Relationship between elevated bilirubin level and subclinical atherosclerosis as well as oxidative stress in Gilbert syndrome

This study aimed to determine oxidant status and left ventricular mass index (LVMI) and their relationship with mild hyperbilirubinemia in patients with Gilbert syndrome (GS). Background: Gilbert syndrome (GS) presents with mild indirect hyperbilirubinemia, normal liver function tests, and normal hepatic histology. Methods: A total of 84 patients, including 41 (48.8%) patients with GS and 43 (51.2%) patients without GS, were included in the study. Total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) were examined for oxidant status. Results: TAS was found to be higher in the GS patients compared to the non-GS patients (1.7±0.1 vs. 1.5±0.2; p=0.002); there was no significant difference between the groups in terms of mean TOS and mean OSI (p>0.05). No significant difference was observed either between the GS and non-GS patients in terms of mean left ventricular volume and mean LVMI (p>0.05). However, subgroup analysis based on sex revealed that GS patients had a lower LVMI for both sexes. In GS patients, TAS level had a positive correlation with albumin (r=0.319; p=0.042), triglyceride (r=0.392; p=0.011), total bilirubin (r=0.420; p=0.006), direct bilirubin (r=0.361; p=0.020), and indirect bilirubin (r=0.338; p=0.0311) levels; no correlation was found between TAS level and other laboratory findings (p>0.05). The regression model indicated that risk factors of direct bilirubin (β±SE=0.13±0.03; p<0.001), uric acid (β±SE=0.04±0.01; p=0.001), and albumin (β±SE=0.17±0.04; p<0.001) were independent predictors of TAS level. Conclusion: This study revealed a relationship between mild hyperbilirubinemia and antioxidant balance in GS. Although statistical significance was not reached, LVMI was found to be lower in the GS group compared to the non-GS group for both sexes.