Effect of Alcohol Consumption on Survival in Nonalcoholic Fatty Liver Disease: A National Prospective Cohort Study

Abstract

Nonalcoholic fatty liver disease (NAFLD) comprises more than two thirds of patients with chronic liver disease in the United States. The effect of alcohol consumption on survival in patients with NAFLD is not clear. We gathered data on National Health and Nutrition Examination Survey participants from 1988 to 2010, and linked them to the National Death Index for follow-up of their survival. We diagnosed NAFLD based on a previously validated biochemical model (Hepatic Steatosis Index). We built multivariate Cox proportional hazards models to evaluate the effect of alcohol consumption on survival of patients with NAFLD. After excluding participants with significant alcohol use, viral hepatitis, or increased transferrin saturation, 4,568 participants with NAFLD were included in the analysis. In a Cox model adjusted for age, sex, and smoking history, drinking 0.5-1.5 drinks per day decreased the risk of overall mortality by 41% (hazard ratio [HR] = 0.59, 95% confidence interval [CI] 0.40-0.85, P = 0.005) compared with not drinking. Drinking ≥1.5 drinks per day showed a trend toward harm (HR = 1.16, 95% CI 0.99-1.36, P = 0.119). After further adjustment for race, physical activity, education level, diabetes, and fiber and polyunsaturated fatty acid intake, drinking 0.5-1.5 drinks per day continued to show a significant protective effect (HR = 0.64, 95% CI 0.42-0.97, P = 0.035), and drinking ≥1.5 drinks per day showed a significant harmful effect on mortality (HR = 1.45, 95% CI 1.01-2.10, P = 0.047). Among patients with NAFLD, modest alcohol consumption is associated with a significant decrease in all-cause mortality, whereas drinking ≥1.5 drinks per day is associated with an increase in mortality. These results help to inform the discussion of potential risks and benefits of alcohol use in patients with NAFLD.

Figure 1

Selection of the study population, from National Health and Nutrition Examination Survey participants from 1988 to 2010 † National Health and Nutrition Examination Survey, ‡ Significant alcohol use is defined as >3 drinks/day for male, and >2 drinks/day for females, ^ Aspartate Aminotransferase (ALT) and Alanine Aminotransferase (ALT), * Hepatic Steatosis Index.

Figure 2

Unadjusted Kalpan-Meier survival curves for effect of alcohol consumption on all-cause mortality in patients with Non-Alcoholic Fatty Liver Disease (NAFLD).

Figure 3

Unadjusted Kalpan-Meier survival curves for effect of alcohol consumption on all-cause mortality in patients with Non-Alcoholic Fatty Liver Disease (NAFLD), separately by gender.