Responsible drinkers being ‘stigmatised’ by flawed alcohol studies

Responsible drinkers are being “stigmatised” by flawed studies on alcohol promulgated by health organisations, who are also ignoring credible science that contradicts their agenda, says a leading nutritionist.

Addressing members of the wine trade virtually in March this year for a webinar on wine and cancer, Professor Nicolai Worm, who holds a PhD in Nutritional Sciences at the University of Giessen, highlighted the flaws in studies being used by bodies such as the World Health Organisation (WHO) and the World Cancer Research Fund International (WCRF) to promote the idea that any level of alcohol consumption carries a health risk.

Not only that, but he said that such associations were “ignoring data that contradicts their agenda”, before stressing that there are numerous, credible scientific studies to show that “light to moderate wine consumption with meals reduces the risk of cardiovascular disease, cancer and total mortality.”

Indeed, responding to a claim by various health bodies that there is “no safe level” of drinking, Worm said that “the best available evidence” proves that moderate wine consumption “should be viewed as safe”.

Expressing incredulity at the flawed nature of certain studies being used to highlight the dangers of drinking, he said that “underreporting” by participants and a failure to take into account the context and patterns of consumption undermined the conclusions from high-profile and oft-quoted pieces of research.

Drawing attention to a report published by The Lancet in September 2018 – which was the source of the “no safe level” conclusion regarding alcohol consumption and cancer – he said that this piece of research, along with similar “mega studies”, should be looked at “critically”, before stressing that cancer is a multi-factorial disease.

“One factor, alcohol, is certainly not enough to cause cancer,” he stated, mentioning a number of important influences, from a person’s genes to their diet, sun exposure to physical activity – before noting that a lack of exercise in particular is a “strong risk factor” when it comes to health problems.

Commenting that pure ethanol and its by-product acetaldehyde, created when the body metabolises alcohol, can trigger cancer development through “a bunch of mechanisms that are still not fully understood”, he said that “the high intake of alcohol should be regarded as a factor in cancer development, but to say that alcohol causes cancer without defining the dosage is not scientific.”

He also pointed out that “the World Health Association says that 4.3% of cancers are attributable to alcohol, so what comes to my mind first of all is that 97.7% of cancers are not attributable to alcohol – which is an interesting and good message.”

Focusing on one source of problems among studies on drinking, Worm said that “there is an immense amount of underreporting when it comes to alcohol: people say that they drink less than they actually do,” which, he added, “makes data very unreliable”.

Continuing, he said that due to the prevalence of underreporting among participants in drinking studies, the actual risk of developing health issues from alcohol might actually emerge among those consuming 2-3 drinks per day, but officially it’s at a lower level, because these people are saying that they are having 1-2 drinks per day.

Referring to a cohort study of more than 120,000 people by Klatsky et al in 2014 that scrutinised this issue, Worm said that it was found that those who accurately reported their alcohol consumption did not have an increased cancer risk.

Indeed, the study, called Moderate alcohol intake and cancer: the role of underreporting, concluded that “the apparent increased risk of cancer among light-moderate drinkers may be substantially due to underreporting of intake.”

As a result, for Worm, “Underreporting is a huge problem when talking about alcohol and cancer risk.”

The other major issue concerns a failure by many studies, particularly those being used to highlight the dangers of drinking, to take into account the context or pattern of consumption.

This is called ‘confounding’, and refers to the mixing of effects that distort the true relationship between, in this case, alcohol and health.

“For example, smoking would be a confounding factor in a study on alcohol and cancer, since smoking is correlated with alcohol consumption, and smoking is associated with cancer,” explained Worm, before listing other “confounders”, such as age or obesity, exercise or social class, as well as, drinking pattern, which is very important,” he said.

For a study on the relationship between alcohol consumption and cancer to be reliable, he continued, it must control for confounders such as age, gender, obesity, sleep, exercise, education, income, social class, sun exposure and countless other factors, including drinking pattern and a multitude of dietary factors.”

By way of example he drew attention to a “famous” piece of research from 1998 by Serge Renaud on drinkers in eastern France, known as the Nancy-Study, that “followed 34,000 men and showed an increased cancer risk for those drinking about 76g of alcohol per day.”

While he recorded that this study was adjusted for age, education, smoking, blood pressure and body mass index (BMI), “we don’t know how much exercise the participants were taking, nor how healthy was their diet, so we don’t know how reliable the results are.”

In conclusion, he said, “If you don’t include all confounding factors then you can create false results.”

Finally, it is worth nothing the beneficial role of taking regular exercise, with Worm recording that a particularly influential factor on the relationship between drinking and cancer is the level of physical activity being taken.

Drawing on the results of a UK study of more than 36,000 men and women over 40 years old by Perreault et al (2016), he said it had been shown that the cancer risk “did not increase at all” for “very active” participants in the study – even among those drinking at “hazardous levels” (14-35 (women); 21-49 (men)).

As this study states, “Stratified analyses showed that the association between alcohol intake and mortality risk was attenuated (all-cause) or nearly nullified (cancer) among individuals who met the PA [physical activity] recommendations (HR (95% CI)).”

Consequently, it concludes, “Meeting the current PA public health recommendations offsets some of the cancer and all-cause mortality risk associated with alcohol drinking.”

As a final and more general point, at the end of the webinar, Worm summed up his two main concerns when it comes to any messaging concerning alcohol and health.

One relates to the challenge for “lay people” to find flaws in studies, and therefore detect whether they are credible or not.

And the other is connected to a failure by governments and health bodies to publicise any science showing the health benefits from drinking. As he said, “There is so much evidence proving that light alcohol consumption and wine drinking might not be a cancer risk, but it’s just not recognised; it just doesn’t suit certain people’s agendas, so it’s not discussed.

“We have to live with this problem,” he concluded.

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