title: Comparison of self-reported and test-identified chlamydial infections among young adults in the United States of America.
abstract: BACKGROUND
  Many studies rely on respondent reports of prior diagnosed sexually transmissible infections (STIs), but these self reports are likely to under-estimate infection prevalence. The extent of bias from using self-reported STI data, and whether bias varies by sex and race, is largely unknown. This gap is addressed using a large, nationally representative sample.
  
  
  METHODS
  Cross-sectional analyses of Wave III of the National Longitudinal Study of Adolescent Health. Participants were 18-26 years old (n = 12,359). Estimates of the prevalence of chlamydial infection based on self-reported diagnoses in the past year were compared with actual prevalence based on nucleic acid amplification testing (NAAT) at the time of data collection. Ratios of test-identified prevalence to self-reported diagnosis prevalence were calculated by sex and race/ethnicity groups. Larger ratios indicate greater extent of self reports under-estimating infection prevalence.
  
  
  RESULTS
  About 4.2% of the sample had a current NAAT-identified chlamydial infection, but only 3.0% reported having been diagnosed with chlamydia in the past year, yielding a ratio of 1.43. The ratio of test-identified infection prevalence to prevalence identified from self-reported diagnoses was larger among men than women (2.07 versus 1.14, P < 0.05). Among men, the ratio was larger among non-Hispanic blacks (2.40) compared with non-Hispanic whites (1.07, P < 0.05).
  
  
  CONCLUSIONS
  Use of self-reported diagnoses under-estimates chlamydial infection prevalence, particularly among men, and among non-Hispanic black men. Reliance on self-reported STIs may consequently lead to biased conclusions, particularly for these groups. Use of biological testing for STIs in research studies is recommended.
authors.affiliation: Pacific Institute for Research and Evaluation, 1516 E. Franklin St., Ste 200, Chapel Hill, North Carolina 27514, USA. iritani@pire.org
authors.forename: Bonita J
authors.initials: BJ
authors.lastname: Iritani
authors.forename: Carol A
authors.initials: CA
authors.lastname: Ford
authors.forename: William C
authors.initials: WC
authors.lastname: Miller
authors.forename: Denise Dion
authors.initials: DD
authors.lastname: Hallfors
authors.forename: Carolyn Tucker
authors.initials: CT
authors.lastname: Halpern
mesh_terms: D000293:Adolescent; D000328:Adult; D002690:Chlamydia Infections / Q000453:epidemiology* / Q000208:ethnology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D021141:Nucleic Acid Amplification Techniques; D015995:Prevalence; D011446:Prospective Studies; D012650:Self Disclosure; D015231:Sexually Transmitted Diseases, Bacterial / Q000453:epidemiology / Q000208:ethnology; D014481:United States / Q000453:epidemiology