Is the truth out there?
by Marin Gazzaniga for MSN Health & Fitness


A new study out of Sweden reports a link between cell phone use and brain tumors. But other recent studies deny any connection. If you are one of the estimated 206 million wireless subscribers in the U.S., whom should you believe?

Researchers Lennart Hardell, Michael Carlberg and Kjell Mild at the Swedish National Institute for Working Life report that there was an increased risk for malignant brain tumors for both cellular and cordless phone users, with the highest risk being for heavy users. Heavy use in this case was more than 2,000 hours over 10 years (which works out to about an hour per workday). They claim the tumors were more common on the side of the head the cell phone was used.

What’s the potential danger?

Cell phones (as well as portable phones, TVs, radios, etc.) emit radiofrequency (RF) radiation. Up for debate is whether RF radiation and the exposure that comes with cell phone use is harmful.

To determine whether there is a correlation between cell phone use and brain tumors, researchers need to address two main issues. The first is to confirm whether there is a biological mechanism that causes a change in cells which in turn can cause a brain tumor. The second is the latency period, meaning that there may be a long time between when someone is exposed and when they start seeing negative health effects, such as brain tumors.

A biological mechanism has not been identified. And the Swedish team argues in its paper, published in the International Archive of Occupational and Environmental Health, that previous studies that reported no link between cell phones and brain tumors had too short a latency period. Again, others disagree with their assessment.

Robert Tarone, biostatistics director of the International Epidemiology Institute, points out that preliminary results from several countries in the Interphone study now under way—a 14-country study on cell phone use spearheaded by the World Health Organization—have found little evidence of increased risk, and many of these studies look at long-term use. “Published papers on Interphone studies in England, Sweden, Denmark and Germany have not found evidence of increased risk of the magnitude reported in the Hardell study,” he says. He also points out that the study is not new data, rather it’s largely a pooled analysis of previous studies that found a link. “Hardell finds extreme results no one else confirms.”

What to do?

“These types of studies showing conflicting results have been coming out for years,” says Robert Tufel of the National Brain Tumor Foundation. “While realizing that proving the cause of brain tumors is a complicated issue, I just hope that researchers can come up with some type of mutual consensus in order to let us know whether we are at risk or not.”

International Epidemiology Institute's Tarone believes that we will have a more definitive answer when the Interphone study’s final analysis comes out (most likely during 2006). In the meantime: “A very high percentage of people in developed countries now use a cell phone,” says Tarone. “If they cause increased risk of the magnitude reported in the Hardell study, we should be seeing something almost like what was seen in the 1940s with cigarette smoking and lung cancer. The increase in malignant brain tumors should be evident in population incidence rates, and that’s not the case.”

While the researchers continue to debate the validity of various studies and what the results mean, the rest of us will have to wait to hear whether there’s a real risk. Until there’s a clear answer, if you are concerned, Tufel suggests people follow the WHO recommendations for cell phone exposure: Limit cell phone use (stick to quick calls and use a land line for long conversations) and use a hands-free headset.

Resources:

National Brain Tumor Foundation (www.braintumor.org) Patient Information Line: 1.800.934.CURE
http://health.msn.com/centers/cancer/articlepage.aspx?cp-documentid=100133094