The impact of an alcohol policy change on developmental trajectories of youth alcohol use: examination of a natural experiment in Canada.

Youth are more likely to transition from abstinence to high-risk regular drinking, and high-risk regular drinkers are more likely to maintain their behaviours in the jurisdictions exposed to the latest change in LCBO policy authorizing grocery stores to sell alcohol. When formulating policy interventions, youth access to alcohol should be considered in order to reduce their harmful alcohol consumption.