title: Demographic and behavioural profile of adults infected with chlamydia: a case-control study.
abstract: OBJECTIVE
  To determine which demographic and behavioural parameters are independently associated with chlamydial infection in adults.
  
  
  METHODS
  Subjects were recruited prospectively from male and female attendees at a large clinic for sexually transmitted infections (STI). All subjects were tested for chlamydia and gonorrhoea and asked to complete a questionnaire addressing demography, sexual and non-sexual (including drug taking) behaviour, and history of STI. Cases were those attending with a new clinical episode and found to be infected with chlamydia, but who did not have gonorrhoea. A control group was selected randomly from those found to be negative on screening for both infections.
  
  
  RESULTS
  986 cases and 1212 controls were recruited over one calendar year. The following were found to be independent risk factors for chlamydial infection on multivariate analysis (odds ratios with 95% confidence intervals in parentheses): being unmarried (1.8; 1.1-3.1); black Caribbean ethnicity (2; 1.5-2.7). Increasing age, fewer partners, and higher reported use of condoms were associated with a lower risk of infection.
  
  
  CONCLUSIONS
  Black Caribbeans are at increased risk from chlamydia after controlling for sexual behaviour and socioeconomic status. Future research should seek an explanation elsewhere-for example, in terms of differences in sexual mixing or effectiveness of healthcare interventions.
authors.affiliation: Whittall Street Clinic, Birmingham, UK. bscht.wmids.nhs.uk
authors.forename: K W
authors.initials: KW
authors.lastname: Radcliffe
authors.forename: S
authors.initials: S
authors.lastname: Ahmad
authors.forename: G
authors.initials: G
authors.lastname: Gilleran
authors.forename: J D
authors.initials: JD
authors.lastname: Ross
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D017691:Caribbean Region / Q000208:ethnology; D016022:Case-Control Studies; D002690:Chlamydia Infections / Q000453:epidemiology* / Q000209:etiology; D002692:Chlamydia trachomatis; D017280:Condoms / Q000706:statistics & numerical data; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D017533:Marital Status; D015999:Multivariate Analysis; D011446:Prospective Studies; D012309:Risk-Taking; D012737:Sex Factors; D012725:Sexual Behavior; D012907:Smoking / Q000009:adverse effects; D012959:Socioeconomic Factors; D019966:Substance-Related Disorders / Q000150:complications; D014526:Urethritis / Q000453:epidemiology* / Q000209:etiology; D002575:Uterine Cervicitis / Q000453:epidemiology* / Q000209:etiology