title: Incident hepatitis C virus infection in men who have sex with men: a prospective cohort analysis, 1984-2011.
abstract: BACKGROUND
  Prospective characterization of hepatitis C virus (HCV) transmission in both human immunodeficiency virus (HIV)-infected and -uninfected men who have sex with men (MSM) over the entire HIV epidemic has not been comprehensively conducted.
  
  
  METHODS
  To determine the trends in and risk factors associated with incident HCV in MSM since 1984, 5310 HCV antibody (anti-HCV)-negative MSM in the Multicenter AIDS Cohort Study were prospectively followed during 1984-2011 for anti-HCV seroconversion.
  
  
  RESULTS
  During 55 343 person-years (PYs) of follow-up, there were 115 incident HCV infections (incidence rate, 2.08/1000 PYs) scattered throughout the study period. In a multivariable analysis with time-varying covariates, older age (incidence rate ratio [IRR], 1.40/10 years, P < .001), enrollment in the later (2001-2003) recruitment period (IRR, 3.80, P = .001), HIV infection (IRR, 5.98, P < .001), drinking >13 alcoholic drinks per week (IRR, 1.68, P < .001), hepatitis B surface antigen positivity (IRR, 1.68, P < .001), syphilis (IRR, 2.95, P < .001), and unprotected receptive anal intercourse with >1 male partner (IRR, 3.37, P < .001) were independently associated with incident HCV. Among HIV-infected subjects, every 100 cell/mm(3) increase in CD4 count was associated with a 7% (P = .002) decrease in the HCV incidence rate up to a CD4 count of 500 cells/mm(3), whereas there was no association with highly active antiretroviral therapy.
  
  
  CONCLUSIONS
  The spread of HCV among both HIV-infected and -uninfected MSM in the United States has been ongoing since the beginning of the HIV epidemic. In HIV-infected men with <500 CD4(+) T cells, the HCV incidence rate was inversely proportional to CD4 T-cell count.
authors.affiliation: Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
authors.forename: Mallory D
authors.initials: MD
authors.lastname: Witt
authors.forename: Eric C
authors.initials: EC
authors.lastname: Seaberg
authors.forename: Annie
authors.initials: A
authors.lastname: Darilay
authors.forename: Stephen
authors.initials: S
authors.lastname: Young
authors.forename: Sheila
authors.initials: S
authors.lastname: Badri
authors.forename: Charles R
authors.initials: CR
authors.lastname: Rinaldo
authors.forename: Lisa P
authors.initials: LP
authors.lastname: Jacobson
authors.forename: Roger
authors.initials: R
authors.lastname: Detels
authors.forename: Chloe L
authors.initials: CL
authors.lastname: Thio
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005500:Follow-Up Studies; D006526:Hepatitis C / Q000453:epidemiology*; D018451:Homosexuality, Male; D006801:Humans; D015994:Incidence; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
keywords: MSM; incident HCV; sexual transmission