Study on cell-phone link to cancer is inconclusive

GENEVA, Switzerland - Frequent cell-phone use may increase the chances of developing a rare but deadly form of brain cancer, according to a $24 million U.N. study spanning a decade and covering 13 nations.

Worryingly, because glioma has a potential latency period of a quarter century - longer than cell phones have been in widespread use - even the study's authors say there is no way yet to tell how big the risk is, if there is one.

Experts were nearly unanimous in saying the results of the study were inconclusive. But the fact that it turned up even some evidence of a cancer risk may have profound consequences for a device that people have become accustomed to seeing as extensions of themselves.

Cell phones send out radioactive energy in a form that is similar to the one used in microwave ovens, but at very low levels. There is no accepted theory to explain how or if these weak radio waves can affect the body, beyond heating it to a very small degree.

All the same, U.S. and European regulators already limit the energy that cell phones can project into the body, and today's digital phones radiate less power than the analog phones that dominated in the early '90s. Common advice for those concerned about the radiation is to use a Bluetooth headset, since these emit even less power.

The survey conducted from 2000 to 2010 of almost 13,000 participants - the biggest ever of its kind - found a 40 percent higher incidence of glioma among the top 10 percent of people who used their mobile phones most.

A lesser spike of 15 percent was observed with meningioma, a more common and frequently benign tumor.Researchers ignored the time spent using hands-free devices, keeping the phone in a pocket, or beside the bed at night because a distance of 4 inches reduces the amount of radiation to the brain to almost zero.

But because cell-phone use has boomed during the 10-year period studied, the researchers' definition of heavy use as 30 minutes of calls or more a day is now common.

The study's users were light compared with today, said Elisabeth Cardis of the World Health Organization's International Agency for Research on Cancer, or IARC, which organized the study.

The highest risk found was for tumors on the same side of the head as users held their phone, particularly for tumors in the temporal lobe closest to the ear, Cardis told reporters in Geneva on Monday. "This is the region of the head which receives the most exposure."

Despite this evidence pointing to a link between cell-phone use and tumors, the 21 researchers involved in the study disagreed on the conclusion, partly because of flaws in how the surveys were done.

For example, the study appeared to show that casual users had a lower risk of getting cancer than people who did not use cell phones at all, a result the researchers described as "implausible" and blamed on methodological problems.

The message? The researchers refused to rule out that cell-phone use caused brain cancer but would not say it did.

"We can't establish without any doubt that there is no link," said Anthony Swerdlow of Britain's Institute of Cancer Research, another of the study's authors. But he added that "it seems unlikely that there are large risks that happen soon."

Handset manufacturers and network providers, who paid for about a quarter of the study, have seized on such conclusions as evidence their products are safe.

Christopher Wild, director of the IARC, cautioned that the results related to a time when cell phones were much less common. "This investigation is a victim of the changing patterns of mobile-phone use over the years," he said.

The scientists involved in the study plan to publish a comprehensive overview of available research within two years.

"Until stronger conclusions can be drawn one way or another," Cardis said, "it may be reasonable to reduce one's exposure." One way to do this would be to make calls using a hands-free device.

"It can't hurt," she said.

Source: Philly.com Health News