To many people, a glass wine with dinner or a nightcap before bed is enjoyable. But a recent study conducted by UC San Francisco shows that even moderate alcohol drinking may change the structure of the heart and increase risk of heart chamber damage.
The finding is published in Journal of the American Heart Association.
Previous research has shown that moderate alcohol drinking may be a risk factor for abnormal heart rhythm (atrial fibrillation), but the mechanism by which alcohol may lead to atrial fibrillation is unknown.
Abnormal heart rhythm is a risk factor for stroke. The irregular pumping of blood can lead to blood clots, which may travel to the brain and cause stroke.
In the study, researchers looked at damage to the left heart chamber (atrium) of the heart as a possible pathway between alcohol and abnormal heart rhythm.
They evaluated data from more than 5,000 adults collected over several years in the Framingham Heart Study, including heart tests, medical history and self-reported alcohol intake.
Most of the participants were white and in their 40s to 60s, reported on average just over one drink per day.
The overall rate of abnormal heart rhythm in the group was 8.4 cases per 1,000 people per year – meaning over a 10-year period, 8 out of 100 people were likely to develop abnormal heart rhythm.
The result also showed that every additional drink per day was associated with a 5% increase in the yearly risk.
Every additional drink per day also was associated with a statistically significant 0.16 mm enlargement of the left heart chamber, which highlighted a possible site of physical damage caused by drinking.
Researchers suggest that the new finding shed light on the complex relationship between alcohol and heart health.
Patients who drink moderately are more likely to have abnormal heart rhythm but less likely to have heart attacks and congestive heart failure.
Alcohol’s abilities to protect and harm the heart likely operate through different mechanisms and vary from person to person.
Future work will try to figure out these mechanisms and inform therapies for heart conditions. Ultimately, the findings will enable physicians to give personalized advice to patients.
Citation: McManus DD, et al. (2016). Alcohol Consumption, Left Atrial Diameter, and Atrial Fibrillation. Journal of the American Heart Association, published online. DOI:10.1161/JAHA.116.004060.
Figure legend: This Knowridge.com image is for illustrative purposes only.