title: Joint effects of alcohol consumption and high-risk sexual behavior on HIV seroconversion among men who have sex with men.
abstract: OBJECTIVE
  To estimate the effects of alcohol consumption and number of unprotected receptive anal intercourse partners on HIV seroconversion while appropriately accounting for time-varying confounding.
  
  
  METHODS
  Prospective cohort of 3725 HIV-seronegative men in the Multicenter AIDS Cohort Study between 1984 and 2008.
  
  
  METHODS
  Marginal structural models were used to estimate the joint effects of alcohol consumption and number of unprotected receptive anal intercourse partners on HIV seroconversion.
  
  
  RESULTS
  Baseline self-reported alcohol consumption was a median 8  drinks/week (quartiles: 2, 16), and 30% of participants reported multiple unprotected receptive anal intercourse partners in the prior 2 years. Five hundred and twenty-nine HIV seroconversions occurred over 35 ,870 person-years of follow-up. After accounting for several measured confounders using a joint marginal structural Cox proportional hazards model, the hazard ratio for seroconversion associated with moderate drinking (1-14 drinks/week) compared with abstention was 1.10 [95% confidence limits: 0.78, 1.54] and for heavy drinking (>14 drinks/week) was 1.61 (95% confidence limits: 1.12, 2.29) (P for trend <0.001). The hazard ratios for heavy drinking compared with abstention for participants with 0-1 or more than 1 unprotected receptive anal intercourse partner were 1.37 (95% confidence limits: 0.88, 2.16) and 1.96 (95% confidence limits: 1.03, 3.72), respectively (P for interaction = 0.42).
  
  
  CONCLUSIONS
  These findings suggest that alcohol interventions to reduce heavy drinking among men who have sex with men should be integrated into existing HIV prevention activities.
authors.affiliation: Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, Chapel Hill, NC, USA.
authors.forename: Petra M
authors.initials: PM
authors.lastname: Sander
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Cole
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Stall
authors.forename: Lisa P
authors.initials: LP
authors.lastname: Jacobson
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Eron
authors.forename: Sonia
authors.initials: S
authors.lastname: Napravnik
authors.forename: Bradley N
authors.initials: BN
authors.lastname: Gaynes
authors.forename: Lisette M
authors.initials: LM
authors.lastname: Johnson-Hill
authors.forename: Robert K
authors.initials: RK
authors.lastname: Bolan
authors.forename: David G
authors.initials: DG
authors.lastname: Ostrow
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000517:prevention & control*; D000328:Adult; D000428:Alcohol Drinking / Q000009:adverse effects*; D006679:HIV Seropositivity / Q000175:diagnosis* / Q000276:immunology; D015497:HIV-1 / Q000276:immunology; D007722:Health Knowledge, Attitudes, Practice; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012309:Risk-Taking; D012747:Sexual Partners; D014481:United States; D047568:Unsafe Sex / Q000523:psychology / Q000706:statistics & numerical data*