TY - JOUR
T1 - Intermachine differences in DXA measurements vary by skeletal site, and impact the assessment of low bone density in children
AU - Zemel, Babette S.
AU - Wasserman, Halley
AU - Kelly, Andrea
AU - Fan, Bo
AU - Shepherd, John
AU - Lappe, Joan
AU - Gilsanz, Vicente
AU - Oberfield, Sharon
AU - Winer, Karen K.
AU - Kalkwarf, Heidi J.
N1 - Funding Information:
This work was funded by the National Institute of Child Health and Human Development (NICHD) contracts NO1-HD-1-3228 , -3329 , -3330 , -3331 , -3332 , and -3333 , the Clinical and Translational Research Center Grant 5-MO1-RR-000240 and UL1 RR-026314 , the Nutrition Center of the Children's Hospital of Philadelphia , and the Children's Hospital of Philadelphia Research Institute . The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Funding Information:
This work was funded by the National Institute of Child Health and Human Development (NICHD) contracts NO1-HD-1-3228, -3329, -3330, -3331, -3332, and -3333, the Clinical and Translational Research Center Grant 5-MO1-RR-000240 and UL1 RR-026314, the Nutrition Center of the Children's Hospital of Philadelphia, and the Children's Hospital of Philadelphia Research Institute. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Publisher Copyright:
© 2020 Elsevier Inc.
PY - 2020/12
Y1 - 2020/12
N2 - Background: Bone mineral content (BMC) and areal-bone mineral density (aBMD) measurements of the lumbar spine (LS) and whole body less head (WBLH) by dual energy X-ray absorptiometry (DXA) are recommended for bone health assessment in children. Intermachine differences were not considered previously in formulating these recommendations. Methodology: DXA measurements of the LS, WBLH, total hip, femoral neck and distal 1/3 radius from the Bone Mineral Density in Childhood Study were examined. Healthy children, ages 6 to 16 years, from five clinical centers participated. The same spine, whole body, and femur phantoms were measured on each Center's DXA machine. Percentage of individuals with low BMC or aBMD (Z-score < −1.5) was determined. Clinical center differences were evaluated by analysis of covariance adjusting for height and BMI Z-score, calcium intake, physical activity, Tanner stage and bone age. Logistic regression assessed odds of low BMC or aBMD across clinical centers. Results: Significant differences among Clinical Centers (p < 0.05) were evident in adjusted mean BMC and aBMD Z-scores (n = 1503) for all skeletal sites. WBLH BMC and aBMD Z-scores had the greatest range across centers (−0.13 to 0.24, and −0.17 to 0.56, respectively). The percentage of children with Z-scores less than −1.5 varied among Clinical Centers from 1.9 [95%CI 0.8, 4.5] to 8.1 [95%CI 5.7, 11.3] for WBLH BMC, 1.1 [95%CI 0.4, 3.5] to 6.3 [95%CI 3.8, 10.1] for WBLH aBMD, and from 4.4 [95%CI 2.8, 7.0] to 12.6 [95%CI 9.3, 16.9] for distal 1/3 radius aBMD. For each skeletal site except total hip aBMD and femoral neck BMC, at least one center had significantly lower odds of low bone density. Conclusions: By design, our reference ranges capture intermachine variability. Most clinical centers don't know where their machine falls within the range of intermachine variability, and this may affect diagnosis of children evaluated for conditions that threaten bone health. Total hip scans showed the least, and whole body scans showed the most intermachine variability. Pediatric bone health assessment recommendations should recognize intermachine differences and address this important issue.
AB - Background: Bone mineral content (BMC) and areal-bone mineral density (aBMD) measurements of the lumbar spine (LS) and whole body less head (WBLH) by dual energy X-ray absorptiometry (DXA) are recommended for bone health assessment in children. Intermachine differences were not considered previously in formulating these recommendations. Methodology: DXA measurements of the LS, WBLH, total hip, femoral neck and distal 1/3 radius from the Bone Mineral Density in Childhood Study were examined. Healthy children, ages 6 to 16 years, from five clinical centers participated. The same spine, whole body, and femur phantoms were measured on each Center's DXA machine. Percentage of individuals with low BMC or aBMD (Z-score < −1.5) was determined. Clinical center differences were evaluated by analysis of covariance adjusting for height and BMI Z-score, calcium intake, physical activity, Tanner stage and bone age. Logistic regression assessed odds of low BMC or aBMD across clinical centers. Results: Significant differences among Clinical Centers (p < 0.05) were evident in adjusted mean BMC and aBMD Z-scores (n = 1503) for all skeletal sites. WBLH BMC and aBMD Z-scores had the greatest range across centers (−0.13 to 0.24, and −0.17 to 0.56, respectively). The percentage of children with Z-scores less than −1.5 varied among Clinical Centers from 1.9 [95%CI 0.8, 4.5] to 8.1 [95%CI 5.7, 11.3] for WBLH BMC, 1.1 [95%CI 0.4, 3.5] to 6.3 [95%CI 3.8, 10.1] for WBLH aBMD, and from 4.4 [95%CI 2.8, 7.0] to 12.6 [95%CI 9.3, 16.9] for distal 1/3 radius aBMD. For each skeletal site except total hip aBMD and femoral neck BMC, at least one center had significantly lower odds of low bone density. Conclusions: By design, our reference ranges capture intermachine variability. Most clinical centers don't know where their machine falls within the range of intermachine variability, and this may affect diagnosis of children evaluated for conditions that threaten bone health. Total hip scans showed the least, and whole body scans showed the most intermachine variability. Pediatric bone health assessment recommendations should recognize intermachine differences and address this important issue.
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U2 - 10.1016/j.bone.2020.115581
DO - 10.1016/j.bone.2020.115581
M3 - Article
C2 - 32795677
AN - SCOPUS:85089795454
VL - 141
JO - Bone
JF - Bone
SN - 8756-3282
M1 - 115581
ER -