MUC5B and idiopathic pulmonary fibrosis: Results: The GT genotype of the MUC5B rs35705950 promoter variant is associated with up to a 4-fold increased risk of UIP (cOR 5.0, 95% CI 1.13–22.10), and the effect was even maintained after adjusting for potentially confounding variables such as sex, age, and time to progression (aOR 5.2, 95% CI 1.04–25.89).