GSTM1 and anemia (phenotype): Anemia affects approximately 30% to 55% of adolescents of all over the world.25 It is particularly more pronounced in adolescents in this age group due to the physical changes that occur at puberty, utilizing a large portion macronutrients, vitamins, and minerals and tend to have an increasing need for energy, especially during the growth spurt.26 Two hundred and thirty one (60%) girls in our study were clinically anemic with Hb<12 g/dl.