Fig. 5
From: Idiopathic pulmonary fibrosis and diabetes mellitus: a meta-analysis and systematic review
Meta-regression analysis presenting the impact of smoking on relevance between DM and IPF. The X-axis represents the ratio of proportion of smokers in IPF group to that in control group in each study (this was used to represent the influence of smoking in each study), while the Y-axis accordingly represents the ratio of the morbidity of DM in IPF group to that in control group (this was used to represent the association between DM and IPF). In the meta-regression analysis, no significant linear correlation was found (P = 0.351 > 0.05) between Y-axis and X-axis, which indicated that smoking didn’t affect the association between DM and IPF