MUC1 and idiopathic pulmonary fibrosis: There were no significant differences in smoking history (Brinkman index: 1100 vs. 990; p = 0.48), serum KL-6 levels (586 vs. 574 U/mL; p = 0.30), radiological UIP patterns (64% vs. 59%; p = 0.67), or pulmonary function (%VC: 99% vs. 104%, p = 0.08; %DLco: 81% vs. 85%, p = 0.86).