Changes in alcohol consumption associated with social distancing and self-isolation policies triggered by COVID-19 in South Australia: a wastewater analysis study

Abstract

Aim: To assess the effects of social distancing and social isolation policies triggered by COVID-19 on alcohol consumption using wastewater analysis in Adelaide, South Australia.

Design: Longitudinal quantitative analysis of influent wastewater data for alcohol concentration.

Setting: Adelaide, South Australia.

Participants: Wastewater catchment area representative of 1.1 million inhabitants.

Measurements: Twenty-four hour composite influent wastewater samples were collected from four wastewater treatment plants in Adelaide, South Australia for 7 consecutive days (Wednesday-Tuesday) every 2 months from April 2016-April 2020. The alcohol metabolite ethyl sulfate was measured in samples using chromatography-tandem mass spectrometry. Data were population-weighted adjusted with consumption expressed as standard drinks/day/1000 people. Weekly consumption and weekend to mid-week consumption ratios were analysed to identify changes in weekday alcohol use pattern.

Findings: Estimated weekend alcohol consumption was significantly lower (698 standard drinks/day/1000 people) after self-isolation measures were enforced in April 2020 compared with the preceding sampling period in February 2020 (1047 standard drinks/day/1000 people), P < 0.05. Weekend to midweek consumption ratio was 12% lower than the average ratio compared with all previous sampling periods. April 2020 recorded the lowest alcohol consumption relative to April in previous years, dating back to 2016.

Conclusions: Wastewater analysis suggests that introduction of social distancing and isolation policies triggered by COVID-19 in Adelaide, South Australia, was associated with a decrease in population-level weekend alcohol consumption.

Keywords: Alcohol consumption; Australia; COVID-19; Social distancing; Stress; Wastewater analysis.

Figure 1

Alcohol consumption in South Australia from April 2016–April 2020. Each column represents the population normalised mean alcohol consumption across four different WWTPs in South Australia and is presented as Wednesday–Tuesday inclusive. The inset highlights the daily differences between February 2020 and April 2020 (including SE). Asterisk in the inset indicated statistically significant weekend differences between February and April (P < 0.05). [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 2

Daily alcohol consumption over the weekly sampling periods in April from 2016–2020. Each box and whisker represent population normalised mean alcohol consumption across four different WWTPs in South Australia. The whiskers comprise the lower and upper consumption values. *Statistically significant difference from 2020 (P < 0.05). [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 3

Each column represents the ratio between peak weekend (Saturday and Sunday) alcohol consumption and low weekday (Tuesday and Wednesday) alcohol consumption. The black line shows the level of April 2020, the yellow line is the average for all April periods (April 2016, 2017, 2018 and 2019) and the orange line is the overall average of all sampling periods from April 2016–December 2019. [Colour figure can be viewed at wileyonlinelibrary.com]