title: Population-based study of chlamydial infection in China: a hidden epidemic.
abstract: BACKGROUND
  Sexually transmitted diseases are increasing rapidly in China. Surveillance data imperfectly indicate current prevalence and risk factors.
  
  
  OBJECTIVE
  To estimate the prevalence of genital chlamydial and gonococcal infections and to describe patterns of infection by subgroup and behavioral patterns.
  
  
  METHODS
  A national stratified probability sample of 3426 Chinese individuals (1738 women and 1688 men) aged 20 to 64 years, who were interviewed between August 1999 and August 2000, completed a computer-administered survey, and provided a urine specimen (69% total participation rate).
  
  
  METHODS
  Positive test result for chlamydial or gonococcal infections.
  
  
  RESULTS
  The overall prevalence per 100 population of chlamydial infection was 2.6 (95% confidence interval [CI], 1.6-4.1) for women and 2.1 (95% CI, 1.3-3.3) for men. For gonococcal infection, the overall prevalence per 100 population was 0.08 (95% CI, 0.02-0.4) for women and 0.02 (95% CI, 0.005-0.1) for men. Risk factors for chlamydial infection among men aged 20 to 44 years were unprotected sex with a commercial sex worker (odds ratio [OR], 8.24; 95% CI, 3.51-19.35), less education (OR, 7.20; 95% CI, 2.31-22.37), and recent sex with their spouse or other steady partner (OR, 7.73; 95% CI, 2.70-22.10). Among women aged 20 to 44 years, risk factors for chlamydial infection were having less education (OR, 2.82; 95% CI, 1.01-7.91) and living in a city (OR, 3.46; 95% CI, 1.67-7.18) or along the southern coast (OR, 2.16; 95% CI, 1.29-3.63) and having a spouse or other steady sexual partner who earned a high income (OR, 2.85; 95% CI, 1.11-7.29), who socialized often (OR, 2.79; 95% CI, 1.08-7.19), or who traveled less than 1 week per year (OR, 5.40; 95% CI, 1.44-20.3).
  
  
  CONCLUSIONS
  The prevalence of chlamydial infection in China is substantial. The patterns of infection suggest potential avenues for intervention.
authors.affiliation: Population Research Center, National Opinion Research Center/University of Chicago, Chicago, Ill, USA. w-parish@uchicago.edu
authors.forename: William L
authors.initials: WL
authors.lastname: Parish
authors.forename: Edward O
authors.initials: EO
authors.lastname: Laumann
authors.forename: Myron S
authors.initials: MS
authors.lastname: Cohen
authors.forename: Suiming
authors.initials: S
authors.lastname: Pan
authors.forename: Heyi
authors.initials: H
authors.lastname: Zheng
authors.forename: Irving
authors.initials: I
authors.lastname: Hoffman
authors.forename: Tianfu
authors.initials: T
authors.lastname: Wang
authors.forename: Kwai Hang
authors.initials: KH
authors.lastname: Ng
mesh_terms: D000328:Adult; D002681:China / Q000453:epidemiology; D002690:Chlamydia Infections / Q000175:diagnosis / Q000453:epidemiology*; D002692:Chlamydia trachomatis / Q000302:isolation & purification; D004196:Disease Outbreaks; D005260:Female; D006069:Gonorrhea / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011159:Population Surveillance / Q000379:methods; D015995:Prevalence; D012307:Risk Factors; D015231:Sexually Transmitted Diseases, Bacterial / Q000175:diagnosis / Q000453:epidemiology*; D012959:Socioeconomic Factors; D016482:Urinalysis