title: Early life influences on the risk of injecting drug use: case control study based on the Edinburgh Addiction Cohort.
abstract: OBJECTIVE
  To investigate childhood influences on onset of injection drug use.
  
  
  METHODS
  Matched case-control study.
  
  
  METHODS
  Edinburgh, Scotland.
  
  
  METHODS
  A total of 432 individuals presenting at a community health facility with injection drug use and 432 age- and sex-matched non-injecting controls recruited through the same facility.
  
  
  METHODS
  Main exposures considered were family structure and experience of public care, carer substance use, physical and sexual victimization and conduct problems, all measured at personal interview. The outcome was history of adult injection drug use recorded in medical records corroborated at personal interview.
  
  
  RESULTS
  Compared to two-parent families all other family structures were associated with increased risk of injection drug use, the greatest increased risk being associated with public care. Violence, criminality and financial problems in the family were also associated with increased risk, as were all types of carer substance use. The greatest increased risk was associated with markers of early conduct problems, particularly school exclusion and childhood contact with the criminal justice system. In multivariable analyses the strongest risk factors for later injecting were always having lived with a relative or family friend (not always a parent) and in care/adopted/foster home at any point [odds ratio (OR) = 2.66, 95% confidence interval (CI): 1.02-6.92 and OR = 2.17, 95% CI: 0.91-5.17, respectively], experienced violence from parent or carer (OR = 2.06, 95% CI: 1.26, 3.38) and early evidence of conduct problems [ever excluded from school (OR = 2.73, 95% CI: 1.68, 4.45); childhood criminality (ever arrested by police pre-adult OR = 3.05, 95% CI: 1.90, 4.89, ever been in borstal/young offenders/list D school OR = 4.70, 95% CI: 2.02, 10.94)]. After adjustment for family structure and conduct problems, sexual victimization was associated weakly with injecting onset (OR = 1.29, 95% CI: 0.76-2.19). More than 70% of injection drug use onset appeared attributable to the risk factors identified.
  
  
  CONCLUSIONS
  Injection drug use in adults is associated strongly with prior childhood adversity, in particular not living with both parents and early conduct problems. Prevention initiatives should also consider these risk factors.
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, UK. john.macleod@bristol.ac.uk
authors.forename: John
authors.initials: J
authors.lastname: Macleod
authors.forename: Matthew
authors.initials: M
authors.lastname: Hickman
authors.forename: Hayley E
authors.initials: HE
authors.lastname: Jones
authors.forename: Lorraine
authors.initials: L
authors.lastname: Copeland
authors.forename: James
authors.initials: J
authors.lastname: McKenzie
authors.forename: Daniela
authors.initials: D
authors.lastname: De Angelis
authors.forename: Jo
authors.initials: J
authors.lastname: Kimber
authors.forename: James R
authors.initials: JR
authors.lastname: Robertson
mesh_terms: D000328:Adult; D017668:Age of Onset; D017028:Caregivers / Q000523:psychology; D016022:Case-Control Studies; D002648:Child; D015331:Cohort Studies; D019955:Conduct Disorder / Q000150:complications; D005191:Family Characteristics; D005260:Female; D006801:Humans; D008016:Life Change Events; D008297:Male; D012307:Risk Factors; D012606:Scotland; D015819:Substance Abuse, Intravenous / Q000523:psychology*; D055815:Young Adult