Bone mineral density in children and adolescents with systemic lupus erythematosus, juvenile dermatomyositis, and systemic vasculitis: relationship to disease duration, cumulative corticosteroid dose, calcium intake, and exercise
Alsufyani, K.A.; Ortiz-Alvarez, O.; Cabral, D.A.; Tucker, L.B.; Petty, R.E.; Nadel, H.; Malleson, P.N.
Journal of Rheumatology 32(4): 729-733
2005
ISSN/ISBN: 0315-162X PMID: 15801032 Document Number: 592799
Objective: To describe the frequency of abnormal bone mineralization in children with juvenile systemic lupus erythematosus (JSLE), juvenile dermatomyositis (JDM) and systemic vasculitis; and to investigate the relationship of bone mineral density (BMD) with cumulative corticosteroid dose, disease duration, Tanner stage, calcium intake and exercise. Methods: A retrospective chart review of children attending the paediatric rheumatology clinic at British Columbia's Children's Hospital, British Columbia, Canada, was conducted to obtain demographic data (sex, ethnicity, disease duration, cumulative corticosteroid dose and mean daily corticosteroid dose). All patients had at least one BMD measurement by dual energy x-ray absorptiometry at the lumbar spine, hip and total body. BMD was expressed as g/cm2 and Z scores; an abnormal Z score was defined as <=-1.5. Daily calcium intake was calculated. Physical activity was scored using a validated 7-day physical activity questionnaire. Results: 36 patients were studied: 25 with SLE, 7 with JDM and 4 with systemic vasculitis. 14 were Caucasian, 13 Asian, 6 East Indian, and 3 Canadian First Nations. An abnormal Z score at one or more sites was found in 10 (40%) patients with JSLE and 3 (27%) with JDM/vasculitis. The mean Z scores (+or-SD) were -1.02 (+or-1.2), -0.88 (+or-1.3) and -0.77 (+or-1.5) for lumbar spine, hip and total body, respectively. Compared to children with normal bone densities, those with lower bone density tended to be younger (13.5+or-2.2 vs. 15.5+or-1.7 years), received higher corticosteroid dosage at the time of the study (0.78+or-0.6 vs. 0.35+or-0.2 mg/kg), and were more often prepubertal (OR for total body scores, 5; 95% CI: 0.7-46). Conclusion: Decreased bone density is common in children with SLE and other systemic rheumatic diseases. Age, corticosteroid dose and pubertal stage appear to have some influence on bone mass in these children.