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.

Alcohol is often cited to be a common cause of cardiomyopathy and heart failure. However, in most available population-based studies, a modest-to-moderate alcohol consumption has been associated with favorable effects on the cardiovascular system, including a lowered risk of heart failure, compared with no alcohol consumption. Available genetic epidemiological data have not supported a causal association between alcohol consumption and heart failure risk, suggesting that alcohol may not be a common cause of heart failure in the community. Data linking alcohol intake with cardiomyopathy risk are sparse, and the concept of alcoholic cardiomyopathy stems mainly from case series of selected patients with dilated cardiomyopathy, where a large proportion reported a history of excessive alcohol intake. This state-of-the-art paper addresses the…
BACKGROUND: Studies evaluating alcohol consumption and cardiovascular diseases have shown inconsistent results. METHODS: We performed a systematic review of peer-reviewed publications from an extensive query of Ovid MEDLINE, Ovid Embase, Ovid Cochrane Database of Systematic Reviews, Scopus, and Web of Science from database inception to March 2022 for all studies that reported the association between alcohol consumption in terms of quantity (daily or weekly amounts) and type of beverage (wine, beer or spirit) and cardiovascular disease events. RESULTS: The study population included a total of 1,579,435 individuals based on 56 cohorts from several countries. We found that moderate wine consumption defined as 1-4 drinks per week was associated with a reduction in risk for cardiovascular mortality when compared with beer…
OBJECTIVES: Many studies have found that moderate alcohol consumption is associated with lower risks of mortality and myocardial infarction (MI). Our aim was to examine the potential effects of alcohol on all-cause mortality and MI in rheumatoid arthritis (RA), a risk factor condition. METHODS: A cohort study (1995-2017) was conducted using medical records of RA patients from The Health Improvement Network in the United Kingdom (UK). Alcohol exposure was divided into non-drinkers, mild (1-7 UK units/week), moderate (8-14 UK units/week), moderate-high (15-21 UK units/week), and high (>21 UK units/week) consumption levels. We calculated hazard ratios (HRs) for the relation of alcohol consumption to all-cause mortality and MI, adjusting for covariates. RESULTS: Of 30,320 RA patients, 5,994 deaths and 1,098 MI…
BACKGROUND: The causal effects of moderate alcohol consumption on cardiovascular diseases (CVDs) are continuously debated, especially on coronary artery disease (CAD). OBJECTIVES: We aimed to explore the causal associations of alcohol consumption with CVDs and all-cause mortality among Chinese males. METHODS: A prospective cohort study was conducted in 40,386 Chinese males, with 17,676 being genotyped for the rs671 variant in the aldehyde dehydrogenase 2 (ALDH2) gene. A Cox proportional hazards model was conducted to estimate the effects of self-reported alcohol consumption. Mendelian randomization (MR) analysis was performed to explore the causality using rs671 as an instrumental variable. RESULTS: During the follow-up of 303,353 person-years, 2406 incident CVDs and 3195 all-cause mortalities were identified. J-shaped associations of self-reported alcohol consumption with…
Background: The treatment of atrial fibrillation (AF) has made significant progress, but the prevention of AF has not received the attention it deserves. A few recent large-sized studies have conducted dose response analysis and reported different conclusions from previous studies on alcohol consumption and AF risk. Objectives: The aim of this study is to examine the potential non-linear association between alcohol consumption and risk of AF and explore the potential differences of gender. Methods: In this updated dose-response meta-analysis, PubMed, Embase and Cochrane databases were searched until June 2022. Risk estimates were reported as relative risk (RR) with 95% confidence intervals (CIs). The random-effects restricted cubic spline models are used to evaluate the potential non-linear association between alcohol consumption and…
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