title: Use of illicit drugs and erectile dysfunction medications and subsequent HIV infection among gay men in Sydney, Australia.
abstract: BACKGROUND
  Use of illicit drugs and oral erectile dysfunction medications (OEM) have been associated with risk behavior among gay men.
  
  
  OBJECTIVE
  To determine the effects of illicit drugs and OEM as risk factors for HIV seroconversion in a community-based cohort of HIV-negative homosexually active men in Sydney, Australia.
  
  
  METHODS
  Drug use in the previous 6 months and at the most recent sexual encounter; Most recent occasions of unprotected and protected anal intercourse; HIV-positive diagnosis.
  
  
  METHODS
  From June 2001 to June 2007, participants were followed up with 6-monthly detailed behavioral interviews and annual testing for HIV. Detailed information about sexual, drug-using and other behavior was collected.
  
  
  RESULTS
  Among 1,427 participants enrolled, 53 HIV seroconverters were identified by June 2007. At baseline, 62.7% reported using illicit drugs in the previous 6 months, including 10.7% who reported at least weekly use. Illicit drug use was associated with unprotected anal intercourse with casual partners (P < 0.001). Use of illicit drugs was associated with increased risk of HIV infection at a univariate level, and this risk increased with greater frequency of use. This was also true of the use of OEM. Use of each type of illicit drug was included in multivariate analysis, and after controlling for sexual risk behaviors, only use of OEM remained significantly predictive of HIV infection (Hazard ratios [HR] = 1.75, CI = 1.31-2.33, P < 0.001), although amyl nitrite was of borderline significance (HR = 1.26, CI = 0.98-1.62, P = 0.074).
  
  
  CONCLUSIONS
  The association between drug use and increased risk of HIV infection was strongest for drugs used specifically to enhance sexual pleasure, particularly OEM. The risk of infection was substantially increased when both OEM and methamphetamine were used. Within more "adventurous" gay community subcultures, the interconnectedness of sexual behavior and drug use may be key to understanding HIV risk and is an appropriate priority in HIV-prevention efforts in this population.
authors.affiliation: National Center in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, Australia. gprestage@nchecr.unsw.edu.au
authors.forename: Garrett
authors.initials: G
authors.lastname: Prestage
authors.forename: Fengyi
authors.initials: F
authors.lastname: Jin
authors.forename: Susan
authors.initials: S
authors.lastname: Kippax
authors.forename: Iryna
authors.initials: I
authors.lastname: Zablotska
authors.forename: John
authors.initials: J
authors.lastname: Imrie
authors.forename: Andrew
authors.initials: A
authors.lastname: Grulich
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000680:Amyl Nitrite; D001315:Australia / Q000453:epidemiology; D015331:Cohort Studies; D016001:Confidence Intervals; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000635:transmission; D006679:HIV Seropositivity; D018451:Homosexuality, Male / Q000706:statistics & numerical data*; D006801:Humans; D013287:Illicit Drugs; D008297:Male; D008875:Middle Aged; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D012307:Risk Factors; D012309:Risk-Taking; D012725:Sexual Behavior; D000068677:Sildenafil Citrate; D013450:Sulfones; D011795:Surveys and Questionnaires; D014665:Vasodilator Agents; D055815:Young Adult
chemical_list: D013287:Illicit Drugs; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014665:Vasodilator Agents; D000680:Amyl Nitrite; D000068677:Sildenafil Citrate