Cell phones do not raise brain cancer risk in children?
By David Liu, Ph.D.
Sunday July 31, 2011 (foodconsumer.org) -- Media companies can't wait to report a new study that found no association between use of cell phones and risk of brain cancers in teens and adolescents. The tone of these reports seems such that it gives readers an assurance that use of cellphones is indeed free of any harm.
What the study published recently in the Journal of the National Cancer Institute found is that regular uses of cellphones were not at a statistically significantly higher risk for brain cancers, compared to nonusers.
Likewise, children who started using cellphones at least five years ago were found not at elevated risk for brain cancers, compared with those who had never used cell phones.
Still, there are some numerical indications that using cell phones may boost the risk. The indications are just not statistically significant.
Editors of the journal say that the statistical method used in this study is not intended to find a small increase in the brain cancer risk if there is any increase due to the use of cell phones. So whether or not cell phones cause a small increase in the risk remains unknown.
Dr. Martin Röösli, the principal investigator for the study called CEFALO, of Swiss Tropical and Public Health Institute, and colleagues say in their report that retrospective studies are not expected to find any association between use of cellphones and risk of brain cancer if there is indeed any.
Röösli et al. suggest that the best way to determine if use of cell phones would increase risk of brain cancers in children is to monitor incidence of the disease because use of cellphones is so prevalent that any increase in the risk would be easily observed.
The study was well performed. However, like many other studies, the current study has its own limitations. For one thing, as many researchers would agree, it may take one or more decades (the so called latency period) for the effect of the cell phone radiation to manifest itself. This study does not seem to have considered this.
After all, even if cell phones do not increase risk of brain tumors in children, it remains unknown whether or not use of cell phones in childhood would have any effect on the risk in adulthood.
The authors are honest. They disclosed the funding sources. Some researchers received funding from organizations sponsored by the industry. But they said no industrial entity has any say about the design of the study.
In summary, this study by itself does not conclude that use of cellphones don't have any impact on risk of brain tumors in childhood under any conditions. The results should be interpreted cautiously.