title: Substance use patterns and unprotected sex among street-involved youth in a Canadian setting: a prospective cohort study.
abstract: BACKGROUND
  Rates of sexually transmitted infections (STI) and unplanned pregnancy are high among youth. While the intersection between drug and alcohol use and unprotected sex is well recognized, few studies have examined the relationship between substance use patterns and unprotected sex among high risk-populations such as street-involved youth.
  
  
  METHODS
  Data were derived from the At-Risk Youth Study (ARYS), a prospective cohort of street-involved youth from Vancouver, Canada. Generalized estimating equations (GEE) were used to examine substance use patterns that were independently associated with unprotected sex, defined as (vaginal or anal) sexual intercourse without consistent condom use.
  
  
  RESULTS
  Between September 2005 and May 2013, 1,026 youth were recruited into the ARYS cohort and 75% (n = 766) reported engaging in recent unprotected sex at some point during the study period. In a multivariable analysis, female gender (adjusted odds ratio [AOR] = 1.46, 95% confidence interval [CI]: 1.18-1.81), Caucasian ancestry (AOR = 1.38, 95% CI: 1.13-1.68), being in a stable relationship (AOR = 4.64, 95% CI: 3.82-5.65), having multiple sex partners (AOR = 2.60, 95% CI: 2.18-3.10) and the following substance use patterns were all independently associated with recent unprotected sex: injection or non-injection crystal methamphetamine use (AOR = 1.21, 95% CI: 1.03-1.43), injection or non-injection cocaine use (AOR = 1.20, 95% CI: 1.02-1.41), marijuana use (AOR = 1.23, 95% CI: 1.02-1.49), ecstasy use (AOR = 1.23, 95% CI: 1.01-1.48) and alcohol use (AOR = 1.31, 95% CI: 1.11-1.55) (all p < 0.05).
  
  
  CONCLUSIONS
  Unprotected sex was prevalent among street-involved youth in this setting, and independently associated with female gender and a wide range of substance use patterns. Evidence-based and gender-informed sexual health interventions are needed in addition to increased access to youth-centered addiction treatment services. STI testing and linkages to healthcare professionals remain important priorities for street-involved youth, and should be integrated across all health and social services.
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, 608-1081 Burrard Street, Vancouver, B.C., Canada, V6Z 1Y6. tcheng@cfenet.ubc.ca.|Faculty of Health Sciences, Simon Fraser University, Blusson Hall, Room 11300, 8888 University Drive, Burnaby, B.C., Canada, V5A 1S6. tcheng@cfenet.ubc.ca.
authors.forename: Tessa
authors.initials: T
authors.lastname: Cheng
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, 608-1081 Burrard Street, Vancouver, B.C., Canada, V6Z 1Y6. caitlinj@sfu.ca.|BC Women Hospital and Health Centre, 4500 Oak St, Vancouver, B.C., Canada, V6H 3V5. caitlinj@sfu.ca.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Johnston
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, 608-1081 Burrard Street, Vancouver, B.C., Canada, V6Z 1Y6. uhri-tk@cfenet.ubc.ca.|Faculty of Medicine, University of British Columbia, 317 - 2194 Health Sciences Mall, Vancouver, B.C., Canada, V6T 1Z3. uhri-tk@cfenet.ubc.ca.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kerr
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, 608-1081 Burrard Street, Vancouver, B.C., Canada, V6Z 1Y6. uhri@cfenet.ubc.ca.
authors.forename: Paul
authors.initials: P
authors.lastname: Nguyen
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, 608-1081 Burrard Street, Vancouver, B.C., Canada, V6Z 1Y6. uhri-ew@cfenet.ubc.ca.|Faculty of Medicine, University of British Columbia, 317 - 2194 Health Sciences Mall, Vancouver, B.C., Canada, V6T 1Z3. uhri-ew@cfenet.ubc.ca.
authors.forename: Evan
authors.initials: E
authors.lastname: Wood
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, 608-1081 Burrard Street, Vancouver, B.C., Canada, V6Z 1Y6. uhri-kd@cfenet.ubc.ca.|School of Public Policy, Simon Fraser University, 515 West Hastings Street, Suite 3271, Vancouver, B.C., Canada, V6B 5K3. uhri-kd@cfenet.ubc.ca.
authors.forename: Kora
authors.initials: K
authors.lastname: DeBeck
mesh_terms: D000293:Adolescent; D000328:Adult; D000428:Alcohol Drinking; D000662:Amphetamines; D002170:Canada; D002188:Cannabis; D003042:Cocaine; D015331:Cohort Studies; D005260:Female; D018453:Homeless Youth; D006801:Humans; D013287:Illicit Drugs; D008297:Male; D016017:Odds Ratio; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D012309:Risk-Taking; D012737:Sex Factors; D012749:Sexually Transmitted Diseases; D019966:Substance-Related Disorders / Q000150:complications*; D047568:Unsafe Sex; D055815:Young Adult
chemical_list: D000662:Amphetamines; D013287:Illicit Drugs; D003042:Cocaine