Light to moderate drinkers may have a lower risk of heart disease than teetotalers, but a new study suggests this doesn't hold true for people with fatty liver disease.
Most people have a little bit of fat in their liver, but fatty liver disease can be diagnosed when more than 5 percent of the liver by weight is made up of fat. If the condition isn't linked to liver damage from heavy drinking, it's known as non-alcoholic fatty liver disease (NAFLD) and is most often associated with obesity and certain eating habits.
For the current study, researchers examined data on 5,115 adults aged 18 to 30, following them for up to 25 years to assess their drinking habits and check for evidence of fatty liver disease, heart disease or risk factors for cardiac problems.
"Heart disease is actually the leading cause of death in people with nonalcoholic fatty liver disease so it is important to investigate possible dietary and lifestyle factors that might help prevent complications of heart disease," said lead study author Dr. Lisa VanWagner of the Northwestern University Feinberg School of Medicine in Chicago.
"We failed to find any association between moderate alcohol use and multiple different markers of heart disease and heart disease risks, including blood pressure, cholesterol or calcium deposits in the arteries of the heart," VanWagner said by email.
To look for a connection between alcohol use and heart disease, researchers focused on 2,479 participants who remained in the study for 25 years and didn't already have a history of heart attack or heart failure, alcohol-related liver damage or other issues like being too obese to fit in CT scanners for liver imaging.
In the final analysis, 570 participants, or 23 percent had NAFLD, researchers report in Gastroenterology.
Roughly 58 percent of the people with NAFLD were light or moderate drinkers, while the rest said they didn't drink at all.
Drinking in moderation was defined as an average of one or two drinks a day for men and one a day for women, VanWagner said.
Drinkers were more likely to be white, male and have more education than nondrinkers. People who used alcohol were also more likely to be obese and have diabetes.
But there wasn't any difference in heart disease or risk factors for heart disease based on whether people with NAFLD abstained or drank moderately.
The study wasn't a controlled experiment designed to prove whether or how alcohol use might influence heart health in people with nonalcoholic fatty liver disease.
It's also possible at least some of the study participants weren't truthful about their drinking habits when they were surveyed, and some might have downplayed their alcohol use or actually had alcoholic fatty liver disease, the authors note.
"Alcohol abuse is a well known risk factor for liver disease, up to cirrhosis and end stage liver damage," said Dr. Valerio Nobili of University La Sapienza and Bambino Gesu Hospital in Rome, Italy.
It's also possible that the study didn't find a protective effect from alcohol for people with nonalcoholic fatty liver disease because of other factors such as how much exercise people got or what they ate, Nobili, who wasn't involved in the study, said by email.
"Today it's very well known that moderate alcohol use compared to abstinence is associated with lower mortality in the general population, decreasing the incidence of coronary heart disease, diabetes and ischemic stroke," Nobili said. "What isn't clear is whether that is also true in people affected by nonalcoholic fatty liver disease."