Alcohol and Immediate Risk of Cardiovascular Events: A Systematic Review and Dose-Response Meta-Analysis

Abstract

Background: Although considerable research describes the cardiovascular effects of habitual moderate and heavy alcohol consumption, the immediate risks following alcohol intake have not been well characterized. Based on its physiological effects, alcohol may have markedly different effects on immediate and long-term risk.

Methods and results: We searched CINAHL, Embase, and PubMed from inception to March 12, 2015, supplemented with manual screening for observational studies assessing the association between alcohol intake and cardiovascular events in the following hours and days. We calculated pooled relative risks and 95% confidence intervals for the association between alcohol intake and myocardial infarction, ischemic stroke, and hemorrhagic stroke using DerSimonian and Laird random-effects models to model any alcohol intake or dose-response relationships of alcohol intake and cardiovascular events. Among 1056 citations and 37 full-text articles reviewed, 23 studies (29 457 participants) were included. Moderate alcohol consumption was associated with an immediately higher cardiovascular risk that was attenuated after 24 hours, and even protective for myocardial infarction and hemorrhagic stroke (≈2-4 drinks: relative risk=30% lower risk) and protective against ischemic stroke within 1 week (≈6 drinks: 19% lower risk). In contrast, heavy alcohol drinking was associated with higher cardiovascular risk in the following day (≈6-9 drinks: relative risk=1.3-2.3) and week (≈19-30 drinks: relative risk=2.25-6.2).

Conclusions: There appears to be a consistent finding of an immediately higher cardiovascular risk following any alcohol consumption, but, by 24 hours, only heavy alcohol intake conferred continued risk.

Keywords: alcohol drinking; cardiovascular diseases; dose-response relationship, drug; epidemiology; meta-analysis.

Figure 1

Selection of studies published in 1966–2015 with information on any recent alcohol intake or a specific dose of recent alcohol intake included in a meta-analysis of alcohol consumption and risk of cardiovascular events. *One study included data on myocardial infarction and hemorrhagic stroke and one study included data on ischemic stroke and hemorrhagic stroke.

Figure 2

Forest plot of relative risks (RRs) and 95% confidence intervals (CIs) for the association between any alcohol consumption relative to no drinking. Squares indicate study-specific RR estimates, with the size of the square reflecting the proportion of the DerSimonian and Laird weights under study; horizontal lines indicate the 95% CI; diamonds indicate the pooled RRs with their 95% CI from a random-effects model. The dotted line indicates the value for no association. *Also included in dose-response meta-analysis.

Figure 3

Forest plot of relative risks (RRs) and 95% confidence intervals (CIs) for the association between alcohol consumption and cardiovascular events in the following day and week by amount of alcohol intake. Squares indicate study-specific RR estimates, with the size of the square reflecting the proportion of the DerSimonian and Laird weights under study; horizontal lines indicate the 95% CI. The dotted line indicates the value for no association.

Figure 4

Relative risk (solid line) and 95% confidence interval (dashed lines) for the association between grams of alcohol and risk of cardiovascular events within 24 hours. Alcohol consumption was modelled with restricted cubic splines in a random-effects dose–response model. The lowest value of zero (non-drinkers) was used to estimate all relative risks. The vertical axis is on a log scale. The dotted line indicates the value for no association.