Uric acid versus metabolic syndrome as markers of fatty liver disease in young people with overweight/obesity

Aims To compare the association of high serum uric acid (HUA) or metabolic syndrome (MetS) with fatty liver disease (FLD) in youths with overweight/obesity (OW/OB). Materials and Methods Cross-sectional study of anthropometrics, biochemical variables, and liver ultrasound of 3104 individuals with OW/OB (age 5-17 years). Metabolic syndrome was defined by >= 3 criteria among (1) high waist circumference; (2) high triglycerides; (3) low high-density lipoproteins; (4) fasting glucose >= 100 mg/dl; (5) blood pressure >= 95(th) percentile in children, and >= 130/80 mmHg in adolescents. High serum uric acid was defined as serum UA value >= 75(th) percentile adjusted for sex. Fatty liver disease was determined by echography. Results The sample was stratified in four categories: (1) no HUA, no MetS (reference category); (2) MetS; (3) HUA; (4) HUA and MetS (HUA + MetS). The prevalence of FLD increased across the four categories from 29.9%, 44.0%, 52.2%, to 67.1%, respectively (p < 0.0001). The ORs for the categorical variables were 1.33 (1.06-1.68) for MetS (p = 0.02), 3.19 (2.51-4.05) for HUA (p < 0.0001) and 3.72 (2.65-5.21) for HUA + MetS (p < 0.0001), versus the reference category regardless of the body mass index. Conclusions HUA represents a useful marker of FLD in youths with OW/OB, given its greater ability to identify those at increased risk of the disease compared to MetS. The ability of both to predict incident FLD must be investigated in longitudinal study.