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Tuesday, 13 August 2019 06:52

“From scientific analysis to media and policy”: a sober analysis

The 42nd World Congress of Vine and Wine was held in Geneva, Switzerland earlier in July. Ursula Fradera & Prof. Nicolai Worm, respectively, scientific coordinator for Wine in Moderation and Chair of the Wine Information Council presented their papers on the hot topics of science and risk communication.

“From scientific evidence to media and policy: Wine – part of a balanced diet or a health risk?” (Ursula Fradera)

Articles of all sorts have been published in the last couple of years questioning the benefits of moderate wine consumption in the frame of a healthy lifestyle.

Because one of these studies, the Global Burden of Disease (GBD) study, is often referenced as an argument for no safe level of consumption and that the adverse health effects associated with the intake of alcoholic beverages outweigh any benefits, a critical analysis was presented by U. Fradera during the OIV congress. The study showed several limitations which also has practical implications:

  • GBD is a population level study but the results are interpreted at individual level. 23 alcohol-related health issues were merged together, however, not everyone experiences them at the same rate. For example, for diabetes and heart disease, the risk decreases with light and moderate drinking. According to the authors, this benefit is neutralized by the increased risk for cancer and tuberculosis. Yet for many individuals, diabetes and heart disease pose a much higher risk than cancer and tuberculosis.
  • No consideration of lifestyle factors: Many lifestyle factors strongly modify the association between the wine/alcoholic beverages consumption and disease risk/outcome. Such lifestyle factors include the drinking patterns, (e.g. moderate vs binge drinking, drinking with or without a meal, type of alcoholic beverage), diet, physical activity, socio-economic status. Not including these factors provides an incomplete assessment of the effects of alcohol on health.
  • Lack of considering country-specific aspects à Results do not provide useful information applicable to a single population: Authors conclude that their results have worldwide implications for setting alcohol policy and changing drinking guidelines. However, their statement that zero intake of alcohol would be preferable everywhere is contradicted by consistent data from numerous large cohort-studies which indicate that non-drinkers have higher risks of cardiovascular disease and total mortality than regular moderate drinkers who do not binge drink.

She summarized that the overall combined results from such divergent populations, as in the GBD study, have little applicability in setting guidelines that would prevent alcohol abuse in any specific group of individuals around the world – they apply to no specific population. It is thus important to carefully interpret and analyse population-based data and their respective conclusions. This study does not suggest that drinking moderately will increase an individual’s risk of disease or death – it only presents correlations on a population level. It does confirm however, that excessive drinking carries many health risks.

Fradera explained that there was no evidence contradicting the well-known J-shaped association between drinking and all-cause mortality, pointing out to the fact that decades of studies demonstrating that moderate wine consumption reduces risk of heart disease and total mortality were omitted and ignored.

She concluded by pointing out that headlines can be very confusing, thus, it is very important to critically analyse the scientific publications and put the findings into perspective. Population-based studies (such as the GBD study) cannot be interpreted at an individual level. The claim there is no safe level of drinking is therefore not justifiable. According to the current scientific evidence, low to moderate wine consumption with the meals (in a non-binge-drinking pattern) has more health benefits than risks and can be part of a healthy lifestyle. Furthermore, focusing only on risks and ignoring benefits cannot be considered as objective evidence-based science. 

 

“How Big is the Cancer Risk with Moderate Wine Consumption as Part of a Mediterranean Type Diet?” (Nicolai Worm)

Renowned German nutritionist, Prof. Nicolai Worm looked at the risk of cancer when wine is consumed in moderation and in the frame of a Mediterranean diet.

  • Absolute versus relative risk: Headlines such as “Even 1 drink increases cancer risk” have multiplied in recent years focusing on the risk associated with drinking alcoholic beverages/wine. He explained how to interpret risk and the difference between absolute and relative risk.

  • Communication of study results misleading: With the example of the Wood et al study, Worm described how the communication and presentation of study results by the scientists can be misleading, with respective headlines in the media. For example, instead of using moderate drinkers as a reference group and “cutting off” the benefits of the J-curve, it would be preferable to use never drinkers as a reference group (as was presented in the appendix of the publication) and differentiating between the alcoholic beverages. Then, the correct conclusions would be: “If you regularly consume wine in moderation (up to 1-2 drinks per day for women or 2-3 drinks for men), risk for total mortality is slight and risk for cardiovascular disease significantly decreased.” In contrast, the study came out saying: “These results support limits for alcohol consumption that are lower than those recommended in most current guidelines”.
  • Wine as part of the Mediterranean diet and cancer risk: Worm also presented various studies with moderate wine consumption as part of a Mediterranean eating pattern where the cancer risk and the total mortality risk was reduced. He pointed out that when examining the components of Med Diet, besides fruits, vegetables and cereals, alcoholic beverages were considered as the most protective items of the diet.

He concluded with the take home message that the best evidence still supports the concept that light to moderate wine consumption with meals – as part of a Mediterranean type diet and lifestyle – has more benefits than harms.

The 42nd World Congress of Vine and Wine was the fourth biggest congress in terms of presentations in the last 10 years, OIV President Regina Vanderlinde, highlighted the excellent quality of the 348 technical and scientific presentations.

For more information on the OIV Congress and the presentation that were during the congress, please visit their website.