The characteristics of women with IIM (n = 847) and comparators without IIM (n = 4202) by age at IIM diagnosis.
| Characteristics | Age at Diagnosis ≤ 25 Yrs | Age at Diagnosis > 25 to ≤ 45 Yrs | Age at Diagnosis > 45 Yrs | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| IIM | Comparators | IIM | Comparators | IIM | Comparators | |||||||
| N | N | N | N | N | N | |||||||
| Birth year, yrs, mean ± SD | ||||||||||||
| Overall | 80 | 1996 ± 8 | 403 | 1996 ± 8 | 156 | 1971 ± 8 | 777 | 1971 ± 8 | 611 | 1947 ± 10 | 3022 | 1947 ± 10 |
| Juvenile IIM | 67 | 1997 ± 7 | 333 | 1998 ± 7 | – | – | – | – | – | – | – | – |
| DM | 5 | 1991 ± 5 | 25 | 1991 ± 4 | 72 | 1972 ± 9 | 359 | 1972 ± 8 | 224 | 1949 ± 10 | 1117 | 1949 ± 10 |
| Other IIM | 8 | 1988 ± 7 | 40 | 1988 ± 7 | 84 | 1969 ± 8 | 418 | 1969 ± 8 | 387 | 1946 ± 9 | 1905 | 1946 ± 9 |
| Age at IIM diagnosis/matching, yrs, mean ± SD | ||||||||||||
| Overall | 80 | 12 ± 6 | 403 | 12 ± 6 | 156 | 37 ± 6 | 777 | 37 ± 6 | 611 | 62 ± 9 | 3022 | 62 ± 9 |
| Juvenile IIM | 67 | 10 ± 4 | 333 | 10 ± 4 | – | – | – | – | – | – | – | – |
| DM | 5 | 22 ± 3 | 25 | 22 ± 2 | 72 | 37 ± 6 | 359 | 37 ± 6 | 224 | 61 ± 10 | 1117 | 61 ± 10 |
| Other IIM | 8 | 22 ± 2 | 40 | 22 ± 2 | 84 | 37 ± 6 | 418 | 37 ± 6 | 387 | 63 ± 9 | 1905 | 62 ± 9 |
| Born in Nordic countries, n (%) | ||||||||||||
| Overall | 80 | 73 (91.25) | 403 | 370 (91.81) | 156 | 116 (74.36) | 777 | 629 (80.95) | 611 | 554 (90.67) | 3022 | 2724 (90.14) |
| Juvenile IIM | 67 | 61 (91.04) | 333 | 308 (92.49) | – | – | – | – | – | – | – | – |
| DM | 5 | 4 (80.00) | 25 | 23 (92.00) | 72 | 49 (68.06) | 359 | 280 (77.99) | 224 | 197 (87.95) | 1117 | 983 (88.00) |
| Other IIM | 8 | 8 (100.00) | 40 | 37 (92.50) | 84 | 67 (79.76) | 418 | 349 (83.49) | 387 | 357 (92.25) | 1905 | 1741 (91.39) |
IIM: idiopathic inflammatory myopathy; DM: dermatomyositis.