Family structures of patients with idiopathic inflammatory myopathies (IIMs) and individuals without IIM, and demographic characteristics of their first-degree relatives*
| Patients with IIM | Individuals without IIM | |||
| Any first-degree relatives, n, mean±SD | 7615 | 4.7±2.2 | 37 309 | 4.8±2.1 |
| Parents | 2306 | 1.4±0.8 | 11 414 | 1.5±0.7 |
| Women, n (%) | 1253 (54) | 6314 (55) | ||
| Birth year, median (Q1–Q3) | 1926 (1916–1943) | 1926 (1916–1943) | ||
| Full siblings | 2464 | 1.5±1.5 | 11 685 | 1.5±1.5 |
| Women, n (%) | 1238 (50) | 5863 (50) | ||
| Birth year, median (Q1–Q3) | 1951 (1943–1962) | 1950 (1943–1963) | ||
| Offspring | 2845 | 1.8±1.3 | 14 210 | 1.8±1.3 |
| Women, n (%) | 1335 (47) | 6960 (49) | ||
| Birth year, median (Q1–Q3) | 1975 (1966–1987) | 1975 (1967–1989) | ||
*Q1: the first quartile; Q3: the third quartile.