Association between serum uric acid and non-alcoholic fatty liver disease in Korean adults

Background: Increased uric acid is associated with the metabolic syndrome, conditions linked to oxidative stress and insulin resistance. Non-alcoholic fatty liver disease (NAFLD) is now considered a hepatic manifestation of insulin resistance. However, little has been written regarding the association between uric acid and NAFLD. Methods: We examined the association between uric acid and the presence of NAFLD in 3768 Koreans (2133 men, 1635 women; aged 20-75 years) in a health examination program. Uric acid quartiles were categorized separately as follows: Q1: ≤291.5, Q2: 291.6-333.1, Q3: 333.2-380.7, and Q4: ≥380.8 μmol/L for men; Q1: ≤202.2, Q2: 202.3-232.0, Q3: 231.1-267.7, and Q4: ≥267.8 μmol/L for women. Hepatic steatosis was diagnosed based on abdominal ultrasonographic findings by hyperechogenicity of liver tissue, difference of echogenicity between the liver and diaphragm, and visibility of vascular structures. The odds ratios (ORs) and 95% confidence intervals (CIs) for NAFLD were calculated across each quartile of serum uric acid. Results: The prevalence of NAFLD was 25.8% (32.2% in men and 17.4% in women). After adjustment for age, body mass index (BMI), smoking, regular exercise, blood pressure, fasting plasma glucose (FPG), triglycerides, and high-density lipoprotein (HDL) cholesterol, the ORs (95% CIs) for NAFLD according to each quartile of uric acid were 1.00, 1.55 (1.13-2.14), 1.77 (1.30-2.41), and 2.01 (1.45-2.78) for men and 1.00, 0.69 (0.40-1.20), 1.12 (0.67-1.88), and 1.94 (1.21-3.13) for women. Conclusions: Serum uric acid is independently associated with the presence of NAFLD, and uric acid may be a useful additional measure in assessing the risk of NAFLD in the clinical setting.