GSTM1 and anemia (phenotype): The prevalence of anemia, defined as Hb < 11 g/dL, was not significantly different between treatment groups at the 12- and 24-month follow-up visits: 1.7% lower in azithromycin-treated communities (95% CI: −8.1 to 4.6%, P = 0.59; ICC = 0.09).