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Background: To study the impact of psoriasis and features associated with psoriasis on classification and outcome in a population-based follow-up cohort of children with juvenile idiopathic arthritis (JIA). Methods: In all, 440 children with JIA were followed for a median of 8 years in a prospective Nordic population-based cohort study. Data for remission was available for 427 of these children. The presence of psoriasis, psoriasis-like rash, dactylitis, nail pitting, enthesitis, tenosynovitis and heredity was assessed in relation to ILAR classification and remission. Results: Clinical findings associated with psoriasis developed consecutively during the 8-year period. Six of 14 children with psoriasis were not classified as juvenile psoriatic arthritis according to the ILAR criteria at 8 year follow-up. Dactylitis was more common in children with early onset of JIA. After 8 years we found a cumulative median number of eleven arthritic joints in children with psoriasis or psoriasis- like rash compared with six in the rest of the cohort (p = 0.02). Also, the chance for not being in remission after 8 years increased significantly in patients with psoriasis, psoriasis-like rash or at least two of: 1) first-degree heredity for psoriasis or psoriatic arthritis, 2) dactylitis or 3) nail pitting, compared with the rest of the group (OR 3.32, p = 0.010). Conclusions: Our results indicate a more severe disease over time in psoriasis- associated JIA, as features of psoriasis develop during the disease course. This group is a major challenge to encompass in a future JIA classification in order to facilitate early tailored treatment.

Objective: To determine the prevalence of orofacial symptoms, dysfunctions, and deformities of the temporomandibular joint (TMJ) in juvenile idiopathic arthritis (JIA) 17 years after disease onset.

Methods: Drawn from a prospective, population-based Nordic JIA cohort with disease onset from 1997 to 2000, 420 consecutive cases were eligible for orofacial evaluation of TMJ involvement. The followup visit included demographic data, a standardized clinical orofacial examination, and full-face cone-beam computed tomography (CBCT). For comparison, 200 age-matched healthy controls were used.

Results: Of 420 eligible participants with JIA, 265 (63%) were included (mean age 23.5 +/- 4.2 yrs) and completed a standardized clinical orofacial examination. Of these, 245 had a full-face CBCT performed. At least 1 orofacial symptom was reported by 33%. Compared to controls, the JIA group significantly more often reported TMJ pain, TMJ morning stiffness, and limitation on chewing. Further, among participants reporting complaints, the number of symptoms was also higher in JIA. The mean maximal incisal opening was lower in the JIA group (p < 0.001), and TMJ pain on palpation was more frequent. Condylar deformities and/or erosions were observed in 61% as assessed by CBCT, showing bilateral changes in about 70%. Risk factors of condylar deformities were orofacial dysfunction or biologic treatment; enthesitis-related arthritis was protective.

Conclusion: This study of the longterm consequences of TMJ involvement in a population-based JIA cohort reports persistence of comprehensive symptoms, dysfunctions, and damage of the TMJ into adulthood. We suggest interdisciplinary followup of JIA patients also in adulthood.

The Juvenile Arthritis Multidimensional Assessment Report (JAMAR) is a new parent/patient-reported outcome measure that enables a thorough assessment of the disease status in children with juvenile idiopathic arthritis (JIA). We report the results of the cross-cultural adaptation and validation of the parent and patient versions of the JAMAR in the Swedish language. The reading comprehension of the questionnaire was tested in 10 JIA parents and patients. Each participating centre was asked to collect demographic, clinical data and the JAMAR in 100 consecutive JIA patients or all consecutive patients seen in a 6-month period and to administer the JAMAR to 100 healthy children and their parents. The statistical validation phase explored descriptive statistics and the psychometric issues of the JAMAR: the 3 Likert assumptions, floor/ceiling effects, internal consistency, Cronbach's alpha, interscale correlations, test-retest reliability and construct validity (convergent and discriminant validity). A total of 68 JIA patients (8.8% systemic, 44.1% oligoarticular, 13.2% RF negative polyarthritis, 33.9% other categories) and 76 healthy children, were enrolled in two centres. The JAMAR components discriminated well healthy subjects from JIA patients. All JAMAR components revealed good psychometric performances. In conclusion, the Swedish version of the JAMAR is a valid tool for the assessment of children with JIA and is suitable for use both in routine clinical practice and clinical research.