Canada's new guidance on alcohol is sparking plenty of debate.Andrew Vaughan/The Canadian Press
There was sobering news about alcohol earlier this month in a new study from the Canadian Centre on Substance Use and Addiction.
The CCSA’s key media message was absolute: No amount of alcohol is safe, and even as few as three standard drinks a week pose a health danger, including higher risk of several cancers and most kinds of cardiovascular diseases.
The findings have quickly become part of the debate over the desirability of tobacco-like warnings on alcohol bottles. They are also no doubt a cause for deep concern among people who followed previous guidelines calling for no more than 10 standard drinks per week for women, and 15 for men.
There is one problem, though: The study’s data don’t align with the apocalyptic headlines it has generated. In turn, that raises questions about what kinds of warnings should be printed on booze containers.
The most obvious omission from the centre’s public statements are the study’s own data – consistent with earlier studies – showing that modest alcohol consumption reduces the risk of some types of cardiovascular disease.
The CCSA study adds a caveat, saying this “protective effect” should be “interpreted with caution” because it cannot be defined as statistically significant and might have resulted from random error.
However, that uncertainty also applies in reverse. There is no statistically significant difference in overall health risk between a lifetime abstainer and a drinker until the latter’s alcohol consumption nears seven standard drinks a week.
The study also shows the risk of some cancers rising with alcohol consumption. But that risk is low for moderate drinkers, and those negative effects at low levels of consumption are much smaller than the positive effects on cardiovascular health.
And what about the centre’s assertion that the risk of “many kinds” of cardiovascular disease rises for those consuming more than six standard drinks a week? In the very narrowest sense, that is true – the risk does rise, compared to those consuming less alcohol.
But that statement glides past the fact, laid out in the centre’s study, that there is a protective effect against three of six identified cardiovascular diseases for those consuming up to seven drinks a week, as compared with lifetime abstainers.
It’s only after that point that drinkers have a statistically measurable higher overall health risk than a lifetime abstainer. By the time someone is consuming 14 standard drinks a week – the equivalent of two drinks a day, every day – any protective effect is dissipated. Those heavier users of alcohol face an elevated risk of cardiovascular disease, cancer and other diseases.
Now, this would be far from the first time that a press release and its media coverage did not capture the full nuance of a scientific study. And if a few wobbly headlines were the only result, who would much care?
The bigger issue, however, is that the study’s headline finding that no amount of alcohol consumption is safe is being presented as a rationale for stepped-up labelling on alcohol bottles.
Some proposals are long overdue, such as stating the number of standard drinks contained in a product. That would be consistent with other kinds of nutritional labelling and give consumers easy-to-understand information to guide their drinking decisions.
There are also proposals for tobacco-like warnings on alcohol bottles that would flag cancer risks, for instance, and urge consumers to reduce their consumption.
Such warnings are an excellent idea for tobacco, whose health effects are demonstrably and entirely negative.
But as the centre’s own study shows, the verdict is not so stark for alcohol. Some drinkers, particularly when individual medical histories are taken into account, could very well benefit from moderate consumption.
The overall risk and/or benefit depends in large part on the consumption habits of the person buying the product; it’s hard to square that nuanced message with health-warning labels.
Standard-drink information, on the other hand, would allow Canadians to make better decisions about responsible alcohol use. That would be a far preferable approach than public health officials – however good their intentions – trying to stampede moderate drinkers toward teetotalling.