Greetings or caution? Researchers question the potential benefits of drinking alcohol

In a recent study published in BMC Medicineresearchers discuss a 2023 study by Tian et al., which analyzed the J-shaped association between health and alcohol consumption, and addresses important factors to consider in interpreting this association.

Study: The relationship between alcohol consumption and health: J-shaped or not is more? Image Credit: Ievgenii Meyer/Shutterstock.com

What did the 2023 study show?

A 2023 study by a team of Chinese scientists led by Xia Wang used a large data set from the National Health Interview Survey conducted between 1997 and 2014.

These data were analyzed to identify an association between levels of light-to-moderate alcohol consumption, as well as specific-cause and all-cause mortality among the US population. From these data, the association formed a J-shaped curve, where low levels of alcohol consumption provide certain health benefits; however, after a certain threshold, health risks increase rapidly.

Light to moderate levels and infrequent alcohol consumption have been associated with a reduced risk of influenza, chronic lower respiratory tract disease, cardiovascular disease, pneumonia and Alzheimer’s disease. Light to moderate consumption also reduced all-cause mortality and mortality associated with various kidney diseases such as diabetes mellitus and nephrosis.

Comparatively, binge drinking or high levels of alcohol consumption were associated with a higher risk of all-cause mortality, accident-related mortality and cancer. Importantly, the J-shaped associations must be interpreted carefully after considering the various factors associated with study methodology.

In the present study, the researchers discuss the various methodological issues to consider when interpreting this J-shaped association between alcohol consumption and risks of disease or mortality.

How do lifestyle habits affect the potential benefits of drinking?

The first factor to consider when interpreting the J-shaped associations related to alcohol use is the definition of the reference group and misclassification issues, which could lead to bias for abstainers and the exclusion of former drinkers from the definition of the reference group. To get around this problem, many studies, including that of Tian et al., used a target group that included only life abstainers.

However, a recent systematic meta-analysis including over 100 cohort studies with nearly half a million participants used lifelong non-drinkers as a reference group. To this end, no protective effect against all-cause mortality was associated with even low levels of alcohol consumption.

In interpreting the J-shaped association between alcohol consumption and health risks, one must also consider reverse causality. Individuals who abstain from drinking may already be in poor health, while those who are active and health conscious may drink in moderation while also following other practices that provide health benefits.

Socioeconomic factors may also be involved, with individuals who are active in the social and family spheres of life, or have a higher socioeconomic status and better access to health care, make healthier choices in life, and drink in moderation. Each of these factors independently contributes to reducing the risk of all-cause mortality.

Is any amount of alcohol healthy?

The beneficial effects of moderate alcohol consumption reported by Tian et al. could encourage alcohol consumption. Given that alcohol is addictive and, among susceptible individuals, even low levels of alcohol intake could lead to addiction, these findings could encourage such individuals to drink, thus leading to drastic consequences.

The theoretical minimum levels of alcohol exposure vary between individuals of different ages and regions, thus posing the problem of defining optimal levels of alcohol consumption. The beneficial effects of alcohol consumption may also vary based on factors such as age, as recommended levels of alcohol consumption for younger people are close to zero.

Furthermore, the beneficial effects of moderate alcohol consumption, such as those related to cardiovascular disease, might be prominent only among populations and regions where the burden related to cardiovascular disease is high.

The threshold for safe alcohol consumption is not very well defined and the established standards are often difficult to meet. Furthermore, the health benefits of moderate alcohol consumption may be outweighed by the increased risk of oesophageal and oral cancers and the shortened life expectancy associated with alcohol consumption.

Because it is difficult to distinguish between the effects of various confounders and biases when determining the association between alcohol consumption and health, a Mendelian randomization approach was used to assess these correlations.

Findings from Mendelian randomization and another genetic epidemiological study reported that the role of light to moderate alcohol consumption in improving cardiometabolic health was inconclusive or noncausal. Considering this, the World Health Organization (WHO) recently issued a statement that no level of alcohol consumption can be considered safe or beneficial to health.

Conclusions

The current study discussed pertinent questions related to a previous study that reported a J-shaped association between levels of light to moderate alcohol consumption and health benefits.

Recent studies using genetic, epidemiological and Mendelian randomization approaches to examine this association, as well as other meta-analyses, have challenged the J-shaped association between alcohol consumption and health risks. Given the various methodological and social problems associated with this discovery, WHO continues to encourage reductions in alcohol consumption.