Cell phones have become a mainstay of personal communication around the world; in the United States, more than 170 million people subscribe to cell phone service. Recent media reports indicating a possible link between cell phones and brain tumors have caused speculation about whether or not cell phone users need to worry about their health.

Like all electrical devices, cell phones emit electromagnetic radiation. Cell phone radiation is in the form of radio-frequency (RF) energy, which, at high levels, can heat living tissue enough to cause biological damage. Cell phones do not emit the high-energy, “ionizing” radiation that has been linked to cancer. Whether the tiny amount of low-energy radiation emitted from a cell phone antenna could cause harm is the subject of debate.

Currently, there is no clear scientific evidence showing negative health effects, but some recent studies have suggested a possible link. A 13-nation study called the Interphone Project is further investigating whether a relationship exists between exposure to RF energy and brain tumors. Researchers in Denmark completed their phase of the study and reported their findings in the April 12, 2005 issue of Neurology .

About the Study

This study was designed to determine whether cell phone use increased the incidence of two types of brain tumors: gliomas and meningiomas . Between September 2000 and August 2002, researchers enrolled Danish people, aged 20–69, and assessed their past cell phone use. Participants included 252 people with gliomas, 175 with meningiomas, and 822 people without disease.

Because this was a “case-control” study, researchers compared patterns of cell phone use in the people with brain tumors (the “cases”) to people from the general population who didn’t have brain tumors (the “controls”), in order to identify a possible link.

The Findings

The findings of this study do not indicate any association between cell phone use and the development of gliomas or meningiomas. People with these tumors did not use their cell phones more often than people without these tumors. This study will likely contribute to more significant findings when its results are considered in the context of the larger Interphone Project.

There are several limitations to this study. First, widespread use of cell phones is relatively new, and very few of the cases or controls had used cell phones for longer than ten years. As a result, the researchers were unable to examine long-term health effects of cell phone usage.

Second, although case-control studies are convenient and relatively inexpensive to carry out, they are considered preliminary forms of research, designed to identify possible causes of disease. This is because these kinds of studies are associated with certain biases and confounding factors that are difficult to control. In this case, for example, assessment of cell phone use depended on the memory of the subjects, some of whom were quite sick with brain cancer.

How Does This Affect You?

Although there is no proof that cell phones are without any risk, there is no consistent evidence—at least so far—that they are dangerous. Given the nature of the low-energy radiation they emit, however, it is reasonable to speculate that cell phones will turn out to be safe. If you are still concerned, make sure you use digital service, since analog service involves higher RF exposure.

In reality, the real risk posed by cell phones has more to do with the user than the phone itself. Far more people have been harmed from motor vehicles accidents linked to cell phone conversation behind the wheel. The predominant safety message concerning cell phones, therefore, should have less to do with radiation and more to do with eliminating cell phone usage while driving.