(TDB) - The definition of the size of a ‘standard drink’ varies wildly across the world, according to new research, giving drinkers a confusing picture of how to drink safely.

The World Health Organization defines a standard drink as 10 g. (grams) of pure ethanol, with both men and women advised not to exceed 2 standard drinks per day.

However, according to a report just published in the scientific journal Addiction, in individual countries the size of a standard drink can vary by as much as 250%, with the smallest in Iceland and the UK (8 g.), and the largest in Austria (20 g.).

Researchers looked at seventy-five countries and found that only thirty-seven of them (less than 50%) provided any definitions of drink size. For those countries that did, the WHO’s definition of a standard drink is the one most often cited, but 50% of countries with drinking guidelines don’t use it.

In Chile, for example, drinkers can take 56 g. per day and still be defined as at low-risk.

Meanwhile – in line with the UK’s advice – Australia, Canada, Denmark, Fiji, France, Mexico, New Zealand, and Poland all offer guidelines allowing you to drink more on special occasions.

The UK’s recently changed guidelines which make the same intake recommendations for men and women bring the country into line with Australia, Grenada, Portugal, and South Africa, but many others still offer separate guidelines for each of the sexes.

Co-author of the report Keith Humphreys of Stanford University School of Medicine in the USA says the inconsistencies mean there’s a substantial chance for misunderstanding.