Growth Velocity and Interleukin 6 Concentrations in Juvenile Idiopathic Arthritis
LETÍCIA S. SOUZA, SANDRA H. MACHADO, CLAITON V. BRENOL, JOÃO CARLOS T. BRENOL, and RICARDO M. XAVIER
Methods. Seventy-nine patients were evaluated. Disease activity was evaluated by a pediatric rheumatologist. Anthropometric data were classified according to the World Health Organization standards. Tanner growth velocity curves were used; values below the Z-score ¾ -2 were considered low growth velocity. Serum concentrations of interleukin 6 (IL-6) were measured by ELISA, and values > 1 pg/ml were considered elevated.
Results. The prevalence of low growth velocity was 25.3%, and it was associated with active disease on followup visit, elevated IL-6, erythrocyte sedimentation rate and C-reactive protein, and higher cumulative glucocorticoid doses. In the multiple linear regression with growth velocity as the dependent variable, only elevated IL-6 level was independently and negatively associated with growth velocity.
Conclusion. Low growth velocity is highly prevalent in children with JIA. Elevated IL-6 levels seem to have an important negative influence on growth in these children, while total glucocorticoid exposure appears to be a secondary factor. (J Rheumatol First Release Oct 1 2008)
Key Indexing Terms:
JUVENILE IDIOPATHIC ARTHRITIS
From the Division of Rheumatology, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Supported by FIPE/HCPA (Fund of Incentive to Research at Hospital de Clínicas de Porto Alegre).
L. Souza, MSc, Hospital de Clínicas de Porto Alegre (HCPA)/ Universidade Federal do Rio Grande do Sul (UFRGS), CAPES Fellow; S.H. Machado, PhD Student, HCPA/UFRGS; C.V. Brenol, MD, MSc, Division of Rheumatology, HCPA; J.C. Brenol, PhD, Assistant Professor, Head, Rheumatology Service, HCPA/UFRGS; R.M. Xavier, MD, PhD, Assistant Professor, Rheumatology Service, HCPA/UFRGS.
Address reprint requests to Dr. R.M. Xavier, Serviço de Reumatologia do Hospital de Clínicas de Porto Alegre, Ramiro Barcelos 2350/sala 645, Porto Alegre/RS 90035-003, Brazil. E-mail:firstname.lastname@example.org
Accepted for publication June 23, 2008.