Changes in Alcohol Consumption Behaviour in a Large Population of Japan during the COVID-19 Pandemic

Alcohol consumption poses a significant public health risk but alcohol may also be used as an anti-anxiolytic by the public. Understanding the actual change in alcohol consumption behaviour is therefore important to formulate appropriate public health policies. This study, for the first time, employed wastewater-based epidemiology (WBE) to estimate alcohol consumption in a catchment of approximately 1.8 million inhabitants in the Kanto region, Japan. Twenty-four-hour composite wastewater samples were collected over four weeks from September to October 2021, during and after a COVID-19 lockdown period. Twenty-seven influent wastewater samples were analysed for ethyl sulfate (EtS), an alcohol biomarker, using the Liquid Chromatography-Tandem Mass Spectrometry (LC-MSMS) method and used to estimate alcohol consumption. EtS was detected in all samples, with concentrations ranging from 11.8 to 45.5 µg/L. The average estimated alcohol consumption in the study population was 52.9 ± 15.3 mL/day/person, which is higher than wastewater data from other countries. Alcohol consumption remained stable throughout the week. Additionally, consumption decreased after the lockdown (p < 0.001), and a strong positive correlation was observed between alcohol intake and daily reported COVID-19 cases (r = 0.735, p < 0.001), likely reflecting population mobility and behavioural responses to restrictions. Higher alcohol consumption during the lockdown was likely due to increased use in private settings rather than public spaces. This study provides the first objective evidence of alcohol consumption prevalence in Japan and warrants a broader wastewater monitoring program to inform policies reducing alcohol-related harm.