Children and adolescents who use mobile phones are at no bigger risk of developing brain cancer than those who do not use them, according to a study of patients aged 7 to 19.
The research, published in the Journal of the National Cancer Institute on July 27 and partially funded by mobile phone operators, addresses concerns that children may be more vulnerable to health risks from electromagnetic radiation from cellphones.
Children's nervous systems are still developing, and there are fears that their smaller head circumferences could allow radiation to penetrate deeper into their brains. But the study - the first to look specifically at children and the risk of cancer from cellphones - found that brain tumour patients were no more likely to be regular phone users than control subjects who did not have cancer.
"If mobile phone use would be a risk factor, you'd expect cancer patients to have a higher amount of usage," said Professor Martin Roosli, who conducted the study at the Swiss Tropical and Public Health Institute in Basel, Switzerland.
Some funding for the study came from the Swiss Research Foundation on Mobile Communication, which is partly supported by Swiss mobile phone operators. They were not involved in the study design or the collection, analysis or interpretation of the data, according the authors. About 5 billion cellphones are in use today, some 30 years after they were introduced commercially.
The World Health Organisation (WHO) reignited interest in possible health risks from cellphones after it said in May that using a mobile phone might increase the risk of certain types of brain tumours.
Roosli's research, conducted between 2004 and 2008 in Norway, Denmark, Sweden and Switzerland, looked at phone use of 352 brain cancer patients and 646 control subjects.
About 55 percent of the patients reported regular mobile phone use compared with 51 percent of the control subjects, according to the study, which defined regular users as making an average of at least one call per week. The study also found that 75.3 percent of cancer patients used mobile phones more than 20 times in their lives before they were diagnosed, and that 72 percent of control subjects reported using them more than 20 times in their lives.
The study involved face-to-face interviews, and Roosli said that he could not be certain about the accuracy of the subjects' recollections of past cellphone use.
He also said teen and child cellphone use has likely increased since they did the study.
One critic of the report said the results were an "unwarranted conclusion."
"Brain tumours can take 10 years to form, and young children certainly have not been heavy cellphone users for very long," said Devra Davis, author of the book "Disconnect: The Truth About Cell Phone Radiation, What the Industry Has Done to Hide It, and How to Protect Your Family."