title: Compromised bone microarchitecture and estimated bone strength in young adults with cystic fibrosis.
abstract: BACKGROUND
  Young adults with cystic fibrosis (CF) are at risk for low bone density and fractures, but the underlying alterations in bone microarchitecture that may contribute to their increased fracture risk are currently unknown.
  
  
  OBJECTIVE
  The main goal of this study was to use high-resolution peripheral quantitative computed tomography (HR-pQCT) to characterize the bone microarchitecture, volumetric bone mineral density (vBMD), and estimated strength of the radius and tibia in young adults with CF compared with healthy volunteers.
  
  
  METHODS
  This was a cross-sectional study at an outpatient clinical research center within a tertiary academic medical center.
  
  
  METHODS
  Thirty young adults with CF, 18 to 40 years of age, were evaluated and compared with 60 healthy volunteers matched by age (±2 years), gender, and race.
  
  
  METHODS
  The primary outcomes were HR-pQCT-derived cortical and trabecular vBMD, bone microarchitecture, and estimates of bone strength.
  
  
  RESULTS
  At the radius and tibia, young adults with CF had smaller bone cross-sectional area and lower vBMD. Cortical and trabecular microarchitecture were compromised at both sites, most notably involving the trabecular bone of the tibia. These differences translated into lower estimated bone strength both at the radius and tibia. After accounting for body mass index differences, young adults with CF had lower bone area and estimated bone strength at the radius and had compromised trabecular microarchitecture and lower total and trabecular vBMD and estimated bone strength at the tibia. Alterations in trabecular bone density and microarchitecture and estimated strength measures of the tibia were also greater than expected based on dual-energy x-ray absorptiometry-derived areal BMD differences.
  
  
  CONCLUSIONS
  Young adults with CF have compromised bone microarchitecture and lower estimated bone strength at both the radius and tibia, even after accounting for their smaller body size. These skeletal deficits likely explain the higher fracture risk observed in young adults with CF.
authors.affiliation: Endocrine Unit (M.S.P., N.D., M.L.B., J.S.F.), and Pulmonary Division (L.S.), Department of Medicine, Massachusetts General Hospital; Pulmonary Division (A.L.), Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts 02114; Divisions of Endocrinology (M.S.P., C.M.G.) and Respiratory Diseases (A.U., G.S.) and Clinical Research Center (C.E.M.), Boston Children's Hospital, Boston, Massachusetts 02115; and Divisions of Adolescent Medicine and Endocrinology (C.M.G.), Hasbro Children's Hospital, Providence, Rhode Island 02903.
authors.forename: Melissa S
authors.initials: MS
authors.lastname: Putman
authors.forename: Carly E
authors.initials: CE
authors.lastname: Milliren
authors.forename: Nicholas
authors.initials: N
authors.lastname: Derrico
authors.forename: Ahmet
authors.initials: A
authors.lastname: Uluer
authors.forename: Leonard
authors.initials: L
authors.lastname: Sicilian
authors.forename: Allen
authors.initials: A
authors.lastname: Lapey
authors.forename: Gregory
authors.initials: G
authors.lastname: Sawicki
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Gordon
authors.forename: Mary L
authors.initials: ML
authors.lastname: Bouxsein
authors.forename: Joel S
authors.initials: JS
authors.lastname: Finkelstein
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density / Q000502:physiology*; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000473:pathology*; D005260:Female; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008297:Male; D011884:Radius / Q000000981:diagnostic imaging / Q000473:pathology* / Q000648:ultrastructure; D018570:Risk Assessment; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology* / Q000648:ultrastructure; D014057:Tomography, X-Ray Computed; D055815:Young Adult