Heavy alcohol consumption may be associated with an increased risk for multiple cardiovascular diseases, while the effects of low to moderate drinking remain uncertain, according to recent research.
In the analysis, investigators reviewed decades of studies examining alcohol’s relationship with cardiovascular outcomes, including hypertension, coronary artery disease, stroke, arrhythmias, heart failure, and alcoholic cardiomyopathy. While observational data have suggested possible benefits from low levels of alcohol intake, newer genetic and clinical trial data challenge these findings.
In the U.S., alcohol consumption is widespread, with 85% of adults reporting use at some point in their lives. Among individuals aged 12 years and older, 61.4 million reported binge drinking in the past month, defined as five or more drinks for men and four or more drinks for women on a single occasion.
For blood pressure, short-term consumption of one to two drinks typically had no effect. However, intake of three or more drinks triggered a biphasic response. Blood pressure initially dropped for up to 12 hours, then rose for 12 to 24 hours, increasing systolic pressure by an average of 3.7 mmHg. In a meta-analysis of 36 trials involving 2,865 participants, the investigators found that consuming more than three drinks per day raised both systolic and diastolic blood pressure, whereas reducing intake led to improvements.
Separate analyses uncovered a linear association between alcohol intake and long-term blood pressure levels. Consuming one drink per day was linked to a 1.25 mmHg increase in systolic pressure, while three drinks daily raised systolic pressure by nearly 5 mmHg. The association was stronger in men compared with in women.
In studies of coronary artery disease, observational data suggested that consuming one to two drinks daily might lower myocardial infarction risk. However, genetic studies using Mendelian randomization didn't confirm a protective effect. Case-control analyses showed a slight reduction in coronary risk at moderate levels, but this benefit disappeared in individuals who engaged in binge or heavy episodic drinking.
Stroke risk increased as alcohol consumption rose. Moderate intake of up to two drinks per day was associated with a small reduction in ischemic stroke risk, but higher consumption increased the risk for all stroke types. Every additional 100 g of alcohol per week raised the risk of ischemic stroke by 13%, intracerebral hemorrhage by 17%, and subarachnoid hemorrhage by 9%.
Higher alcohol intake was also linked to increased atrial fibrillation risk, with no clear safe threshold. Randomized studies demonstrated that abstaining from alcohol reduced atrial fibrillation burden, whereas real-time monitoring demonstrated an increased likelihood of episodes following drinking.
Long-term heavy drinking was strongly associated with alcoholic cardiomyopathy, characterized by left ventricular dilation and impaired function. The condition developed following the consumption of seven to fifteen drinks daily over 5 to 15 years, with risk influenced by genetic factors. Women developed alcoholic cardiomyopathy at lower levels and shorter durations compared with men.
Heart failure risk rose significantly when alcohol intake exceeded 21 drinks per week. In patients with underlying cardiac abnormalities, consuming five or more drinks weekly increased the likelihood of progressing from asymptomatic to symptomatic heart failure.
The investigators emphasized the ongoing uncertainty regarding any cardiovascular benefit of light to moderate drinking. They identified multiple research gaps, including insufficient randomized trials, limited biomarker data, and underrepresentation of women in studies.
Full disclosures can be found in the published study.
Source: Circulation