GSTM1 and anemia (phenotype): Since Hb values in apparently healthy elderly individuals are generally lower than those in younger adults and the differences between males and females tend to disappear with aging (Patel, 2008), a Hb value < 12 g/dL is now commonly considered indicative of anemia in elderly of both sexes (Izaks et al., 1999; Andrès et al., 2013).