title: A meta-analysis of marijuana and alcohol use by socio-economic status in adolescents aged 10-15 years.
abstract: OBJECTIVE
  A majority of population-based studies suggest prevalence of drug and alcohol risk behaviour increases during late adolescence to early adulthood. The purpose of this systematic literature review is to clarify if socio-economic status (SES) is a determinant of marijuana and alcohol risk behaviour in adolescents between the ages of 10-15 years.
  
  
  METHODS
  We performed a meta-analysis to identify published or unpublished papers between January 1, 1980 and February 9, 2007 that reviewed marijuana and alcohol risk behaviour by SES in adolescents aged 10-15 years.
  
  
  RESULTS
  We found nine studies that fulfilled our inclusion criteria and passed the methodological quality review. The prevalence of marijuana and alcohol risk behaviour was 22% higher (RR = 1.22; 95% CI 1.14-1.31) in adolescents with low SES in comparison to adolescents with higher SES. Stratification by country of origin revealed that American and New Zealand studies had statistically significant variability in the reported effects as compared to European and UK studies.
  
  
  CONCLUSIONS
  The evidence suggests that low SES has an inverse association with the prevalence of marijuana and alcohol risk behaviour in adolescents between the ages of 10-15 years. Higher rates of marijuana and alcohol risk behaviour among lower SES adolescents may impact emotional development, limit future educational and occupational achievement, and increase the likelihood for adult marijuana and alcohol addiction.
  
  
  CONCLUSIONS
  Lower SES adolescents have higher rates of marijuana and alcohol risk behaviour than higher SES adolescents.
authors.affiliation: Population Health Research Unit, Saskatoon Health Region, Saskatoon, SK. mark.lemstra@saskatoonhealthregion.ca
authors.forename: Mark
authors.initials: M
authors.lastname: Lemstra
authors.forename: Norman R
authors.initials: NR
authors.lastname: Bennett
authors.forename: Cory
authors.initials: C
authors.lastname: Neudorf
authors.forename: Anton
authors.initials: A
authors.lastname: Kunst
authors.forename: Ushasri
authors.initials: U
authors.lastname: Nannapaneni
authors.forename: Lynne M
authors.initials: LM
authors.lastname: Warren
authors.forename: Tanis
authors.initials: T
authors.lastname: Kershaw
authors.forename: Christina R
authors.initials: CR
authors.lastname: Scott
mesh_terms: D000293:Adolescent; D000428:Alcohol Drinking / Q000453:epidemiology*; D002648:Child; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology*; D009520:New Zealand / Q000453:epidemiology; D012923:Social Class; D014481:United States / Q000453:epidemiology