Risk of brain tumours in relation to estimated RF dose from mobile phones

Two new papers were published on Friday 10 June 2011 on the website of Occupational and Environmental Medicine. These papers present work conducted within the International INTERPHONE study (http://www.iarc.fr/en/research-groups/RAD/RCAd.html, Cardis et al 2007), coordinated by Elisabeth Cardis (Research Professor in Radiation Epidemiology at CREAL and former head of the Radiation Group at the International Agency for Research on Cancer – IARC – in Lyon). These papers have been used in the evaluation of the carcinogenicity of radiofrequency radiation in the recent WHO-IARC Monographs meeting (http://www.iarc.fr/en/media-centre/pr/2011/pdfs/pr208_E.pdf)

Background

• Epidemiological studies of brain tumours in relation to mobile phone use have mainly analysed risk in relation to amount and duration of use of mobile phones.
• Most studies have not observed increased ORs (risk) in relation to ever having been a mobile phone user. There were suggestions, however, of an increased risk of glioma in long term and heavy users, though biases and errors prevent a causal interpretation.

What is new

• While amount and duration of use are important determinants of the amount of RF energy in the brain, the actual relationship between RF energy absorbed at the tumour location and mobile phone use history is complex. In addition to amount of use, it depends on phone type, network properties, conditions of use and tumour location. It is therefore important to take these into account in analyses of risk of brain tumours in relation to RF exposure in Interphone and future case-control and cohort studies.
• An algorithm was therefore developed to estimate the amount of RF energy deposition at the centre of tumours in the brain as a measure of RF dose.
• The present paper is the first to use estimates of RF dose from mobile phones in analyses of risk brain tumours.

Results

• An increased risk of glioma was seen in individuals at the highest quintile of RF dose though reduced risks were seen in the four lower quintiles. When risk was examined as a function of dose received in different time windows before diagnosis, an increasing trend was observed with increasing RF dose for exposures 7 or more years in the past. Complementary case-case analyses, made possible by tumour localisation, also indicated an increased risk in the most exposed region of the brain compared to other areas among long-term users.
• Patterns of risk for meningioma in relation to RF dose were similar, although increases in risk were much smaller than for glioma, and not statistically significant.


Conclusions

• Our results suggest there may be an increase in risk of glioma in the most exposed area of the brain among long-term, heavy users of mobile phones. These results are still uncertain (in light of the uncertainties associated with tumour centre localisation, RF dose estimation, and sample size) and require replication before they can be taken to indicate a cause-effect relationship.

References:

• Cardis E, Armstrong BK, Bowman JD, Giles GG, Hours M, Krewski D, McBride M, Parent ME, Sadetzki S, Woodward A, Brown J, Chetrit A, Figuerola J, Hoffmann C, Jarus-Hakak A, Montestruq L, Nadon L, Richardson L, Villegas R, Vrijheid M. Risk of brain tumours in relation to estimated RF dose from mobile phones: results from five Interphone countries. Occup Environ Med. 2011 Jun 9. [Epub ahead of print] DOI: 10.1136/oemed-2011-100155
  http://oem.bmj.com/content/early/2011/06/09/oemed-2011-100155.abstract
   
• Cardis E, Varsier N, Bowman JD, Deltour I, Figuerola J, Mann S, Moissonnier M, Taki M, Vecchia P, Villegas R, Vrijheid M, Wake K, Wiart J. Estimation of RF energy absorbed in the brain from mobile phones in the Interphone Study. Occup Environ Med. 2011 Jun 9. [Epub ahead of print] DOI: 10.1136/oemed-2011-100065  http://oem.bmj.com/content/early/2011/06/09/oemed-2011-100065.abstract