Lost in laterality: interpreting preferred side of the head during mobile phone use and risk of brain tumour'' associations

Due to the highly localized exposure from mobile phones, the preferred side of the head during their use is important information when investigating a possible link with brain tumour risk, but at the same time, error and bias hamper the assessment of this information in case-control studies. Current studies provide evidence of reporting bias insofar as cases appear to over-report the side of the head where the tumour occurred as the one that they preferred in the past when using mobile phones. More refined methods of analysis among only cases or prospective studies with an assessment of the laterality of mobile phone use before the diagnosis of disease are needed to evaluate whether associations seen in some studies are entirely due to reporting bias or a mixture of reporting bias and a causal effect.