Aydin et al.
The first case-control study on mobile phone use and brain tumor risk among children and adolescents (CEFALO study) has recently been published. In a commentary published in Environmental Health, Soderqvist and colleagues argued that CEFALO suggests an increased brain tumor risk in relation to wireless phone use. In this article, we respond and show why consistency checks of case-control study results with observed time trends of incidence rates are essential, given the well described limitations of case-control studies and the steep increase of mobile phone use among children and adolescents during the last decade. There is no plausible explanation of how a notably increased risk from use of wireless phones would correspond to the relatively stable incidence time trends for brain tumours among children and adolescents observed in the Nordic countries. Nevertheless, an increased risk restricted to heavy mobile phone use, to very early life exposure, or to rare subtypes of brain tumors may be compatible with stable incidence trends at this time and thus further monitoring of childhood brain tumor incidence rate time trends is warranted.