Minimum purchasing age for alcohol and traffic crash injuries among 15- to 19-year-olds in New Zealand.
OBJECTIVE
In 1999, New Zealand lowered the minimum purchasing age for alcohol from 20 to 18 years. We tested the hypothesis that this increased traffic crash injuries among 15- to 19-year-olds.


METHODS
Poisson regression was used to compute incidence rate ratios for the after to before incidence of alcohol-involved crashes and hospitalized injuries among 18- to 19-year-olds and 15- to 17-year-olds (20- to 24-year-olds were the reference).


RESULTS
Among young men, the ratio of the alcohol-involved crash rate after the law change to the period before was 12% larger (95% confidence interval [CI]=1.00, 1.25) for 18- to 19-year-olds and 14% larger (95% CI=1.01, 1.30) for 15- to 17-year-olds, relative to 20- to 24-year-olds. Among young women, the equivalent ratios were 51% larger (95% CI=1.17, 1.94) for 18- to 19-year-olds and 24% larger (95% CI=0.96, 1.59) for 15- to 17-year-olds. A similar pattern was observed for hospitalized injuries.


CONCLUSIONS
Significantly more alcohol-involved crashes occurred among 15-to 19-year-olds than would have occurred had the purchase age not been reduced to 18 years. The effect size for 18- to 19-year-olds is remarkable given the legal exceptions to the pre-1999 law and its poor enforcement.
Kypri
Kypros
K
University of Newcastle, 2 Edison St, Adamstown Heights, NSW 2289 Australia. kypri@tpg.com.au
Voas
Robert B
RB
Langley
John D
JD
Stephenson
Shaun C R
SC
Begg
Dorothy J
DJ
Tippetts
A Scott
AS
Davie
Gabrielle S
GS
D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D000293:Adolescent; D000294:Adolescent Behavior; D000328:Adult; D000428:Alcohol Drinking / Q000331:legislation & jurisprudence*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D009520:New Zealand / Q000453:epidemiology