People who drink alcohol have a lower risk of the most common heart disease compared with abstainers. That is the conclusion of a new meta-analysis that was recently published in the scientific journal Journal of Studies on Alcohol and Drugs.
The meta-analysis1 shows that people who drink alcohol (regardless of the amount) have a lower risk of coronary heart disease compared with abstainers. Former drinkers, on the other hand, have an increased risk of coronary heart disease. That appears from the results of the meta-analysis that included 45 studies and was corrected for multiple confounding factors.
The researchers performed detailed analyses to try to correct for additional potentially confounding factors. No significant association between alcohol and coronary heart disease was found in studies with a younger study population (< 55 year), studies of high quality, or studies that controlled for heart health.
A commentary, that was written in response to this meta-analysis, emphasizes several limitations of the study2. First of all, the researchers use a statistical method that is not suitable for this meta-analysis, possibly leading to invalid results. Additionally, the researchers indicate that the association between alcohol and coronary heart disease is not significant in sub-analyses. Because of smaller sample sizes in these subgroups this often leads to less significant results. However, the results overlap with the overall analysis meaning that the association still stands.
In the past decades many studies have looked into the association between alcohol and cardiovascular diseases. Most of these studies confirm the so-called J-curve: moderate alcohol consumption lowers the risk compared to non-drinking.
Despite the fact that many studies confirm the protective effect of moderate alcohol consumption, the question remains whether other confounding factors can explain the effect. The authors of the commentary doubt that results of any observational study will satisfy sceptics on both sides of this debate. They advocate for a large-scale randomized trial to unravel the true association between alcohol and cardiovascular disease for once and for all.
1. Jinhui Zhao, Tim Stockwell, Audra Roemer, Timothy Naimi, and Tanya Chikritzhs. Alcohol Consumption and Mortality from Coronary Heart Disease: An Updated Meta-Analysis of Cohort Studies. (2017) Journal of Studies on Alcohol and Drugs, 78(3): 375-386
2. Eric L. Ding, Kenneth J. Mukamal. Robustness of the J-Shaped Association of Alcohol with Coronary Heart Disease Risk. (2017) Journal of Studies on Alcohol and Drugs, 78:3, 389-391