title: Sexual behaviour in Britain: reported sexually transmitted infections and prevalent genital Chlamydia trachomatis infection.
abstract: BACKGROUND
  Studies of the epidemiology of sexually transmitted infections (STI) are largely based on surveillance data. As part of a national survey of sexual attitudes and lifestyles (Natsal 2000) in Britain, we estimated the frequency of self-reported STIs, and the prevalence of urinary Chlamydia trachomatis infection.
  
  
  METHODS
  We did a stratified probability sample survey of 11161 men and women aged 16-44 years in Britain. Computer assisted self-interviews contained items on the nature and timing of previously diagnosed STIs. Half of all sexually experienced respondents aged 18-44 years were invited to provide a urine sample for ligase chain reaction testing for C trachomatis infection.
  
  
  RESULTS
  10.8% of men and 12.6% of women reported ever having an STI, 3.6% of men and 4.1% of women reported ever being diagnosed with genital warts, and 1.4% of men and 3.1% of women reported previous infection with C trachomatis. 76% of men and 57% of women ever diagnosed with an STI had been to a GUM clinic. C trachomatis was found in 2.2% (95% CI 1.5-3.2) of men and 1.5% (95% CI 1.11-2.14) of women with age-specific prevalence being highest among men aged 25-34 (3.1%) and women aged 16-24 years (3.0%). Non-married status, age, and reporting partner concurrency or two or more sexual partners in the past year were independently associated with infection with C trachomatis.
  
  
  CONCLUSIONS
  We show substantial heterogeneity in distribution of reported STIs, and the demographic and behavioural determinants of prevalent genital chlamydial infection. The results have potentially wide application for proposed chlamydia screening programmes which, given the demonstrated prevalence, must now proactively seek to involve men.
authors.affiliation: Centre for Infectious Disease Epidemiology, Department of Primary Care, Royal Free and University College London Medical School, London, UK.
authors.forename: K A
authors.initials: KA
authors.lastname: Fenton
authors.forename: C
authors.initials: C
authors.lastname: Korovessis
authors.forename: A M
authors.initials: AM
authors.lastname: Johnson
authors.forename: A
authors.initials: A
authors.lastname: McCadden
authors.forename: S
authors.initials: S
authors.lastname: McManus
authors.forename: K
authors.initials: K
authors.lastname: Wellings
authors.forename: C H
authors.initials: CH
authors.lastname: Mercer
authors.forename: C
authors.initials: C
authors.lastname: Carder
authors.forename: A J
authors.initials: AJ
authors.lastname: Copas
authors.forename: K
authors.initials: K
authors.lastname: Nanchahal
authors.forename: W
authors.initials: W
authors.lastname: Macdowall
authors.forename: G
authors.initials: G
authors.lastname: Ridgway
authors.forename: J
authors.initials: J
authors.lastname: Field
authors.forename: B
authors.initials: B
authors.lastname: Erens
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002690:Chlamydia Infections / Q000453:epidemiology* / Q000652:urine; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D008297:Male; D017533:Marital Status; D011159:Population Surveillance; D015995:Prevalence; D017678:Sex Distribution; D012725:Sexual Behavior; D012749:Sexually Transmitted Diseases / Q000453:epidemiology*; D012923:Social Class; D006113:United Kingdom / Q000453:epidemiology