Both alcohol and obesity are associated with hepatic steatosis. However, little is known about whether the toxicity of alcohol to the liver is influenced by adiposity. We examined the relationship of alcohol drinking and binge drinking with abnormal serum aminotransferase activity in normal weight, overweight, and obese persons in a national, population-based study.

Data were analyzed from 13,580 adult participants in the third US National Health and Nutrition Examination Survey, 1988–1994, after excluding participants with hepatitis B or C or iron overload. Abnormal aminotransferase levels were defined by using sex-specific cutoffs for ALT and AST. Analyses were adjusted for other liver injury risk factors.

The prevalence of abnormal aminotransferase activity was elevated with consumption of >2 drinks per day or with overweight and obesity. In multivariate analysis, there was no association of alcohol intake with a higher prevalence of elevated aminotransferase levels among normal weight persons. In contrast, among overweight persons, consumption of >2 drinks per day increased the risk of elevated aminotransferase levels, and among the obese, ≥1 drink per day was associated with a higher risk. Results were similar with elevated ALT alone as the outcome. With elevated AST alone as the outcome, intake of >2 drinks per day increased the risk, even among normal weight persons. Binge drinking was associated with aminotransferase elevation among obese consumers of 1–2 drinks per day.

In this large, national, population-based study, overweight and obesity increased the risk of alcohol-related abnormal aminotransferase activity.