Background: Excess alcohol consumption has serious adverse effects on health and violence-related harm. In the UK around 37% of men and 29% of women drink to excess and 20% and 13% report binge drinking. The potential impact on population health from a reduction in consumption is considerable. One proposed method to reduce consumption is to reduce availability through controls on alcohol outlet density. In this study we investigate the impact of a change in the density of alcohol outlets on alcohol consumption and alcohol-related harms to health in the community.
Methods/design: A natural experiment of the effect of change in outlet density between 2005-09, in Wales, UK; population 2.4 million aged 16 years and over. Data on outlets are held by the 22 local authorities in Wales under The Licensing Act 2003. The study outcomes are change in (1) alcohol consumption using data from annual Welsh Health Surveys, (2) alcohol-related hospital admissions using the Patient Episode Database for Wales, (3) Accident & Emergency department attendances between midnight-6am, and (4) alcohol-related violent crime against the person, using Police data. The data will be anonymously record-linked within the Secure Anonymised Information Linkage Databank at individual and 2001 Census Lower Super Output Area levels. New methods of network analysis will be used to estimate outlet density. Longitudinal statistical analysis will use (1) multilevel ordinal models of consumption and logistic models of admissions and Accident & Emergency attendance as a function of change in individual outlet exposure, adjusting for confounding variables, and (2) spatial models of the change in counts/rates of each outcome measure and outlet density. We will assess the impact on health inequalities and will correct for population migration.
Discussion: This inter-disciplinary study requires expertise in epidemiology and public health, health informatics, medical statistics, geographical information science, and research into alcohol-related violence. Information governance requirements for the use of record-linked data have been approved together with formal data access agreements for the use of the Welsh Health Survey and Police data. The dissemination strategy will include policy makers in national and local government. Public engagement will be through the Clinical Research Collaboration-Cymru "Involving People" network, which will provide input into the implementation of the research.