CXCL8 and chronic obstructive pulmonary disease: Among all variables included in the model, only post-bronchodilator FEV1 (aOR = 0.84; 95% CI: 0.74–0.95; p = 0.006) and IS IL-8 levels ≥ 3.096 pg/mL (aOR = 12.82; 95% CI: 1.41–116.47; p = 0.023) remained strongly and independently associated with the COPD-A etiotype.