GSTM1 and anemia (phenotype): Mean hemoglobin levels were significantly higher in all age groups in the IRS district (overall Hb levels were 12.8 g/dL in the IRS district vs 12.3 g/dL in the non-IRS district, p<0.001) and the overall prevalence of anemia was lower in the IRS district (2.4% in the IRS district vs 3.6% in the non-IRS district) but there were no differences in the prevalence of anemia overall or within specific age categories.