The new recommendations from the National Board of Health and Welfare state that health services should offer support to people who drink ten standard glasses or more per week, or four standard glasses or more per occasion once a month or more often. Ephi spoke to epidemiologist Måns Rosén who questions the National Board of Health and Welfare's assessment after reviewing the research on which the advice is based.
- When the National Board of Health and Welfare says that the less alcohol you drink, the lower your risk of illness or premature death, it is simply not true.
The words are Måns Rosén's. Rosén is an epidemiologist and former head of the Epidemiological Center at the National Board of Health and Welfare, former Director General of the Swedish Agency for Health and Social Research (SBU) and formerly active at Karolinska Institutet and Umeå University.
He says this in the light of the much-publicized new limits for the risky use of alcohol in healthcare, which the National Board of Health and Welfare updated and published in September 2023.
The limit that the National Board of Health and Welfare considers to be at risk is now the same for women as for men: a maximum of 10 standard glasses of alcohol per week, or a maximum of 4 standard glasses on a single occasion once a month. The new guidelines are not aimed directly at the general public, but at healthcare professionals to assess when healthcare support should be offered to help a patient reduce their alcohol consumption.
The National Board of Health and Welfare's communication on the new guidelines is clear: the more alcohol a person drinks, the higher the risk of ill health or even premature death. It is not possible to set a limit for when alcohol consumption is risk-free.
But is that really true?
To understand how the National Board of Health and Welfare came to the conclusion that less alcohol is always better, some background is needed. Almost everyone knows that people who drink alcohol in moderation enjoy better health than those who drink heavily. There is no doubt that drinking too much alcohol can have devastating consequences, both for the drinker and for the people around them.
But a lot of research has also long shown that people who drink in moderation also seem to have slightly better health compared to those who don't drink at all. This could be for a number of reasons: it could be due to some effect of the alcohol itself, but it could also be that people who drink in moderation have more social contacts than others, which we know is good for health. The poorer health of teetotallers could be because they have fewer social contacts than others, but it could also be because some teetotallers have had problems with alcohol in the past. But even after controlling for these factors, there is still a tendency for people with moderate alcohol consumption to have slightly better health than others.
I the knowledge base which form the basis of the National Board of Health and Welfare's new guidelines, refer to new research. The research that is supposed to show that the previous results that moderate drinking could be healthy are not correct. Måns Rosén has read the evidence base and reacts to the fact that it is not very comprehensive:
- "I'm surprised that the evidence base is so thin, and focuses a lot on other countries' recommendations. There are many systematic reviews in the field of alcohol consumption and health, but the one referred to by the National Board of Health and Welfare is questionable," says Rosén.
The overview study that Rosén refers to and which, according to Rosén, has had a major impact on the National Board of Health and Welfare's new assessment is a article from January 2023 published in the journal JAMA Network Open, and is a reference in the National Board of Health and Welfare's knowledge base. There are reasons to delve into that article.
The title is "Association between Daily Alcohol Intake and Risk of All-Cause Mortality", and it reviews 107 other studies covering a total of 4.8 million people whose alcohol consumption and health were studied. It is thus a so-called meta-study, which uses and compiles the results of other studies and analyzes them. If you read the summary as a lay person, the results of the meta-study are clear:
"Low-volume alcohol drinking was not associated with protection against death from all causes."
Hard to misunderstand, you might think. According to the article's summary, low alcohol consumption has no protective effect, contrary to popular belief.
But the study has been criticized for how it handles statistics. A criticism that Måns Rosén shares.
The study distinguishes between 'non-drinkers', who do not drink alcohol at all, and 'low-volume drinkers', who do drink alcohol, but no more than 24 grams of pure alcohol per day. This is equivalent to two standard Swedish glasses: roughly two small glasses of wine or two 33 cl cans of strong beer a day.
The study analyzes the relative risk of death for moderate drinkers compared to abstainers. If the result is above 1, it means that the relative risk of death is higher among moderate drinkers compared to abstainers. It also indicates a confidence interval, which in simple terms is a higher and lower limit for the result that shows how certain the estimate is. A 95% confidence level is often used in research of this type.
The relative risk for moderate consumers is, perhaps somewhat surprisingly given the conclusion, 0.86. Moderate alcohol consumption thus seems to lead to a 14% lower risk of dying compared to the risk of death of sober people. The confidence interval is between 0.83 and 0.88.
- But then the study takes the next step, and tries to control for so-called confounders, factors that can co-vary with mortality and confound the results. Some of this makes sense, such as adjusting for socioeconomics and smoking. Other parameters you include are more questionable. It is difficult to know how these parameters interact with each other," says Måns Rosén.
When these parameters are included, the result is 0.93. Thus, there still appears to be a 7% lower relative mortality risk for moderate drinkers. However, the result also becomes more uncertain, which is reflected in an increase in the confidence interval: it becomes 0.85-1.01. It thus extends on both sides of 1, albeit by the smallest possible margin. From this, the study concludes that there is no significant result. Formally, this is true.
- Now the authors have used the 95% confidence level. But if they had used the 92% confidence level instead, the confidence interval would have been slightly smaller, and the results would still have shown that moderate consumers had a lower relative risk of mortality compared with those who did not drink alcohol. In other words, we can say that with a 92 percent probability, the study's conclusion is not correct," concludes Måns Rosén.
