title: Impacts of New Zealand's lowered minimum purchase age on context-specific drinking and related risks.
abstract: OBJECTIVE
  The minimum purchase age (MPA) for alcohol in New Zealand (NZ) was reduced from 20 to 18 years in 1999. We assessed the degree to which this change was associated with alterations in uses of drinking contexts, drinking and related problems.
  
  
  METHODS
  NZ National Alcohol Surveys among people 14+ years of age provided demographics, frequencies and amounts consumed in drinking places, and problem measures for 1995, 2000 and 2004. Censored regression estimates of parameters of a context-specific dose-response model identified MPA-associated changes in drinking and problems.
  
  
  RESULTS
  The lowered MPA was associated with more frequent drinking at pubs/nightclubs among the newly of-age 18-19-year-olds (b = 15.26, P = 0.009), moderated drinking quantities at these places (b = -0.94, P = 0.034) and greater quantities consumed at home (b = 1.01, P = 0.010) and others' homes (b = 0.87; P = 0.029). Drinking frequency and quantity in the 16-17-year age group increased at home (b = 22.11, P = 0.040 and b = 1.22, P = 0.002) and others' homes (b = 11.65, P = 0.002 and b = 0.91, P = 0.021). Problems associated with drinking contexts changed post-MPA (G(2)  ≥ 27.45, P ≤ 0.002), specifically increased association with drinking in pubs/nightclubs (b = 0.09, P < 0.001) across both age groups.
  
  
  CONCLUSIONS
  The 1999 change in New Zealand's minimum purchase age for alcohol from 20 to 18 years appears to have been associated with substantive changes in uses of drinking contexts, drinking and associated drinking problems among 16-19-year-olds.
authors.affiliation: Prevention Research Center, Pacific Institute for Research and Evaluation, Oakland, CA, USA.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Gruenewald
authors.affiliation: Prevention Research Center, Pacific Institute for Research and Evaluation, Oakland, CA, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Treno
authors.affiliation: Prevention Research Center, Pacific Institute for Research and Evaluation, Oakland, CA, USA.
authors.forename: William R
authors.initials: WR
authors.lastname: Ponicki
authors.affiliation: SHORE and Whariki, Massey University, Palmerston North, New Zealand.
authors.forename: Taisia
authors.initials: T
authors.lastname: Huckle
authors.affiliation: SHORE and Whariki, Massey University, Palmerston North, New Zealand.
authors.forename: Li-Chia
authors.initials: LC
authors.lastname: Yeh
authors.affiliation: SHORE and Whariki, Massey University, Palmerston North, New Zealand.
authors.forename: Sally
authors.initials: S
authors.lastname: Casswell
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000428:Alcohol Drinking / Q000453:epidemiology / Q000331:legislation & jurisprudence*; D019973:Alcohol-Related Disorders / Q000453:epidemiology; D063425:Binge Drinking / Q000453:epidemiology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D012307:Risk Factors; D011795:Surveys and Questionnaires; D000066608:Underage Drinking / Q000331:legislation & jurisprudence*; D055815:Young Adult
keywords: Minimum age; alcohol dependence; alcohol-related disorder; dose-response models; drinking contexts; drinking patterns; drinking places; drinking problems; heavy drinking; underage drinking