A Longitudinal Study of Influences on Alcohol Consumption and Related Harm in Central Australia: with a Particular Emphasis on the Role of Price
Total Page:16
File Type:pdf, Size:1020Kb
A longitudinal study of influences on alcohol consumption and related harm in Central Australia: with a particular emphasis on the role of price ANNMartynUAL Symons REPODennis GrayRT Tanya Chikritzhs Steven Skov Sherry Saggers John Boffa 2009 Jennifer Low The National Drug Research Institute at Curtin University is supported by funding from the Australian Government under the Substance Misuse Prevention and Service Improvement Grants Fund WHO Collaborating Centre for the Prevention of Alcohol and Drug Abuse Tier 1 Research Centre ndri.curtin.edu.au National Drug Research Institute Curtin University Health Research Campus GPO Box U1987 Perth, Western Australia, 6845 Telephone: (08) 9266 1600 Facsimile: (08) 9266 1611 Email: [email protected] Corresponding Author: Dennis Gray MPH PhD Professor & Deputy Director National Drug Research Institute Curtin University GPO Box U1987 Perth, WA, 6845 Email: [email protected] CRICOS Provider Code: 00301J (WA), 02637B (NSW) ISBN 978-0-9873641-0-4 20130002 A longitudinal study of influences on alcohol consumption and related harm in Central Australia: with a particular emphasis on the role of price Martyn Symons,1 Dennis Gray,1 Tanya Chikritzhs,1 Steven Skov,2 Sherry Saggers,1 John Boffa,3 Jennifer Low1 October 2012 1. National Drug Research Institute, Curtin University 2. Department of Health, Northern Territory 3. Central Australian Aboriginal Congress National Drug Research Institute Curtin University Health Research Campus GPO Box U1987 Perth WA 6845 telephone +61 8 9266 1600 [email protected] ndri.curtin.edu Preventing harmful drug use in Australia Funded by the National Drug Strategy CRICOS Provider Code 00301J (WA), 02637B (NSW) Corresponding author: Dennis Gray MPH PhD Professor & Deputy Director National Drug Research Institute Curtin University GPO Box U 1987 PERTH WA 6845 [email protected] Contents Acknowledgements ........................................................................................... iv Executive Summary ........................................................................................... v 1. Introduction ........................................................................................... 1 2. Research Methods ................................................................................... 3 3. Alcohol Control Measures.......................................................................19 4. Alcohol Consumption .............................................................................27 5. Alcoholic Beverage Prices ...................................................................... 42 6. Health Indicators ...................................................................................52 7. Crime and Public Order .......................................................................... 95 8. Summary ............................................................................................. 121 9. Appendices .......................................................................................... 133 10. References ........................................................................................... 145 iii Acknowledgements The, then, Deputy Chief Minister of the Northern Territory, the Honourable Delia Lawrie, gave us permission to access NT data collections and undertake this study. The Northern Territory Department of Justice and the Licensing Commission, the Department of Health, and NT Police provided access to the data from their routine statistical collections on which this report is based. Officers from those agencies were extremely helpful in facilitating access and answering our numerous queries. Wenbin Liang and William Gilmore from the National Drug Research Institute provided additional statistical advice. The project was funded by the Australian Government Department of Families, Housing, Community Services and Indigenous Affairs. The National Drug Research Institute at Curtin University is supported by funding from the Australian Government under the Substance Misuse Prevention and Service Improvement Grants Fund. iv Executive Summary Aims and objectives The aim of this project was to examine and report on the impact of various alcohol control measures on levels of alcohol consumption and related harm in Central Australia for the period 2000–2010. Specific objectives were to: • describe trends in alcohol consumption in Central Australia; • describe trends in key indicators of alcohol-related harm; • describe key interventions aimed at reducing alcohol-related harm; • identify any changes in consumption and indicators of harm and to test whether, or to what extent, these can be attributed to particular interventions or combinations of them; and, • report on the implications for alcohol policy and strategies to reduce alcohol- related harm. Methods The project was conducted in three overlapping stages using both quantitative and qualitative methods. Data on wholesale sales of alcoholic beverages were converted to litres of pure alcohol and were used as a proxy measure of consumption. Alcohol-related hospital separations, emergency department presentations and police incident data were used as indicators of harm. The geographic area of study was the Central Northern Territory Statistical Sub- Division with ‘Greater Darwin’ as a control region. Two methods were used to calculate an appropriate population denominator for the calculation of rates: Estimated Residential Population (ERP) aged ≥15 years plus data on tourist numbers from various sources; and Adjusted Enumerated Population (AEP) based on adjustments to, and extrapolations from, the Enumerated Populations of persons aged ≥15 years at the 1996, 2001 and 2006 Censuses. The differences between these were small and for convenience, the latter was used. Access to quarterly data on the volume of wholesale sales of alcoholic beverages was provided by the NT Licensing Commission. These data were converted to wholesale sales of litres of pure alcohol. Estimates of annual and quarterly per capita consumption of pure alcohol among persons aged 15 years or older were calculated by dividing wholesale sales of pure alcohol by Adjusted Enumerated Population. To enable examination of changes in the relative contribution of particular beverage types to per capita consumption, estimates were also made of quarterly per capita consumption of each beverage type. v In the absence of detailed data on retail prices an attempt was made to estimate this based on a large sample of newspaper advertisements. This provided incomplete and unsatisfactory estimates. As an proxy measure, we relied on CPI adjusted data on wholesale prices provided by the Licensing Commission and used these to calculate average wholesale price per litre of pure alcohol. Hospital separations were used as indicators of health-related harms. In particular, we examined: • all alcohol-attributable conditions (those with any alcohol-attributable ætiologic fraction); • a small number of key conditions which are wholly alcohol-attributable, and larger groups that have an alcohol-attributable ætiologic fraction of greater than 0.8 (High), have an alcohol-attributable ætiologic of between 0.3 and 0.8 (Medium), or which have a lower ætiologic fraction but have a high frequency including pedestrian and non-pedestrian road traffic injuries (Low); and, • groups of acute and chronic conditions – as the time courses for responses to restrictions may vary. Hospital Emergency Department (ED) presentation data were also used as indicators of harm. Unfortunately, it was not possible to accurately identify the contribution of alcohol to various acute conditions such as injuries. For this reason we had to rely on presentations for medical conditions that are known to be significantly related to alcohol consumption and presentations identified as ‘assault’ at triage. As a proxy measure of alcohol-related harm and public disorder we used: offences that are, by definition, alcohol-related (e.g. drunk and disorderly behaviour, drink driving offences); or offences which have been shown to be commonly alcohol-related (assaults, protective custody, anti-social incidents and domestic violence). Three major statistical approaches were used to explore associations: • cross-correlations to measure the strength of associations between variables; • time series modelling (ARIMA and exponential smoothing with forecasting) to model indicator time-series and to test if either consumption and/or price made a significant contribution to improving the fit of the model, to test whether individual restrictions contributed significantly to constructing a model of best-fit, and to test whether trends observed in indicators during specific periods in time were different to trends expected to have occurred had an intervention not taken place; and, • Poisson Regression to compare the Incidence Rate Ratio (IRR) between alcohol- and non-alcohol-attributable events in particular time periods after introduction of restrictions with the ratio immediately prior to the restrictions. Alcohol control measures The impacts of the following alcohol control measures in Alice Springs and/or Central Australia were considered. vi • 2002 Licensing Commission Decision – Alice Springs Trial Restrictions. • 2003 Licensing Commission Decision – Alice Springs Amended Restrictions. • 2006 Alcohol Court Act NT. 2006 Alice Springs Alcohol Management Plan. • 2006 Licensing Commission Decision – Alice Springs Liquor Supply Plan (LSP). • 2007 Northern Territory Emergency