title: Determinants of non- response to a second assessment of lifestyle factors and body weight in the EPIC-PANACEA study.
abstract: BACKGROUND
  This paper discusses whether baseline demographic, socio-economic, health variables, length of follow-up and method of contacting the participants predict non-response to the invitation for a second assessment of lifestyle factors and body weight in the European multi-center EPIC-PANACEA study.
  
  
  METHODS
  Over 500.000 participants from several centers in ten European countries recruited between 1992 and 2000 were contacted 2-11 years later to update data on lifestyle and body weight. Length of follow-up as well as the method of approaching differed between the collaborating study centers. Non-responders were compared with responders using multivariate logistic regression analyses.
  
  
  RESULTS
  Overall response for the second assessment was high (81.6%). Compared to postal surveys, centers where the participants completed the questionnaire by phone attained a higher response. Response was also high in centers with a short follow-up period. Non-response was higher in participants who were male (odds ratio 1.09 (confidence interval 1.07; 1.11), aged under 40 years (1.96 (1.90; 2.02), living alone (1.40 (1.37; 1.43), less educated (1.35 (1.12; 1.19), of poorer health (1.33 (1.27; 1.39), reporting an unhealthy lifestyle and who had either a low (<18.5 kg/m2, 1.16 (1.09; 1.23)) or a high BMI (>25, 1.08 (1.06; 1.10); especially ≥30 kg/m2, 1.26 (1.23; 1.29)).
  
  
  CONCLUSIONS
  Cohort studies may enhance cohort maintenance by paying particular attention to the subgroups that are most unlikely to respond and by an active recruitment strategy using telephone interviews.
authors.affiliation: Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht, Utrecht University, PO Box 85500, 3508, GA, Utrecht, The Netherlands. a.m.may@umcutrecht.nl
authors.forename: Anne M
authors.initials: AM
authors.lastname: May
authors.forename: Lotte E
authors.initials: LE
authors.lastname: Adema
authors.forename: Dora
authors.initials: D
authors.lastname: Romaguera
authors.forename: Anne-Claire
authors.initials: AC
authors.lastname: Vergnaud
authors.forename: Antonio
authors.initials: A
authors.lastname: Agudo
authors.forename: Ulf
authors.initials: U
authors.lastname: Ekelund
authors.forename: Annika
authors.initials: A
authors.lastname: Steffen
authors.forename: Philippos
authors.initials: P
authors.lastname: Orfanos
authors.forename: Nadia
authors.initials: N
authors.lastname: Slimani
authors.forename: Sabina
authors.initials: S
authors.lastname: Rinaldi
authors.forename: Traci
authors.initials: T
authors.lastname: Mouw
authors.forename: Sabine
authors.initials: S
authors.lastname: Rohrmann
authors.forename: Silke
authors.initials: S
authors.lastname: Hermann
authors.forename: Heiner
authors.initials: H
authors.lastname: Boeing
authors.forename: Manuela M
authors.initials: MM
authors.lastname: Bergmann
authors.forename: Marianne Uhre
authors.initials: MU
authors.lastname: Jakobsen
authors.forename: Kim
authors.initials: K
authors.lastname: Overvad
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Wareham
authors.forename: Carlos
authors.initials: C
authors.lastname: Gonzalez
authors.forename: Anne
authors.initials: A
authors.lastname: Tjonneland
authors.forename: Jytte
authors.initials: J
authors.lastname: Halkjaer
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Key
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Spencer
authors.forename: Veronica
authors.initials: V
authors.lastname: Hellstrom
authors.forename: Jonas
authors.initials: J
authors.lastname: Manjer
authors.forename: Bo
authors.initials: B
authors.lastname: Hedblad
authors.forename: Eiliv
authors.initials: E
authors.lastname: Lund
authors.forename: Tonje
authors.initials: T
authors.lastname: Braaten
authors.forename: Françoise
authors.initials: F
authors.lastname: Clavel-Chapelon
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Boutron-Ruault
authors.forename: Laudina
authors.initials: L
authors.lastname: Rodríguez
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Sánchez
authors.forename: Miren
authors.initials: M
authors.lastname: Dorronsoro
authors.forename: Aurelio
authors.initials: A
authors.lastname: Barricarte
authors.forename: Jose Maria
authors.initials: JM
authors.lastname: Huerta
authors.forename: Androniki
authors.initials: A
authors.lastname: Naska
authors.forename: Antonia
authors.initials: A
authors.lastname: Trichopoulou
authors.forename: Domenico
authors.initials: D
authors.lastname: Palli
authors.forename: Valeria
authors.initials: V
authors.lastname: Pala
authors.forename: Teresa
authors.initials: T
authors.lastname: Norat
authors.forename: Amalia
authors.initials: A
authors.lastname: Mattiello
authors.forename: Rosario
authors.initials: R
authors.lastname: Tumino
authors.forename: Daphne
authors.initials: D
authors.lastname: van der A
authors.forename: H Bas
authors.initials: HB
authors.lastname: Bueno-de-Mesquita
authors.forename: Elio
authors.initials: E
authors.lastname: Riboli
authors.forename: Petra H M
authors.initials: PH
authors.lastname: Peeters
mesh_terms: D000328:Adult; D000368:Aged; D000886:Anthropometry; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology*; D003430:Cross-Sectional Studies; D004435:Eating; D002149:Energy Intake; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology*; D011446:Prospective Studies; D012147:Restaurants; D012307:Risk Factors; D012737:Sex Factors; D015430:Weight Gain / Q000502:physiology; D017132:Workplace / Q000706:statistics & numerical data