Is Moderate Drinking Protective Against Heart Disease? The Science, Politics and History of a Public Health Conundrum

Is low-level alcohol consumption really health-protective? A critical review of approaches to promote causal inference and recent applications

Heavy and disordered alcohol consumption is a known risk factor for several health conditions and is associated with considerable disease burden. However, at low-to-moderate levels, evidence suggests that drinking is associated with reduced risk for certain health outcomes. Whether these findings represent genuine protective effects or mere methodological artifacts remains unclear, but has substantial consequences for policy and practice. This critical review introduces methodological advances capable of enhancing causal inference from observational research, focusing on the 'G-methods' and Mendelian Randomization. We also present and evaluate recent research applying these methods and compare findings to the existing evidence base. Future directions are proposed for improving our causal understanding of the relationships between alcohol and long-term health outcomes.

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.

Alcohol use in the older adult US population: Trends, causes, and consequences

Alcohol use, binge drinking, and alcohol use disorders have been increasing among older adults in the US population, including adults over 50 as well as adults over 65. Increases in consumption are sharper among women, and among those who use additional substances such as cannabis, and those who are relatively healthy in older adulthood (i.e. those without multimorbidites). This commentary describes these trends as well as provides hypotheses, and the data underlying them, for both supply-side (alcohol marketing and messaging) and demand-side (healthier aging, increased financial stress) potential drivers of these increases. The need for additional resources and focus on older adult drinking is increasingly urgent, as alcohol-attributable deaths escalate among older adults in the United States.

Binge Drinking and Alcohol Problems Among Moderate Average-Level Drinkers

INTRODUCTION

A significant amount of binge drinking among adults escapes public health scrutiny because it occurs among individuals who drink at a moderate average level. This observational study examined the role of a binge pattern of drinking in predicting alcohol problems among moderate drinkers in a U.S. national sample of adults.

METHODS

Participants were 1,229 current drinkers aged ≥30 years from 2 waves of the study of Midlife Development in the United States, with a 9-year time lag (2004-2015) (analyzed in 2021‒2022). Negative binomial regression analyses were used to examine the number of alcohol problems, and binary logistic regression analyses were used to examine multiple (≥2) alcohol problems.

RESULTS

Independent of the average level of drinking, binge drinking was linked with an almost 3 times increase in the number of concurrent alcohol problems and a 40% increase in the number of alcohol problems prospectively 9 years later. Moderate average level drinkers accounted for most cases of binge drinking and multiple alcohol problems. Among moderate drinkers, binge drinking was linked with a close to 5 times increase in concurrent multiple alcohol problems and a >2 times increase in multiple alcohol problems prospectively 9 years later.

CONCLUSIONS

These results substantially broaden an increasing recognition that binge drinking is a public health concern among adults. Moderate average-level drinkers should be included in efforts to reduce alcohol problems in adults. These findings are applicable to primary and secondary prevention of alcohol problems with the potential to advance population health.

Age, Period, and Cohort Effects in Alcohol Use in the United States in the 20th and 21st Centuries: Implications for the Coming Decades

This article is part of a Festschrift commemorating the 50th anniversary of the National Institute on Alcohol Abuse and Alcoholism (NIAAA). Established in 1970, first as part of the National Institute of Mental Health and later as an independent institute of the National Institutes of Health, NIAAA today is the world's largest funding agency for alcohol research. In addition to its own intramural research program, NIAAA supports the entire spectrum of innovative basic, translational, and clinical research to advance the diagnosis, prevention, and treatment of alcohol use disorder and alcohol-related problems. To celebrate the anniversary, NIAAA hosted a 2-day symposium, "Alcohol Across the Lifespan: 50 Years of Evidence-Based Diagnosis, Prevention, and Treatment Research," devoted to key topics within the field of alcohol research. This article is based on Dr. Keyes' presentation at the event. NIAAA Director George F. Koob, Ph.D., serves as editor of the Festschrift.

Alcohol, cardiovascular disease and industry funding: A co-authorship network analysis of systematic reviews

BACKGROUND

Alcohol's effects on heart health is the site of a major scientific controversy. We conducted a co-authorship network analysis of systematic reviews on the impacts on alcohol on cardiovascular disease (CVD) in order to investigate patterns of co-authorship in the literature, with particular attention given to industry funding.

METHODS

We used Epistemonikos to identify systematic reviews. Review characteristics, influential authors, co-authorship subnetworks, prior histories of alcohol industry funding, study outcomes and citations were investigated.

RESULTS

60 systematic reviews with 231 unique authors met our inclusion criteria. 14 systematic reviews were undertaken by authors with histories of alcohol industry funding, including 5 that were funded directly by the alcohol industry itself. All 14 such reviews identified a cardioprotective effect of alcohol. These formed distinct co-authorship subnetworks within the literature. Of reviews by authors with no prior histories of alcohol industry funding, the findings were mixed, with 54% (25/46) concluding there was evidence of health protective effects. These two groups of reviews differed in other respects. Those with industry funding were more likely to study broader outcomes such as 'cardiovascular disease' or 'coronary heart disease' as opposed to specific CVD issues such as hypertension or stroke (93% [13/14] versus 41% [19/46]) (chi-squared 12.4, p < 0.001) and have more included studies (mean of 29 versus 20). They were also more widely cited by others. Over time the proportions of systematic reviews on CVD and alcohol undertaken by authors with no prior histories of alcohol industry funding has increased.

CONCLUSIONS

Systematic reviews undertaken by authors with histories of alcohol industry funding were more likely to study broader outcomes, and be cited more widely, and exclusively reported favorable conclusions.

The role of alcohol consumption in pathogenesis of gout

Alcohol is recognized a risk factor for increased uric acid and gout flare. The aim of the study was to review the literature in order to find out what is the role of alcohol consumption in pathogenesis of gout. A search in PubMed, Google Scholar, Medline Complete database was performed in January 2021. The databases were searched with the phrases: "uric acid and alcohol," "alcoholic beverages and gout," "hyperuricemia and alcoholic beverages consumption" published between 2000 and 2021. A total of 2642 results were found. The 99 non-duplicate citations were screened. Then 81 articles were excluded after abstract screen. After that 18 articles were retrieved. Eventually 15 articles were included for systematic review. Several authors see the positive correlation between beer or distilled spirits consumption and gout. Some include wine to the list of triggers of gout. Others state that moderate wine consumption protects from gout attacks due to antioxidants and phytoestrogen content. Majority noticed the relationship between episodic alcohol consumption and gout attacks. Episodic alcohol intake triggers gout attacks, regardless of type of alcohol. Thus, individuals with established gout and pre-existing risk factors should limit all types of alcohol intake to prevent gout episodes.

Consensus and Controversy in the Debate over the Biphasic Impact of Alcohol Consumption on the Cardiovascular System

In the past few decades, research has focused on the importance of addressing modifiable risk factors as a means of lowering the risk of cardiovascular disease (CVD), which represents the worldwide leading cause of death. For quite a long time, it has been considered that ethanol intake has a biphasic impact on the cardiovascular system, mainly depending on the drinking pattern, amount of consumption, and type of alcoholic beverage. Multiple case-control studies and meta-analyses reported the existence of a "U-type" or "J-shaped" relationship between alcohol and CVD, as well as mortality, indicating that low to moderate alcohol consumption decreases the number of adverse cardiovascular events and deaths compared to abstinence, while excessive alcohol use has unquestionably deleterious effects on the circulatory system. However, beginning in the early 2000s, the cardioprotective effects of low doses of alcohol were abnegated by the results of large epidemiological studies. Therefore, this narrative review aims to reiterate the association of alcohol use with cardiac arrhythmias, dilated cardiomyopathy, arterial hypertension, atherosclerotic vascular disease, and type 2 diabetes mellitus, highlighting literature disagreements over the risk and benefits of low to moderate drinking on the cardiovascular system.

Benefits and hazards of alcohol-the J-shaped curve and public health

Purpose

The purpose of this paper is a review of updated evidence of a J-shaped association between alcohol consumption and the risk of coronary heart disease (CHD) and all-cause mortality in relation to public health issues to create a basis for sensible individual health deliberations.

Design/methodology/approach

A review of the evidence from the first observation of a J-shaped association between a moderate alcohol intake and CHD in 1926 to recent studies of the effect of healthy lifestyles (including moderate alcohol intake) on life expectancy free of cardiovascular disease (CVD), cancer and Type 2 diabetes. An update on the biological plausibility of the J-shaped association with focus on recent findings of the association of alcohol intake and blood lipid levels.

Findings

Plausible J-shaped relations between light to moderate alcohol consumption and the risk of CHD, CVD mortality and all-cause mortality have been found in a large number of robust epidemiological studies. Among the potential mechanisms underlying the proposed protective effects are higher levels of high-density lipoprotein lacking apolipoprotein C3, reduced platelet aggregability, increased level of endothelial cell fibrinolysis, increased insulin sensitivity and decreased inflammation.

Originality/value

The existence of a J-shaped association between alcohol consumption and the risk of CHD and all-cause mortality is based on observational evidence and accordingly challenged by a degree of uncertainty leading some public health circles to state: “there is no safe level of alcohol consumption.” The authors propose that communication on the pros and cons of alcohol intake should emphasize the nadir of a J-shaped curve as a healthy range for the general population while advice regarding the consumption of alcohol should be adjusted to factor in the risks and potential benefits for each individual patient considering age, sex, family history, personal drinking history and specific medical history.

A safe level of alcohol consumption: the right answer demands the right question

Alcohol has been produced by humans for nearly ten millennia, but gold-standard evidence by which to judge the health effects of limited alcohol consumption remains elusive, introducing serious difficulty in considering the safety of alcohol consumption. To do so, physicians and policymakers must consider the population, dose and context of alcohol consumption and the end-point, preferably a holistic composite, of interest. The limitations of new research trends, such as mega-cohorts, genetic instrumental variable analysis and modelling studies, must also be viewed against the much larger backdrop of existing evidence. Some existing guidelines, such as the 2015-2020 Dietary Guidelines for Americans, succeed remarkably in this task. Nonetheless, large-scale randomized trials are urgently needed if future generations are to enjoy any greater insight into the health effects of population-wide alcohol consumption than the current one has.

Health Disparities and Cardiovascular Disease

The number one leading cause of death in 2017 for Americans was cardiovascular disease (CVD), and health disparities can exacerbate risks. This study evaluates the 2018 Behavioral Risk Factor Surveillance System (BRFSS) (n = 437,436) to estimate population risks for behavioral, socio-economic, psychological, and biological factors. A general linear model with a quasi-binomial link function indicated higher risks for the following groups: smokers (odds ratio, OR = 0.688), individuals with higher body mass index scores (OR = 1.023), persons unable to work (OR = 2.683), individuals with depression (OR = 1.505), workers who missed more days due to mental issues (OR = 1.12), the elderly, males (OR = 1.954), those in race categories "indigenous Americans, Alaskan non-Hispanics", "Black Hispanics," or "other, non-Hispanic," and individuals with lower income. Surprisingly, increased consumption of alcohol was not found to be a risk factor as in other studies. Additional study of alcohol risk factors is needed. Further, Black non-Hispanics were associated with lower rates of CVD/MI (myocardial infarction), a finding that is supported by recent evidence of more unhealthy behaviors in other races. The results of this study highlight 2018 CVD/MI disparities based on the BRFSS and suggest the need for additional policy interventions including education and providing increased access to health care for the disadvantaged. The principles of beneficence and justice require policy interventions such as these.

Mendel's laws, Mendelian randomization and causal inference in observational data: substantive and nomenclatural issues

We respond to criticisms of Mendelian randomization (MR) by Mukamal, Stampfer and Rimm (MSR). MSR consider that MR is receiving too much attention and should be renamed. We explain how MR links to Mendel's laws, the origin of the name and our lack of concern regarding nomenclature. We address MSR's substantive points regarding MR of alcohol and cardiovascular disease, an issue on which they dispute the MR findings. We demonstrate that their strictures with respect to population stratification, confounding, weak instrument bias, pleiotropy and confounding have been addressed, and summarise how the field has advanced in relation to the issues they raise. We agree with MSR that "the hard problem of conducting high-quality, reproducible epidemiology" should be addressed by epidemiologists. However we see more evidence of confrontation of this issue within MR, as opposed to conventional observational epidemiology, within which the same methods that have demonstrably failed in the past are simply rolled out into new areas, leaving their previous failures unexamined.