A wastewater-based assessment of the impact of a minimum unit price (MUP) on population alcohol consumption in the Northern Territory, Australia

Wastewater-based evaluation of the efficacy of oxycodone regulations in Australia

BACKGROUND AND AIMS

Between 2018 and 2020, Australia implemented major policy changes to improve the quality and safety of opioid prescribing, with a specific focus on oxycodone. This study used wastewater-based epidemiology to assess the efficacy of Australia's regulatory reforms by measuring change in consumption of oxycodone via exploratory analysis.

DESIGN, SETTING, PARTICIPANTS, MEASUREMENTS

Wastewater analysis data on oxycodone consumption was from the National Wastewater Drug Monitoring Program. The program captures data from more than 50 wastewater treatment plant catchments across Australia, equivalent to more than 50% of the national population. Geographic trend analyses were conducted for both major cities and regional areas within all states and territories of Australia over a 6-year period between 2017 and 2023.

FINDINGS

Oxycodone consumption showed a statistically significant increase nationally from 78 mg/day/1000 people (95% confidence interval [CI] = 71, 84) in 2017 to 120 mg/day/1000 people in August 2019 (95% CI = 110, 120), an increase of 52% (95% CI = 42, 62, P < 0.0001). From August 2019 to December 2020, there was a statistically significant decrease from 120 to 65 mg/day/1000 people (95% CI = 60, 71), a decrease of 45% (95% CI = 40, 51), followed by a modest 2.4% increase to the end of the study period in April 2023 (95% CI [2.0,2.7]).

CONCLUSIONS

A 45% reduction in oxycodone consumption in Australia from 2019 to 2020 coincided with national policy changes that aimed to reduce consumption of prescription opioids. The overall declining trend in consumption was suggestive of the effectiveness of national interventions in reducing pharmaceutical opioid use. Wastewater-based epidemiology provides an effective approach for assessing the effectiveness of controlled substances policy changes.

Assessing the impact of stricter drink driving policy on alcohol consumption in a population of Hanoi, Vietnam using wastewater analysis

INTRODUCTION

On 1 January 2020, Vietnam introduced a new law with harsher fines and penalties for driving under the influence of alcohol. Reports of empty beer restaurants following this implementation suggested the new law has the potential to reduce population-level alcohol consumption. This pilot study aims to quantify short-term changes in alcohol consumption levels after the implementation of the new law and assess whether it could lead to a reduction in total alcohol consumption in the population.

METHODS

Wastewater samples were collected from two sites along a sewage canal in Hanoi during two periods: Period 1 (15 December 2018 to 14 January 2019) and Period 2 (15 December 2019 to 14 January 2020). Ethyl sulfate, a specific metabolite of alcohol, was quantified to monitor the trend of alcohol consumption. Both interrupted time series and controlled interrupted time series approaches were utilised, with Period 1 and Period 2 serving as the control and intervention periods, respectively.

RESULTS

Our analysis indicated that the implementation of the new law did not result in an immediate and significant reduction in alcohol consumption at the population level. Meanwhile, there was no significant difference in alcohol consumption between weekdays and weekends both before and after the implementation of the new law.

DISCUSSION AND CONCLUSIONS

Long-term monitoring is needed to assess the impact of stricter DUI policy on alcohol consumption in the urban areas of Vietnam.

Seven-years of alcohol consumption in Australia by wastewater analysis: Exploring patterns by remoteness and socioeconomic factors

BACKGROUND

Wastewater analysis provides a complementary measure of alcohol use in whole communities. We assessed absolute differences and temporal trends in alcohol consumption by degree of remoteness and socioeconomics indicators in Australia from 2016 to 2023.

METHODS

Alcohol consumption estimates from 50 wastewater treatment plants (WWTP) in the Australian National Wastewater Drug Monitoring Program were used. Trends were analysed based on 1) site remoteness: Major Cities, Inner Regional and a combined remoteness category of Outer Regional and Remote, and 2) using two socioeconomic indexes from the Australian Bureau of Statistics (ABS) relating to advantage and disadvantage for Income, education, occupation, and housing.

RESULTS

Consumption estimates were similar for Major Cities and Inner Regional areas (14.3 and 14.4L/day/1000 people), but significantly higher in Outer Regional and Remote sites (18.6L/day/1000 people). Consumption was decreasing in Major cities by 4.5% annually, Inner Regional by 2.4%, and 3.5% in the combined Outer Regional and Remote category. Consumption estimates were higher in socioeconomically advantaged quartiles than those of lower advantage (0%-25% mean = 13.0, 75%-100% mean = 17.4). Consumption in all quartiles decreased significantly over the 7 year period with annual rates of decrease of 0.9%, 3.7%, 3.6%, and 3.0% for the lowest to highest quartile, respectively.

CONCLUSIONS

Declines in Australian alcohol consumption have been steeper in large urban areas than regional and remote areas. There were smaller annual decreases in the most socioeconomically disadvantaged areas. If continued, these trends may increase Australian health inequalities. Policy and prevention work should be appropriately targeted to produce more equitable long-term outcomes.

Assessing the early influence of COVID-19 in an analysis of the immediate implementation of Minimum Pricing for Alcohol on drinkers in Wales

Background: The Welsh Government has commissioned a number of projects to consider the influence their implementation of Minimum Pricing for Alcohol (MPA) legislation in March 2020 had on the alcohol consumption and related behaviours of drinkers. Given the MPA's overlap with the COVID-19 pandemic and its related lockdown measures and restrictions, this rapidly became a story about the early impact of COVID-19 as it did MPA. This paper captures the core thematic messages from this specific strand of work, and in doing so reflects on (1) how early experiences of COVID-19 and the first lockdown influenced consumption and purchasing of alcohol behaviours and, in turn, (2) how relevant the introduction of MPA was for any of these. Methods: Semi-structured interviews were conducted by telephone with 32 drinkers 9 months after the implementation of the legislation in March 2020. The sample was recruited from three sources: the National Survey for Wales; a third sector organisation offering housing support to the homeless; and through an online survey on MPA. Results: COVID-19 had more relevance than MPA to drinkers. Furthermore, when MPA did have an influence on their behaviour, it was felt most keenly by the harmful drinkers in the study. These drinkers described spending more on alcohol, switching to other potentially more harmful substances, such as crack cocaine and synthetic cannabinoids, and more involvement in acquisitive crime and begging after the price increase. While our results might be an early indication of the influence of MPA on harmful drinkers, the small sample of this group in our study limits the generalisability of the findings. Conclusion: To date, the implementation of MPA has had little influence on the drinking patterns or lives of the drinkers in our sample. It is important that future research examines the longer-term influences of MPA before any conclusions on its effectiveness can be drawn.

Wastewater-based Epidemiology to Investigate Spatio-Temporal Trends in Alcohol Consumption in Aotearoa, New Zealand

Alcohol is an influential drug that has extensive societal impact. In Aotearoa New Zealand, there are a number of worrying trends related to alcohol consumption including rates of alcohol-related harm and violence and heavy episodic drinking. To understand and address these issues, alcohol consumption rates and related trends need to be understood. A wastewater-based epidemiology study was carried out over the course of six months (April-September 2021), sampling one week per month from ten catchment areas covering ~40 % of the national population. The average alcohol consumption was found to be 12.2 mL/person/day. Temporal and geographical trends in alcohol consumption were found; there was higher alcohol consumption on the weekends compared to weekdays, alcohol consumption was inversely related to settlement size, there was increased alcohol consumption due to public holidays and alcohol consumption was not seen to increase during COVID restrictions, however there was a notable change in the weekly trend during lockdowns. This application of alcohol WBE to Aotearoa New Zealand represents a comprehensive national study to understand alcohol consumption and its influences. The knowledge obtained will allow appropriate services and public policies to be reviewed to best serve communities.

Reducing alcohol use through alcohol control policies in the general population and population subgroups: a systematic review and meta-analysis

We estimate the effects of alcohol taxation, minimum unit pricing (MUP), and restricted temporal availability on overall alcohol consumption and review their differential impact across sociodemographic groups. Web of Science, Medline, PsycInfo, Embase, and EconLit were searched on 08/12/2022 and 09/26/2022 for studies on newly introduced or changed alcohol policies published between 2000 and 2022 (Prospero registration: CRD42022339791). We combined data using random-effects meta-analyses. Risk of bias was assessed using the Newcastle-Ottawa Scale. Of 1887 reports, 36 were eligible. Doubling alcohol taxes or introducing MUP (Int$ 0.90/10 g of pure alcohol) reduced consumption by 10% (for taxation: 95% prediction intervals [PI]: -18.5%, -1.2%; for MUP: 95% PI: -28.2%, 5.8%), restricting alcohol sales by one day a week reduced consumption by 3.6% (95% PI: -7.2%, -0.1%). Substantial between-study heterogeneity contributes to high levels of uncertainty and must be considered in interpretation. Pricing policies resulted in greater consumption changes among low-income alcohol users, while results were inconclusive for other socioeconomic indicators, gender, and racial and ethnic groups. Research is needed on the differential impact of alcohol policies, particularly for groups bearing a disproportionate alcohol-attributable health burden.

Funding

Research reported in this publication was supported by the National Institute on Alcohol Abuse and Alcoholism of the National Institutes of Health under Award Number R01AA028009.

Estimating the impact of the minimum alcohol price on consumers' alcohol expenditure in the Northern Territory, Australia

OBJECTIVE

From October 2018, the Northern Territory (NT) government introduced a minimum unit price (MUP) for alcohol of $1.30 per standard drink. We assessed industry claims that the MUP penalised all drinkers by examining the alcohol expenditure of drinkers not targeted by the policy.

METHODS

Participants recruited by a market research company using phone sampling (n=766, 15% consent fraction) completed a survey in 2019, post-MUP. Participants reported their drinking patterns and their preferred liquor brand. Estimated annual alcohol expenditure for each participant was calculated by collating the cheapest advertised price per standard drink of their preferred brand pre-and-post-MUP. Participants were grouped as consuming within the Australian drinking guidelines ("moderate") or over them ("heavy").

RESULTS

Based on post-MUP drinking patterns, moderate consumers had an average annual alcohol expenditure of AU$327.66 (CIs=325.61, 329.71) pre-MUP, which increased by AU$3.07 (0.94%) post-MUP. Heavy consumers had an estimated average annual alcohol expenditure of AU$2898.82 (CIs=2877.06, 2920.58) pre-MUP, which increased by AU$37.12 (1.28%).

CONCLUSIONS

The MUP policy was associated with an increase of AU$3.07 in alcohol annual expenditure for moderate consumers.

IMPLICATIONS FOR PUBLIC HEALTH

This article provides evidence that counters the alcohol industry's messaging, enabling an evidence-based discussion in an area dominated by vested interest.

A wastewater-based evaluation of the effectiveness of codeine control measures in Australia

BACKGROUND AND AIM

From 1 February 2018, codeine was rescheduled from an over-the-counter (OTC) to a prescription-only medicine in Australia. We used wastewater-based epidemiology to measure changes in population codeine consumption before and after rescheduling.

METHODS

We analysed 3703 wastewater samples from 48 wastewater treatment plants, taken between August 2016 and August 2019. Our samples represented 10.6 million people, 45% of the Australian population in state capitals and regional areas in each state or territory. Codeine concentrations were determined by liquid chromatography-tandem mass spectrometry and converted to per-capita consumption estimates using the site daily wastewater volume, catchment populations and codeine excretion kinetics.

RESULTS

Average per-capita consumption of codeine decreased by 37% nationally immediately after the rescheduling in February 2018 [95% confidence interval (CI) = 35.3-39.4%] and substantially in all states between 24 and 51% (95% CI = 22.4-27.0% and 41.8-59.4%). The decrease was sustained at the lower level to August 2019. Locations with least pharmacy access decreased by 51% (95% CI = 41.7-61.7%), a greater decrease than 37% observed for those with greater pharmacy access (95% CI = 35.1-39.4%). Regional areas decreased by a smaller margin to cities (32 versus 38%, 95% CI = 30.2-34.1% versus 34.9-40.4%, respectively) from a base per-capita usage approximately 40% higher than cities.

CONCLUSION

Wastewater analysis shows that codeine consumption in Australia decreased by approximately 37% following its rescheduling as a prescription-only medicine in 2018. Wastewater-based epidemiology can be used to evaluate changes in population pharmaceutical consumption in responses to changes in drug scheduling.

A Framework for Public Health Authorities to Evaluate Health Determinants for Wastewater-Based Epidemiology

BACKGROUND

Wastewater-based epidemiology (WBE) is rapidly developing as a powerful public health tool. It can provide information about a wide range of health determinants (HDs), including community exposure to environmental hazards, trends in consumption of licit and illicit substances, spread of infectious diseases, and general community health. As such, the list of possible candidate HDs for WBE is almost limitless. Consequently, a means to evaluate and prioritize suitable candidates for WBE is useful, particularly for public health authorities, who often face resource constraints.

OBJECTIVES

We have developed a framework to assist public health authorities to decide what HDs may be appropriate for WBE and what biomarkers could be used. This commentary reflects the experience of the authors, who work at the interface of research and public health implementation.

DISCUSSION

To be suitable for WBE, a candidate HD should address a public health or scientific issue that would benefit from better understanding at the population level. For HDs where information on individual exposures or stratification by population subgroups is required, WBE is less suitable. Where other methodologies are already used to monitor the candidate HD, consideration must be given to whether WBE could provide better or complementary information to the current approach. An essential requirement of WBE is a biomarker specific for the candidate HD. A biomarker in this context refers to any human-excreted chemical or biological that could act as an indicator of consumption or exposure to an environmental hazard or of the human health state. Suitable biomarkers should meet several criteria outlined in this commentary, which requires background knowledge for both the biomarker and the HD. An evaluation tree summarizing key considerations for public health authorities when assessing the suitability of candidate HDs for WBE and an example evaluation are presented. https://doi.org/10.1289/EHP11115.

Impact of alcohol policy changes on substance‐affected patients attending an emergency department in the Northern Territory with police

OBJECTIVE

Assess the impact of Northern Territory alcohol policy changes to ED utilisation at Royal Darwin-Palmerston Regional Hospitals.

METHODS

Interrupted time series analysis explored trends in monthly ED attendance numbers and the proportion self-discharging prior to policy changes (September 2016 to August 2017) and after three sequential interventions; the Banned Drinker Register, introduced September 2017, system changes to the sobering shelter, January 2018, and the minimum unit floor price (MUFP), October 2018. A targeted cohort of attendances transported by police as an alternative to the sobering shelter or police watch-house when there is a medical concern was selected as they are likely impacted by all policy changes.

RESULTS

Police transported 1176 patients on 2070 occasions from September 2016 to March 2019. There was a downward trend in monthly attendances across the study period, with no significant change attributable to the Banned Drinker Register, a significant step decrease with the sobering shelter changes (P = 0.002), and a significant gradual decrease following the MUFP (P = 0.025). This represented an immediate decrease of 3.82 attendances per month/10 000 residents following the sobering shelter changes and a gradual decrease of 0.92 attendances/10 000 residents after the MUFP. Rates of self-discharge were high, 45% in the pre-intervention phase, decreasing to 28% following the MUFP but this trend did not reach significance with any intervention.

CONCLUSION

The sequential introduction of broad sweeping alcohol policy changes introduced by the Northern Territory government was associated with significant reductions in ED utilisation. The proximity of the introduction of interventions creates difficulties identifying individual policy influence.

Causal inference with observational data in addiction research

Randomized controlled trials (RCTs) are the gold standard for making causal inferences, but RCTs are often not feasible in addiction research for ethical and logistic reasons. Observational data from real-world settings have been increasingly used to guide clinical decisions and public health policies. This paper introduces the potential outcomes framework for causal inference and summarizes well-established causal analysis methods for observational data, including matching, inverse probability treatment weighting, the instrumental variable method and interrupted time-series analysis with controls. It provides examples in addiction research and guidance and analysis codes for conducting these analyses with example data sets.