April 12, 2018

expert reaction to study looking at drinking alcohol, life expectancy and alcohol limits

A new analysis of data, published in The Lancet, reports that recommended alcohol limits in many countries should be lowered to around 100g/week for men and women.

Prof David Spiegelhalter, Winton Professor for the Public Understanding of Risk, University of Cambridge, said:

“This is a massive and very impressive study.  It estimates that, compared to those who only drink a little, people who drink at the current UK guidelines suffer no overall harm in terms of death rates, and have 20% fewer heart attacks.

“But above two units a day, the death rates steadily climb.  The paper estimates a 40-year-old drinking 4 units a day above the guidelines has roughly 2 years lower life expectancy, which is around a twentieth of their remaining life.  This works out at about an hour per day.  So it’s as if each unit above guidelines is taking, on average, about 15 minutes of life, about the same as a cigarette.

“Of course it’s up to individuals whether they think this is worthwhile.”

Prof Petra Meier, Professor of Public Health, University of Sheffield, said:

“This study is of very high quality and addresses several of the key problems which affect estimates of the health risks associated with drinking.  It will provide very useful information for countries looking to set or review their drinking guidelines.  However, the recommendation that drinking guidelines internationally be lowered should be interpreted with some caution.  The authors suggest guidelines should be set at 100 grams of pure alcohol a week as this is the consumption threshold associated with the lowest level of risk.  From our study of guidelines development processes in several different countries this is not the threshold that is typically considered most appropriate.  Instead, guideline developers tend to recognise that, in line with many other voluntary behaviours, drinkers are likely to be willing to accept some level of risk and have set guideline thresholds accordingly.  For example, the revised 2016 UK drinking guidelines are to not regularly exceed 14 units (i.e. 112 grams of pure alcohol) per week for both men and women.

“Also, the health risk associated with alcohol consumption can vary between countries depending on other conditions, for example rates of smoking, obesity or the prevalence of other underlying health problems, so it may well make sense to set country-specific drinking guidelines.”

Prof Tim Chico, Professor of Cardiovascular Medicine and Honorary Consultant Cardiologist, University of Sheffield, said:

“It is difficult to accurately estimate the risks of alcohol to health, but the large size and design of this study make its findings both reliable and applicable to countries around the world.  It shows that drinking more than 100g of alcohol per week (12.5 units, as 1 unit is 8g of neat alcohol) increases the chance of early death due to all causes.  As expected, the more alcohol someone drinks, the greater the increased risk of early death; if someone drinks 18.75 units per week then their risk of dying early is 1.2 times that of someone drinking less than 12.5 units.  However, drinking 43 units per week leads to a risk of early death that is about 1.5 times greater than people drinking less than 12.5 units.  This means that for a 40-year-old drinking more than 43 units per week, their lives are on average 4-5 years shorter than someone who drinks less than 12.5 units.  This is in comparison to the average of 10 years of life lost by smoking.  However, we think from previous evidence that it is likely that people drinking a lot more than 43 units are likely to lose even more life expectancy, and I would not be surprised if the heaviest drinkers lost as many years of life as a smoker.

“This study makes clear that on balance there are no health benefits from drinking alcohol, which is usually the case when things sound too good to be true.  Although non-fatal heart attacks are less likely in people who drink, this benefit is swamped by the increased risk of other forms of heart disease including fatal heart attacks and stroke.

“Should the guidelines be reduced further?  This depends on what they aim to achieve.  In my view the role of doctors and scientists is to explain the evidence as clearly as possible in order to allow people to make their own informed decisions.  I tell my patients that overall drinking alcohol has no health benefits and over more than about 12-14 units per week it does measurably increase the chance of serious health problems including death.”

Dr Tony Rao, Visiting Lecturer in Old Age Psychiatry, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, said:

“This research adds to a growing number of studies supporting current UK guidelines for lower risk drinking.  It also highlights the need to reduce alcohol related harm in baby boomers, an age group currently at highest risk of rising alcohol misuse.

“The strength of this study is its follow-up of large numbers of people without evidence of pre-existing cardiovascular disease, so it is likely to be relevant to the population at large.  It has also taken into account a number of factors that could have influenced meaningful interpretation of its findings.  However, it does not take into account the possibility of accompanying mental disorders such as dementia, which could explain reduction in alcohol consumption over the follow up period.  Under-reporting of alcohol intake could also have influenced the overall conclusions.  So, there remains considerable scope for similar studies with a longer follow-up period that take into account a broader range of health measures and closer examination of variation in drinking patterns.”

* ‘Risk thresholds for alcohol consumption: combined analysis of individual-participant data for 599 912 current drinkers in 83 prospective studies’ by Angela M Wood et al. published in the Lancet on Thursday 12 April 2018.

Declared interests

Prof David Spiegelhalter: “No conflicts of interest.”

Prof Petra Meier: “Professor Meier was a scientific expert involved in the recent UK guidelines development process.”

Prof Tim Chico: “No conflicts.”

Dr Tony Rao: “No interests to declare.”