A meta-analysis of studies on intracranial tumors and mobile phone use published by the end of 2012 was performed to evaluate the overall consistency of findings, assess the sensitivity of results to changes in the dataset, and try to detect the sources of between-study heterogeneity.
Following 29 publications were included: Muscat et al. 2000, Muscat et al. 2002, Inskip et al. 2001, Auvinen et al. 2002, Hardell et al. 1999, Hardell et al. 2002, Hardell et al. 2003, Hardell et al. 2005, Hardell et al. 2006, Hardell et al. 2006, Hardell et al. 2006, Christensen et al. 2004, Christensen et al. 2005, Lönn et al. 2004, Lönn et al. 2005, Hepworth et al. 2006, Schüz et al. 2006, Schlehofer et al. 2007, Takebayashi et al. 2006, Takebayashi et al. 2008, Klaeboe et al. 2007, Hours et al. 2007, Schoemaker et al. 2005, Lahkola et al. 2007, Lahkola et al. 2008, Interphone Study Group 2010, Interphone Study Group 2011, Schüz et al. 2011, and Frei et al. 2011.
|Reference group 1||never (regular) use|
|Group 2||ever (regular) use|
|Group 3||short-term use: 0.5 - 6.5 years|
|Group 4||medium-term use: 5 - 9 years|
|Group 5||long-term use: ≥ 10 years|
Five combinations of non-overlapping studies per outcome were identified and the combined relative risks were calculated. For meningioma the combined relative risks in long-term mobile phone users (≥ 10 years) ranged between 0.98 (CI 0.75-1.28) and 1.11 (CI 0.86-1.44), with little heterogeneity across studies. High heterogeneity was detected across estimates of glioma and acoustic neuroma risk in long term users, with combined relative risks ranging between 1.19 (CI 0.86-1.64) and 1.40 (CI 0.96-2.04), and from 1.14 (CI 0.65-1.99) to 1.33 (CI 0.65-2.73), respectively. A meta-regression of primary studies (excluding pooled analyses) showed that the methodological differences embedded in the variable 'study group' (based on design, case ascertainment, control selection, and exposure assessment) explained most of the overall heterogeneity in results. Summary risk estimates based on heterogeneous findings should not be over-interpreted.
The authors conclude that overall the results of their meta-analysis detract from the hypothesis that mobile phone use affects the occurrence of intracranial tumors.