Dispelling the Myth of Alcohol and Heart Disease

Volume 26, Issue 1

In a recent issue of Talking Therapeutics, we explored the relationship between one of America’s favorite beverages (coffee) and heart health. The study I discussed in that column aimed to explore whether coffee consumption is associated with cardiovascular harm. 

Contrary to caffeine, moderate alcohol consumption has long been purported to have beneficial effects on cardiovascular health. Most of this data comes from the Mediterranean diet studies, where the primary alcohol ingested was red wine. Despite this fairly limited representative sample, the idea that moderate alcohol intake is cardioprotective has been applied to all forms of alcohol in all types of patients. 

In this week’s issue, we look at a sweeping new study published in JAMA Network Open which attempts to address this issue with a significantly higher sample size than prior studies. 

Point 1: No Overall Signal for Benefit 

In this sweeping new meta-analysis, researchers evaluated 107 cohort studies with a total of 4,838,825 participants. The authors took great care to adjust their analysis for many potential confounding variables, such as sampling variation and former drinker bias. 

In their adjusted analysis, there was no significantly reduced risk of all-cause mortality among occasional drinkers (>0 to <1.3 g of ethanol per day; relative risk [RR], 0.96; 95% CI, 0.86 to 1.06; P = .41) or low-volume drinkers (1.3 to 24.0 g per day; RR, 0.93; P = .07) compared with lifetime nondrinkers.

They noted a nonsignificantly increased risk of all-cause mortality among those who consumed 25 to 44 g per day (RR, 1.05; P = .28), and a significantly increased risk for those who drank from 45 to 64 g and 65 g or more per day (RR, 1.19 and 1.35; P < .001). These negative health effects were more pronounced in women than in men. 

Point 2: What’s the Deal? 

There are several possible explanations for the discordant findings between this study and prior research. The bottom line is that prior studies likely contained inherent bias and confounding variables that skewed the data in favor of the moderate drinkers. 

Researchers listed some examples of systematic biases, including the following: 

• moderate drinkers may be systematically healthier than current abstainers on other health factors like dental hygiene, exercise routines, diet, weight, income;
• lifetime abstainers may be systematically biased toward poorer health;  
• the abstainer reference group may contain biases by including “sick quitters” or former drinkers, many of whom cut down or stop for health reasons; and
• most studies include a disproportionate number of older White men.