There was an inverse relationship between spirometric values and TGF-β in healthy subjects (FVC % pred R = −0.50, p < 0.05 and FEV1 % pred R = −0.48, p < 0.05) and untreated IPF (FEV1 % pred R = −0.54, p < 0.05) and an inverse relationship between IGFBP-1 and DLCO in treated IPF (R = −0.52, p < 0.05). Here, IGFBP1 is linked to idiopathic pulmonary fibrosis.