So about that no safe level of alcohol

David Spieghalter from the Winton Centre writes:

A recent paper published by the Lancet demonstrating the global impact of alcohol consumption was a huge exercise from the Gates Foundation-funded Institute for Health Metrics and Evaluation (IHME) in Seattle. They built a large and complex statistical model from a vast range of data sources, and conclude that while moderate alcohol consumption may be preventive for some conditions such as ischaemic heart disease and diabetes, when combined with increasing risk of cancers and other outcomes there is a steadily increasing harm from alcohol consumption, as shown in Figure 5 from the paper reproduced below. This leads them to argue that there is ‘no safe level’ of alcohol.

Which contrasts with the bulk of scientific evidence to date that moderate drinkers have better health outcomes than non drinkers.

But in spite of the Lancet’s own guidelines for meta-analyses saying

“For risk changes or effect sizes, give absolute values rather than relative changes”

the paper did not report any absolute risks, meaning that readers couldn’t tell how dangerous drinking alcohol really was for them. 

Almost everything we do has some risk or danger – working, skiing, drinking, chocolate etc. The important thing is how big is the risk. Smoking is a huge risk, chocolate less so.

Specifically, comparing no drinks with one drink a day the risk of developing one of the 23 alcohol-related health problems was 0.5% higher — meaning 914 in 100,000 15–95 year olds would develop a condition in one year if they did not drink, but 918 people in 100,000 who drank one alcoholic drink a day would develop an alcohol-related health problem in a year. 

So the increase in risk is four people in every 100,000 will develop an alcohol related health problem if they have a drink a day.

I’d have a drink to those odds.

Let’s consider one drink a day (10g, 1.25 UK units) compared to none, for which the authors estimated an extra 4 (918–914) in 100,000 people would experience a (serious) alcohol-related condition.

That means, to experience one extra problem, 25,000 people need to drink 10g alcohol a day for a year, that’s 3,650g a year each.

To put this in perspective, a standard 70cl bottle of gin contains 224 g of alcohol, so 3,650g a year is equivalent to around 16 bottles of gin per person. That’s a total of 400,000 bottles of gin among 25,000 people, being associated with one extra health problem. Which indicates a rather low level of harm in these occasional drinkers.

A nice fact check.

Next look at 2 drinks a day, that’s 20g, or 2.5 units, slightly above the current UK guidelines of 14 units a week for both men and women.

In this case, compared to non-drinkers an extra 63 (977–914) in 100,000 people experience a health problem each year. That means, to experience one extra problem, 1,600 people need to drink 20g alcohol a day for a year, in which case we would expect 16 instead of 15 problems between them. That’s 7.3 kg a year each, equivalent to around 32 bottles of gin per person. So a total of 50,000 bottles of gin among these 1,600 people is associated with one extra health problem. Which still indicates a very low level of harm in drinkers drinking just more than the UK guidelines.

This analysis supports the current UK guidelines as being low-risk, but perhaps would better be described as ‘very low-risk’.

So the current guidelines are pretty good.

The paper argues that their conclusions should lead public health bodies “to consider recommendations for abstention”.

But claiming there is no ‘safe’ level does not seem an argument for abstention. There is no safe level of driving, but government do not recommend that people avoid driving.

Come to think of it, there is no safe level of living, but nobody would recommend abstention.

Presumably people who choose to drink alcohol moderately get some pleasure from it, and any risk needs to be traded off against this enjoyment.