Study: No evidence of brain cancer increase in mobile phone users

Photo: Marus/Wikimedia

A retrospective study of 60,000 people in Scandinavia who had developed a glioma or meningioma tumor during a 30-year period paints a somewhat reassuring picture for mobile phone users. Researchers believe the small uptick in brain tumors diagnosed during the study time frame (1973-2003) reflects not increased cell phone use but the introduction of medical scanning technology which improved tumor diagnosis. A larger study is to be published soon.

The polemic on mobile phone risks is continuing apace, with all eyes riveted on the major Interphone European study on mobile phone use which is scheduled to be published in the next few weeks. That study will involve 37 scientists in 13 countries.

Whilst waiting for those results though, another study has just been published in the Journal of The National Cancer Institute.  It evaluated data on brain tumors between 1973 and 2003 in Denmark, Sweden, Finland and Norway with the objective of establishing if the introduction of widespread mobile phone use in the early 1990s resulted in an upsurge in those tumors.

The study’s prior knowledge criteria states that “... neither a biological mechanism to explain this association nor the etiology of brain tumors is known.”

Data from national cancer registries concerning a total of 59,984 men and women aged between 20 and 79 who have suffered a glioma or meningioma tumor during the 30 years of the study period was evaluated.

Results demonstrate an increased incidence of gliomas of 0.5 percent in men and 0.2 percent in women. For meningiomas the figures were 0.8 percent and 3.8 percent, respectively.

The researchers attribute the increases principally to the introduction of brain scanners in the 1970s and nuclear magnetic resonance imagery (MRI) in the 1980s, both of which detect tumors more effectively. Another factor is the increase in life expectancy in Western European countries, which has mechanically increased the incidence of brain tumors and the majority of other cancers, too.

“No change in incidence trends were observed from 1998 to 2003, the time when possible associations between mobile phone use and cancer risk would be informative about an induction period of 5–10 years,” according to the authors.

They also conclude that the possibility of risk cannot be definitively excluded, either because the possibility of risk is too weak to be measured using existing epidemiological diagnostic tools or because mobile phones have not been in existence long enough to be sure of the risks, if any, involved.

The preliminary results of the much larger Interphone study indicate that it has come to the same conclusions, although a question mark remains concerning intensive mobile phone users.

Data is also lacking on the heavy use of mobile phones by children, again because the phenomena has not existed long enough to be evaluated.

Citation:

J Natl Cancer Inst. 2009 Dec 3. [Epub ahead of print] Time Trends in Brain Tumor Incidence Rates in Denmark, Finland, Norway, and Sweden, 1974-2003. doi:10.1093/jnci/djp415