Adjusted ORs (aORs) of having first-degree relatives affected by idiopathic inflammatory myopathies (IIMs) in patients with IIM compared with individual without IIM*
| Patients with IIM, n/N (%) | Individuals without IIM, n/N (%) | aOR† (95% CI) | aOR‡ (95% CI) | |
| ≥1 relative | 13/1620 (0.80) | 16/7797 (0.21) | 4.32 (2.00 to 9.34) | – |
| Any first-degree relatives | 13/7615 (0.17) | 16/37309 (0.04) | 2.61 (1.80 to 3.78) | 2.61 (1.80 to 3.79) |
| Parents | 2/2306 (0.09) | 5/11414 (0.04) | – | – |
| Full siblings | 9/2464 (0.37) | 10/11685 (0.09) | 2.54 (1.62 to 3.99) | 2.53 (1.62 to 3.96) |
| Offspring | 2/2845 (0.07) | 1/14210 (0.01) | – | – |
*≥1 relative: comparison between patients with IIM and individuals without IIM; any first-degree relatives, parents, full siblings and offspring: comparison between relative pairs of patients with IIM and relative pairs of individuals without IIM.
†Controlled for sex, birth year and residential area of index persons.
‡Controlled for sex, birth year and residential area of index persons, sex and birth year of first-degree relatives.