16 November 2018

Light to moderate alcohol consumption is associated with lowered mortality compared to not drinking alcohol at all

alcohol

In April a Lancet paper on risk thresholds for alcohol consumption led to worldwide media attention with headlines such as “One extra glass of wine will shorten your life by 30 minutes”. However, more critical and in-depth scrutiny of the research reveals the inaccuracy of these messages, as stated by Professor Arne Astrup from University of Copenhagen, and Dr. Simona Costanzo and Professor Giovanni de Gaetano from Department of Epidemiology and Prevention, IRCCS NEUROMED, Italy, in a correspondence published in the Lancet this week.

Professor Astrup and colleagues pinpointed a number of analytical errors with weighty implications for the conclusions.

Non-drinkers eliminated

Professor Arne Astrup, MD, DMSc, from the Department of Nutrition, Exercise and Sports at the University of Copenhagen: “We were highly surprised that non-drinkers were eliminated from the analysis, without valid scientific justification.” For almost a century, the scientific community has been aware of the J-shaped curve between alcohol consumption and mortality. Moderate drinkers seem to live longer than abstainers and heavy drinkers, mainly due to lower mortality from cardiovascular diseases.

J-curve confirmed

By taking out the non-drinkers as reference group, the obvious consequence is that this eliminates the left rising arm of the J-curve (see figure). Professor De Gaetano: “There is actually very little novelty in this study. Like many other studies this study suggests that the mortality curve bends at around one to two drinks per day. Hence these findings do not justify the conclusion in the Lancet publication that the thresholds for safer alcohol use should be lowered.”

Professor Astrup and colleagues conclude that the totality of evidence still supports that light to moderate alcohol consumption is associated with health benefits and lower mortality compared to not drinking alcohol at all.

Figure: Shape of association of usual alcohol consumption with various risks The J-shaped curve of association between alcohol consumption and various risks usually includes never-drinkers as the reference group; ex-drinkers must be omitted. Excluding the non-drinkers means the lowest risk is no longer found in those consuming 250–350 g of alcohol per week, but instead is found in those consuming up to 50 g of alcohol per week.
Figure: Shape of association of usual alcohol consumption with various risks The J-shaped curve of association between alcohol consumption and various risks usually includes never-drinkers as the reference group; ex-drinkers must be omitted. Excluding the non-drinkers means the lowest risk is no longer found in those consuming 250–350 g of alcohol per week, but instead is found in those consuming up to 50 g of alcohol per week.

Link to the article originally published in The Lancet: ‘Risk thresholds for alcohol consumption: combined analysis of individual-participant data for 599 912 current drinkers in 83 prospective studies

Link to the correspondence by Arne Astrup, Simona Costanzo and Giovanni de Gaetano also published in The Lancet: ‘Risk thresholds for alcohol consumption.’

About the authors

Arne Astrup is a member of the external scientific board of Dutch Beer Institute, is an author of a popular book on beer and health, and is editor of American Journal of Clinical Nutrition.

Simona Costanzo is the principal investigator of an ongoing study supported by a research grant from the European Foundation for Alcohol Research (EA1767).

Giovanni de Gaetano is a member of the International Scientific Forum on Alcohol Research, an independent organisation of scientists that prepares critiques of emerging research reports on alcohol and health. The members of the forum donate their time and effort to the review of papers, and receive no financial  support. The forum itself receives no support from any organisation or company in the alcoholic beverage industry.

He is also a consultant for the web newsletter of Assobirra, the Italian Association of the Beer and Malt Industries, and a corresponding member of the non-profit Accademia Italiana della Vite e del Vino.