title: Z score prediction model for assessment of bone mineral content in pediatric diseases.
abstract: The objective of this study was to develop an anthropometry-based prediction model for the assessment of bone mineral content (BMC) in children. Dual-energy X-ray absorptiometry (DXA) was used to measure whole-body BMC in a heterogeneous cohort of 982 healthy children, aged 5-18 years, from three ethnic groups (407 European- American [EA], 285 black, and 290 Mexican-American [MA]). The best model was based on log transformations of BMC and height, adjusted for age, gender, and ethnicity. The mean +/- SD for the measured/predicted in ratio was 1.000 +/- 0.017 for the calibration population. The model was verified in a second independent group of 588 healthy children (measured/predicted In ratio = 1.000 +/- 0.018). For clinical use, the ratio values were converted to a standardized Z score scale. The whole-body BMC status of 106 children with various diseases (42 cystic fibrosis [CF], 29 juvenile dermatomyositis [JDM], 15 liver disease [LD], 6 Rett syndrome [RS], and 14 human immunodeficiency virus [HIV]) was evaluated. Thirty-nine patients had Z scores less than -1.5, which suggest low bone mineral mass. Furthermore, 22 of these patients had severe abnormalities as indicated by Z scores less than -2.5. These preliminary findings indicate that the prediction model should prove useful in determining potential bone mineral deficits in individual pediatric patients.
authors.affiliation: US Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Ellis
authors.forename: R J
authors.initials: RJ
authors.lastname: Shypailo
authors.forename: D S
authors.initials: DS
authors.lastname: Hardin
authors.forename: M D
authors.initials: MD
authors.lastname: Perez
authors.forename: K J
authors.initials: KJ
authors.lastname: Motil
authors.forename: W W
authors.initials: WW
authors.lastname: Wong
authors.forename: S A
authors.initials: SA
authors.lastname: Abrams
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000293:Adolescent; D000367:Age Factors; D001827:Body Height; D015519:Bone Density; D001842:Bone and Bones / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003550:Cystic Fibrosis / Q000503:physiopathology; D003882:Dermatomyositis / Q000503:physiopathology; D005260:Female; D015658:HIV Infections / Q000503:physiopathology; D006801:Humans; D016014:Linear Models; D008107:Liver Diseases / Q000503:physiopathology; D008297:Male; D008954:Models, Biological; D010372:Pediatrics; D011159:Population Surveillance / Q000379:methods; D011237:Predictive Value of Tests; D015518:Rett Syndrome / Q000503:physiopathology; D012737:Sex Factors