A recent GWAS meta-analysis of idiopathic pulmonary fibrosis (IPF) confirmed the strong association of mucin 5B (MUC5B) with incidence26. We reanalysed 612 UK cases and 3366 UK controls that we had contributed to that meta-analysis, obtaining an odds ratio of 5.64 for the SNP rs35705950 in MUC5B (95% CI: 2.73–6.72; Wald test P = 2.9e-83), and conducted a GWAS of survival time in 565 of the cases (Methods). Similar to previous studies27 the risk allele of rs35705950 was associated with increased survival in our study (hazard ratio 0.766; 95% CI: 0.634–0.925; Wald test P = 0.0057). This apparently paradoxical result could arise from index event bias, given the strong odds ratio for incidence. We applied our regression-based adjustment using 140,092 LD-pruned SNPs with imputation \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R^2 \ge 0.99$$\end{document}R2≥0.99 (Methods). Here, we focus only on the effect of rs35705950 in MUC5B; full results of the survival GWAS will be reported separately.
