title: Non-participation in chlamydia screening in The Netherlands: determinants associated with young people's intention to participate in chlamydia screening.
abstract: BACKGROUND
  In The Netherlands, a national chlamydia screening program started in 2008, but the participation was low and the screening was not cost-effective. This study aimed to explore unconscious and conscious associations with chlamydia screening (16-29 year-olds). In addition, we examined whether information presented in chlamydia screening invitation letters had an effect on the evaluation of these determinants compared to a no-letter group.
  
  
  METHODS
  An Internet survey was conducted that included self-report measures of attitude, susceptibility, severity, unrealistic optimism, subjective, moral, and descriptive norm, perceived behavioral control, outcome expectations, barriers, intention, and a response time measure to assess unconscious associations of chlamydia screening with annoyance, threat and reassurance.
  
  
  RESULTS
  On the unconscious level, participants (N = 713) who received no information letter associated testing for chlamydia with annoyance and threat, but also with reassurance (all p's < .001). On the self-report measures, participants showed a low intention towards chlamydia screening (M = 1.42, range 1-5). Subjective norm, moral norm, perceived susceptibility and attitude were the most important predictors of the intention to screen (R2 = .56). Participants who rated their susceptibility as high also reported more risky behaviors (p < .001).In the groups that received a letter (N = 735), a weaker unconscious association of chlamydia screening with annoyance was found compared with the no-letter group (p < .001), but no differences were found in reassurance or threat. Furthermore, the letters caused a higher intention (p < .001), but intention remained low (M = 1.74). On a conscious level, giving information caused a more positive attitude, higher susceptibility, a higher subjective and moral norm, and more positive outcome expectations (all p's < .001).
  
  
  CONCLUSIONS
  Subjective norm, moral norm, susceptibility, and attitude towards chlamydia might be crucial targets to increase chlamydia screening behavior among sexually active young people. This study shows that informational invitation letters increase the intention and the intention-predicting variables. More evidence is needed on whether screening behavior can be increased by the use of an alternative information letter adapted to the specific unconscious and conscious determinants revealed in this study, or that we need other, more interactive behavior change methods.
authors.affiliation: Department of Work & Social Psychology, Maastricht University, P,O, Box 616, 6200MD Maastricht, The Netherlands. Gill.tenHoor@MaastrichtUniversity.nl.
authors.forename: Gill A
authors.initials: GA
authors.lastname: ten Hoor
authors.forename: Robert A C
authors.initials: RA
authors.lastname: Ruiter
authors.forename: Jan E A M
authors.initials: JE
authors.lastname: van Bergen
authors.forename: Christian J P A
authors.initials: CJ
authors.lastname: Hoebe
authors.forename: Katrijn
authors.initials: K
authors.lastname: Houben
authors.forename: Gerjo
authors.initials: G
authors.lastname: Kok
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001294:Attitude to Health; D002690:Chlamydia Infections / Q000175:diagnosis* / Q000453:epidemiology; D002692:Chlamydia trachomatis / Q000302:isolation & purification; D003430:Cross-Sectional Studies; D005260:Female; D015438:Health Behavior; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D020407:Internet; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000706:statistics & numerical data; D020380:Needs Assessment; D009426:Netherlands; D010358:Patient Participation / Q000706:statistics & numerical data*; D045808:Refusal to Participate; D012309:Risk-Taking; D012737:Sex Factors; D015231:Sexually Transmitted Diseases, Bacterial / Q000175:diagnosis / Q000453:epidemiology; D055815:Young Adult