title: High degree of discordance between three-dimensional and two-dimensional lumbar spine bone mineral density in Turner's syndrome.
abstract: Low bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) has been described in Turner's syndrome (TS). One of the error factors of DXA is short stature, a common finding in TS patients. Aimed to evaluate the influence of a low stature on BMD, we compared the two-dimensional (2D) or conventional BMD (cBMD) with three-dimensional (3D) or volumetric BMD (vBMD) in 62 females (10 to 48 yr old) with TS diagnosis in a case control study. They were compared to 102 normal females (7 to 45 yr old) grouped by age-ranges. All patients were subjected to a lumbar spine densitometry by DXA in the PA and lateral projections, obtained the cBMD and vBMD and calculated for the apparent BMD (appBMD). In TS, the mean of Z-score for cBMD was significantly lower than that for vBMD and for appBMD (-2.31 +/- 1.42; -0.64 +/- 1.55; and -1.72 +/- 1.5; respectively). Most of the patients (83.8%) had a Z-score <-1 for cBMD, whereas the majority (58.1%) had a Z-score <-1 for vBMD. Concluding, the cBMD underestimates the bone mass of the lumbar spine in patients with TS inducing to false diagnoses of bone fragility. Volumetric BMD approached the bone mass of control patients, while appBMD just partially do that.
authors.affiliation: Division of Endocrinology, São Paulo Federal University, São Paulo, Brazil.
authors.forename: Andrea Z
authors.initials: AZ
authors.lastname: Lage
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Brandão
authors.forename: Judite R T
authors.initials: JR
authors.lastname: Mendes
authors.forename: Martha K
authors.initials: MK
authors.lastname: Huayllas
authors.forename: Bernardo
authors.initials: B
authors.lastname: Liberman
authors.forename: Berenice B
authors.initials: BB
authors.lastname: Mendonça
authors.forename: Elaine M F
authors.initials: EM
authors.lastname: Costa
authors.forename: Ieda T
authors.initials: IT
authors.lastname: Verreschi
authors.forename: Marise
authors.initials: M
authors.lastname: Lazaretti-Castro
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D015519:Bone Density; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000293:injuries; D008875:Middle Aged; D015588:Observer Variation; D012307:Risk Factors; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000209:etiology; D014424:Turner Syndrome / Q000150:complications / Q000000981:diagnostic imaging*