title: Assessment of bone remodelling in childhood-onset systemic lupus erythematosus.
abstract: OBJECTIVE
  To identify predictors of bone remodelling in children and young adults with SLE.
  
  
  METHODS
  Ninety subjects with SLE aged 8-22 years underwent yearly measurements of height, bone age, bone turnover markers, serum Type I IFNs, SLEDAI and BMD. Predictors of bone turnover were examined using serum osteocalcin as a marker of bone formation and both serum tartrate-resistant acid phosphatase (TRAP) and urine N-telopeptide (NTx) as markers of bone resorption.
  
  
  RESULTS
  Subjects demonstrated short stature, high BMI and bone age delay. A spine BMD Z-score of less than -2.0 was seen in 16.1% of subject visits. Serum osteocalcin was negatively correlated with glucocorticoid dose (Spearman rank correlation coefficient R = -0.34, P < 0.0001) but was not associated with SLEDAI after adjustment for confounders. Serum TRAP was negatively associated with SLEDAI, even after controlling for confounders (P = 0.04). Similar results were obtained for urine NTx. There was a negative association between TRAP and serum IFN-β (P = 0.03).
  
  
  CONCLUSIONS
  In this population of children and young adults with moderate lupus disease activity, glucocorticoid dose was a negative predictor of bone formation, whereas lupus disease activity was not. Interestingly, lupus disease activity was a negative predictor of bone resorption, suggesting that lupus disease activity is not the primary factor contributing to the bone deficits of childhood-onset SLE. The potential protective role of IFN-β and the effects of SLE treatment on bone loss require further study.
authors.affiliation: Department of Medicine, University of California, San Francisco, CA, USA.
authors.forename: Julie C
authors.initials: JC
authors.lastname: Baker-LePain
authors.forename: Mary C
authors.initials: MC
authors.lastname: Nakamura
authors.forename: John
authors.initials: J
authors.lastname: Shepherd
authors.forename: Emily
authors.initials: E
authors.lastname: von Scheven
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D015992:Body Mass Index; D016723:Bone Remodeling; D002648:Child; D005260:Female; D006801:Humans; D016899:Interferon-beta / Q000097:blood*; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000503:physiopathology*; D008297:Male; D011237:Predictive Value of Tests; D012720:Severity of Illness Index
chemical_list: D016899:Interferon-beta