There is a growing public concern that radiofrequency fields from mobile phone use might be associated with adverse health effects, and that children might be more sensitive than adults to this exposure. There are, however, as yet no epidemiologic studies of children. In some countries, authorities recommend, as a precautionary measure, that children should refrain from using mobile phones, whereas other countries do not have such recommendations. The lack of knowledge leads to conflicting messages from different authorities, which contribute to uncertainty and a growing concern in the general population. A high priority on the WHO research agenda is a case–control study of childhood brain tumors in relation to mobile phone use.
The CEFALO study, an international case–control study of the association between mobile phone use and the risk of brain tumors in children aged 7 to 19 years has recently started in Denmark, Norway, Sweden, and Switzerland. Cases are identified through a close collaboration with the clinics treating these patients in combination with a regular search of nationwide cancer registers. In addition to this, cases diagnosed up to 2 years before the date of start of the study have been identified. In total, the study will include approximately 550 cases of brain tumors. For each case, 2 control persons will be randomly selected from the general population matched on date of birth, sex, and geographic regions.
Information about past mobile phone use, and known and suspected risk factors for childhood brain tumors, will be obtained by means of personal interviews conducted by a nurse or an interviewer trained for this purpose.
Furthermore, whenever possible, information about the frequency and duration of mobile phone use will be obtained from the mobile phone operators. In Denmark, a pilot study was conducted, including 20 healthy children, in the study-specific age group. It was possible to identify all available mobile telephone traffic information up to 5 years back in time, providing the unique opportunity of an objective and precise exposure measure.
The experience gained by the CEFALO study, as well as the data collected, will also be useful for a future larger “INTERPHONE-Kids” study. Feasibility studies for an INTERPHONE-Kids study are currently being set up in several countries.