Elevated serum uric acid levels are associated with non-alcoholic fatty liver disease independently of metabolic syndrome features in the United States: Liver ultrasound data from the National Health and Nutrition Examination Survey.

OBJECTIVE

Experimental and observational studies suggest a role for uric acid in non-alcoholic fatty liver disease (NAFLD). We examined the association between serum uric acid levels and NAFLD in a large population-based study from the United States.

MATERIALS/METHODS: A cross-sectional analysis of 10,732 nondiabetic adults who participated in the National Health and Nutrition Examination Survey 1988-1994. Sex specific uric acid quartiles were defined: ≤5.2, 5.3-6.0, 6.1-6.9, and >6.9mg/dL for men and ≤3.7, 3.8-4.5, 4.6-5.3, and >5.3mg/dL for women. NAFLD presence and severity were defined by ultrasonographic detection of steatosis in the absence of other liver diseases. We modeled the probability that more severe NAFLD would be associated with the highest quartiles of uric acid.

RESULTS

Compared to the 1st quartile, the odds ratio for NAFLD was 1.79 (95% C.I. 1.49-2.15, p<0.001) and 3.14 (95% C.I. 2.63-3.75, p<0.001) for the 3rd and 4th quartiles, respectively. After adjusting for demographics, hypertension, waist circumference, triglycerides, high-density lipoprotein-cholesterol, homeostasis model assessment-estimated insulin resistance, estimated glomerular filtration rate, and aspartate aminotransferase, uric acid (4th quartile) was significantly associated with NAFLD (odds ratio 1.43; 95% C.I. 1.16-1.76, p<0.001). Positive parameter estimates suggest increasing uric acid is associated with greater severity of NAFLD.

CONCLUSIONS

Elevated uric acid level is independently associated with ultrasound-diagnosed NAFLD in a nationally representative sample of United States nondiabetic adults. Increasing uric acid is associated with increasing severity of NAFLD on ultrasonography. These findings warrant further studies on the role of uric acid in NAFLD.