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.

Wine is a complex matrix consisting primarily of water (86%) and ethyl alcohol (12%), as well as other different molecules, such as polyphenols, organic acids, tannins, compound minerals, vitamins and biologically active compounds which play an important role in the specific characteristics of each wine. According to the Dietary Guidelines for Americans 2015-2020, moderate red wine consumption-defined as up to two units of alcohol per day for men and up to one unit of alcohol per day for women-significantly reduces the risk of cardiovascular disease which represents the major causes of mortality, and disability, in developed countries. We reviewed the available literature concerning the potential relationship between moderate red wine consumption and cardiovascular health. We searched Medline, Scopus and Web…
Underlying mechanisms of the inverse relationship between moderate alcohol consumption and cardiometabolic disorders are unclear. Modification by types of alcoholic beverages consumed and drinking pattern remains understudied. We aimed to provide insight into the mechanisms by examining 14 insulinemic/glycemic, inflammatory and lipid markers. We used cross-sectional data from 15,436 women in the Nurses' Health Study, 19,318 women in the Nurses' Health Study II, and 6872 men in the Health Professionals Follow-up Study. Multivariable linear regression was used to estimate the percentage differences in biomarker concentrations according to alcohol intakes. The average alcohol intake in the combined cohort was 3.3 servings/week. We found a 1 serving/d increment in alcohol intake (14 g ethanol, 44 ml liquor or 355 ml beer or…
BACKGROUND: The incidence of stroke in China is increasing, along with a clear trend in the prevalence of risk factors. Alcohol consumption is also a risk factor for stroke. Many cohort studies have explored the relationship between alcohol consumption and stroke risk. However, findings have been inconsistent. METHODS: We used cluster sampling to select 13 districts and counties (at the same level) in Chongqing, China. Then, we used stratified random sampling to distribute the number of people in each district and county. 23,308 adults aged 30-79 were recruited between October 2018 and February 2019. Follow-up was conducted through a monitoring system and questionnaires until September 2022. Information on alcohol consumption and other covariates was collected using a standardized questionnaire. Participants…
BACKGROUND: Alcohol consumption may increase blood pressure but the details of the relationship are incomplete, particularly for the association at low levels of alcohol consumption, and no meta-analyses are available for nonexperimental cohort studies. METHODS: We performed a systematic search of longitudinal studies in healthy adults that reported on the association between alcohol intake and blood pressure. Our end points were the mean differences over time of systolic (SBP) and diastolic blood pressure (DBP), plotted according to baseline alcohol intake, by using a dose-response 1-stage meta-analytic methodology. RESULTS: Seven studies, with 19 548 participants and a median follow-up of 5.3 years (range, 4-12 years), were included in the analysis. We observed a substantially linear positive association between baseline alcohol intake…
A large number of observational studies have found a J-shaped relationship between alcohol intake and ischemic heart disease (IHD) risk. However, some studies suggest that the alleged cardio-protective effect may be an artifact in the way that the elevated risk for abstainers is due to self-selection on risk factors for IHD. The aim of this paper is to estimate the association between alcohol and IHD-mortality on the basis of aggregate time-series data, where the problem with selection effects is not present. In addition, we will analyze SES-specific mortality to investigate whether there is any socio-economic gradient in the relationship at issue. SES was measured by educational level. We used IHD-mortality in three educational groups as outcome. Per capita alcohol consumption…
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