Associations between Low to Moderate Consumption of Alcoholic Beverage Types and Health Outcomes: A Systematic Review

The association between alcohol consumption and all-cause mortality: An umbrella review of systematic reviews using lifetime abstainers or low-volume drinkers as a reference group

BACKGROUND AND AIMS

Systematic reviews of the relationship between alcohol consumption and all-cause mortality have reported different relative risk (RR) curves, possibly due to the choice of reference group. Results have varied from 'J-shaped' curves, where low-volume consumption is associated with reduced risk, to monotonically increased risk with increasing consumption. We summarised the evidence on alcohol consumption and all-cause mortality exclusively from systematic reviews using lifetime abstainers or low-volume/occasional drinkers as the reference group.

METHODS

We conducted a systematic umbrella review of systematic reviews of the relationship between alcohol consumption and all-cause mortality in prospective cohort studies using a reference group of lifetime abstainers or low-volume/occasional drinkers. Several databases (PubMed/Medline/Embase/PsycINFO/Cochrane Library) were searched to March 2022. Reviews were assessed for risk of bias, and those with reference groups containing former drinkers were excluded.

RESULTS

From 2149 articles retrieved, 25 systematic reviews were identified, and five did not include former drinkers in the reference group. Four of the five included reviews had high risk of bias. Three reviews reported a J-shaped relationship between alcohol consumption and all-cause mortality with significant decreased risk for low-volume drinking (RR range 0.84 to 0.95), while two reviews did not. The one review at low risk of bias reported monotonically increased risk with greater consumption (RRs = 1.02, 1.13, 1.33 and 1.52 for low-, medium-, high- and higher-volume drinking, respectively, compared with occasional drinking). All five reviews reported significantly increased risk with higher levels of alcohol consumption (RR range 1.28 to 3.70). Sub-group analyses were reported by sex and age; however, there were evidence gaps for many important factors. Conversely, 17 of 20 excluded systematic reviews reported decreased mortality risk for low-volume drinking.

CONCLUSIONS

Over 70% of systematic reviews and meta-analyses published to March 2022 of all-cause mortality risk associated with alcohol consumption did not exclude former drinkers from the reference group and may therefore be biased by the 'sick-quitter effect'.

Alcohol, cardiovascular disease and industry funding: A co-authorship network analysis of epidemiological studies

INTRODUCTION

Alcohol's effects on cardiovascular disease (CVD) are controversial. Alcohol industry actors have shown particular interest in this subject, and been extensively involved through research funding, and in other ways, generating concerns about bias, particularly in reviews.

MATERIAL & METHODS

We conducted a co-authorship network analysis of the primary studies included within a previous co-authorship study of 60 systematic reviews on the impact of alcohol on CVD. Additionally, we examined the relationships between declared alcohol industry funding and network structure.

RESULTS

There were 713 unique primary studies with 2832 authors published between 1969 and 2019 located within 229 co-authorship subnetworks. There was industry funding across subnetworks and approximately 8% of all papers declared industry funding. The largest subnetwork dominated, comprising 43% of all authors, with sparse evidence of substantial industry funding. The second largest subnetwork contained approximately 4% of all authors, with largely different industry funders involved. Harvard affiliated authors who at the review level formed co-authorship subnetworks with industry funded authors were seen at the primary study level to belong to the largest epidemiological subnetwork. A small number of key authors make extensive alcohol industry funding declarations.

CONCLUSIONS

There was no straightforward relationship between co-authorship network formation and alcohol industry funding of epidemiological studies on alcohol and CVD. More fine-grained attention to patterns of alcohol industry funding and to key nodes may shed further light on how far industry funding may be responsible for conflicting findings on alcohol and CVD.

High-density lipoprotein functionality, cardiovascular health, and patterns of alcohol consumption: new insights and future perspectives

PURPOSE OF REVIEW

Cardiovascular diseases (CVD) pose a significant public health challenge, contributing to 422 million disability-adjusted life years in 2021. The role of high-density lipoproteins (HDL) and alcohol consumption, one of their major modifiable determinants, remains controversial. The objective of this review is to provide a comprehensive narrative overview of HDL functionality and its predictive value for CVD in relation to patterns of alcohol consumption.

RECENT FINDINGS

HDL phenotypes beyond HDL-cholesterol (HDL-c) such as distribution of HDL subspecies, HDL particle abundance, and reverse cholesterol transport capacity are promising indicators of atherosclerotic CVD risk. Low-to-moderate alcohol consumption seems to improve HDL functionality and reduce the incidence of CVD among primarily middle-aged men and postmenopausal women. Advancements in our understanding of HDL biogenesis, structure, and function hold promise for improving HDL-related measures and their predictive value for cardiovascular health.

SUMMARY

Low-to-moderate alcohol consumption appears to not only increase HDL-c concentration found in the HDL fraction of plasma but also enhance HDL functionality, providing insights into the underlying mechanisms linking alcohol exposure and cardiovascular health benefits. However, rigorous, well designed intervention trials of alcohol consumption on hard cardiovascular outcomes are needed to identify robust causal associations of HDL phenotypes and alcohol consumption with cardiovascular risk.