Demographic data of probands and relatives participating in the Swiss AS follow-up family study by HLA-B27 status and presence of sacroiliitis by the modified New York criteria at baseline (1985)
| Number (%) | Males (%) | Females (%) | Mean age 2019 (SD) | |
| All participants | 485 | 238 (49.1) | 247 (50.9) | 64.6 (9.7) |
| All AS probands | 125*† | 78* (62.4) | 47† (37.6) | 72.8 (7.3) |
| - HLA-B27 positive AS probands | 110/123 (89.4) | 73 (66.4) | 37 (33.6) | 72.5 (7.2) |
| Sacroiliitis present (1985) | 79/110 (71.8) | 54 (68.4) | 25 (31.6) | |
| Sacroiliitis absent | 31/110 (28.2) | 19 (61.3) | 12 (38.7) | |
| - HLA-B27 negative AS probands | 13/123 (10.6) | 4 (30.8) | 9 (69.2) | 75.5 (8.7) |
| Sacroiliitis present (1985) | 3/13 (23.1) | 2 (66.7) | 1 (33.3) | |
| Sacroiliitis absent (1985) | 10/13 (76.9) | 2 (20.0) | 8 (80.0) | |
| All relatives | 360 | 160 (44.4) | 200 (55.6) | 61.7 (8.8) |
| All relatives with axial SpA | 45/360 (12.5) | 18 (40.0) | 27 (60.0) | 58.0 (8.0) |
| HLA-B27 positive relatives | 42/45 (93.3) | 17 (40.5) | 25 (59.5) | 57.7 (8.2) |
| Sacroiliitis present (1985) | 7/42 (16.7) | 3 (42.9) | 4 (57.1) | |
| Sacroiliitis absent (1985) | 27/42 (66.7) | 11 (40.7) | 16 (59.3) | |
| No pelvic X-ray available (1985) | 8/42 (19.0) | 3 (37.5) | 5 (62.5) | |
| HLA-B27 negative relatives | 3/45 (6.7) | 1 (33.3) | 2 (66.7) | 62.0 (5.3) |
| Sacroiliitis absent (1985) | 3/3 (100) | 1 (33.3) | 2 (66.7) | |
| All healthy relatives | 315‡ | 142 (45.1) | 173 (54.9) | 62.2 (8.8) |
| - Healthy relatives of HLA-B27+ AS probands | 262 | 118 (45.0) | 144 (55.0) | 62.1 (9.2) |
| HLA-B27 positive relatives | 120/260 (46.2) | 50§ (41.7) | 70¶ (58.3) | 61.3 (8.9) |
| HLA-B27 negative relatives | 140/260 (53.8) | 66** (47.1) | 74†† (52.9) | 62.9 (9.3) |
| HLA-B27 unknown relatives | 2/262 (0.8) | 2‡‡ (100) | 0 (0) | 55.5 (14.9) |
| - Healthy relatives of HLA-B27- AS probands | 29 | 16 (55.2) | 13 (44.8) | 60.8 (6.7) |
| HLA-B27 positive relatives | 0/29 (0) | |||
| HLA-B27 negative relatives | 29/29 (100) | 16 (55.2) | 13 (44.8) | 60.76 (6.7) |
| - Healthy relatives of HLA-B27? AS probands | 24 | 8 (33.3) | 16 (66.7) | 65.3 (6.0) |
| HLA-B27 positive relatives | 9/24 (37.5) | 4 (44.4) | 5 (55.6) | 68.1 (5.7) |
| HLA-B27 negative relatives | 15/24 (62.5) | 4 (26.7) | 11§§ (73.3) | 63.7 (5.4) |
*Unknown HLA-B27 status of one male proband with sacroiliitis.
†Unknown HLA-B27 status of one female proband with sacroiliitis.
‡HLA-B27 status of 2 AS probands unknown (1 relative HLA-B27(−); 1 relative HLA-B27(+)).
§No pelvic radiograph available for five men.
¶No pelvic radiograph available for 11 women.
**No pelvic radiograph available for four men.
††No pelvic radiograph available for five women.
‡‡No pelvic radiograph available for one male.
§§No pelvic radiograph available for two women.
AS, ankylosing spondylitis.