By Soumen Khatua, M.D., assistant professor, Department of Pediatrics
The use of cell phones among children has increased dramatically over the last decade. So has the rising concern over whether cell phone use causes brain tumors.
A survey in 2003 showed 30% of Americans believe there's a correlation between the two. Since then, many studies have been done, which have failed to draw any robust conclusions Thus, the controversy continues.
The effects of continuous exposure to electromagnetic radiation (EMR) emitted from mobile devices have been studied intensely. Some preliminary studies of EMR effects on animals have raised concern.
Dysfunction of the blood brain barrier due to radiation has been reported in animals, which could allow leakage of cancer-causing substances into brain. This could result in the potential increase of tumor formation.
Children are likely to be more susceptible to these effects because of their developing brain, deeper penetration of the radiation due to their inherent anatomy and longer lifetime exposure than adults.
Certain tissues and nerves in the brain are closest to the surface of the ear and head and maximally exposed to EMR. Tumors stemming from these areas such as glioma, meningioma and acoustic neuroma have received particular attention as a result.
Some studies have shown increased risk of glioma, acoustic neuroma and meningioma on the same side where the mobile phone was used. Other studies also concluded the increased risk of similar tumors in cell phone users over 10 years. These studies do have limitations due to reported bias, failure to reproduce the data and short periods of follow-up.
Martin Roosli, a leading Swedish epidemiologist, concluded "no larger or immediate risk of brain tumors in children from use of cell phones" in a population aged 7 to 19 years.
In addition, a major study by A. Auvinen in 2006 found no increase in brain tumors associated with the use of such devices.
A recent large case-control study from Japan showed no overall risk of glioma or meningioma in relation to regular mobile phone use. The 13-nation Interphone study last year concluded no increase in the risk of glioma or meningioma with use of mobile phones; though, there were suggestions of formation of gliomas at the highest exposure levels.
These studies have their limitations, too. Most of them are performed in adults and lack long-term follow-up over 10 to 20 years. Also, relying on memories of cell phone users fails to provide robust conclusions and strong reassurances.
More research needed
Though these studies demonstrate no increased risk of brain cancers, the important point to remember is we have not been able to define a flawless conclusion of "no risk."
Larger prospective long-term studies are needed in children using cell phones to validate and define "no risk" brain tumor conclusions. It seems as of now, no definite proof exists of increased brain tumor risk with the use of cell phones and similar technology.
However, with the increased use of these mobile devices by younger children and changes in pattern of its use, continued surveillance and research is imperative to better define its relation to brain tumors.
Children and Adolescent Cell Phone Users at No Greater Risk of Brain Cancer Than Non-Users, Study Suggests
Mobile Phone Use and Brain Tumors in Children and Adolescents: A Multicenter Case-Control Study
National Cancer Institute: Cell Phones and Cancer Risk Fact Sheet
Journal of the Nation Cancer Institute: Cell Phones, Cancer and Children