CHI3L1 and chronic obstructive pulmonary disease: Additionally, each analysis revealed unique sets of genes previously related to COPD (Supplemental Table 6), cross-sectional (TNF, TLR4, IL6R), FEV1 change (CHI3L1, VEGFA, FOXO3), and longitudinal (MMP9, IL1RL1, ALOX5AP), highlighting context-specific markers of lung function decline.