Page last updated: August 15, 2017June 25, 2018
Critique 214: Some methodologic problems in a recent paper urging changes in drinking guidelines – 23 April 2018

Using individual-participant data from a number of large studies, predominantly from the UK and other European countries, the authors of the present paper have estimated the association between the reported level of alcohol intake among drinkers with cardiovascular outcomes and mortality. They conclude that the lowest risk of these outcomes is from the intake of less than 100 g of alcohol per week, and that guidelines for the public should reduce the upper limits for the amount of alcohol that could be safely consumed.

Forum members identified a number of flaws in these analyses, including failure to separate advice for men versus women or for older adults versus young people. Further, the authors do not point out the effects of under-reporting of intake, the marked differences in many health effects according to type of alcoholic beverage (such differences are shown only in their supplement but not mentioned in the abstract); also, there is little discussion of the importance of the pattern of drinking on health results.

Most important, by excluding never-drinkers as a reference group in their main analyses, the authors essentially eliminated the ability to evaluate for any potentially beneficial (or adverse) effects of light-to-moderate drinking as compared with non-drinking. This is problematic, as in essentially all previous large studies, moderate drinkers are those for whom significant and large benefits have been reported for risk of cardiovascular disease and total mortality.

Guidelines for the public regarding alcohol intake relate to many factors, including the net overall physiologic effects on health as well as the particular needs of different countries and cultures. And, as in this study, the inclusion of results from so many different cultures is a problem for determining appropriate guidelines for alcohol intake. Given that culturally specific drinking patterns, type of beverage, and many other lifestyle factors modify the health effects of alcohol, mixing data from markedly different cultures may give results that may not be appropriate for any specific population.

Reference: Wood AM, Kaptoge S, Butterworth AS . . . John Danesh, et al, for the Emerging Risk Factors Collaboration/EPIC-CVD/UK Biobank Alcohol Study Group (120 authors). Risk thresholds for alcohol consumption: combined analysis of individual-participant data for 599 912 current drinkers in 83 prospective studies. Lancet 2018;391:1513-1523.



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