The effect of glucocorticoids on bone indices in children with rheumatic and oncological conditions

Jennifer Harrington; Etienne Sochett; Marc Grynpas

doi:10.1530/boneabs.2.P42

Children with chronic medical conditions are at increased risk for bone fragility from multiple mechanisms, related both to the underlying condition and its treatment, in particular glucocorticoids. The differential effects of the underlying medical disease on bone micro-architecture have not been well elucidated.

Objectives: To describe the bone micro-architectural characteristics in children with rheumatic and oncological disorders treated with glucocorticoids, and to determine associations between micro-architectural findings with clinical variables.

Methods: Trans-iliac biopsies were performed on 25 children (13.9±3.4 years, 10 males) on chronic glucocorticoids; 15 with either systemic lupus erythematosis or idiopathic juvenile arthritis, 10 with previous malignancy or transplant. Subjects presented with at least one vertebral compression fracture. Static histomorphometry results were compared between groups and to published controls.

Results: Mean duration of glucocorticoid exposure was 3.7 (0.4–14.4) years with a cumulative prednisone dose of 0.27±0.26 mg/kg per day in the 12 months prior to biopsy. Lumbar spine bone mineral density (BMD) was reduced (Z-score −3.3±1.4), with no difference between groups. On histomorphometry, there were significantly lower structural and formation parameters compared to controls, but no difference between groups.

Glucocorticoid dose correlated with bone volume (BV/TV r=−0.5, P=0.01), osteoblast surface (r=−0.42, P=0.02) and bone adipose volume (r=0.47, P=0.02), while steroid duration was associated with osteoid volume (r=−0.42, P=0.03). Controlling for glucocorticoid dose, lower bone volume was associated with slower growth velocity (r=0.51, P=0.01). Lower bone formation (P=0.01) and greater bone adipose tissue (P=0.02) was seen in females compared to males. There were no significant associations between lumbar spine BMD and histomorphometry parameters.


	Total cohort	P value^a	Rheumatic group	Oncological group	P value^b
Bone volume BV/TV (%)	21.0 (6.5)	0.02	21.4 (6.9)	20.3 (6.3)	0.71
Trabecular thickness (μm)	118.6 (55.2)	0.01	114.7 (33.2)	125.2 (83.9)	0.70
Trabecular separation (μm)	470.6 (123.8)	0.49	469.5 (133.1)	469.7 (114.4)	0.99
Osteoid volume (%)	1.9 (0.1)	0.02	1.8 (0.7)	2.0 (0.7)	0.75
Osteoid surface (%)	19.5 (9.5)	0.02	18.5 (7.8)	21.5 (12.9)	0.55
Osteoblast surface	4.6 (1.6)	0.01	4.6 (1.6)	4.6 (1.6)	0.99
Adipose volume (%)	25.5 (7.0)	NA	24.3 (8.0)	28.3 (3.5)	0.30
Data are mean (S.D.).
^aCompared to published controls (Glorieux et al. 2000).
^bBetween groups.

Conclusion: Children on chronic glucocorticoids have significant impairments in bone structural and formation parameters, independent of the underlying condition. These deficits relate primarily to cumulative glucocorticoid dose.

Bone Abstracts

P42