For both COPD and control cohorts, ferritin and hepcidin levels were significantly lower in ID versus IR individuals (COPD cohort medians: ferritin 28.3 vs 79.9 μg/L, p<0.001; hepcidin 21.4 vs 33.4 μg/L, p=0.013; control cohort medians: ferritin 10.5 vs 76.3 μg/L, p=0.008; hepcidin 3.33 vs 35.1 μg/L, p=0.007). Here, HAMP is linked to chronic obstructive pulmonary disease.