Participant characteristics at the index date of MS individuals and matched controls
| Characteristic | Case definition 1* | Case definition 2† | ||
| Cases n (%) | Controls n (%) | Cases (%) | Controls (%) | |
| Total study population | 6109 | 49 479 | 5592 | 43 327 |
| Sex‡ | ||||
| Male | 1791 (29.32) | 14 705 (29.72) | 1601 (28.63) | 12 550 (28.97) |
| Female | 4318 (70.68) | 34 774 (70.28) | 3991 (71.37) | 30 777 (71.03) |
| Year of birth‡ | ||||
| 1964–1968 | 2032 (33.26) | 16 686 (33.72) | 1855 (33.17) | 14 715 (33.96) |
| 1969–1973 | 1575 (25.78) | 12 793 (25.86) | 1451 (25.95) | 11 326 (26.14) |
| 1974–1978 | 1226 (20.07) | 9864 (19.94) | 1115 (19.94) | 8685 (20.05) |
| 1979–1983 | 825 (13.50) | 6450 (13.04) | 766 (13.7) | 5602 (12.93) |
| 1984–1988 | 370 (6.06) | 3002 (6.07) | 333 (5.95) | 2482 (5.73) |
| 1989–1991 | 81 (1.33) | 684 (1.38) | 72 (1.29) | 517 (1.19) |
| Age (years) at index‡ | ||||
| 20–29 | 2327 (38.09) | 19 458 (39.33) | 2149 (38.43) | 17 308 (39.95) |
| 30–39 | 2844 (46.55) | 22 559 (45.59) | 2607 (46.62) | 19 947 (46.04) |
| 40–49 | 938 (15.35) | 7462 (15.08) | 836 (14.95) | 6072 (14.01) |
| Education | ||||
| Compulsory | 482 (7.89) | 3459 (6.99) | 426 (7.62) | 3039 (7.01) |
| Postcompulsory | 2938 (48.09) | 23 428 (47.35) | 2678 (47.89) | 20 410 (47.11) |
| Postsecondary | 2665 (43.62) | 22 464 (45.4) | 2471 (44.19) | 19 768 (45.63) |
| Unknown | 24 (0.39) | 128 (0.26) | 17 (0.3) | 110 (0.25) |
*Case definition 1: at least one MS diagnosis over age 20 years from the PR or MSR.
†Case definition 2: two or more MS diagnoses over age 20 years from the PR or diagnosis in the MSR.
‡Matching variable.
MSR, Multiple Sclerosis Register; PR, National Patient Register.