A natural experiment: Assessment of Danish high-school students' alcohol drinking patterns from 2014 and 2019 after...

In this study, using national survey data from 2014 and 2019, we tested the hypothesis that students at schools who introduced a common alcohol policy in 2017 drank less than students at schools without a common policy.

We used survey data from 41 high schools that participated in the Danish National Youth Study in 2014 and 2019. We perceived the introduction of a common high-school alcohol policy in 2017 among local groups of high schools as a natural experiment and assessed it using difference-in-difference analyses. We assessed drinking patterns from 2014 and 2019 among students at schools with and without a common alcohol policy combined and stratified by sex in negative binominal regression and logistic regression models. Drinking patterns were measured as average weekly alcohol use, average alcohol intake at last school party, proportion of non-drinkers and frequent binge drinkers.

Drinking patterns were similar among students in schools with and without a common alcohol policy. For example, among students at schools with a common alcohol policy, the average alcohol intake at the last school party among drinkers was 8.7 units in 2014 and 8.5 units in 2019, whereas average alcohol intake among students at schools without a common alcohol policy was 8.8 units in 2014 and 8.9 units in 2019 (p=0.413).

No statistically significant effects were observed following the introduction of a common alcohol policy on students' drinking patterns, and alcohol consumption among high-school students was stable and remained high in 2014 and in 2019.