Objective. To compare the clinical, functional, and radiographic outcomes in patients with enthesitisrelated arthritis (ERA) with those in patients with other subtypes of juvenile idiopathic arthritis (JIA) and healthy controls, and to determine genetic markers, patient characteristics, and early disease variables that predict the development of remission, sacroiliitis, and physical limitations in ERA.Methods. Fifty-five children with ERA who were first admitted to Rikshospitalet Medical Center between 1980 and 1985 were studied. Patients with oligoarthritis or polyarthritis who were admitted during the same period (n ‫؍‬ 55) and individuals from a national population registry (n ‫؍‬ 55) were matched for sex and age and used as controls. Health status was assessed after a median of 15.3 years of disease (range 11.7-21.9 years) and, in some patients, was reassessed after a median of 23.0 years (range 19.7-29.4 years) of disease, by use of the 36-item Short Form health survey and the Health Assessment Questionnaire. Clinical and radiographic examinations were performed at the 15-year followup visit. Variables relating to the onset of disease were retrospectively obtained by chart review. HLA alleles were determined by genotyping and serologic testing.Results. Patients with ERA had lower levels of physical functioning, poorer physical health, and more bodily pain compared with patients with oligoarthritis or polyarthritis (after a median of 15.3 and a median of 23.0 years) and normal controls (after a median of 15.3 years). Among patients with ERA, remission occurred in 44%, sacroiliitis was observed in 35%, and reduced spinal flexion was observed in 75%. Predictors of failure to attain disease remission included the following: ankylosing spondylitis (AS) in a first-degree relative, the presence of HLA-DRB1*08, and ankle arthritis within the first 6 months. HLA-DPB1*02 was a protective factor, whereas a persistently elevated erythrocyte sedimentation rate (ESR), and hip arthritis within the first 6 months were risk factors for sacroiliitis. Female sex, a family history of AS, and high numbers of affected joints within the first 6 months predicted poor physical health status after 23 years. Male sex was associated with reduced anterior flexion of the spine.Conclusion. In this study, patients with ERA had poorer physical outcomes compared with patients with oligoarticular or polyarticular JIA and controls from the general population. A family history of related diseases, sex, the presence of HLA-DRB1*08, the absence of HLA-DPB1*02, a persistently elevated ESR, early hip or ankle arthritis, and high numbers of affected joints were predictors of an unfavorable outcome.Enthesitis-related arthritis (ERA) is an HLA-B27-associated type of pediatric inflammatory arthritis characterized by the involvement of the entheses and the axial skeleton in addition to the peripheral joints. This

Objective. To explore early changes and predictors of bone mass in children with juvenile idiopathic arthritis (JIA) in order to identify patients who will develop bone mass reductions.Methods. We conducted a prospective cohort study of 108 children with early JIA (ages 6-18 years; mean disease duration 19.3 months) who were individually matched with 108 healthy children for age, sex, race, and county of residence. Bone mass and changes in total body, spine, femur, and forearm bone mineral density and bone mineral content (BMC), body composition, growth, and biochemical parameters of bone turnover were examined at baseline and at followup a mean of 24 months later. Low bone mass was defined as a Z score >1 SD below the reference population.Results. Of the 200 children evaluated at followup, the 100 healthy children had greater gains in total body BMC (P ‫؍‬ 0.035), distal radius BMC (P < 0.001), and total body lean mass (P < 0.001) than did the 100 JIA patients. Low or very low total body BMC was observed in 24% of the patients and 12% of the healthy children. Bone formation, bone resorption, and weight-bearing activities were reduced in the patients compared with the healthy children. Multiple regression analysis showed that in patients with JIA, serum bonespecific alkaline phosphatase, serum C-telopeptide of type I collagen, and weight-bearing activities were independent predictors of changes in total body BMC. Total body BMC was lower in patients with polyarticular onset than in those with oligoarticular disease onset.Conclusion. Patients with JIA have moderate reductions in bone mass gains, bone turnover, and total body lean mass early in the disease course.

Objective. To determine the frequency of low bone mineral content (BMC) and low bone mineral density (BMD) as long-term complications in adolescents with early-onset juvenile idiopathic arthritis (JIA), and to identify disease variables, patient characteristics, and biochemical bone markers related to low bone mass.Methods. One hundred five (87%) of 121 adolescent patients with early-onset JIA (ages 13-19 years, 80 girls and 25 boys, mean age at onset of JIA 2.8 years), from a cohort first admitted to the hospital between 1980 and 1985, were assessed after a mean disease duration of 14.2 years. BMC and BMD of the total body, the lumbar spine at L2-L4, and the femoral neck were measured by dual-energy x-ray absorptiometry. Ageand sex-specific reference values from a pooled, healthy reference population were used to calculate Z scores. Low bone mass was defined as a Z score less than ؊1 SD.Results. Among the 103 adolescent JIA patients who underwent total-body imaging, 41% had low totalbody BMC and 34% had low total-body BMD. Compared with adolescent JIA patients who had normal total-body BMC, those with low BMC had lower mean weight (P < 0.001), height (P < 0.001), lean mass (P < 0.001), and remission rates (P ‫؍‬ 0.016), had longer duration of active disease (P ‫؍‬ 0.013), had higher numbers of active and mobility-restricted joints (P < 0.001 and P ‫؍‬ 0.001, respectively), had more disability (P ‫؍‬ 0.011), had higher frequencies of joint erosions (P < 0.001), and had higher erythrocyte sedimentation rates (P ‫؍‬ 0.033). In multiple linear regression analyses of total-body BMC, 88% of the variance was explained by the duration of active disease, the number of joints with restricted mobility, the bone area, urinary deoxypyridinoline values, age, weight, and height.Conclusion. Forty-one percent of the adolescents with early-onset JIA had low bone mass >11 years after disease onset. The development of low total-body BMC was related to the duration of active disease, disease severity, measures of bone resorption, weight, and height.Osteoporosis is a public health problem worldwide. An important determinant of osteoporosis and future fracture risk is the peak bone mass achieved during the period of skeletal growth. Skeletal maturation in children is dependent on the rate of bone formation exceeding the rate of bone resorption. Peak bone mass is defined as the bone mass present at the end of skeletal maturation, which occurs after age 20 years. If a sound foundation for peak bone mass, which is partly genetically determined, is not established during the second decade of life, the young adult will experience osteopenia and an increased fracture risk (1). Children with a chronic illness such as arthritis are at risk of developing osteopenia that is influenced by (in addition to heredity and hormones) inflammation, medication, nutrition, and physical inactivity.

In the current study, radiographically evident sacroiliitis had developed in 6% of JIA patients after a median disease duration of 14.9 years. HLA-B27, absence of DPB1*02, late onset of disease, and early hip involvement were predictors of sacroiliitis.

Objective. To examine the distribution of HLA class I1 alleles in clinically distinct juvenile rheumatoid arthritis (JRA) subsets.Methods. We typed 298 patients and 181 controls for HLA-DRBI, DQAl, DQBl, and DPBl alleles using polymerase chain reaction and oligonucleotide probe techniques.Results. Each JRA subset was characterized by a distinct distribution of HLA class I1 alleles. For the persistently pauciarticular and rheumatoid factornegative polyarticular JRA subsets, certain combinations of DRBl and DPBl alleles were characteristic. In patients without antinuclear antibodies and chronic iridocyclitis, there was an increase of