Misleading UK alcohol industry criticism of Canadian research on minimum pricing

Abstract

We would like to respond to criticism of our research by the UK Wine and Spirit Trade Association 1, a UK alcohol industry trade magazine 2 and the Scotch Whisky Association 3. Our study, published recently in Addiction 4, reported a significant negative association between minimum alcohol prices and rates of wholly alcohol-caused deaths. We are accused of misleading the public by reporting false estimates of the effects of minimum price changes on rates of death estimated ‘hypothetically’ to be caused by alcohol and not ‘real deaths’ such as those we report on our own website 5-7. We are also charged with publishing results which contradict official trends in alcohol-related deaths in British Columbia (BC), the Canadian province on which our research has focused. Finally, it is claimed that minimum pricing in Canada bears no relation to what is being proposed for the United Kingdom. Our critics highlight small increases in the numbers of alcohol-related deaths for BC between 2002 and 2009 (from 1073 to 1169) reported on our website 5, 7, which they describe as ‘real’ deaths 2. In fact, these numbers of deaths are estimated using the attributable fraction method, a method our detractors describe as ‘hypothetical’. The population of BC has been rising fairly fast, so that age- and sex-standardized rates of these estimated deaths actually fell during this period, from 25 to 24 per 100 000 residents 5, 6. Furthermore, the main results highlighted in our Addiction paper did not require the use of attributable fractions because they concern causes of death that are wholly alcohol-attributable, e.g. alcohol poisoning, alcoholic gastritis, alcoholic cardiomyopathy. Figure 1 below reports trends for the two main variables used in our analyses. One line shows age- and sex-standardized rates of death that, according to the BC Statistics Agency, were caused wholly by alcohol. The second line shows changes in the inflation-adjusted average minimum price for all alcohol sold in BC calculated as dollars per Canadian standard drink (=13.45 g of ethanol, somewhat larger than a UK ‘unit’ of 8 g). It can be seen that in the first 4 years rates of death were increasing, while average minimum prices were decreasing relative to inflation. In 2006 there was a marked increase in minimum price which was associated with a marked drop in the rate of wholly alcohol-caused deaths. A significant negative association was found between these two variables in our original analysis 4, from which we estimated that a 10% increase in the average minimum price of alcohol would be associated with a 32% decrease in wholly alcohol-caused deaths. We could equally well have said that a 10% decrease in minimum price would be associated with a 32% increase in wholly alcohol-related deaths. The Pearson coefficient of correlation between the minimum price and wholly alcohol-caused deaths was −0.504, (P < 0.010). Details of the methods involved in estimating rates of death and average minimum prices can be found in our original paper 4. Rates of 100% alcohol-attributable deaths and Consumer Price Index (CPI)-adjusted minimum alcohol prices in British Columbia, 2002–2009 Canada is one of a handful of countries to have already implemented minimum alcohol prices. In several provinces, including BC where our study was conducted, much of the alcohol is sold in some form of private liquor store. In BC there are also a small number of government-owned liquor stores which are different only in that they are usually larger and are open for slightly shorter hours. It is likely that the consumer's experience of purchasing alcohol for off-premise consumption is very similar in Canada and the United Kingdom, and they are similarly responsive to changes in retail prices. In summary, the criticisms of our research from these alcohol industry sources have no foundation. Minimum alcohol prices and rates of wholly alcohol-caused (‘real’) deaths were associated significantly and strongly negatively in BC during the time-period of our study. When the value of minimum prices fell with inflation, deaths tended to increase. When minimum price rates were increased by the government, there was an associated decrease in these deaths. We also report delayed effects 2–3 years after minimum price changes on rates of serious diseases attributable to alcohol. We believe that these findings have wide relevance to other jurisdictions, where consideration is being given to using minimum pricing as a strategy to reduce alcohol-related deaths, injuries and illnesses. They are a small part of a much wider literature connecting alcohol prices and availability to public health outcomes 8. None to declare. We are grateful to Paul Gruenewald and Thomas Babor for comments on an earlier draft of this letter. Funding was provided by Canadian Institutes for Health Research Operating Grant #102627 ‘Does minimum pricing reduce the burden of injury and illness attributable to alcohol?’ (Principle Investigator: Tim Stockwell).