the most common types of brain tumors —for instance, astrocytomas and meningiomas. Ahlbom declined to reveal his results for the other types of brain cancer, but he did say that, “If acoustic neuromas are possible, then the argument that effects are biologically implausible does not apply, and we don’t know what is possible.”
“This is just the tip of the iceberg,” said Dr. Sam Milham, an epidemiologist who has worked on electromagnetic radiation effects for over 20 years. “If cell phones can cause acoustic neuromas, they can also cause all the other types of brain tumors,” he told Microwave News.
The new Swedish findings support earlier work by Prof. Lennart Hardell and Kjell Hansson Mild of Sweden’s Öreboro University. In a paper published two years in the European Journal of Cancer Prevention, Hardell and Mild reported a close to doubling of all types of brain tumors among those who had used a mobile phone for more than ten years, a statistically significant result. The highest risk was for acoustic neuromas, which was three and a half times the rate among controls, very similar to the 3.9-fold increased risk reported by Ahlbom.
“This is a replication of our finding” Hardell told Microwave News. “We regard acoustic neuroma to be a signal tumor for the increased cancer risk from mobile phones. The results may predict an increased risk for other types of brain tumors,” he added. (See also MWN, M/A02).
When Hardell’s results appeared in 2002, they were sharply criticized by many others, including Prof. Magnus Ingelman-Sundberg, the vice-chair of the Karolinska’s Institute of Environmental Medicine, where Ahlbom leads the department of epidemiology. Ingelman-Sundberg called Hardell’s paper “alarmist” and “irresponsible”.
Ahlbom’s is the second report on acoustic neuromas to appear from the Interphone study. In February, a Danish group led by Christoffer Johansen of the Danish Cancer Society in Copenhagen found no increased risk, but this study only had two cases of acoustic neuroma who had used a mobile phone for more than ten years. Ahlbom’s has 12 such cases.
In an editorial accompanying the Ahlbom paper, Dr. David Savitz of the University of Carolina, Chapel Hill, tries to put a positive spin on the new results. Calling the neuroma risk “still highly unlikely,” Savitz writes: “This uncertainty regarding long-term use should not distract from the growing evidence, enhanced by this study, that neither acoustic neuroma nor brain tumors is associated with cell phone use of less than ten years.”
But, in his paper, Ahlbom notes that there may in fact still be a risk from the short-term use of cell phones. “We cannot exclude the possibility that short-term exposure has an effect that can be detected only after a long latency period,” he writes. And others, like Milham never thought that an increased tumor risk would become apparent so soon. “From what we know about the latency of solid tumors, you would not expect to see an increase for at least 10 years and it would more likely be 20 years,” he said.
Hardell predicts that the new findings will “have an impact on how cell phones are used, especially by young people.”
In the U.S., the American Cancer Society (ACS) has dismissed the possibility of a brain tumor risk from cell phones. In the last couple of years, the mobile phone companies have argued that enough research has been carried out to be confident that there are no health effects from the use of cell phones. Dr. Mays Swicord of Motorola, speaking on behalf of the Mobile Manufacturers Forum (MMF) made this case, most recently, at a seminar held in Brussels last month.