National Wastewater Surveillance of Illicit Tobacco and Vaping Use Trends in Australia.

Importance: Australia is leading the world in efforts to reduce tobacco use by implementing high cigarette taxes and restrictive regulations on nicotine vaping products. However, concerns have emerged that these policies may unintentionally drive the expansion of illicit tobacco and vaping markets, potentially undermining public health gains. Objectives: To assess spatial and temporal changes in total nicotine, tobacco-derived nicotine, and illicit tobacco use across Australian regions of different remoteness from 2017 to 2023. Design, Setting, and Participants: This longitudinal, cross-sectional wastewater study was performed from April 2017 to April 2023. Wastewater samples were collected from as many as 55 wastewater treatment plants (WWTPs) in Australia, including 3 remoteness levels: major cities, inner regional, and outer regional to remote areas. The selected WWTPs serve more than 50% of the Australian population. Main Outcomes and Measures: Nicotine metabolites (cotinine and hydroxycotinine) and the tobacco-specific alkaloid (anabasine) were analyzed in wastewater samples using a validated liquid-chromatography tandem mass spectrometry method. Total nicotine and tobacco-derived nicotine consumption were back-estimated. Illicit tobacco use was identified in combination with the tobacco sales data. Results: Wastewater samples collected across Australia, representing 14 million people, were analyzed for back-estimation. Total nicotine consumption declined fastest in outer regional to remote areas (-2.2% annually; 95% CI, -3.2% to -1.1%), followed by inner regional areas (-1.4% annually; 95% CI, -2.1% to -0.8%), and remained stable in major cities. By comparison, tobacco-derived nicotine consumption decreased faster in major cities (-5.0% annually; 95% CI, -8.3% to -1.9%) and inner regional areas (-9.8% annually; 95% CI, -12.5% to -7.3%) than in the outer regional to remote areas (-2.3% annually; 95% CI, -6.0% to 1.8%). Illicit tobacco use was estimated to have increased from 1350 to 3400 tons from 2017 to 2023. Conclusions and Relevance: In this cross-sectional study of wastewater surveillance in Australia, different trends of tobacco use were observed across regions, accompanied by increasing use of illicit tobacco and vaping products. These findings provide evidence for future tobacco and vaping control policies. Ongoing wastewater monitoring is essential for evaluating new tobacco and vaping product control measures implemented in 2024.