Appraising the causal role of smoking in idiopathic pulmonary fibrosis: a Mendelian randomization study.

Smoking has been considered a risk factor for idiopathic pulmonary fibrosis (IPF) in observational studies. To assess whether smoking plays a causal role in IPF, we performed a Mendelian randomization study using genetic association data of 10 382 cases with IPF and 968 080 controls. We found that genetic predisposition to smoking initiation (based on 378 variants) and lifetime smoking (based on 126 variants) were associated with a higher risk of IPF. Our study suggests a potential causal effect of smoking on increasing IPF risk from a genetic perspective.