Wednesday, 21 July 2021 07:50

Study with careful analysis shows: the J curve is valid!

When results of observational studies show health benefits for moderate wine drinkers and an increased risk for teetotallers (“J curve”), criticism often arises, assuming that methodological limitations might be responsible for the results. Constantly, critics question that a J-shaped relationship between moderate consumption of alcoholic beverages, in particular wine, and various health benefits exists. In some international reports, it is being communicated that any consumption of alcoholic beverages is harmful to health and a complete abstinence is preferable. The association between the consumption of alcoholic beverages and chronic diseases is indeed complex, particularly due to possible bias/confounding with the selection of the reference group, pattern of drinking, type of alcoholic beverages, etc. However, with a careful analysis of the data, it can be reproducibly shown that the known J curve is valid.

One of the most recent study on the matter, an elaborate analysis of data from 16 - mostly European - studies (MORGAM project) with almost 150.000 participants and around 16.000 deaths, represent additional supporting evidence. The MORGAM study examined the relationship between the volume of alcohol consumed and the total and cause-specific mortality, taking into account the drinking pattern and drinking frequency.

 

Hard endpoints, careful analysis of the data

The international research team chose total mortality as well as cardiovascular and cancer deaths and deaths from other causes as important endpoints. As opposed to using risk factors such as high blood pressure or cholesterol levels as endpoints, these are considered “hard” endpoints because of their high health significance. 

Furthermore, the scientists made sure to carefully subdivide those participants who identified as non-drinkers in two sub-categories: lifetime abstainers and former drinkers. The reason being that lifetime abstainers have a completely different health profile and often also a different lifestyle than former drinkers, who quit drinking alcoholic beverages because of health problems. Not making this distinction leads to the so called “sick quitter effect”, that distorts the results of those studies, which pooled all abstainers. Being a valid point of criticism of older studies, most recent studies are taking care of making this distinction among non-drinkers.

 

J-curve – once again - confirmed

The results of the current study confirm that a moderate consumption (up to 20 g of alcohol/day) is associated with a lower mortality risk than abstinence while, with a higher consumption, the risk increases: without any doubt, a J curved association. The study also showed that, in comparison with lifetime abstainers, ex-drinkers had a higher mortality risk, proving once again how important it is to make a distinction among non-drinkers in the studies. Furthermore, light to moderate consumption was not associated with cancer mortality, what cannot be said in the case of excessive consumption and with former drinkers, where the risk significantly increased.

 

Best results for wine drinkers

Such a J-shaped association of alcoholic beverages intake with mortality was observed for all European countries but the magnitude somewhat varied according to countries, which might be an indication of different drinking patterns and beverage preference. In Mediterranean countries, alcoholic beverages are typically consumed during main meals and largely in the form of wine. When the researchers subdivided the data according to beverage preference, among those who preferred drinking wine, such as in Italy and France, considerable differences were observed: the area (of the J curve) of improved life expectancy was much wider than in countries where other alcoholic beverages were consumed (up to approx. 40 g of alcohol per day). The authors concluded that the intake of alcoholic beverages was associated with a reduced mortality risk, resulting more evident in individuals preferring wine. At light to moderate intake (but not zero intake) the balance is in favor of total, cardiovascular and “other cause” mortality risk reduction, without any apparent increased cancer mortality risk.

 

Di Castelnuovo, A et al., 2021, Alcohol Intake and Total Mortality in 142,960 Individuals from the MORGAM Project: a population-based study. Addiction; doi:10.1111/add.15593

For more information about this abstract, click here.

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