GSTM1 and anemia (phenotype): Mousa et al. examined the prevalence of iron deficiency and IDA in 912 adolescent girls residing in five different villages from Upper Egypt, wherein 39.9% were anemic (Hb < 12 g/dL), 30.2% had IDA (Hb < 12 g/dL, serum ferritin < 15 ng/mL), and 11.4% were iron deficient without anemia (serum ferritin < 15 ng/mL) [71].