Heavy drinkers who cut back see major heart health benefits, study finds

By Vijay Kumar MalesuReviewed by Susha Cheriyedath, M.Sc.Mar 31 2024

In a recent study published in JAMA Network Open, a group of researchers explored the link between lowering alcohol intake and the occurrence of major adverse cardiovascular events (MACEs) in heavy drinkers, focusing on different subtypes of cardiovascular disease (CVD).

Study: Reduced Alcohol Consumption and Major Adverse Cardiovascular Events Among Individuals With Previously High Alcohol Consumption. Image Credit: Vaclav Mach / Shutterstock

Background 

Alcohol consumption significantly influences both individual and public health, with research showing its complex relationship with CVD. While light to moderate drinking is believed to offer some protection against CVD, this effect varies by the type of CVD, and the relationship between alcohol intake and heart health is not linear. Previous studies have typically measured alcohol consumption at a single point in time and compared drinkers to non-drinkers without considering changes in drinking habits over time. Further research is essential to understand the mechanisms underlying the cardiovascular benefits of reduced alcohol consumption and to establish tailored guidelines for different populations and CVD subtypes.

About the study 

In the present study, researchers utilized data from the Korean National Health Insurance Service–Health Screening (NHIS-HEALS) database to examine a representative sample of Korean adults aged 40 to 79. Approved by Chungbuk National University Hospital's institutional review board (IRB) and adhering to the Declaration of Helsinki and Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines, the study utilized the National Health Screening Program's (NHSP's) broad coverage to analyze information on demographics, medical histories, and lifestyle factors, including alcohol consumption. This careful documentation provided a foundation for a detailed investigation into the effects of alcohol on health.

Participant selection was methodical, excluding non-drinkers in the latter period to avoid confounding factors like the sick-quitter effect. The study's rigor extended to defining heavy drinking based on established criteria and dividing participants into groups based on their drinking habits over time. 

Confounding variables were identified with precision, including a range of demographic, health, and lifestyle factors. The study's outcomes centered on MACEs, with detailed coding and procedures to ensure accuracy. Statistical analyses were conducted with sophisticated tools and methods, including propensity score matching (PSM) and multivariate Cox proportional hazards regression models, to draw reliable conclusions about the relationship between alcohol consumption and cardiovascular health.

Study results 

In the comprehensive study analyzing 21,011 participants with initially high alcohol consumption levels, 14,220 maintained their heavy drinking habits, while 6,791 reduced their intake to mild or moderate levels. Predominantly male (90.3%) and averaging 56 years of age, this cohort provided a detailed snapshot of baseline health and lifestyle characteristics. Initially, the heavy drinkers were younger on average and had a higher proportion of males compared to those who reduced their alcohol consumption.

Clinical indicators such as body mass index (BMI), blood pressure, and various biochemical markers showed differences between the groups, with the sustained heavy drinkers generally presenting poorer health metrics. Interestingly, despite the health disparities, after PSM, these groups were closely aligned on most variables, allowing for a more accurate comparison of outcomes.

Over the course of the study, the incidence of MACEs was notably higher in the group that continued heavy drinking compared to those who reduced their intake, with a significant divergence in outcomes over time. Specifically, reduced drinking was associated with a 23% lower risk of experiencing a MACE. When examining specific CVDs, reductions in alcohol consumption significantly lowered the risk of coronary artery disease (CAD), angina, any stroke, ischemic stroke, and all-cause mortality, while no benefits were observed for nonfatal myocardial infarction (MI) or hemorrhagic stroke.

Subgroup analyses highlighted the cardiovascular advantages of reducing alcohol intake across various demographics and health statuses, including age, gender, BMI, smoking status, and levels of physical activity. Notably, these benefits were evident regardless of pre-existing conditions like atrial fibrillation and chronic kidney disease and were consistent across different socioeconomic statuses and comorbidities.

Further sensitivity analyses, which excluded variables potentially modifiable by alcohol consumption changes, reaffirmed the cardiovascular benefits of reducing alcohol intake. 

Conclusions 

To summarize, in the study, heavy drinkers who reduced their alcohol intake demonstrated a significantly lower risk of cardiovascular events over a decade, with notable health improvements visible three years post-reduction. This reduction in alcohol consumption correlated with a broad array of cardiovascular benefits, especially in lowering the risk of ischemic stroke and angina-related interventions. The study clarifies the complex biological mechanisms through which moderate alcohol consumption may confer cardiovascular protection, highlighting improvements in lipid regulation, endothelial function, and reduced inflammation. Importantly, it revealed specific reductions in CAD and ischemic stroke risk among heavy drinkers, underlining the potential health benefits of moderating alcohol intake.