GSTM1 and anemia (phenotype): However, compared with children with no infection of any of the three types of STHs, children with Trichuris only infection had significantly lower Hb (p<0.001), lower HAZ (p<0.001) and lower WAZ (p<0.001) after controlling for confounding factors although their mean anemia rate and BmiAZ are not statistically different (Panel B).