Wednesday October 1 2014
A pint of beer has around 2-3 units of alcohol
“‘Hundreds of lives lost' over failure to bring in minimum alcohol pricing,” The Independent reports.
The news is based on research that modelled the effect of a minimum alcohol price per unit of around 40-50p. It suggested that this would be 50 times more effective than the current ban on "below-cost sales" (where alcohol is sold at a loss to attract sales of other goods).
The statistical analyses conducted in this study were based on a number of well-respected data sets, such Hospital Episodes Statistics from 2005 to 2006, showing alcohol-related admissions to hospital.
The model estimated that a minimum cost of 45p per unit of alcohol would affect 23.2% of alcohol units sold, compared to just 0.7% for the ban on below-cost selling. This would mean saving 624 alcohol-related deaths per year, compared to 14 for the ban on below-cost selling, as well as 23,700 fewer admissions to hospital per year, compared to 500 for the ban on below-cost selling.
It’s worth remembering the scientific truism that “all models are wrong, but some are useful”. Based on its methodology, this appears to be one of the useful ones.
We are unlikely to see a minimum alcohol price in 2014, but policymakers will be sure to consider this new study alongside other emerging evidence on how best to protect public health, while allowing people the freedom to enjoy their booze.
Where did the story come from?
The study was carried out by researchers from the University of Sheffield and was funded by the Medical Research Council and Economic and Social Research Council, in the UK.
The study was published in the peer-reviewed British Medical Journal on an open access basis, so it is free to read online.
Media reporting was accurate and provided comments from the chief executives of Alcohol Concern and Addaction regarding the importance of the findings.
What kind of research was this?
This was a modelling study that aimed to estimate the impact that different alcohol control measures might have on alcohol-related deaths, illnesses, admissions to hospital and quality-adjusted life years.
In May 2014, the government implemented a ban on "below-cost selling" of alcohol (selling at less than the cost of producing and selling the alcohol) in England and Wales. The researchers outline that as there is the alcohol beverage-specific duty tax and value added tax (VAT) of 20%, this ban affects drinks with higher duty rates such as spirits, and has less effect on drinks with lower duty rates, such as cider.
The government had previously considered alternative strategies, including having a minimum unit price for alcohol of between 40p and 50p. Minimum unit pricing would effectively target drinks that are high in alcohol content and sold relatively cheaply.
It is these types of drinks, such as extra-strength cider or lager, or cheap spirits, which many experts hold responsible for causing the increase in alcohol-related health problems that have occurred in recent years. For example, in some supermarket chains, cider with an alcohol content of 8% ABV is cheaper to buy than some brands of bottled water.
The researchers wanted to model the potential effects that different minimum unit prices would have on outcomes compared to the ban on below-cost selling of alcohol.
Modelling studies can provide a framework to look at the potential effects of different policies or procedures, but they cannot accurately predict the precise number that would be affected.
What did the research involve?
The researchers used data from the 2009 general lifestyle survey, which captured average daily and weekly alcohol intake for 11,385 people in England.
Estimates on the price paid for various different types of alcoholic drinks between 2001 and 2009 were acquired from annual two week purchasing diary surveys of around 6,500 UK households, which amounted to 227,933 transactions.
The researchers looked at 96 different subgroups from the sample, split by age, sex, mean consumption (moderate, hazardous and harmful) and income (below or above the poverty line), and compared the amount and cost of alcohol they purchased.
They then estimated the effect that different price changes would have on alcohol consumption in each of the subgroups. They looked at a ban on below-cost selling and minimum unit price policies with thresholds of 40p, 45p and 50p.
An example of the statistical model is that a 1% increase in the price of beer would be estimated to result in a 0.98% reduction in the amount purchased, but this might cause a slight increase in wine purchased of 0.096%. They performed different analyses according to the subgroups, accounting for:
- younger men drinking more beer on nights out
- middle-aged women drinking more wine at home
- harmful drinkers spending less per unit of alcohol
- people who drink cheaper cider being more affected by an increase in the minimum price per unit
Lastly, the researchers used this estimated change in alcohol consumption to model its effect on the mortality and disease prevalence of 47 conditions that are related to harmful alcohol use. These conditions include oesophageal cancer. The researchers used data from the Office for National Statistics and Hospital Episodes Statistics from 2005 to 2006.
What were the basic results?
A ban on below-cost selling is estimated to:
- affect 0.7% of alcohol units sold
- reduce harmful drinkers' mean annual consumption by 0.08% – around 3 units per year
- save 14 deaths and 500 admissions to hospital per year
A minimum cost of 45p per unit of alcohol is estimated to:
- affect 23.2% of alcohol units sold
- reduce harmful drinkers’ mean annual consumption by 3.7% – around 137 units per year
- save 624 deaths and 23,700 admissions to hospital per year
Interestingly, estimates of the impact on supermarkets and shops selling alcohol suggested minimum unit pricing would increase alcohol revenues by 5.6%, while banning below-cost selling would lead to a much smaller rise of 0.2%. The team expected this would translate into bigger profits for the retailers, but could not confirm this for sure because they weren’t able to access the commercially sensitive data needed to calculate this information.
How did the researchers interpret the results?
The researchers conclude that, “the UK government’s recently implemented ban on below-cost selling affects just 0.7% of alcohol units currently sold, and is estimated to have small effects on consumption and health harm. The previously considered policy of a minimum unit price, if set at expected levels between 40p and 50p per unit, is estimated to have an approximately 40 to 50 times greater effect”.
This modelling study provides a framework to look at the potential effects of two different alcohol control measures on alcohol-related illness and death across the UK. The policy background to this story is that the UK government originally announced plans to introduce minimum unit pricing, but later changed its view.
Instead, the government implemented a ban on below-cost selling. This modelling study suggested that minimum unit alcohol pricing originally announced (at between 40p and 50p) would have a 40 to 50 times greater beneficial impact on public health compared with a ban on selling alcohol below-cost price.
As it was based on a mathematical model, this study cannot accurately predict the precise number of deaths that could be avoided by changing alcohol use. However, it can provide an approximation, which is useful for policymakers.
Limitations for this particular model include its reliance on estimates from surveys, which could be open to recall bias regarding the amount of alcohol purchased or consumed. However, strengths of the model include the large number of people who were surveyed and that the survey was conducted without participants knowing that the information would be used in this way.
The researchers carried out a number of sensitivity analyses to test the reliability of their model using different inputs. The team said, “these effects suggest that the relative scale of impact between a ban on below cost selling and a minimum unit price are robust to a variety of assumptions and uncertainties”. This gives an added degree of confidence to the main findings.
If you are concerned that you may be drinking more than you should, then it may be useful to keep a “drink diary” in which you keep a note of the amount of units you drink over the course of a week. It could be a lot higher than you think. Download the drinks diary leaflet (PDF, 697kb) to work out your alcohol intake over a week. You can also download the NHS Choices drink tracker app, which is available for iOS devices.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.