Last week a number of international news outlets latched onto a story coming from a study in the Lancet, which appeared to suggest that just one alcoholic drink a day will shorten your life.
However British publication, The Spectator, has looked deeper into the study and found that while at first glance the study does support some of these claims, there was a shift in the data collection which brought about the shift in the advice in favour of moderation.
As The Spectator’s Christopher Snowdon explained: “Decades of epidemiology have shown that the relationship between alcohol consumption and mortality is J-shaped. At moderate rates of consumption, mortality risk falls below that of a teetotaller and then rises, exceeding that of a teetotaller at around 30-40 units per week. The exact shape of the curve varies depending on your criteria for inclusion but the basic conclusion is always the same: moderate drinkers live longer than teetotallers.
“In the new Lancet study, a J-curve is only apparent with cardiovascular disease and the protective effect is weaker than in previous studies. There seems to be no overall mortality benefit.”
Snowdon added: “This is a surprising result which, if true, could have justified some of the scary headlines.”
However further insights into the Lancet graphs, which were the source of these media claims, showed that non-drinkers were excluded and Snowdon says that once the non-drinkers are included in the comparisons, the new study does not contradict the existing evidence that a moderate intake of alcohol does have some health benefits.
“The mortality risk of those who have never drunk alcohol is 20 per cent higher than that of those who drink 100g per week (12.5 units) and is the same as those who drink 300g per week (37.5 units),” Snowdon reports.
“The study’s authors got rid of the J-Curve by cutting off part of the J. Instead of using non-drinkers as their baseline, they used the most moderate of moderate drinker.
“If you look at the data in the study and ignore the editorialising of its authors, the study doesn’t tell us anything we did not already know. Moderate drinking reduces mortality risk and is particularly good for the heart. Light drinkers have the best outcomes, but drinkers who consume double the 14 units recommended by the [UK’s] Chief Medical Officer do better than those who do not drink at all.”
Snowdon went on to say: “The Lancet study appeared to produce different findings from its predecessors because it was asking a different question. The conventional, common sense way of setting drinking guidelines is to identify the point on the J-Curve at which a drinker’s mortality risk rises to the same level as that of a teetotaller. If it is considered safe to abstain from alcohol, it makes sense to use non-drinkers as the baseline for acceptable risk. But the Lancet study is based on the unspoken assumption that the guidelines should be set at the point at which the health benefits of drinking are maximised, ie. at the lowest point of the J-Curve.
“It’s an unusual assumption with little practical relevance. It may be true that 12.5 units of alcohol per week is the ideal quantity to consume if you want the best health outcomes, but an ideal quantity is different to a safe limit. If we are going to start setting guidelines based on what is ideal, 12.5 units should be not just the maximum recommendation but also the minimum. In other words, we should tell non-drinkers to start drinking and tell light drinkers to drink more. Needless to say, the ‘public health’ lobby has no intention of doing this.”
You can read Snowdon’s complete analysis of the study and the headline-grabbing way it was reported around the world on The Spectator website.