title: Bone mineral density at diagnosis determines fracture rate in children with acute lymphoblastic leukemia treated according to the DCOG-ALL9 protocol.
abstract: OBJECTIVE
  To elucidate incidence and risk factors of bone mineral density and fracture risk in children with Acute Lymphoblastic Leukemia (ALL).
  
  
  METHODS
  Prospectively, cumulative fracture incidence, calculated from diagnosis until one year after cessation of treatment, was assessed in 672 patients. This fracture incidence was compared between subgroups of treatment stratification and age subgroups (Log-Rank test). Serial measurements of bone mineral density of the lumbar spine (BMDLS) were performed in 399 ALL patients using dual energy X-ray absorptiometry. We evaluated risk factors for a low BMD (multivariate regression analysis). Osteoporosis was defined as a BMDLS≤-2 SDS combined with clinical significant fractures.
  
  
  RESULTS
  The 3-year cumulative fracture incidence was 17.8%. At diagnosis, mean BMDLS of ALL patients was lower than of healthy peers (mean BMDLS=-1.10 SDS, P<0.001), and remained lower during/after treatment (8months: BMDLS=-1.10 SDS, P<0.001; 24months: BMDLS=-1.27 SDS, P<0.001; 36months: BMDLS=-0.95 SDS, P<0.001). Younger age, lower weight and B-cell-immunophenotype were associated with a lower BMDLS at diagnosis. After correction for weight, height, gender and immunophenotype, stratification to the high risk (HR)-protocol arm and older age lead to a larger decline of BMDLS (HR group: β=-0.52, P<0.01; age: β=-0.16, P<0.001). Cumulative fracture incidences were not different between ALL risk groups and age groups. Patients with fractures had a lower BMDLS during treatment than those without fractures. Treatment-related bone loss was similar in patients with and without fractures (respectively: ΔBMDLS=-0.36 SDS and ΔBMDLS=-0.12 SDS; interaction group time, P=0.30). Twenty of the 399 patients (5%) met the criteria of osteoporosis.
  
  
  CONCLUSIONS
  Low values of BMDLS at diagnosis and during treatment, rather than the treatment-related decline of BMDLS, determine the increased fracture risk of 17.8% in children with ALL.
authors.affiliation: Department of Pediatric Oncology/Hematology, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands.
authors.forename: Mariël L
authors.initials: ML
authors.lastname: te Winkel
authors.affiliation: Department of Pediatric Oncology/Hematology, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands; Dutch Childhood Oncology Group, The Hague, The Netherlands.
authors.forename: Rob
authors.initials: R
authors.lastname: Pieters
authors.affiliation: Department of Biostatistics, Erasmus MC - University Medical Center, Rotterdam, The Netherlands.
authors.forename: Wim C J
authors.initials: WC
authors.lastname: Hop
authors.affiliation: Department of Radiology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Jan C
authors.initials: JC
authors.lastname: Roos
authors.affiliation: Dutch Childhood Oncology Group, The Hague, The Netherlands; Department of Pediatric Oncology/Hematology, University Medical Center St Radboud, Nijmegen, The Netherlands.
authors.forename: Jos P M
authors.initials: JP
authors.lastname: Bökkerink
authors.affiliation: Dutch Childhood Oncology Group, The Hague, The Netherlands; Department of Pediatric Oncology, Beatrix Children's Hospital, University of Groningen, Groningen, The Netherlands.
authors.forename: Jan A
authors.initials: JA
authors.lastname: Leeuw
authors.affiliation: Dutch Childhood Oncology Group, The Hague, The Netherlands; Department of Pediatric Oncology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Marrie C A
authors.initials: MC
authors.lastname: Bruin
authors.affiliation: Dutch Childhood Oncology Group, The Hague, The Netherlands; Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Wouter J W
authors.initials: WJ
authors.lastname: Kollen
authors.affiliation: Dutch Childhood Oncology Group, The Hague, The Netherlands; Department of Pediatric Oncology/Hematology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Anjo J P
authors.initials: AJ
authors.lastname: Veerman
authors.affiliation: Dutch Childhood Oncology Group, The Hague, The Netherlands.
authors.forename: Hester A
authors.initials: HA
authors.lastname: de Groot-Kruseman
authors.affiliation: Department of Pediatric Oncology/Hematology, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands.
authors.forename: Inge M
authors.initials: IM
authors.lastname: van der Sluis
authors.affiliation: Department of Pediatric Oncology/Hematology, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands; Dutch Childhood Oncology Group, The Hague, The Netherlands. Electronic address: m.vandenheuvel@erasmusmc.nl.
authors.forename: Marry M
authors.initials: MM
authors.lastname: van den Heuvel-Eibrink
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D015519:Bone Density; D002648:Child; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D015994:Incidence; D016014:Linear Models; D008159:Lumbar Vertebrae / Q000473:pathology / Q000503:physiopathology; D008297:Male; D015999:Multivariate Analysis; D009426:Netherlands / Q000453:epidemiology; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy*; D012307:Risk Factors
keywords: Bone mineral density; Childhood acute lymphoblastic leukemia; Fractures; Steroids