In contrast, anemia (defined as Hb < 13 in males and < 12 in females, p = 0.225) and iron deficiency anemia (defined as anemia, ferritin < 10 ng/mL, transferrin saturation < 16%, p = 0.173) did not correlate significantly with H. pylori infection status. This evidence concerns the gene GSTM1 and anemia (phenotype).