Wireless phones and brain tumour risk in young people: results of the multi-national MOBI-Kids study

Background and aim. The possibility that wireless (mobile and cordless) phone use might increase brain tumour (BT) risk, has long been a concern, particularly in young people. We studied the association between wireless phone use and subsquently radiofrequency (RF) and extremely low frequency (ELF) electromagnetic fields (EMF) exposure) in childhood/adolescence with BT risk. Methods. MOBI-Kids, a 14-country case-control study, recruited 899 BT cases and 1910 hospital controls aged 10-24 years. Each participant answered a questionnaire on history of mobile communication devices use. Analyses were conducted both in relation to the history of use of wireless phones and to estimated RF and ELF dose from use of wireless phones (based on algorithms developed in the project), adjusting for parental education. Numerous substudies and sensitivity analyses were conducted to address potential biases. Results. Mean ages of cases and controls were 16.5 and 16.6 years, respectively. The vast majority of participants were wireless phones users, with substantial numbers of long-term (>10 years) users. Most tumours were neuroepithelial (NBT; n=671). The adjusted odds ratios (OR) of NBT appeared to decrease with increasing time since start of use of wireless phones, cumulative number of calls and cumulative call time, particularly in the 15-19 years old age group. A decreasing trend in ORs was also observed with increasing estimated cumulative RF specific energy and ELF induced current density. These decreasing trends are attributable mainly to differential recall by proxies and prodromal symptoms affecting phone use before case diagnosis. Results remain unchanged despite the large number of sensitivity analyses we conducted. Conclusions. Our study provides no evidence of a causal association between wireless phone use and brain tumours in young people. However, possible residual biases prevent us from ruling out a small increased risk. Keyworks: brain tumours, young people, wireless phones