Heterogeneity, horizontal pleiotropy, and outlier tests
| Exposure | Outcome | IVW Q statistic (P-value) | MR-Egger intercept (P-value) | Outliers detected by MR-PRESSO |
| Smoking initiation | IPF (International IPF Genetics Consortium) | 516 (<0.001) | −0.005 (0.551) | rs6948707 |
| Smoking initiation | IPF (Global Biobank Meta-analysis Initiative) | 366 (<0.001) | −0.005 (0.436) | NA |
| Lifetime smoking | IPF (International IPF Genetics Consortium) | 140 (0.141) | 0.014 (0.229) | NA |
| Lifetime smoking | IPF (Global Biobank Meta-analysis Initiative) | 118 (0.262) | −0.034 (0.002) | NA |
IVW, inverse variance weighted; MR, Mendelian randomization; NA, not available; PRESSO, pleiotropy residual sum and outlier.