Han YY, Kano H, Davis DL, Niranjan A, Lunsford LD. Cell phone use and acoustic neuroma: the need for standardized questionnaires and access to industry data. Surg Neurol. 2009 Mar 26 Ahead of print.
Evidence from several published studies has indicated that radiofrequency exposures have biologic effects on organic tissue. There has been rising concern that such exposure from the recent widespread use of cell phones may increase the risk of malignant brain tumors and of acoustic neuroma (AN), which is a benign tumour arising from the eighth cranial nerve that leads from the brain to the inner ear. Evidence to-date has not been sufficient to truly determine whether cell phone use or other environmental factors is the primary contributor to the increased rates of acoustic neuroma. The present article is a systematic and critical review of current epidemiologic studies of acoustic neuroma and mobile phone use.
The authors searched PubMed for published articles on the association between cell phone use and brain tumors, with an emphasis on acoustic neuroma. They identified 12 articles, including 1 cohort study, 10 case-control studies, and 1 meta-analysis on the risk of acoustic neuroma associated with cell phone use. A systematic review of all studies was conducted.
Among the 10 case-control studies, odds ratios for acoustic neuroma associated with regular cell phone use ranged from 0.5 (95% confidence limits: 0.2, 1.0) to 4.2 (1.8, 10). The meta-analysis (of three case-control studies) resulted in an estimate of 2.4 (1.1, 5.3). The results, biases, and various limitations were reported for each of the publications.
Discussion and Conclusion
In reviewing each of the publications, the authors concluded that the studies generally lacked sufficient statistical power to find excess risks of acoustic neuroma or other brain tumors. The inconsistent results across studies may be explained by differences in design and exposure characteristics. The authors also point out that for acoustic neuroma and most brain tumors, a 10-year latency period is believed to be required for development of tumors from any given exposure, and that there is a lack of evidence concerning long-term exposure to common cordless phones. A number of research priorities were identified: creation of prospective and retrospective access to phone records, conducting follow-up cell phone studies in children and teenagers, assessing cell phone exposure using industry data, creating standardized questionnaires, collecting information on potential covariates, such as environmental and occupational exposures, medical radiation history, smoking, family history, and genetic background.