In the study, moderate alcohol consumption was linked to heart damage in elderly individuals, with women at highest risk.
Published in Circulation: Cardiovascular Imaging - a journal of the American Heart Association - the study also reveals that severity of heart damage increases alongside a rise in alcohol intake.
The research team, including senior author Dr. Scott Solomon, professor of medicine at Harvard Medical School and director of noninvasive cardiology at Brigham and Women's Hospital - both in Boston, MA - says their findings "reinforce" guidelines recommending that when people drink, they should do so in moderation.
According to the Dietary Guidelines for Americans, moderate alcohol intake is defined at consuming up to one alcoholic beverage daily for women - such as beer, wine or liquor - and up to two alcoholic drinks a day for men.
Light to moderate drinking has previously been hailed for its heart benefits. In January, for example, Medical News Today reported on a study claiming that drinking one alcoholic beverage a day could protect against heart failure.
But this latest research indicates that even moderate drinking may have negative implications for the heart.
Increasing alcohol intake linked to enlarged left ventricle, poorer heart function
To reach their findings, Dr. Solomon and colleagues analyzed data of 4,466 men and women of an average age of 76 who are taking part in the ongoing Atherosclerosis Risk in Communities Study.
Based on their self-reported alcohol intake, the participants were allocated to one of four groups: nondrinkers, less than seven drinks weekly, 7-14 drinks weekly and more than 14 drinks a week.
The heart size, structure and function of all participants were assessed via echocardiograms.
The researchers found that the more alcohol participants consumed weekly, the more damage their heart sustained. Increasing alcohol consumption was linked to enlargement of the heart's left ventricle - the main pumping chamber - in both men and women, with this effect most prominent among men who consumed more than 14 drinks weekly.
As well as left ventricle enlargement, moderate alcohol consumption in women was also linked to poorer heart function. Specifically, women who drank just one alcohol beverage a day had lower left ventricular ejection fraction - a reduced ability to pump blood from the left ventricle - and greater strain in the left ventricle. This association became stronger as alcohol intake increased.
The team says their results indicate that increasing alcohol intake in the elderly is associated with poorer heart structure and function, with elderly women at high susceptibility even with moderate alcohol intake.
Commenting on the findings, the researchers say:
"In summary, we found that increasing alcohol intake in among the elderly is associated with mild alterations in cardiac structure and function.
In women, moderate alcohol consumption was associated with modest reduction in systolic function, potentially contributing to a higher risk of alcoholic cardiomyopathy [diseases of the heart muscle], for any given level of alcohol intake."
The strengths of the study include its large size and the ability to control for potential confounders, according to the team.
However, the study is subject to some limitations. The researchers note that alcohol consumption was self-reported, meaning participants could have under-reported their intake. In addition, the study only included people aged 65 and older, so the findings may not be generalizable to younger individuals.
In a Spotlight feature last month, MNT investigated the potential health benefits associated with moderate alcohol consumption.