title: Baseline participation in a health examination survey of the population 65 years and older: who is missed and why?
abstract: BACKGROUND
  Public health monitoring depends on valid health and disability estimates in the population 65+ years. This is hampered by high non-participation rates in this age group. There is limited insight into size and direction of potential baseline selection bias.
  
  
  METHODS
  We analyzed baseline non-participation in a register-based random sample of 1481 inner-city residents 65+ years, invited to a health examination survey according to demographics available for the entire sample, self-report information as available and reasons for non-participation. One year after recruitment, non-responders were revisited to assess their reasons.
  
  
  RESULTS
  Five groups defined by participation status were differentiated: participants (N = 299), persons who had died or moved (N = 173), those who declined participation, but answered a short questionnaire (N = 384), those who declined participation and the short questionnaire (N = 324), and non-responders (N = 301). The results confirm substantial baseline selection bias with significant underrepresentation of persons 85+ years, persons in residential care or from disadvantaged neighborhoods, with lower education, foreign citizenship, or lower health-related quality of life. Finally, reasons for non-participation could be identified for 78% of all non-participants, including 183 non-responders.
  
  
  CONCLUSIONS
  A diversity in health problems and barriers to participation exists among non-participants. Innovative study designs are needed for public health monitoring in aging populations.
authors.affiliation: Department of Epidemiology and Health Monitoring, Robert-Koch-Institute, General-Pape-Str. 62-66, D-12101, Berlin, Germany. gaertnerb@rki.de.
authors.forename: Beate
authors.initials: B
authors.lastname: Gaertner
authors.affiliation: Department of Epidemiology and Health Monitoring, Robert-Koch-Institute, General-Pape-Str. 62-66, D-12101, Berlin, Germany.
authors.forename: Ina
authors.initials: I
authors.lastname: Seitz
authors.affiliation: Department of Epidemiology and Health Monitoring, Robert-Koch-Institute, General-Pape-Str. 62-66, D-12101, Berlin, Germany.
authors.forename: Judith
authors.initials: J
authors.lastname: Fuchs
authors.affiliation: Department of Epidemiology and Health Monitoring, Robert-Koch-Institute, General-Pape-Str. 62-66, D-12101, Berlin, Germany.
authors.forename: Markus A
authors.initials: MA
authors.lastname: Busch
authors.affiliation: Institute of Biometry and Clinical Epidemiology, Charité - University Medicine Berlin, Hindenburgdamm 30, D-12203, Berlin, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Holzhausen
authors.affiliation: Department of Clinicial Epidemiology and Applied Biometry, Eberhard Karls Universität, Silcherstr. 5, D-72076, Tübingen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Martus
authors.affiliation: Department of Epidemiology and Health Monitoring, Robert-Koch-Institute, General-Pape-Str. 62-66, D-12101, Berlin, Germany.
authors.forename: Christa
authors.initials: C
authors.lastname: Scheidt-Nave
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003144:Communication Barriers; D005260:Female; D005858:Germany; D006306:Health Surveys / Q000379:methods; D006801:Humans; D008297:Male; D010358:Patient Participation / Q000523:psychology / Q000706:statistics & numerical data; D018579:Patient Selection; D011634:Public Health / Q000379:methods / Q000706:statistics & numerical data; D011788:Quality of Life; D045808:Refusal to Participate / Q000523:psychology / Q000706:statistics & numerical data; D057566:Self Report; D011795:Surveys and Questionnaires