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

KHAYRIAH A. ALSUFYANI, OLIVIA ORTIZ-ALVAREZ, DAVID A. CABRAL, LORI B. TUCKER, ROSS E. PETTY, HELEN NADEL, and PETER N. MALLESON

ABSTRACT.

Objective. To describe the frequency of abnormal bone mineralization in a population of children with juvenile systemic lupus erythematosus (JSLE), juvenile dermatomyositis (JDM), and systemic vasculitis; and to investigate the relationship of bone mineral density (BMD) to cumulative corticosteroid dose, disease duration, Tanner stage, calcium intake, and exercise in these patients.

Methods. A retrospective chart review of children attending the pediatric rheumatology clinic at British Columbia's Children's Hospital 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 (DEXA) at 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 activities questionnaire.

Results. A total of 36 patients were studied. Twenty-five patients had SLE, 7 had JDM, and 4 had systemic vasculitis. Fourteen subjects were Caucasian, 13 Asian, 6 East Indian, and 3 Canadian First Nations. An abnormal Z score at one or more sites was found in 10/25 (40%) with JSLE, and in 3/11 (27%) JDM/vasculitis patients. The mean Z scores (± SD) for lumbar spine were –1.02 (± 1.2), for hip –0.88 (± 1.3), and for total body –0.77 (± 1.5). Compared to children with normal bone densities, those with lower bone density tended to be younger (13.5 ± 2.2 vs 15.5 ± 1.7 yrs), received higher corticosteroid dosages at the time of the study (0.78 ± 0.6 vs 0.35 ± 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 all appear to have some influence on bone mass in these children. (J Rheumatol 2005;32:72-33)

Key Indexing Terms:

BONE DENSITY
OSTEOPOROSIS
CHILD
SYSTEMIC LUPUS ERYTHEMATOSUS
JUVENILE DERMATOMYOSITIS
SYSTEMIC VASCULITIS
CORTICOSTEROIDS

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From the Division of Rheumatology, Department of Pediatrics, University of British Columbia; and Department of Radiology, British Columbia's Children's Hospital, Vancouver, British Columbia, Canada.

K.A. Alsufyani, MD, Research Fellow; O. Ortiz-Alvarez, MD, Research Associate; L.B. Tucker, MD, FAAP, Clinical Associate Professor; R.E. Petty, MD, PhD, FRCPC, Professor; P.N. Malleson, MBBS, MRCP (UK), FRCPC, Professor, Department of Pediatrics, University of British Columbia; D.A. Cabral, MBBS, FRCPC, Clinical Assistant Professor; H. Nadel, MD, FRCPC, Pediatric Radiology, Department of Radiology, British Columbia's Children's Hospital.

Address reprint requests to Dr. P.N. Malleson, Room K4-122, British Columbia's Children's Hospital, 4480 Oak Street, Vancouver, BC V6H 3V4. E-mail: pmalleson@cw.bc.ca

Submitted December 30, 2003; revision accepted November 30, 2004.

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