title: Impact of random and systematic recall errors and selection bias in case--control studies on mobile phone use and brain tumors in adolescents (CEFALO study).
abstract: Whether the use of mobile phones is a risk factor for brain tumors in adolescents is currently being studied. Case--control studies investigating this possible relationship are prone to recall error and selection bias. We assessed the potential impact of random and systematic recall error and selection bias on odds ratios (ORs) by performing simulations based on real data from an ongoing case--control study of mobile phones and brain tumor risk in children and adolescents (CEFALO study). Simulations were conducted for two mobile phone exposure categories: regular and heavy use. Our choice of levels of recall error was guided by a validation study that compared objective network operator data with the self-reported amount of mobile phone use in CEFALO. In our validation study, cases overestimated their number of calls by 9% on average and controls by 34%. Cases also overestimated their duration of calls by 52% on average and controls by 163%. The participation rates in CEFALO were 83% for cases and 71% for controls. In a variety of scenarios, the combined impact of recall error and selection bias on the estimated ORs was complex. These simulations are useful for the interpretation of previous case-control studies on brain tumor and mobile phone use in adults as well as for the interpretation of future studies on adolescents.
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.
authors.forename: Denis
authors.initials: D
authors.lastname: Aydin
authors.forename: Maria
authors.initials: M
authors.lastname: Feychting
authors.forename: Joachim
authors.initials: J
authors.lastname: Schüz
authors.forename: Tina Veje
authors.initials: TV
authors.lastname: Andersen
authors.forename: Aslak Harbo
authors.initials: AH
authors.lastname: Poulsen
authors.forename: Michaela
authors.initials: M
authors.lastname: Prochazka
authors.forename: Lars
authors.initials: L
authors.lastname: Klaeboe
authors.forename: Claudia E
authors.initials: CE
authors.lastname: Kuehni
authors.forename: Tore
authors.initials: T
authors.lastname: Tynes
authors.forename: Martin
authors.initials: M
authors.lastname: Röösli
mesh_terms: D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D016022:Case-Control Studies; D040421:Cell Phone / Q000706:statistics & numerical data*; D002648:Child; D003198:Computer Simulation; D003625:Data Collection / Q000379:methods; D006801:Humans; D011939:Mental Recall; D016017:Odds Ratio; D012107:Research Design; D012306:Risk; D012307:Risk Factors; D015983:Selection Bias