Is start time a risk factor for amounts consumed on a given day if drinking duration is taken into account? An event-level study

Background: This study investigates the impact of COVID-19 restrictions on typical drinking patterns and the relationship between drinking start time and duration on daily drinks and drinking pace. Methods: 573 participants from New South Wales (NSW), Australia completed five waves of weekly diaries assessing a ‘typical week’s alcohol consumption’ between March and November 2020. We examined the impact of COVID-19 restrictions on drinking start time, duration and pattern. Multilevel regression and mediation models were then conducted to ascertain the associations between start time and duration on the quantity and pace of drinking. Results: Participants started drinking significantly earlier in the day during lockdown compared to pre-lockdown. The earlier drinking started on a given day the higher the number of drinks consumed that day. Earlier start times led to increased consumption indirectly, via increased duration. After adjusting for duration, later start times were associated with increased consumption. The daily drinking pace also increased significantly with later start times. Conclusions: Our study demonstrates that start time is a risk factor for heavier alcohol consumption, but only because it leads to increased drinking duration. Later start times are associated with increased drinking pace, and after adjusting for duration, lead to higher daily drinking volumes.