UGT1A1 and cholelithiasis: Meta-analysis including 34 studies showed that the risk of developing cholelithiasis was significantly associated with lower total hemoglobin level (p=0.002), lower hemoglobin F level (p=0.003), higher total serum bilirubin level (p ≤ 0.001), higher reticulocytes count (p=0.007), and UDP-glucuronosyltransferase-1A1 enzyme (UGT1A1) promoter polymorphism [21].