Cardiovascular System

Is the “J-Curve” Real?

  

1. J-curve - Lower risk for light to moderate drinkers compared to abstainers

For many decades, epidemiological studies have consistently shown that light-to-moderate  consumers of alcoholic beverages have a lower risk of cardiovascular disease (CVD) and a lower risk of death from all causes (including total cancer) compared with non-drinkers or those who drink heavily. It is not limited to alcohol-related causes of death, but instead captures all deaths combined (Brien et al 2011, Ronksley et al 2011, di Castelnuovo et al 2006, Roerecke et al 2012, Ferrari et al 2014, Jayasekara et al 2014, Xi et al 2017, Wood et al 2018, Colpani et al 2018).

  • Such a J-shaped relationship (J-curve) has been shown in many different populations and dozens of observational studies. In different degrees, it is also seen in men and women and with other types of alcoholic beverages.
  • Observational studies cannot prove causality but the observed association is considered biologically plausible (see below). However, there is a scientific debate at which level of consumption the nadir of this curve lies.

 

  • Such a J-shaped relationship (J-curve) has been shown in many different populations and dozens of observational studies. In different degrees, it is also seen in men and women and with other types of alcoholic beverages.
  • Observational studies cannot prove causality but the observed association is considered biologically plausible (see below). However, there is a scientific debate at which level of consumption the nadir of this curve lies.

 

2. Comparison to Smoking

WHO and other institutions have repeatedly declared the risks of alcohol consumption equivalent to smoking. However, no benefit of “moderate smoking” has ever been found.

WHO and other institutions have repeatedly declared the risks of alcohol consumption equivalent to smoking. However, no benefit of “moderate smoking” has ever been found.

 

De Gaetano et al, 2017, Alcohol and health – praise of the J-curve, J Am Coll Cardiology, vol 70, no 8

 

3. J-shape also for other diseases

In addition to CVD and total mortality, a J-shaped curve exists for the risk of other diseases, for example for type-2 diabetes and dementia. 

 

4. Correlation or cause?

Observational studies can only provide statistical associations and present absolute or relative risks of developing certain diseases and cannot be interpreted as a proof of a causal relationship. However, the associations described are biologically plausible: controlled experiments have proven the beneficial physiological effects of light to moderate drinking of wine/alcoholic beverages.

 

Biologically plausible: How does it work?

Effect of alcohol:

  • Improvement of cholesterol levels: „good“ HDL increases, „bad“ LDL decreases
  • Lowering of blood viscosity (blood becomes „thinner“)

Effect of phenolic, non-alcoholic compounds of wine:

  • Improvement of endothelial function
  • Antioxidant effect/scavenger of free radicals

 

5. Wine versus other alcoholic beverages

Light to moderate wine consumption may be more beneficial than consuming other alcoholic beverages. An increasing number of both animal experiments and human trials demonstrate that non-alcoholic substances (polyphenols) in wine provide additional protective effects against risk factors and diseases.

 

6. Influencing factors

Most epidemiological studies have only used the average amount of alcohol consumed (over a week or month) as the measure of exposure, however, other factors play an important role in the health outcome. i.e. Regular moderate consumers of alcoholic beverages had considerable health advantages compared to binge drinkers, even though they consumed on average the same amount.

  • Drinking pattern (moderate, regular vs. binge drinking)
  • Drinking with the meals
  • Alternate wine with water
  • The famous advice of Serge Renaud is: “You drink water, but you sip wine”.

 

7. Underreporting

An important problem of observational studies is “under-reporting” of alcohol intake. This subsequently affects the J-curve. When “under-reporters” are removed from the study analysis, the curve shifts to the right, which means that the lowest risk of moderate drinkers is actually related to a higher amount of alcohol intake and the increased risk starts at a higher dosage.

 

8. Moderate wine consumption within a healthy lifestyle

Light to moderate consumption of wine/alcoholic beverages should be considered only one component of lifestyle factors related to health. The most important aspects are:

  • Don’t smoke
  • Maintain a normal body weight (avoid becoming obese)
  • Exercise regularly
  • Eat a healthy diet (e.g., a Mediterranean-type diet)
  • Consume alcoholic beverages moderately and regularly with food, unless contraindicated

These lifestyle factors contribute not only to a longer life expectancy but also a longer life free of chronic diseases.

 

9. Sick-quitters

Earlier studies included ex-drinkers in the non-drinking reference/control group that may have artificially increased the risk of disease for “current abstainers”, thus, confounding the J-shaped curve and negating a protective relationship with moderate drinking. However, more recent studies have corrected this flaw and when including only lifetime abstainers in the non-drinking category, a similar J-shaped curve was found and disproved the so called “sick-quitters” hypothesis.

There is a paucity of studies on the influence of alcohol intake among non-drinkers. We evaluated the association between an increase in alcohol consumption and primary prevention of major adverse cardiovascular events (MACE) among non-drinkers. Data collected by the National Health Insurance Service in the Korea between 2007 and 2013 were analysed. A total of 112,403 subjects were included and followed up from 1 January 2011 to 31 December 2013. Increases in alcohol consumption, measured as glasses per day, at the second medical check-up, were categorized into maintenance of nondrinking (0), > 0- 1- 2- 4. Hazard ratios (HRs) for MACE and all-cause mortality on increase in alcohol consumption were calculated. Compared to that in non-drinkers at the second check-up,…
BACKGROUND: The causal role of alcohol consumption for cardiovascular disease remains unclear. We used Mendelian randomization (MR) to predict the effect of alcohol consumption on 8 cardiovascular diseases. METHODS: Up to 94 single-nucleotide polymorphisms were used as instrumental variables for alcohol consumption. Genetic association estimates for cardiovascular diseases were obtained from large-scale consortia and UK Biobank. Analyses were conducted using the inverse variance-weighted, weighted median, MR-PRESSO, MR-Egger, and multivariable MR methods. RESULTS: Genetically predicted alcohol consumption was consistently associated with stroke and peripheral artery disease across the different analyses. The odds ratios (ORs) per 1-SD increase of log-transformed alcoholic drinks per week were 1.27 ([95% CI, 1.12-1.45] P=2.87x10(-4)) for stroke and 3.05 ([95% CI, 1.92-4.85] P=2.30x10(-6)) for peripheral artery disease…
Previous studies reported an inverse association between healthy dietary patterns (such as Mediterranean diet) and the incidence of cardiovascular events. As the mechanism accounting for cardiovascular disease is prevalently due to the atherothrombosis, where a pivotal role is played by platelet activation, it would be arguable that diets with protective effects against cardiovascular disease exert an anti-atherothrombotic effect via inhibition of platelet activation. There are several and sparse typologies of studies, which investigated if single nutrients by diets recognized as having cardiovascular protection may exert an antithrombotic effect. The most investigated nutrients are key components of the Mediterranean diets such as fruits and vegetables, fish, olive oil, and wine; other diets with protective effects include nuts and cocoa. Here we…
BACKGROUND AND AIMS: Many addictive substances, such as tobacco and alcohol, influence atherosclerosis development. Whether or not tobacco's pro-atherosclerotic effect is influenced by alcohol consumption is unknown. We aimed to estimate the impact of alcohol intake on the presence of subclinical atherosclerosis in femoral arteries in smoking and non-smoking middle-aged men. DESIGN, SETTING AND PARTICIPANTS: Cross-sectional analysis of a subset of the Aragon Workers Health Study (AWHS), comprising 2099 men with mean age 50.9 years without previous cardiovascular disease. MEASUREMENTS: The presence of plaques in femoral arteries was assessed by high-resolution sonography. Self-reported alcohol consumption over the previous year was measured with a food frequency questionnaire. The sample was divided into four groups according to their daily grams of alcohol…
The effects of alcohol on cardiovascular health are heterogeneous and vary according toconsumption dose and pattern. These effects have classically been described as having a J-shapedcurve, in which low-to-moderate consumption is associated with less risk than lifetime abstention,and heavy drinkers show the highest risk. Nonetheless, the beneficial effects of alcohol have beenquestioned due to the difficulties in establishing a safe drinking threshold. This review focuses onthe association between alcohol consumption and cardiovascular risk factors and the underlyingmechanisms of damage, with review of the literature from the last 10 years.
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