title: Hepatitis B and hepatitis C virus infections: risk factors among drug users in Northwest England.
abstract: OBJECTIVE
  to identify the risk factors for hepatitis B (HBV) and hepatitis C (HCV) virus infections in drug users attending two drug treatment centres in Northwest England, and to evaluate the effect of both needle exchange and hepatitis B vaccination on the prevalence of hepatitis B and hepatitis C infections.
  
  
  METHODS
  a retrospective, cross-sectional study performed at the Regional Infectious Disease Unit and a Primary Care Centre for drug users in Liverpool. The study population included 773 drug users who had hepatitis serology performed between January 1992 and April 1996. Information on risk factors was obtained from clinical records; hepatitis serology data were obtained from the Liverpool Public Health Laboratory database.
  
  
  RESULTS
  the overall seroprevalences of exposure markers for HBV (anti-HBc antibody) and HCV (anti-HCV antibody) were 48% and 67%, respectively. Duration of injecting drug use was the strongest predictor of HCV infection, with a crude odds ratio of 8.9 (95% confidence interval (CI): 4.5-17) for >10 compared to <3 years of injecting, and was also a strong predictor of HBV infection, with an adjusted odds ratio (controlled for the effects of HBV vaccination) of 5.7 (95% CI: 3.2-10) for >10 compared to <3 years' injecting. Vaccination against HBV was associated with greatly reduced HBV seroprevalence (crude odds ratio 0.11, 95% CI: 0.06-0.18). Overall, HCV was acquired earlier in the injecting career than HBV, but drug users who were not vaccinated against HBV acquired markers for HBV even more rapidly than for HCV. We found no independent protective effect for either anti-HBc or anti-HCV acquisition after the introduction of a needle-exchange scheme.
  
  
  CONCLUSIONS
  hepatitis C is highly prevalent among Merseyside drug users and is likely to prove difficult to control because of rapid acquisition early in the injecting career. Vaccination against hepatitis B is the best means of protecting drug users from hepatitis B, and should be offered before injecting is commenced.
authors.affiliation: Regional Infectious Disease Unit, Fazakerley Hospital, Liverpool, UK.
authors.forename: K H
authors.initials: KH
authors.lastname: Lamden
authors.forename: N
authors.initials: N
authors.lastname: Kennedy
authors.forename: N J
authors.initials: NJ
authors.lastname: Beeching
authors.forename: D
authors.initials: D
authors.lastname: Lowe
authors.forename: C L
authors.initials: CL
authors.lastname: Morrison
authors.forename: H
authors.initials: H
authors.lastname: Mallinson
authors.forename: K J
authors.initials: KJ
authors.lastname: Mutton
authors.forename: Q
authors.initials: Q
authors.lastname: Syed
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D004739:England / Q000453:epidemiology; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology* / Q000517:prevention & control; D017325:Hepatitis B Vaccines / Q000627:therapeutic use; D006526:Hepatitis C / Q000453:epidemiology* / Q000517:prevention & control; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D018671:Needle-Exchange Programs; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D019966:Substance-Related Disorders / Q000097:blood / Q000821:virology*
chemical_list: D017325:Hepatitis B Vaccines