The impact of later trading hours for bars and clubs on alcohol-related ambulance call-outs and crimes in Scotland: a controlled interrupted time series study

Background Alcohol-related harms are prevalent late at night, especially on weekends, when high levels of intoxication contribute to increased rates of injury and violence. Reducing or increasing alcohol trading hours late at night in bars and clubs is generally associated with reduced and increased harms, respectively. This study evaluates the impact of later alcohol trading hours in the Scottish cities of Aberdeen and Glasgow on alcohol-related ambulance call-outs and crimes. Under local policy changes, 38 bars in Aberdeen had trading hours extended between 1 to 3 hours up to 3am, and 10 nightclubs in Glasgow had a 1-hour extension to 4am. Methods Following a natural experiment evaluation framework, we used a controlled interrupted time series design to compare outcomes before and after policy changes, from 2015 to 2021. The primary outcome was a count of total weekend night-time alcohol-related ambulance call-outs. Secondary outcomes included weekend night-time crimes. Results In Aberdeen, the policy led to a significant relative increase of 17.4% (effect size=7.061; 95% CI=3.902 to 10.220; p<0.001) in alcohol-related ambulance call-outs, and 7.9% (effect size=3.187; 95% CI=0.564 to 5.810; p=0.017) in reported crimes (not robust across sensitivity analyses), at weekend night-times compared to Edinburgh (control). Findings were not significant and robust across analyses for Glasgow. Conclusion Later alcohol trading hours had a significant negative impact on alcohol-related ambulance call-outs in Aberdeen (where more premises had longer extensions) but not in Glasgow, suggesting the number, capacity and type of premises moderated outcomes. This is important for the design of future national and local licensing policies and regulations.