title: Methamphetamine use and risky sexual behaviors during heterosexual encounters.
abstract: OBJECTIVE
  This study examined the association between event-level methamphetamine use and heterosexual risk behaviors.
  
  
  METHODS
  Data on 1213 heterosexual encounters were collected using audio-computer assisted self interviews from 703 injecting drug users in North Carolina. Data were obtained by asking participants a series of questions about the last time that they had sex (oral, vaginal, and/or anal). Although participants were interviewed at up to 3 time points, data were analyzed at the event level rather than as longitudinal because we were interested in the co-occurrence of methamphetamine use and sexual risk behaviors. Multivariate generalized estimating equations models were developed to examine the association between co-occurring methamphetamine use and each of 6 heterosexual risk behaviors.
  
  
  RESULTS
  Methamphetamine was used in 7% of encounters. Methamphetamine use by either or both partners was associated with an increased likelihood of anal intercourse (odds ratio [OR] = 2.41, 95% confidence interval [CI] = 1.29-4.53), vaginal and anal intercourse (OR = 2.41, 95% CI = 1.22-4.77), and sex with a new partner (OR = 1.98, 95% CI = 1.09-3.61). In addition to these behaviors, methamphetamine use by both partners was also significantly associated with unprotected intercourse with a new partner (OR = 5.20, 95% CI = 2.09-12.93) and unprotected anal intercourse (OR = 4.63, 95% CI = 1.69-12.70).
  
  
  CONCLUSIONS
  Methamphetamine use during heterosexual encounters appears to increase sexual risk-taking, especially when both partners are using it.
authors.affiliation: Substance Abuse Treatment Evaluations and Interventions Program, RTI International, Research Triangle Park, North Carolina, USA. zule@rti.org
authors.forename: William A
authors.initials: WA
authors.lastname: Zule
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Costenbader
authors.forename: William J
authors.initials: WJ
authors.lastname: Meyer
authors.forename: Wendee M
authors.initials: WM
authors.lastname: Wechsberg
mesh_terms: D000328:Adult; D017677:Age Distribution; D019969:Amphetamine-Related Disorders / Q000150:complications / Q000453:epidemiology* / Q000517:prevention & control; D005006:Ethnicity; D005260:Female; D020010:Heterosexuality; D006801:Humans; D008297:Male; D009657:North Carolina / Q000453:epidemiology; D012309:Risk-Taking; D017678:Sex Distribution; D012725:Sexual Behavior; D012749:Sexually Transmitted Diseases / Q000150:complications / Q000453:epidemiology* / Q000517:prevention & control; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires