A meta-analysis was conducted in the USA to examine the effect of cellular phone use and the risk of brain tumor. Following nine studies published between 2000 and 2006 were included: Auvinen et al. 2002, Christensen et al. 2005, Hepworth et al. 2005, Inskip et al. 2001, Lönn et al. 2004, Lönn et al. 2005, Muscat et al. 2000, Schoemaker et al. 2005, and Schüz et al. 2006.
Only studies meeting all of the following criteria were included in the meta-analysis: 1) published in English, 2) case-control study design, 3) sufficient data so that the crude odds ratios could be derived, and 4) exposure to cellular phones was clearly defined.
Regular use of cellular phone was defined as at least one call per week for 6 months or more or as having a subscription to a cellular telephone service.
|Reference group 1||not exposed|
|Group 2||regular cellular telephone use|
|Group 3||regular cellular telephone use: ≥ 10 years|
|Group 4||regular cellular telephone use: analog|
|Group 5||regular cellular telephone use: digital|
No overall increased risk of brain tumors associated with cellular phone use was found. A slightly increased risk (OR 1.25; CI: 1.01-1.54) for patients with 10 or more years of exposure was observed. No increased risk was observed in analog or digital cellular telephone users.