Description of instruments depending on exposure and outcome used in the iterative univariable Mendelian randomisation analyses
| Characteristic | Rheumatoid arthritis | Multiple sclerosis | Psoriasis | Psoriasis arthritis |
| Birth weight (fetal effect) | ||||
| SNPs used in first iteration | 126 | 120 | 146 | 146 |
| SNPs used in last iteration | 112 | 107 | 142 | 140 |
| Explained variance by instruments considered* | 2.3% | 2.3% | 2.8% | 2.8% |
| F-statistics, mean (min; max)* | 54.48 (29.85; 370.54) | 56.35 (29.85; 370.54) | 56.93 (29.87; 370.54) | 56.93 (29.87; 370.54) |
| Birth weight (maternal effect) | ||||
| SNPs used in first iteration | 64 | 69 | 74 | 74 |
| SNPs used in last iteration | 57 | 61 | 70 | 72 |
| Explained variance by instruments* | 1.6 % | 1.8 % | 1.9 % | 1.9 % |
| F-statistics, mean (min; max) | 51.86 (29.83; 169.74) | 52.36 (29.83; 163.92) | 53.44 (29.83; 169.74) | 53.44 (29.83; 169.74) |
*Regarding the first iteration.
SNP, single-nucleotide polymorphism.