title: Evaluation of bone mineral density of the lumbar spine in patients with beta-thalassemia major with dual-energy x-ray absorptiometry and quantitative computed tomography: a comparison study.
abstract: Osteoporosis is a common, multifactorial cause of morbidity in patients with beta-thalassemia. The present study was performed to compare bone mineral density (BMD) results in the lumbar spine of thalassemic patients measured by both dual-energy x-ray absorptiometry (DEXA) and quantitative computed tomography (QCT), and to determine their correlations with the markers of bone turnover. BMD was measured in the lumbar spine of 13 regularly transfused patients with beta-thalassemia major by both DEXA and QCT. Blood and urine samples were obtained for the determination of biochemical and hormonal profiles. Both T-scores and Z-scores were higher when measured by QCT (T-score = -0.41 +/- 1.31, Z-score = -0.56 +/- 1.08, mean +/- SD) compared with the values given by DEXA (T-score = -2.57 +/- 0.88, Z-score = -2.32 +/- 1.11, P = 0.0005). In comparison to DEXA, QCT T-scores were more closely correlated with age (r = -0.19 vs. r = -0.70, P = 0.0068). Strong negative correlation was found between QCT values and age (r = -0.67, P = 0.01). In comparison to DEXA T-scores, QCT T-scores were more closely correlated with osteocalcin, urine N-telopeptide cross-links of type I collagen, and deoxypyridinoline, but without statistical significance. DEXA T-scores were better correlated only with urine C-terminal telopeptides of type I collagen, but again without statistical significance. These results imply that the two methods cannot be used interchangeably in assessing BMD in thalassemic patients. However, which one of these two techniques more precisely determines the overall strength of vertebrae in patients with beta-thalassemia remains to be investigated.
authors.affiliation: Endocrine Department, Hippokrateion Hospital of Athens, Athens, Greece. drangelnick@hotmail.com
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Angelopoulos
authors.forename: Eugenia
authors.initials: E
authors.lastname: Katounda
authors.forename: Grigorios
authors.initials: G
authors.lastname: Rombopoulos
authors.forename: Anastasia
authors.initials: A
authors.lastname: Goula
authors.forename: Victoria
authors.initials: V
authors.lastname: Kaltzidou
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Kaltsas
authors.forename: Pappas
authors.initials: P
authors.lastname: Ioannis
authors.forename: George
authors.initials: G
authors.lastname: Tolis
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000469:Alkaline Phosphatase / Q000097:blood; D000596:Amino Acids / Q000652:urine; D015415:Biomarkers; D015519:Bone Density; D003094:Collagen / Q000652:urine; D024042:Collagen Type I; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D015675:Osteocalcin / Q000097:blood; D010024:Osteoporosis / Q000097:blood / Q000000981:diagnostic imaging / Q000209:etiology* / Q000652:urine; D010455:Peptides / Q000652:urine; D011237:Predictive Value of Tests; D014057:Tomography, X-Ray Computed / Q000379:methods*; D065227:Transfusion Reaction; D017086:beta-Thalassemia / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy
chemical_list: D000596:Amino Acids; D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; C036020:deoxypyridinoline; D003094:Collagen; D000469:Alkaline Phosphatase