Guzman J, et al. – This paper focused on the height, weight, and body mass index (BMI) of children with juvenile idiopathic arthritis (JIA). Collected evidence showed that most of the children with JIA grew and gained weight as children in the general population. However, about 1 in 10 children who had systemic arthritis, uncontrolled disease and/or prolonged corticosteroid use, had an increased risk of growth impairment.

Methods

• Canadian children newly–diagnosed with JIA 2005–2010 had weight and height measurements every 6 months for 2 years, then yearly up to 5 years.
• In this study, these measurements were used to calculate mean age– and sex–standardized Z–scores, and estimate prevalence and cumulative incidence of growth impairments, and the impact of disease activity and corticosteroids on growth.

Results

• For median 35.5 months, 1147 children were followed.
• In the whole cohort, mean Z–scores, and the point prevalence of short stature (height < 2.5th percentile, 2.5% to 3.4%) and obesity (BMI > 95th percentile, 15.8% to 16.4%) remained unchanged.
• Investigations showed that 33 children (2.9%) developed new–onset short stature, while 27 (2.4%) developed tall stature (>97.5th percentile).
• Children with systemic arthritis (n = 77) had an estimated 3–year cumulative incidence of 9.3% (95%CI: 4.3–19.7) for new–onset short stature and 34.4% (23–49.4) for obesity. 
• Most children (81.7%) received no systemic corticosteroids, but 1 mg/Kg/day prednisone–equivalent maintained for 6 months corresponded to a drop of 0.64 height Z–scores (0.56–0.82) and an increase of 0.74 BMI Z–scores (0.56–0.92).
• An increase of 1 in the 10–cm physician global assessment of disease activity maintained for 6 months corresponded to a drop of 0.01 height Z–scores (0–0.02).