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.

AIMS: To investigate associations of life-time hazardous and binge drinking with biomarkers of cardiometabolic health, liver function, cardiovascular disease (CVD) and mortality. DESIGN: Prospective cohort study with median follow-up time to CVD incidence of 4.5 years. SETTING: London, UK: civil servants within the Whitehall II Study. PARTICIPANTS: A total of 4820 drinkers aged 59-83 years with biological measurements during the 2011-12 survey. MEASUREMENTS: Hazardous drinking was defined as having an AUDIT-C score >/= 5 calculated at each decade of life, forming the following groups: never hazardous drinker, former early (stopping before age 50), former later (stopping after age 50), current hazardous drinker and consistent hazardous drinker (hazardous drinker at each decade of life). FINDINGS: More than half the sample had…
BACKGROUND: Among different investigators studying the same exposures and outcomes, there may be a lack of consensus about potential confounders that should be considered as matching, adjustment, or stratification variables in observational studies. Concerns have been raised that confounding factors may affect the results obtained for the alcohol-ischemic heart disease relationship, as well as their consistency and reproducibility across different studies. Therefore, we assessed how confounders are defined, operationalized, and discussed across individual studies evaluating the impact of alcohol on ischemic heart disease risk. METHODS: For observational studies included in a recent alcohol-ischemic heart disease meta-analysis, we identified all variables adjusted, matched, or stratified for in the largest reported multivariate model (i.e. potential confounders). We recorded how the variables were…
BACKGROUND/AIM: The association between alcohol consumption and subclinical atherosclerosis is still unclear. Using data from a European multicentre study, we assess subclinical atherosclerosis and its 30-month progression by carotid intima-media thickness (C-IMT) measurements, and correlate this information with self-reported data on alcohol consumption. METHODS: Between 2002-2004, 1772 men and 1931 women aged 54-79 years with at least three risk factors for cardiovascular disease (CVD) were recruited in Italy, France, Netherlands, Sweden, and Finland. Self-reported alcohol consumption, assessed at baseline, was categorized as follows: none (0 g/d), very-low (0 - 5 g/d), low (> 5 to 10 to 10 to 20 g/d for women, > 30 g/d for men). C-IMT was measured in millimeters at baseline and after 30 months. Measurements…
BACKGROUND: Light-to-moderate alcohol drinking reduces the risk of ischemic heart disease, and this effect of alcohol is mainly explained by alcohol-induced elevation of HDL cholesterol. Hypo-HDL cholesterolemia is a potent risk factor for cardiovascular disease. The aim of this study was to clarify how alcohol relates to cardiovascular risk factors in men with hypo-HDL-cholesterolemia. METHODS: The subjects were middle-aged men with hypo-HDL cholesterolemia (< 40mg/dl), and they were divided into four groups by daily alcohol consumption (non-; light, < 22g ethanol/day; moderate, >/=22g ethanol and /=44g ethanol/day). Each risk factor was compared among the groups after adjustment for age and histories of smoking and regular exercise. RESULTS: Systolic and diastolic blood pressure levels, log-transformed lipid accumulation product and log-transformed cardio-metabolic…
BACKGROUND: The potential impacts of beverage intake during the midlife on future subclinical atherosclerosis among women are unclear. The aim of this study was to evaluate the prospective associations between the intakes of eight beverage groups and subclinical carotid atherosclerosis in midlife women. METHODS: Data came from the Study of Women's Health Across the Nation, a multicenter, multiethnic, and prospective cohort study. A total of 1,235 midlife women had measures of subclinical carotid atherosclerosis and repeatedly beverage intake data collected using a validated food frequency questionnaire. Beverages were aggregated into eight groups, including coffee, tea, sugar-sweetened beverages, artificially sweetened beverages, fruit juices, whole milk, milk with lower fat content, and alcoholic beverages. The associations of beverage intake with common carotid…
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