Journal of Exposure Science and Environmental Epidemiology (2009) 19, 369–381; doi:10.1038/jes.2008.27; published online 21 May 2008

Recall bias in the assessment of exposure to mobile phones

Martine Vrijheida,b, Bruce K Armstrongc, Daniel Bédardd, Julianne Brownc, Isabelle Deltoura, Ivano Iavaronee, Daniel Krewskid, Susanna Lagoriof, Stephen Moorec, Lesley Richardsona, Graham G Gilesg, Mary Mcbrideh, Marie-Elise Parenti, Jack Siemiatyckij and Elisabeth Cardisa,b

  1. aRadiation Group, International Agency for Research on Cancer, Lyon, France
  2. bCentre for Research in Environmental Epidemiology (CREAL), Municipal Institute of Medical Research (IMIM), Barcelona, Spain
  3. cSydney Cancer Centre and School of Public Health, The University of Sydney, Sydney, New South Wales, Australia
  4. dMcLaughlin Centre for population Health Risk Assessment, University of Ottawa, Ottawa, Ontario, Canada
  5. eDepartment of Environment & Primary Prevention, Istituto Superiore di Sanità, Rome, Italy
  6. fNational Centre for Epidemiology, Surveillance and Health Promotion, Istituto Superiore di Sanità, Rome, Italy
  7. gCancer Epidemiology Centre, The Cancer Council Victoria, Melbourne, Victoria, Australia
  8. hB.C. Cancer Agency, Vancouver, British Columbia, Canada
  9. iINRS-Institut Armand-Frappier, Université du Québec, Laval, Quebec, Canada
  10. jUniversity of Montreal, Montreal, Quebec, Canada

Correspondence: Dr. Martine Vrijheid, Centre for Research in Environmental Epidemiology (CREAL), Municipal Institute of Medical Research (IMIM), Doctor Aiguader 88, 08003 Barcelona, Spain. Tel. +34 9330 160 671; E-mail:

Received 29 January 2008; Accepted 2 April 2008; Published online 21 May 2008.



Most studies of mobile phone use are case–control studies that rely on participants’ reports of past phone use for their exposure assessment. Differential errors in recalled phone use are a major concern in such studies. INTERPHONE, a multinational case–control study of brain tumour risk and mobile phone use, included validation studies to quantify such errors and evaluate the potential for recall bias. Mobile phone records of 212 cases and 296 controls were collected from network operators in three INTERPHONE countries over an average of 2 years, and compared with mobile phone use reported at interview. The ratio of reported to recorded phone use was analysed as measure of agreement. Mean ratios were virtually the same for cases and controls: both underestimated number of calls by a factor of 0.81 and overestimated call duration by a factor of 1.4. For cases, but not controls, ratios increased with increasing time before the interview; however, these trends were based on few subjects with long-term data. Ratios increased by level of use. Random recall errors were large. In conclusion, there was little evidence for differential recall errors overall or in recent time periods. However, apparent overestimation by cases in more distant time periods could cause positive bias in estimates of disease risk associated with mobile phone use.


bias, recall, case–control studies, cellular phone, brain neoplasms


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