title: Predictors of Chlamydia Trachomatis testing: perceived norms, susceptibility, changes in partner status, and underestimation of own risk.
abstract: BACKGROUND
  It is hard to convince people to participate in chlamydia screening programs outside the clinical setting. In two earlier studies (BMC Public Health. 2013;13:1091; J Med Internet Res. 2014;16(1):e24), we identified explicit and implicit determinants of chlamydia screening behavior and attempted, unsuccessfully, to improve participation rates by optimizing the recruitment letter. In the present study, we examined the links between a number of social-cognitive determinants (e.g., stereotypical beliefs about a person with chlamydia, intentions, changes in partner status), and self-reported chlamydia testing behavior six months after the initial study.
  
  
  METHODS
  The present study is a follow-up to our first study (T0). We assessed self-reported testing behavior 6 months after the first measure by means of an online questionnaire (T1; N = 269). Furthermore, at T1, we measured the social-cognitive determinants in more detail, and explored the influence of stereotypical beliefs and any changes in partner status during this six month period.
  
  
  RESULTS
  In total, 25 (9.1 %) of the participants tested for chlamydia at some point during the six months between baseline (T0) and follow up (T1). Testing behavior was influenced by testing intentions in combination with changes in risk behavior. The higher the participants' own numbers of partners ever, the higher they estimated the number of partners of the stereotypical person with chlamydia. Testing intentions were most strongly predicted by perceived norms and susceptibility, and having had multiple partners in the last 6 months (R(2) = .41).
  
  
  CONCLUSIONS
  The most relevant determinants for testing intentions and behavior were susceptibility, subjective norms and changes in partner status. We found a systematic tendency for individuals to underestimate their own risk, especially the risk of inconsistent condom use. Future research should focus on more promising alternatives to population-based interventions, such as online interventions, screening in primary care, the rescreening of positives, and clinic-based interventions. This future research should also focus on making testing easier and reducing barriers to testing, as well as using social and sexual networks in order to reach more people.
authors.affiliation: Department of Work & Social Psychology, Maastricht University, P.O. Box 616, 6200 MD, Maastricht, The Netherlands. Gill.tenHoor@MaastrichtUniversity.nl.
authors.forename: Gill A
authors.initials: GA
authors.lastname: Ten Hoor
authors.affiliation: Department of Work & Social Psychology, Maastricht University, P.O. Box 616, 6200 MD, Maastricht, The Netherlands.
authors.forename: Robert A C
authors.initials: RAC
authors.lastname: Ruiter
authors.affiliation: STI AIDS Netherlands, Keizersgracht 390, 1016GB, Amsterdam, The Netherlands.|Department of General Practice, AMC-University of Amsterdam, P.O. Box 19268, 1000GG, Amsterdam, Netherlands.
authors.forename: Jan E A M
authors.initials: JEAM
authors.lastname: van Bergen
authors.affiliation: Department of Sexual Health, Infectious Disease and Environmental Health, Public Health Service South Limburg, P.O. Box 2022, 6160HA, Geleen, The Netherlands.|Department of Medical Microbiology, Maastricht University, P.O. Box 5800, 6202AZ, Maastricht, The Netherlands.
authors.forename: Christian J P A
authors.initials: CJPA
authors.lastname: Hoebe
authors.affiliation: Department of Sexual Health, Infectious Disease and Environmental Health, Public Health Service South Limburg, P.O. Box 2022, 6160HA, Geleen, The Netherlands.|Department of Medical Microbiology, Maastricht University, P.O. Box 5800, 6202AZ, Maastricht, The Netherlands.
authors.forename: Nicole H T M
authors.initials: NHTM
authors.lastname: Dukers-Muijrers
authors.affiliation: Department of Work & Social Psychology, Maastricht University, P.O. Box 616, 6200 MD, Maastricht, The Netherlands.
authors.forename: Gerjo
authors.initials: G
authors.lastname: Kok
mesh_terms: D000293:Adolescent; D000328:Adult; D000554:Ambulatory Care Facilities; D002690:Chlamydia Infections / Q000175:diagnosis* / Q000523:psychology*; D002692:Chlamydia trachomatis; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D033182:Intention; D008297:Male; D010342:Patient Acceptance of Health Care; D018570:Risk Assessment; D012309:Risk-Taking; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D066262:Social Norms; D055815:Young Adult