Table 3.
Characteristics of the study population
| Characteristics | Number (%) | Average age at disease onset (years) | Average age at time of MRI and HR-US (years) | Disease duration at time of first orthodontic presentation (years) |
| Gender | ||||
| Male | 3 (15%) | 9 | 12.0 | 3 |
| Female | 17 (85%) | 6.5 | 10.9 | 4.4 |
| JIA-subtype | ||||
| Oligoarthritis | 10 (50%) | 4.25 | 10.1 | 5.85 |
| Polyarthritis | 2 (10%) | 5.5 | 8.5 | 3 |
| Psoriatic arthritis | 5 (25%) | 10 | 13 | 3 |
| Systemic arthritis | 1 (5%) | 10 | 15 | 5 |
| Enthesitis related | 2 (10%) | 11.5 | 11.5 | 0 |
| Serological results | ||||
| RF | 5 (25%) | 3.9 | 10 | 6.1 |
| ANA | 11 (55%) | 6.6 | 10.9 | 4.3 |
| AST | 5 (25%) | 3.6 | 9.6 | 6 |
| HLA-B27 | 1 (5%) | 11 | 11 | 0 |
| Borrelia AB | 2 (10%) | 7 | 9 | 2 |
| No proof | 3 (15%) | 4.5 | 6.5 | 2.5 |
AB, antibodies; ANA, antinuclear antibodies; AST, antistreptolysin titre; HLA-B27, human leukocyte antigen B27; HR-US, high-resolution ultrasonography; RF, rheumatoid factor.