Aim: To assess alcohol-related harms and offences in New Zealand from 1990 to 2003, a period of alcohol policy liberalization, that included the lowering of the purchase age from 20 to 18 years in 1999.
Design, setting and participants: Time trend analyses were carried out on routinely collected data for prosecutions for driving with excess alcohol; alcohol-involved vehicle crashes (all and fatal) and prosecutions for disorder offences. These were carried out separately for those aged 14-15, 16-17, 18-19, 20-24 and 25 years and over.
Measurements: Rates of: prosecutions for driving with excess alcohol (1990-2003); rates of alcohol- involved vehicle crashes (all and fatal) (1990-2003); and rates of prosecutions for disorder offences (1994-2003).
Findings: Effects of alcohol policy liberalization: positive trends were found in the rates of prosecutions for disorder in the 16-17, 18-19, 20-24 and 25 + age groups; with 18-19-year-olds and 16-17-year-olds having the largest rates and largest positive trend in rates. For 16-17-year-olds, there was a positive trend in the rates of prosecutions for excess breath alcohol. Negative trends in rates were found for alcohol-related crashes (all and fatal) among all age groups. Negative trends for those over 16-17 years were found for prosecutions for driving with excess breath alcohol (this was prior to the lowering of the purchase age). Effects of lowering the minimum purchase age: the lowering of minimum purchase age coincided with an increase in the trend of alcohol-related crashes for 18-19-year-olds; the next largest increase was among the 20-24-year-olds (all other age groups also increased but at a much lower rate). A similar result was found for driving with excess alcohol for those aged 18-19 (and those aged 20-24 years). An increase in the rates of prosecutions for disorder offences occurred for the 14-15-year-old group following the lowering of the purchase age.
Conclusion: The liberalization of alcohol throughout the 1990s may have influenced younger people more, as reflected in increases in their disorder offences and drink driving. The lowering of the minimum purchase age may have led to an increase in drink-driving among the 18-19-year-olds (those directly affected by the change in purchase age).