Significant differences in genotypic distributions (χ(2)=6.319, p=0.042 for rs2869967; χ(2)=6.062, p=0.048 for rs3821104) and allele distributions (χ(2)=4.014, p=0.045 for rs2869967; χ(2)=5.607, p=0.018 for rs3821104) were observed between patients and control subjects for variants rs2869967 and rs3821104, whereas no statistically significant associations for genotypic and allelic distribution between IREB2 rs2568494 and COPD phenotype (p>0.05) were identified.