Growth and puberty in juvenile dermatomyositis: a longitudinal cohort study.

Objective To study growth and puberty in a multinational longitudinal prospective cohort of children with juvenile dermatomyositis (DM). Methods Children from 31 countries who were ages DM in active phase were studied, and analyses of height, weight, and pubertal development were conducted in those who had follow-up visits during a 2-year period and for whom anthropometric data was available. Results A total of 196 of 275 children (71%) were included. We found a significant reduction in parent-adjusted height Z score over time in female patients (P < 0.0001) and male patients (P = 0.001), but with catch-up growth at the final study visit. Median body mass index Z score peaked at 6 months (P < 0.0001) and was still significantly above baseline at the final study visit, which was at a median of 26 months after baseline (P = 0.007), with no difference between sexes. Female patients with a disease duration >= 12 months after onset had significantly lower parent-adjusted height Z score (P = 0.002) and no 2-year catch-up growth. At the final study visit, growth failure was seen in 20 of 97 female patients (21%) and in 11 of 73 male patients (15%). Height deflection ( increment height Z score less than -0.25/year) was observed in 29 of 116 female patients (25%) and 25 of 80 male patients (31.3%). Delayed puberty was seen in 20 of 55 female patients (36.4%) and in 11 of 31 male patients (35.5%). Children in early pubertal stage at baseline had the highest risk of growth failure. Conclusion Juvenile DM in the active phase and/or its treatment has a significant impact on growth and puberty in affected children. Children with recent onset of puberty or previous growth failure have the highest risk of delayed pubertal development and further growth retardation.