title: Childhood-onset disease carries a higher risk of low bone mineral density in an adult population of systemic lupus erythematosus.
abstract: OBJECTIVE
  To study the BMD of patients with SLE according to the age of disease onset.
  
  
  METHODS
  Consecutive SLE patients were screened for BMD at the hip, lumbar spine and whole body by the dual-energy X-ray absorptiometry (DXA). Comparison was made between patients who had disease onset in childhood (<18 years) and adulthood (≥18 years). Factors associated with low BMD were studied by linear regression.
  
  
  RESULTS
  A total of 395 SLE patients were studied (94% women; 11% childhood-onset disease). Osteoporosis of the lumbar spine and the hip/femoral neck was present in 20 and 10% of the patients, respectively. Childhood-onset SLE patients were less likely to be post-menopausal, but had significantly lower BMI, longer SLE duration and a higher frequency of ever use of high-dose CSs, CYC and AZA. Despite a significantly younger age, the BMD of the hip, femoral neck and lumbar spine was significantly lower in childhood- than adult-onset SLE patients. In linear regression models, childhood-onset disease was an independent factor for lower BMD at the lumbar spine (β = -0.18; P = 0.002), hip (β = -0.20; P = 0.001) and femoral neck (β = -0.16; P = 0.01) after adjustment for age, sex, BMI, smoking, menopause, SLE duration and damage index, duration and current dose of prednisolone treatment and the ever use of high-dose glucocorticoids, other immunosuppressive agents, calcium, vitamin D and the bisphosphonates.
  
  
  CONCLUSIONS
  In adult SLE patients, childhood-onset disease carries a higher risk of osteoporosis, which may possibly be related to a higher cumulative dose of glucocorticoids used for more active disease and failure to achieve a normal peak bone mass during puberty.
authors.affiliation: Department of Medicine, Tuen Mun Hospital, New Territories, Hong Kong, SAR, China. ccmok2005@yahoo.com
authors.forename: Chi Chiu
authors.initials: CC
authors.lastname: Mok
authors.forename: Sik Nin
authors.initials: SN
authors.lastname: Wong
authors.forename: Kwok Man
authors.initials: KM
authors.lastname: Ma
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D015992:Body Mass Index; D015519:Bone Density; D003430:Cross-Sectional Studies; D005260:Female; D005938:Glucocorticoids / Q000009:adverse effects / Q000627:therapeutic use; D006615:Hip / Q000503:physiopathology; D006801:Humans; D015994:Incidence; D016014:Linear Models; D008180:Lupus Erythematosus, Systemic / Q000150:complications* / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000209:etiology* / Q000503:physiopathology; D012307:Risk Factors; D012720:Severity of Illness Index; D013131:Spine / Q000503:physiopathology; D055815:Young Adult
chemical_list: D005938:Glucocorticoids