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Critique 181: Support for a causal role of alcohol consumption in improving the lipid profile — 16 February 2016

The present paper is based on data from more than 10,000 Americans of European descent who were participants in the Atherosclerosis Risk in Communities (ARIC) study. Common and rare variants in alcohol dehydrogenase and acetaldehyde dehydrogenase genes were evaluated using Mendelian randomization (MR), and then a genetic score based on 5 SNPs was used in regression analyses for the association of alcohol with lipids. Results reported by the authors state: “Alcohol consumption significantly increased HDL2-c and reduced TG, total cholesterol, LDL-c, sdLDL-c, and apoB levels. For each of these lipids a non-linear trend was observed. Compared to the first quartile of alcohol consumption, the third quartile had a 12.3% lower level of TG (p < 0.001), a 7.71 mg/dL lower level of total cholesterol (p = 0.007), a 10.3% higher level of HDL2-c (p = 0.007), a 6.87 mg/dL lower level of LDL-c (p = 0.012), a 7.4% lower level of sdLDL-c (p = 0.037), and a 3.5% lower level of apoB (p = 0.058, P overall = 0.022).”

The authors thus conclude that “This study supports the causal role of regular low-to-moderate alcohol consumption in increasing HDL2-c, reducing TG, total cholesterol, and LDL-c, and provides evidence for the novel finding that low-to-moderate consumption of alcohol reduces apoB and sdLDL-c levels among European-Americans.”

Forum members considered this to be a well-done and important study, the results of which indicate favorable effects of moderate alcohol consumption on lipid factors. However, they doubt that the inclusion of the genetic score from MR played a large part in the results; the authors state that the genetic score used in this paper explained only approximately 0.1% variance of alcohol consumption, suggesting that it was a weak instrumental variable for the MR. Several Forum members stated that randomized control trials, especially cross-over trials, testing the effects of alcohol intake on risk factors, may provide even better evaluation of alcohol’s effects on lipids. Until large-scale RCTs of alcohol and disease occurrence can be are carried out, such RCTs may provide the most reliable data on mechanisms of alcohol’s effects on the risk of cardiovascular disease.

Overall, the present study provides important data indicating that light-to-moderate alcohol consumption has favorable effects on most lipid values. The effects shown for HDL-cholesterol support much earlier data, and the effects on small dense LDL-cholesterol and ApoB provide key new information. The effects on lipids are surely important factors in the protective effects of moderate drinking against cardiovascular disease that have been seen in almost all well-done cohort studies.

Reference: Vu KN, Ballantyne CM, Hoogeveen RC, Nambi V, Volcik KA, Boerwinkle E, Morrison AC. Causal Role of Alcohol Consumption in an Improved Lipid Profile: The Atherosclerosis Risk in Communities (ARIC) Study. PLoS One 2016;11:e0148765. doi: 10.1371/journal.pone.0148765. eCollection 2016.

For the full critique of this paper by members of the International Scientific Forum on Alcohol Research, please click here.
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