However, the meta‐analyses showed that occurrence of gallstones was significantly higher among patients with lower total Hb level (SMD = −0.45; 95% CI, −0.73 to −0.32), lower Hb F level (SMD = −0.85; 95% CI, −1.38 to −0.27), higher total serum bilirubin level (SMD = 1.15; 95% CI, 0.74–1.55), and higher reticulocytes count (SMD = 0.44; 95% CI, 0.12–0.75) (Table 2). Here, GSTM1 is linked to gallstones.