Being overweight or having obesity significantly increases the risk for liver disease and the likelihood of dying from it compared with being of normal weight, regardless of level of alcohol consumption, new research shows.
"People in the overweight or obese range who drank were found to be at greater risk of liver diseases compared with participants within a healthy weight range who consumed alcohol at the same level," senior author Emmanuel Stamatakis, PhD, of the Charles Perkins Centre and the Faculty of Medicine and Health, Sydney, said in a press statement.
"Even for people who drank within alcohol guidelines, participants classified as obese were at over 50% greater risk of liver disease," he said.
"Obesity is an independent risk factor for steatosis, acute alcoholic hepatitis, and cirrhosis in alcoholic liver disease (ALD), which may increase the risk of mortality in ALD patients," the study's first author, Elif Inan-Eroglu, PhD, a postdoctoral research fellow at the Charles Perkins Centre, said in an interview.
Further prospective studies are needed to better understand the underlying mechanisms behind the association between alcohol consumption and liver disease across different adiposity levels, the authors say.
Meanwhile, the take-home message from the findings should be that "clinicians should consider the presence of overweight and obesity when they discuss defining safe alcohol levels for their patients, keeping in mind that there is no 'safe' level of alcohol," Dr. Inan-Eroglu said.
"Alcohol drinking guidelines need to acknowledge that two-thirds of the adult population are overweight or obese and consider specific recommendations for this majority population group," he said.
First and largest study of its kind
Obesity, well-known to be an independent risk factor for nonalcoholic fatty liver disease (NAFLD), is also known to worsen outcomes in ALD. And likewise, alcohol consumption, the cause of ALD, can promote obesity and therefore increase the risk of NAFLD.
Dr. Stamatakis and colleagues sought to evaluate the roles of the combined factors in terms of incidence and mortality in both ALD and NAFLD.
For the study, published online May 31 in the European Journal of Clinical Nutrition, they evaluated data from 465,437 participants in the U.K. Biobank. The study is said to be the first and largest of its kind.
In the cohort, a total of 1,090 liver disease deaths were recorded, including 230 deaths from ALD and 192 from NAFLD over an average follow-up of 10.5 years.
After a multivariate adjustment, the overall risk of ALD, NAFLD, and liver disease incidence and mortality were significantly higher in participants who were overweight or had obesity, compared with those of normal weight, at all levels of alcohol consumption.
For instance, among those with alcohol use exceeding guidelines, the risk of ALD was significantly increased in normal weight individuals versus never-drinkers (hazard ratio [HR], 5.38), and the risk was even higher among those who were also overweight or had obesity (HR, 8.58).
In terms of the risk of death related to ALD, among those reporting alcohol consumption above guidelines, the risk was nearly double among those who were overweight or had obesity (HR, 10.29) versus those with normal weight (HR, 5.84), when each group was compared to those drinking within guidelines.
Regarding NAFLD, consistent with evidence that low to moderate alcohol consumption is, in fact, linked to a reduced risk, those in the study who reported alcohol consumption within guidelines and normal weight did show a reduced risk of NAFLD compared with an index group of never-drinkers (HR, 0.85).
However, being overweight or having obesity increased the risk of NAFLD in those participants (HR, 1.51).
Furthermore, even those reporting alcohol consumption above guidelines who were of normal weight had a reduced risk of NAFLD compared with never drinkers of normal weight (HR, 0.89).
Regarding the risk of liver disease among those reporting alcohol consumption above guidelines compared with never-drinkers, the risk was again lower among those of normal weight versus those who were overweight or had obesity (HR, 0.95 vs. 1.52), as were the risks of mortality (HR, 1.24 vs. 2.20).
Overall, "we found evidence that being overweight/[having obesity] amplified the harmful effect of alcohol on the liver disease incidence and mortality," the authors conclude.
The authors have reported no relevant financial relationships.
A version of this article first appeared on Medscape.com