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

In 2015, the Liquor Control Board of Ontario (LCBO) authorized sale of alcohol in some Ontario grocery stores. This research evaluates the impact of the new policy on alcohol use patterns of youth in a quasi-experimental setting with two control groups.The sample consists of 2267 grade 9 students attending 60 secondary schools across Ontario (n = 56) and Alberta (n = 4), who provided 4-year linked longitudinal data (2013-2014 to 2016-2017) in the COMPASS study. The study used the frequency of drinking and the frequency of binge drinking to characterize alcohol use behaviours.Latent transition analysis found four statuses of alcohol use: abstainer, periodic drinker, low-risk drinker, and high-risk regular drinker. The new policy had no negative impact among periodic and low-risk drinkers, but the risk of transitioning from the abstainer (lowest risk status) to high-risk regular drinker (highest risk status) among the exposed cohort was 1.71 times greater post-policy than pre-policy change, compared with those of Ontario-unexposed (0.50) and Alberta-unexposed cohorts (1.00). The probability of sustaining high-risk drinking among the exposed cohort increased by a factor of 1.76, compared with 1.13-fold and 0.89-fold among the Ontario-unexposed and Alberta-unexposed cohorts, respectively.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.RéSUMé: OBJECTIFS: Depuis 2015, la Régie des alcools de l’Ontario (LCBO) autorise la vente d’alcool dans certaines épiceries de la province. Nous évaluons ici l’incidence de la nouvelle politique sur les habitudes de consommation d’alcool des jeunes dans un milieu quasi-expérimental avec deux groupes témoins. MéTHODE: Notre échantillon est constitué de 2 267 élèves de 9