title: Recall bias in the assessment of exposure to mobile phones.
abstract: 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.
authors.affiliation: Radiation Group, International Agency for Research on Cancer, Lyon, France. mvrijheid@creal.cat
authors.forename: Martine
authors.initials: M
authors.lastname: Vrijheid
authors.forename: Bruce K
authors.initials: BK
authors.lastname: Armstrong
authors.forename: Daniel
authors.initials: D
authors.lastname: Bédard
authors.forename: Julianne
authors.initials: J
authors.lastname: Brown
authors.forename: Isabelle
authors.initials: I
authors.lastname: Deltour
authors.forename: Ivano
authors.initials: I
authors.lastname: Iavarone
authors.forename: Daniel
authors.initials: D
authors.lastname: Krewski
authors.forename: Susanna
authors.initials: S
authors.lastname: Lagorio
authors.forename: Stephen
authors.initials: S
authors.lastname: Moore
authors.forename: Lesley
authors.initials: L
authors.lastname: Richardson
authors.forename: Graham G
authors.initials: GG
authors.lastname: Giles
authors.forename: Mary
authors.initials: M
authors.lastname: McBride
authors.forename: Marie-Elise
authors.initials: ME
authors.lastname: Parent
authors.forename: Jack
authors.initials: J
authors.lastname: Siemiatycki
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Cardis
mesh_terms: D016022:Case-Control Studies; D040421:Cell Phone; D004781:Environmental Exposure; D006801:Humans; D011939:Mental Recall