Alcohol consumption in relation to cardiovascular diseases and mortality: a systematic review of Mendelian randomization studies

The causal effects of alcohol-in-moderation on cardiometabolic health are continuously debated. Mendelian randomization (MR) is an established method to address causal questions in observational studies. A systematic review of the current evidence from MR studies on the association between alcohol consumption and cardiometabolic diseases, all-cause mortality and cardiovascular risk factors was performed.
A systematic search of the literature, including search terms on type of design and exposure was conducted and researchers assessed methodological quality based on key elements of the MR design: use of a full instrumental variable analysis and validation of the three key MR assumptions. The search yielded 24 studies that were eligible for inclusion. A full instrumental variable analysis was performed in 17 studies and 13 out of 24 studies validated all three key assumptions. Five studies assessed potential non-linearity.
In general, null associations were reported for genetically predicted alcohol consumption with the primary outcomes cardiovascular disease and diabetes, while the only study on all-cause mortality reported a detrimental association.
Considering the heterogeneity in methodological quality of the included MR studies, the researchers state that it is not yet possible to draw conclusions on the causal role of moderate alcohol consumption on cardiometabolic health. They add that as MR is a rapidly evolving field, they expect that future MR studies, especially with recent developments regarding instrument selection and non-linearity methodology, will further substantiate this discussion.
Source: van de Luitgaarden, I.A.T., van Oort, S., Bouman, E.J. et al. Alcohol consumption in relation to cardiovascular diseases and mortality: a systematic review of Mendelian randomization studies. Eur J Epidemiol (2021). doi.org/10.1007/s10654-021-00799-5.