What do We Know about Brain Tumors in Children and Adolescents Resulting from Exposure to Radiofrequency radiation?

Brain tumors are rare at any age, including childhood, but among the types of cancer appearing in childhood (under age 20), they are the most frequent type, after leukemia.  In Israel (in 2006) tumors of the brain and central nervous system constituted 18% of all cancer morbidity in children and adolescents up to the age of 19.

 

The following is a brief review of studies that were and are being conducted to date, on the possible relationship between personal exposure to radiofrequency radiation and the development of brain tumors in children and adolescents.

 

CEFALO study

This was a case-control study conducted during 2004-2008 in Denmark, Norway, Sweden, and Switzerland.  The aim of the study was to assess the possible association between the use of mobile phones by children and the risk of developing brain tumors during childhood.  In this study, 352 children (aged 7-19) diagnosed with brain tumors were interviewed.  At the same time, 646 healthy children (unaffected with brain tumors) of the same ages and in the same localities were interviewed.  The children were asked about the way they used their phones (how long they had the phone,  the number and duration of conversations, the side of the head they usually held the phone close to, and whether they used a hands-free device).  In some cases, wherever possible, the researchers compared the children's reports on their patterns of use with usage data obtained from the mobile phone companies on the same users. 

 

The results showed that about half of the children spoke on the phone at least once a week – these were labelled 'users'. The sample of children who had the phone for more than 5 years and had accumulated 144 hours of use or more, and/or accumulated 2638 conversations or more, was only about 13%. The risk ratio for developing brain tumors was calculated by the researchers based on the usage patterns, and after standardization for other risk factors known to be related to the development of brain tumors (reported X-ray exposure, infectious diseases or head injuries in the past).  These results revealed a 36% increase in the risk of developing brain tumors among children who used the phone at least once a week over a 6-month period.  This increased risk was not statistically significant (95% confidence interval 0.92-2.02).  Similarly, no increased risk of developing this disease was observed even after long-term use (more than 5 years), nor was there an increased risk for those parts of the brain absorbing the highest doses of radiation.

 

In the article reporting the above results, the researchers concluded: "The absence of an exposure-response relationship either in terms of the amount of mobile phone use or by localization of the brain tumor argues against a causal association."

 

It is interesting to note, on closer perusal of the results reported in the article, that in a subanalysis, which included objective usage data obtained from the mobile phone companies (as distinct from the self-reporting based on the children's recall), it was found that the risk of developing brain tumors about three years after the start of use was twice as high as in children not classed as 'users'. This result was statistically significant (95% confidence interval 1.07-4.29).

 

The absence of statistical significance may reflect a situation where the use of mobile phones by children is unrelated to the risk of developing brain tumors in childhood. Alternatively, it may also be due to a small sample size.  Indeed, the study was based on a relatively small number of children (998 altogether) and on a short follow-up period.  It is also important to note that the extent of mobile phone use described in this study was relatively low compared to use patterns today, especially in Israel.  Even children classed as 'heaviest' users in the study had spoken for a mere total of 144 accumulated hours, or conducted a total of only 2638 conversations since they started using the phone.

 

Ecological studies investigating the relationship between the rate of brain and central nervous system tumors in children and the increased use of mobile phones during the same years

In addition to the study described above, the CEFALO researchers also conducted an ecological study, in which they investigated the rate of brain and central nervous system tumors in children aged 5-19 during the years 1990-2009.  They hypothesized that the sharp increase in the use of mobile phones during those years would be expressed in a parallel increase in morbidity.  Morbidity data on brain tumors were obtained from the Scandinavian Cancer Registry (a database recording all cases of cancer in Scandinavian countries).  The data on the use of mobile phones were obtained from the questionnaires used for children in the case-control CEFALO study, as well as from usage data obtained from mobile phone companies in Sweden.

 

The researchers' hypothesis was not validated; despite the increased use of mobile phones, there was no increase in the incidence of brain tumors during those years.  Similar ecological studies conducted in the USA and Scandinavian countries (Denmark, Finland, Norway and Sweden) confirmed that the rate of brain tumors in children and adolescents remained unchanged during those years.

 

It should be mentioned again that during the years 1990-2009 the use of mobile phones among children was still relatively low. In addition, ecological studies provide less reliable scientific evidence than case-control or cohort studies (to learn more see the section on Research Methodology – Population studies).

 

The Mobikids study

The Mobikids study  is an international case-control study in which research centers in 14 countries (including the Cancer and Radiation Epidemiology Unit at the Gertner Institute, Tel Hashomer, Israel) are participating.  The aim of the study is to assess the potential risk of developing brain tumors among children and adolescents as a result of environmental exposure to non-ionizing radiation (including the use of communications devices and other exposure to electromagnetic fields).  In this study, which began in 2010 and is still in progress, about 3000 children, adolescents and young adults (aged 10-24) are expected to participate (about 1000 children diagnosed with brain tumors and 2000 healthy subjects).  This study is part of the 7th Framework Program of the European Union.  Prof. Elizabeth Cardis, of the Center for Environmental Epidemiology (CREAL) in Barcelona heads the study.  Prof Siegal Sadetzki heads the Israeli branch of the study.

 

Because of the dearth of studies published to date, there is a general and unequivocal consensus that one should exercise great care with the exposure of children to radiofrequency radiation and act according to the precautionary principle when dealing with this population.  The reasons for this are as follows:

 

  • Children constitute a susceptible population.
  • Today's children are expected to continue to use radiofrequency radiation-emitting devices throughout their lives, thus accumulating long durations of exposure.
  • Children are not expected to make decisions for themselves on critical topics, as long as they are the responsibility of adults.

 

The precautionary principle is expressed in the policy restricting exposure of children to radiofrequency radiation. All over the world, health policy-makers are deliberating, among other issues, whether to restrict the use of mobile phones by age, and whether to restrict the purchase of mobile phones for children under a certain age.  This problem also raises the question of the upper age-limit of childhood in the context of the consequences of exposure to non-ionizing radiation.

 

In addition, there is much discussion around the question of how to use the radiofrequency radiation-emitting technologies in schools while safeguarding the children's health (to learn more see the section on Public polemic on the use of the wireless network (Wi-Fi) in schools).

 

Recommendations of the Israeli Ministry of Health on the educated use of devices emitting radiofrequency radiation:

The Israeli Ministry of Health recommends exercising great caution regarding children, and restricting their exposure to mobile phones. It also recommends considering the age at which use begins, restricting the extent of use, and in any case, using corded headsets (not wireless) or hands-free devices when using the phones.

References

 

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