title: Temporal changes in HCV genotype distribution in three different high risk populations in San Francisco, California.
abstract: BACKGROUND
  Hepatitis C virus (HCV) genotype (GT) has become an important measure in the diagnosis and monitoring of HCV infection treatment. In the United States (U.S.) HCV GT 1 is reported as the most common infecting GT among chronically infected patients. In Europe, however, recent studies have suggested that the epidemiology of HCV GTs is changing.
  
  
  METHODS
  We assessed HCV GT distribution in 460 patients from three HCV-infected high risk populations in San Francisco, and examined patterns by birth cohort to assess temporal trends. Multiple logistic regression was used to assess factors independently associated with GT 1 infection compared to other GTs (2, 3, and 4).
  
  
  RESULTS
  Overall, GT 1 was predominant (72.4%), however younger injection drug users (IDU) had a lower proportion of GT 1 infections (54.7%) compared to older IDU and HIV-infected patients (80.5% and 76.6%, respectively). Analysis by birth cohort showed increasing proportions of non-GT 1 infections associated with year of birth: birth before 1970 was independently associated with higher adjusted odds of GT 1: AOR 2.03 (95% CI: 1.23, 3.34). African-Americans as compared to whites also had higher adjusted odds of GT 1 infection (AOR: 3.37; 95% CI: 1.89, 5.99).
  
  
  CONCLUSIONS
  Although, HCV GT 1 remains the most prevalent GT, especially among older groups, changes in GT distribution could have significant implications for how HCV might be controlled on a population level and treated on an individual level.
authors.affiliation: Núcleo de Estudos e Pesquisas em Atenção ao Uso de Drogas (NEPAD)-Universidade do Estado do Rio de Janeiro (State University of Rio de Janeiro), 20940-200 Rio de Janeiro, RJ, Brasil.
authors.forename: Paulo Telles
authors.initials: PT
authors.lastname: Dias
authors.forename: Judith A
authors.initials: JA
authors.lastname: Hahn
authors.forename: Eric
authors.initials: E
authors.lastname: Delwart
authors.forename: Brian
authors.initials: B
authors.lastname: Edlin
authors.forename: Jeff
authors.initials: J
authors.lastname: Martin
authors.forename: Paula
authors.initials: P
authors.lastname: Lum
authors.forename: Jennifer
authors.initials: J
authors.lastname: Evans
authors.forename: Alex
authors.initials: A
authors.lastname: Kral
authors.forename: Steve
authors.initials: S
authors.lastname: Deeks
authors.forename: Michael P
authors.initials: MP
authors.lastname: Busch
authors.forename: Kimberly
authors.initials: K
authors.lastname: Page
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D005838:Genotype; D016174:Hepacivirus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D019698:Hepatitis C, Chronic / Q000453:epidemiology* / Q000821:virology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D012495:San Francisco / Q000453:epidemiology; D013997:Time Factors; D044465:White People