TNFRSF9 and idiopathic pulmonary fibrosis: Given that the primary purpose of this research is to identify groups at an increased risk for pulmonary fibrosis, it is important to note that although both methods identify groups with reduced lung volumes (an effect noticeably greater with ILA detection methods based on lung density), the genetic factor most strongly associated with IPF (MUC5B promoter genotype) [15, 24–28] is similarly associated with ILA when defined by visual assessment [10] but not with ILA when defined by thresholds of lung density.