Apparent Cardioprotective Effects of Moderate Alcohol Consumption Likely Explained by Other Lifestyle Factors

Some observational studies demonstrate a lower risk of cardiovascular disease (CVD) with light-moderate alcohol intake compared with abstinence or heavy consumption. However, confounding lifestyle factors may explain these patterns. Researchers explored the association between alcohol consumption and CVD using a large genetic databank with 371,463 participants that included blood samples and lifestyle information. They constructed a “genetic instrument” based on single nucleotide polymorphisms (SNPs) associated with an alcohol use disorder diagnosis and AUDIT-C answers, but independent of other lifestyle factors.* Researchers measured the association between these SNPs and adverse cardiovascular outcomes to minimize confounding and establish a causal relationship.

• For every 1 standard deviation increase in genetically predicted alcohol consumption, the risk of hypertension and coronary artery disease increased (odds ratios, 1.3 and 1.4, respectively).
• The risk for CVD with alcohol consumption increased exponentially, beginning at 7–14 drinks in a week. This pattern was also found for all-cause mortality.
• Similarly, there was a positive and quadratic association between alcohol consumption and systolic blood pressure, diastolic blood pressure, and LDL cholesterol level.

* Defined as: smoking, body mass index, physical activity, vegetable intake, red meat intake, overall health rating, C-reactive protein level, and total cholesterol level.

Comments: Using a novel method to reduce confounding, this study supports a causal and exponential association between alcohol intake and CVD, beginning at low levels of consumption. These findings suggest that the apparent cardioprotective effects of moderate alcohol consumption found in some observational studies are due to confounding lifestyle factors. Moreover, this study supports the theory that no amount of alcohol is protective against CVD.

Lea Selitsky, MD, MPH** and Darius A. Rastegar, MD

** Contributing editorial intern and Addiction Medicine Fellow, Johns Hopkins University.

Reference: Biddinger KJ, Emdin CA, Haas ME, et al. Association of habitual alcohol intake with risk of cardiovascular disease. JAMA Netw Open. 2022;5(3):e223849.