GSTM1 and anemia: According to hemoglobin (Hb) cut-off levels defined by the World Health Organization (WHO) (<12 g/dL for females, <13 g/dL for males) [5], anemia is present in 10% of women and 11% of men over the age of 65, increasing to 20% of women and 26% of men over 85 [6].