Proportion of children stunted with increasing age, stratified for β-globin genotypes. ● represents HbAA; ■, HbAS; and ♦, HbAC. GEE analyses with adjustment for within-group effects, between-group effects, and age dependency were performed with autoregressive correlation structure of order 5 and assumption of binomial variable distribution. HbAA versus HbAS (OR = 0.56; 95% CI, 0.33-0.96, P = .035). HbAA versus HbAC (OR = 0.93; 95% CI, 0.58-1.50, P = .77).