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.

PURPOSE: To examine the acute and chronic effects of alcohol on blood pressure (BP) and the incidence of hypertension. We discuss the most current understanding of the mechanisms underlining these effects and their associations with the putative cardioprotective effects of consumption of low-to-moderate amounts of alcoholic beverages. RECENT FINDINGS: A recent meta-analysis confirmed findings of experimental studies, demonstrating an acute biphasic effect of ethanol on BP, decreasing up to 12 h of ingestion and increasing after that. This effect is mediated by vagal inhibition and sympathetic activation. A meta-analysis found that chronic consumption of alcoholic beverages was associated with a high incidence of hypertension in men and women; it also found that, in women, the risk begins at moderate alcohol…
BACKGROUND: Population-based studies generally show J-shaped associations between alcohol intake and mortality from cardiovascular diseases (CVD). Little is known about alcohol and long-term mortality risk after myocardial infarction (MI). OBJECTIVE: We examined alcohol intake in relation to all-cause, CVD and ischemic heart disease (IHD) mortality in Dutch post-MI patients of the Alpha Omega Cohort. DESIGN: The analysis comprised 4,365 patients (60-80 y, 79% male) with an MI 0-2 g/d, n = 385), light (M: >2-10, F: >2-5 g/d, n = 1125), moderate (M: >10-30, F: >5-15 g/d, n = 1207) or heavy drinkers (M: >30, F: >15 g/d, n = 692). Hazard ratios (HRs) of mortality for alcohol intake were obtained from Cox models, adjusting for age, sex, education, smoking,…
OBJECTIVE: This study aimed to investigate the association between alcohol consumption and the prevalence of stroke in Chinese adults aged 40 years and over. METHOD: We conducted a cross-sectional analysis among 113,573 Chinese adults aged >/= 40 years in the China National Stroke Prevention Project (2014-2015) to examine correlations of alcohol consumption with the prevalence of stroke. Logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs), controlling for various confounders, e.g., gender, age, smoking, physical activity and other health conditions. RESULTS: Within the study population, a total of 12,753 stroke survivors were identified. The prevalence of light to moderate and of heavy alcohol consumption was 10.1% and 5.7% respectively. The multivariate logistic regression results…
Background Although previous studies have demonstrated a U-shaped relationship between alcohol and sudden cardiac death (SCD), there is a paucity of evidence on the role of alcohol specifically on incident ventricular arrhythmias (VAs). Objective The purpose of this study was to characterize associations of total and beverage-specific alcohol consumption with incident VA and SCD using data from the UK Biobank. Methods Alcohol consumption reported at baseline was calculated as UK standard drinks (8 g of alcohol) per week. Outcomes were assessed through hospitalization and death records. Alcohol consumption was modeled as restricted cubic splines in multivariate Cox regression models and corrected for regression dilution bias. Results We studied 408,712 middle-aged individuals (52.1% female) over a median follow-up time of 11.5…
BACKGROUND: We investigated the association of alcohol consumption with cardiovascular and non-cardiovascular mortality in elderly Chinese men. METHODS: Our participants were recruited from residents living in a suburban town of Shanghai (>/=60 years of age, n = 1702). Alcohol intake was classified as non-drinkers, past drinkers (stopped drinking for >/=12 months), and current light-to-moderate (1 to 299 g/week) and heavy drinkers (>/=300 g/week). Alcoholic beverages were classified as beer/wine, rice aperitif and liquor/mix drinking. RESULTS: During 5.9 years (median) of follow-up, all-cause, cardiovascular and non-cardiovascular deaths occurred in 211, 98 and 113 participants, respectively. The corresponding incidence rates were 23.6/1000, 10.9/1000 and 12.6/1000 person-years, respectively. Both before and after adjustment for confounding factors, compared with non-drinkers (n = 843), past…
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