Long-term Mobile Phone Use and Acoustic Neuroma Risk – Swedish Nationwide Case-Control Study

Abstract

Background: There is a concern that the radiofrequency fields emitted by mobile phones could cause cancer. Epidemiological findings so far do not support an association between mobile phone use and acoustic neuroma, but the evidence concerning long term use is limited. We conducted a case-control study with the largest number of long term (?10 years) users to date. Aims: The aim was to study: the long term effects of mobile phone use on acoustic neuroma risk, the impact of the method chosen for asking about preferred side of mobile phone use, and possible differences in the detection of acoustic neuromas between users and non-users of mobile phones. Methods: A population based case-control study was conducted in Sweden from September 2002 to August 2007. Incident acoustic neuroma cases between 20 and 69 years of age were identified in collaboration with treating clinics and from the Swedish cancer register. Controls were randomly selected from the population register, matched on age, sex and residential area. The Postal questionnaires that were used to collect exposure information were completed by 451 cases (83%) and 710 controls (65%). Results: There was no significant association between acoustic neuroma and regular use of mobile phones or with long term use (?10 years). Decreased risk estimates for use on the same side as the tumor were seen together with increased estimates for use on the opposite side when preferred side at the time of diagnosis or later, was used. This difference was greatly reduced when side changes up to 10 years before diagnosis were considered. Odds ratios were generally lower when restricting the analyses to only histologically confirmed cases. Conclusions: The data does not imply that long term mobile phone use increases the risk of acoustic neuroma. Laterality specific risk estimates for acoustic neuroma are prone to bias from reversed causality and there are indications of differential detection of this tumor.