Schoemaker MJ, Swerdlow AJ, Ahlbom A, Auvinen A, et al. (2005)
This study is part of the INTERPHONE collaboration. Results are presented for 5 of the participating countries - the four Nordic countries and UK. (In the UK 2 separate studies were included). The risk of acoustic neuroma with cell phone use was examined. The methods have been previously discussed (Cardis 1999; Christensen 2004; Lonn 2004). The study design is case-control. Included were 678 cases and 3553 age-, sex-, and region-matched controls. Most subjects participated in face-to-face interviews. The participation rate was 84% for cases and 61% for controls.
The Odds Ratio (OR) of acoustic neuroma for regular use of cell phone was 0.9. There was no significant heterogeneity for the different centres. Risk of acoustic neuroma did not increase with increasing time since first regular phone use or lifetime number of years of use. There was no trend in risk with lifetime cumulative hours of phone use or cumulative number of calls. Regular use of analogue, or of digital, phones showed no association with risk. The OR of a tumour on the same side as the cell phone use was 0.9. First use 10 or more years ago showed an OR for ipsilateral tumours of 1.3 (CI 0.8-2.0), and for 10 or more years cumulative use the OR was 1.8 (CI 1.0-3.3).
The authors discuss in detail the analysis of risk of ipsilateral tumours, and note potential sources of bias. They state:
Schoemaker and colleagues mention that the Swedish part of the study had previously reported results showing a moderately raised risk (OR 1.9; CI 0.9-4.1) 10 years after the start of mobile phone use. This was significantly increased when restricted to tumours ipsilateral to reported phone use (OR 3.9; CI 1.6-9.5). These results are different from those of the other participating centres.