title: Reasons for non-participation in follow-up research on eating disorders.
abstract: OBJECTIVE
  Lack of participation in follow-ups is thought to be a serious bias in outcome research on eating disorders; however, little systematic knowledge exists about the problem. The present study aimed to delineate non-participation in long-term follow-up research, and explore the reasons for non-participation.
  
  
  METHODS
  Eating disorder patients (N=840) entering a naturalistic, longitudinal multi-centre study were divided into participators (N=508) and non-participators (N=332) in 36-month follow-ups. Non-participators were further classified as either active (i.e. refused participation or failed to attend scheduled appointments) or passive non-participators (i.e. could not be traced).
  
  
  RESULTS
  Active non-participators exhibited significantly lower levels of general and eating disorder psychopathology at intake compared to participators, while passive non-participators reported higher levels of hostility.
  
  
  CONCLUSIONS
  Systematic exploration of non-participation in longitudinal research can help to mitigate the problem of indistinct results due to missing data. Barriers to successful longitudinal research and how to overcome non-participation at endpoint are discussed.
authors.affiliation: Psychiatric Research Centre, Orebro County Council, S-701 16 Orebro, Sweden. tabita.bjork@orebroll.se
authors.forename: T
authors.initials: T
authors.lastname: Björk
authors.forename: D
authors.initials: D
authors.lastname: Clinton
authors.forename: C
authors.initials: C
authors.lastname: Norring
mesh_terms: D000328:Adult; D017668:Age of Onset; D000704:Analysis of Variance; D015992:Body Mass Index; D015897:Comorbidity; D001068:Feeding and Eating Disorders / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008393:Marriage / Q000706:statistics & numerical data; D001523:Mental Disorders / Q000453:epidemiology; D008875:Middle Aged; D009790:Occupations / Q000706:statistics & numerical data; D010358:Patient Participation / Q000706:statistics & numerical data*; D012649:Self Concept; D016312:Treatment Refusal / Q000706:statistics & numerical data