Independent association between nonalcoholic fatty liver disease and cardiovascular disease in the US population.

BACKGROUND & AIMS: Nonalcoholic fatty liver disease (NAFLD) and cardiovascular diseases (CVDs) have common metabolic risk factors. Despite reports from clinical studies, the association between NAFLD, cardiovascular disease, and cardiovascular mortality are not clear at the population level.

METHODS: We analyzed data from the National Health and Nutrition Examination Survey III, conducted from 1988 to 1994, and compared hepatic ultrasound and mortality data. Participants were classified into those with NAFLD (moderate or severe hepatic steatosis, based on ultrasound analysis, without any evidence of other liver disease; n = 2492) and those without (absence of NAFLD or any other chronic liver diseases: controls). The prevalence of CVD was compared between subjects with and without NAFLD. Additional comparisons were made between NAFLD patients who had increased levels of liver enzymes and those who had normal levels. Independent predictors of CVD and cardiovascular mortality also were studied.

RESULTS: During the follow-up period (median, 171 mo), 12.21% of the National Health and Nutrition Examination Survey III participants died; cardiovascular mortality was 3.76%. Regardless of whether levels of liver enzymes were increased or not, individuals with NAFLD were older, predominantly male, more likely to be Hispanic, and less likely to be African American than controls. They also had a higher prevalence of all components of metabolic syndrome and CVD. Regardless of levels of liver enzymes, NAFLD was associated independently with CVD, after adjusting for major demographic, clinical, and metabolic confounders (odds ratio, 1.23; 95% confidence interval, 1.04-1.44). The independent association of NAFLD with cardiovascular mortality was not statistically significant.

CONCLUSIONS: NAFLD is associated independently with an increased risk of CVD. However, NAFLD did not increase cardiovascular mortality over a 14-year period.