No link between cell phone use and increased risk for brain cancer: European study

By Dr. Ananya Mandal, MDJul 27 2011

A new study that looked at cell phone users under the age of 20 found no link between cell phone use and an increased risk for brain cancer. Researchers from the Swiss Tropical and Public Health Institute in Basel, Switzerland, studied data collected in Norway, Denmark, Sweden and Switzerland.

Dr. Keith Black of Cedars-Sinai Medical Center in Los Angeles said, “What we know is that the microwave radiations from cell phones may penetrate deeper into the child's brain. More of the radiation goes into their brain because their scalp is thinner.”

In this study researchers compared cell phone use in healthy children and 352 brain tumor patients between the ages of 7 and 19 between 2004 and 2008. The study also included 646 control subjects.

They found that 265 patients (75.3 per cent) and 466 control subjects (72.1 per cent) reported having spoken on a mobile phone more than 20 times prior to when the case patient was diagnosed with a tumor. Also, a slightly higher proportion of tumor patients versus control subjects — 55 per cent against 51 per cent — reported regular cell phone usage. But these differences were not statistically significant. In a subset of study participants for whom data was available from their cell phone company on their mobile usage, brain tumor risk was not found to be related to amount of use. No increased risk of brain tumors was observed for brain areas receiving the highest amount of exposure. The research comes out just two months after the World Health Organization categorized cell phones as “possibly carcinogenic.”

The study is published in the Journal of the National Cancer Institute. Researcher Martin Roosli said no previous paper has examined whether cell phone use among children and teens is associated with a difference in brain tumor risk. “Because we did not find a clear exposure-response relationship in most of these analyses, the available evidence does not support a causal association between the use of mobile phones and brain tumors,” Roosli and his fellow researchers write.

“[This study] provides quite some evidence that use of less than five years does not increase the chance of a brain tumor, but naturally we don't have a lot of long-term users,” Roosli said. “If there is a risk it would be a really small risk,” he said.

Seventy-five percent of teenagers now have a cell phone, up from 45 percent in 2004, so a clearer picture of safety will only come from long-term studies. “What we're really concerned about,” said Black, “the child that begins using the cell phone at seven or 12, when they become an adult after 20 or 30 years of using the cell phone for, is that risk higher? That is not answered by this study.”