We have been the DXA quality assurance site for many NIH-funded studies, CDC, and many more. Dr. Shepherd holds the patent that Hologic uses to measure body composition. He has also served as a past president of the ISCD and has either chaired or been a participant in all ISCD Position Development Conferences.

We work closely with the manufacturers and maintain workstations for Hologic and GE systems with the rights to use that software on scans other than those at our site. Our involvement in DXA quality assurance involves tasks such as,

  • Reviewing and revising DXA image data to ensure consistency by defining the same regions of interest within and among participants so that analyses of demographic differences and longitudinal change are assured that differences are not contaminated by differing definitions of body parts
  • Harmonizing data acquired for a Lunar DXA with data subsequently acquired from a Hologic scanner, so that investigators can examine changes in body composition and bone mineral density from different waves of participants, which may include creating a new master archive storage, cross-calibration equations, longitudinal correction and calibration of DXA data
  • Performing quality control checks on all DXA scans to insure correct participant alignment, appropriate location and accurate positioning of all regions of interest
  • Defining a protocol for ensuring consistency within and among participants’ DXA scan
  • Establishing procedures for continued quality control checks, reanalysis, and data generation for ongoing scans, which may include site manuals, training presentations/materials for site personnel, methods for validating DXA personnel

Below you will find past and current QA studies conducted at SRL, as well as QA-related publications. For inquiries, please contact us for more information.

Current Studies


Dual-energy x-ray absorptiometry (DXA) scan analysis and quality control review for NHANES 2018-2022

National Health and Nutrition Examination Survey (NHANES)

In this study, we are working on NHANES 2018-2022 to review the existing procedures manuals and update as needed by detailing procedures for obtaining the DXA scans for the protocol, perform longitudinal calibrations and cross-calibrations, and provide correction factors, if necessary. Specifically, we will be looking at DXA scans of the hip, spine, VFA spine, and whole body acquired at NHANES mobile examination centers. This data, along with data from similar studies will be used to examine age, sex, and racial/ethnic differences during the life cycle and to explore the relationship between body composition and behavioral factors such as diet and physical activity.

IMPAACT cover photo

IMPAACT 2009: Pharmacokinetics, Feasibility, Acceptability, and Safety of Oral Pre-Exposure Prophylaxis for Primary HIV Prevention during Pregnancy and Breast Feeding in Adolescents and Young Women and their Infants

IMPAACT 2010: Phase III Study of the Virologic Efficacy and Safety of Dolutegravir-Containing versus Efavirenz-Containing Antiretroviral Therapy Regimens in HIV-1-Infected Pregnant Women and their Infants

International Maternal Pediatric Adoloscent AIDS Clinical Trials (IMPAACT) Network

Our work with IMPAACT is divided between two studies: IMPAACT 2009 and IMPAACT 2010. IMPAACT 2009 is a study that evaluates daily oral Truvada PrEP in pregnant and lactating women. IMPAACT 2010 is a Phase III study of Virologic Efficacy and safety of Dolutegravir-containing versus Efavirenz-containing Antiretroviral therapy regimens in HIV-1-infected pregnant women and their infants. In both studies, our role is to monitor changes in bone mineral density (BMD), which will include central analysis of spine, femur, and whold body DXA scans. The IMPAACT 2009 study provides an important opportunity to study the effect of PrEP use and lactation on bone mass in young women who are yet to achieve peak bone mass. The IMPAACT 2010 study represents an important opportunity to learn more about the effects of the regimens on maternal and infant bone and renal outcomes.

Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS)

HANDLS

The HANDLS study is a multidisciplinary, community-based, prospective longitudinal epidemiologic study examining the influence of race and socioeconomic status (SES) on the development of age-related health disparities among socioeconomically diverse African Americans and whites in Baltimore. This study investigates whether health disparities develop or persist due to differences in SES, differences in race, or their interaction. Similar to our work with NHANES, we are working on HANDLS to provide DXA analysis and quality control for their body composition and bone mineral density data. We are in the process of establishing procedures manuals and will review/update them as needed by detailing procedures for obtaining the DXA scans for the protocol, perform longitudinal calibrations and cross calibrations, and provide corrections factors, if necessary.

Extended use of NHANES Visceral Adiposity Cancer Risk Factors to GE Systems

The NHANES VAT measures will become the national reference data for VAT upon its release since there isn’t any other representative sample of VAT. However, the NHANES data was acquired on one make of DXA system, Hologic. VAT measures on Hologic DXA systems are substantially different than on GE systems, which complicate the pooling of VAT measures from different systems in multi-center clinical trials and make it difficult to compare VAT measures over time when a patient is scanned on different systems. Furthermore, with GE systems accounting for approximately 50% of the DXA clinical installation base, this means that half of the DXA users won’t be able to access the new NHANES VAT reference data. The objective of this study is to determine the relationship between Hologic and GE Lunar system for VAT measurements in children and adults, repost the NHANES VAT data in GE units, and provide cutoff points relevant for high risk of cancer and metabolic conditions.

Past Studies


Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY)

National Institute of Diabetes and Digestive and Kidney Diseases

The TODAY study was a nationwide research study to compare the efficacy and safety of three interventions to treat adolescents and youth with type 2 diabetes. The primary outcome was time to treatment failure due to loss of glycemic control, defined as hemoglobin A1c >= 8% for 6 months.  Secondary outcomes included measures of beta cell function and insulin resistance, body composition, nutrition, physical activity and aerobic fitness, cardiovascular risk factors, microvascular complications, quality of life, and psychological outcomes.  The influence of individual and family behaviors on treatment response and the relative cost-effectiveness of the three treatment arms were also evaluated. This study has provided information fundamental to improving treatments and outcomes for youth with type 2 diabetes. Learn more.

National Institute of Child Health and Human Development

Bone Mineral Density in Childhood Study

BMDCS

The BMDCS (2001-2011) offered an unprecedented opportunity to identify predictors of the timing and magnitude of peak bone mass, a major determinant of osteoporosis in later adulthood. BMDCS investigators provided reference curves for bone accrual and linear growth velocity that are comparable to the Centers for Disease Control and Prevention linear growth and weight gain curves for children and adolescents. The reference curves generated by this carefully executed study provided the gold standard for normal bone accrual for generations to come. The study’s results enable practitioners to identify the adverse effects that chronic illness has on bone. Additionally, the results have clarified the effects that the timing of pubertal onset have on bone density and linear growth, as well as the need for height adjustment for dual-energy X-ray absorptiometry results in children. Learn more.

BeMyKids Study: Bone Mineral Accretion in Young Children

National Institute of Child Health and Human Development

Led by Dr. Heidi Kalkwarf, the BeMyKids study seeks to understand bone mineral accrual in children 1 to 5 years of age. A glaring deficit is the inability to evaluate bone health of children younger than 5 years due to lack of appropriate bone density reference data. This gap is problematic as there are numerous clinical conditions (e.g., neuromuscular disease, cancer, glucocorticoid treatment, extreme prematurity) that threaten bone health in this young age group. The findings from this study will facilitate medical care of children with chronic medical conditions that threaten bone health, and it will develop and validate novel methods for bone and body composition assessment in this age range. It will also add generalizable knowledge to enhance understanding of the growing skeleton, and its relationship to motor and somatic development. Learn more.

Safety Study of a Tenofovir-containing Drug Regimen for the Prevention of Mother-to-child Transmission of HIV and HBV – Tenofovir in Pregnancy (TiP) Study

TiP Study on the ClinicalTrials.gov site

The Tenofovir in Pregnancy (TiP) study was designed to test the safety of an antiretroviral combination containing TDF in pregnant women co-infected with HIV and HBV and their infants in Guangxi, China. The study’s objectives were to evaluate the renal, liver, and bone mineral density effects of TDF, administered from the second trimester of pregnancy, to women and their infants through a year postnatally. Learn more.

IMPAACT cover photo

IMPAACT P1084s: Maternal and Infant Monitoring for Evidence of Toxicity Related to Tenofovir Exposure: The Bone and Kidney Health Substudy of PROMISE

International Maternal Pediatric Adolescent AIDS Clinical Trials Network (IMPAACT)

P1084s is a nested, comparative substudy of HIV-1-infected women and their infants randomized in PROMISE (Promoting Maternal and Infant Survival Everywhere) to receive a maternal tenofovir-containing regimen or no maternal tenofovir-containing regimen during pregnancy or breastfeeding for prevention of mother-to-child transmission. The substudy was designed to examine bone, renal and growth outcomes of tenofovir exposure during pregnancy or during breastfeeding in 1077BF and 1077FF. Learn more.

DXA QA/QC Publications

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Kourtis, A P; Wiener, J; Wang, L; Fan, B; Shepherd, J A; Chen, L; Liu, W; Shepard, C; Wang, L; Wang, A; Bulterys, M

Tenofovir Disoproxil Fumarate Use during Pregnancy and Infant Bone Health: the Tenofovir in Pregnancy Pilot Study Journal Article

In: Pediatr Infect Dis J, 37 (11), pp. e264-e268, 2018, ISSN: 1532-0987 (Electronic) 0891-3668 (Linking).

Links | BibTeX | Tags: adverse effects, Agents, Bone and Bones, Bone Density, China, Coinfection, drug effects, drug therapy, DXA QA/QC, Female, Hepatitis B, HIV Infections, Humans, Infant, Infant Health, Infectious, Pilot Projects, Pregnancy, Pregnancy Complications, Tenofovir, therapeutic use, virology, Young Adult

Mitchell, J A; Chesi, A; McCormack, S E; Cousminer, D L; Kalkwarf, H J; Lappe, J M; Gilsanz, V; Oberfield, S E; Shepherd, J A; Kelly, A; Grant, S F A; Zemel, B S

Physical Activity and Bone Accretion: Isotemporal Modeling and Genetic Interactions Journal Article

In: Med Sci Sports Exerc, 50 (5), pp. 977-986, 2018, ISSN: 1530-0315 (Electronic) 0195-9131 (Linking).

Links | BibTeX | Tags: Adolescent, Alleles, Bone and Bones, Bone Density, Child, Exercise, Female, genetics, Humans, Male, Models, physiology, Preschool, Theoretical, Wnt Signaling Pathway

Chesi, A; Mitchell, J A; Kalkwarf, H J; Bradfield, J P; Lappe, J M; Cousminer, D L; Roy, S M; McCormack, S E; Gilsanz, V; Oberfield, S E; Hakonarson, H; Shepherd, J A; Kelly, A; Zemel, B S; Grant, S F

A Genomewide Association Study Identifies Two Sex-Specific Loci, at SPTB and IZUMO3, Influencing Pediatric Bone Mineral Density at Multiple Skeletal Sites Journal Article

In: J Bone Miner Res, 32 (6), pp. 1274-1281, 2017, ISSN: 1523-4681 (Electronic) 0884-0431 (Linking).

Links | BibTeX | Tags: Adolescent, Analysis, Bone and Bones, Bone Density, Child, Dxa analysis, Female, Genetic research, genetics, Genome-Wide Association Study, Human association studies, Humans, Immunoglobulins, Male, Membrane Proteins, Molecular Sequence Annotation, physiology, quantitation of bone, Quantitative Trait Loci, Sex Characteristics, Spectrin, Young Adult

Shepherd, J A; Sommer, M J; Fan, B; Powers, C; Stranix-Chibanda, L; Zadzilka, A; Basar, M; George, K; Mukwasi-Kahari, C; Siberry, G

Advanced Analysis Techniques Improve Infant Bone and Body Composition Measures by Dual-Energy X-Ray Absorptiometry Journal Article

In: Journal of Pediatrics, 181 , pp. 248-253 e3, 2017, ISSN: 1097-6833 (Electronic) 0022-3476 (Linking).

Links | BibTeX | Tags: Absorptiometry, Body Composition, Bone and Bones, Bone Density, Bone mineral density, Cross-Sectional Studies, DXA QA/QC, Humans, Infant, metabolism, methods, Newborn, Photon, precision, Reproducibility of Results

Mitchell, J A; Chesi, A; Elci, O; McCormack, S E; Roy, S M; Kalkwarf, H J; Lappe, J M; Gilsanz, V; Oberfield, S E; Shepherd, J A; Kelly, A; Grant, S F; Zemel, B S

Physical Activity Benefits the Skeleton of Children Genetically Predisposed to Lower Bone Density in Adulthood Journal Article

In: J Bone Miner Res, 31 (8), pp. 1504-12, 2016, ISSN: 1523-4681 (Electronic) 0884-0431 (Linking).

Links | BibTeX | Tags: Adolescent, Adult, Bone and Bones, Bone Density, Bone mineral density, Child, children, Cohort Studies, Exercise, Female, Genetic, Genetic Loci, Genetic Predisposition to Disease, genetics, Humans, Male, Physical activity, physiology, Polymorphism, Risk Factors, Single Nucleotide

Mitchell, J A; Chesi, A; McCormack, S E; Roy, S M; Cousminer, D L; Kalkwarf, H J; Lappe, J M; Gilsanz, V; Oberfield, S E; Shepherd, J A; Kelly, A; Zemel, B S; Grant, S F

Rare EN1 Variants and Pediatric Bone Mass Journal Article

In: J Bone Miner Res, 31 (8), pp. 1513-7, 2016, ISSN: 1523-4681 (Electronic) 0884-0431 (Linking).

Links | BibTeX | Tags: Alleles, anatomy & histology, Bone and Bones, Bone Density, Child, Childhood, dxa, Female, General population studies, Genetic Association Studies, Genetic Loci, Genetic research, Genetic Variation, genetics, Humans, Male, Organ Size, Polymorphism, Puberty, Single Nucleotide

Mitchell, J A; Chesi, A; Elci, O; McCormack, S E; Kalkwarf, H J; Lappe, J M; Gilsanz, V; Oberfield, S E; Shepherd, J A; Kelly, A; Zemel, B S; Grant, S F

Genetics of Bone Mass in Childhood and Adolescence: Effects of Sex and Maturation Interactions Journal Article

In: J Bone Miner Res, 30 (9), pp. 1676-83, 2015, ISSN: 1523-4681 (Electronic) 0884-0431 (Linking).

Links | BibTeX | Tags: Adolescent, Adult, Bone, Bone and Bones, Bone Density, Bone development, Calcium, Child, Childhood, Densitometry, Dietary, dxa, Female, Fractures, General population studies, Genetic Predisposition to Disease, Genetic research, genetics, Genotype, Humans, Longitudinal Studies, Low Density Lipoprotein Receptor-Related Protein-5, Male, pathology, Phenotype, physiology, Polymorphism, Preschool, Prospective Studies, Puberty, Sex Factors, Single Nucleotide, United States, Young Adult

Short, D F; Gilsanz, V; Kalkwarf, H J; Lappe, J M; Oberfield, S; Shepherd, J A; Winer, K K; Zemel, B S; Hangartner, T N

Anthropometric models of bone mineral content and areal bone mineral density based on the bone mineral density in childhood study Journal Article

In: Osteoporosis International, 26 (3), pp. 1099-108, 2015, ISSN: 1433-2965 (Electronic) 0937-941X (Linking).

Links | BibTeX | Tags: Absorptiometry, Adipose Tissue, Adolescent, Age Factors, Algorithms, Anthropometry, Body Height, Body Weight, Bone and Bones, Bone Density, Child, Continental Population Groups, Female, Humans, Longitudinal Studies, Male, methods, Models, Photon, physiology, Preschool, Sex Factors, Theoretical, Young Adult

Gregson, C L; Paggiosi, M A; Crabtree, N; Steel, S A; McCloskey, E; Duncan, E L; Fan, B; Shepherd, J A; Fraser, W D; Smith, G D; Tobias, J H

Analysis of body composition in individuals with high bone mass reveals a marked increase in fat mass in women but not men Journal Article

In: Journal of Clinical Endocrinology & Metabolism, 98 (2), pp. 818-28, 2013, ISSN: 1945-7197 (Electronic) 0021-972X (Linking).

Links | BibTeX | Tags: 80 and over, Adipose Tissue, Adult, Age Factors, Aged, blood, Body Composition, Body Mass Index, Bone and Bones, Bone Density, Case-Control Studies, diagnostic imaging, Female, Humans, Male, Middle Aged, Osteocalcin, physiology, Radiography, Sex Factors

Looker, A C; Borrud, L G; Hughes, J P; Fan, B; Shepherd, J A; Sherman, M

Total body bone area, bone mineral content, and bone mineral density for individuals aged 8 years and over: United States, 1999-2006 Journal Article

In: Vital Health Stat 11, (253), pp. 1-78, 2013, ISSN: 0083-1980 (Print) 0083-1980 (Linking).

Links | BibTeX | Tags: 80 and over, Absorptiometry, Adolescent, Adult, Aged, Bone and Bones, Bone Density, Child, diagnostic imaging, Ethnic Groups, Female, Humans, Male, Middle Aged, Nutrition Surveys, Photon, physiology, United States, Young Adult

Shepherd, J A; Fan, B; Lu, Y; Wu, X P; Wacker, W K; Ergun, D L; Levine, M A

A multinational study to develop universal standardization of whole-body bone density and composition using GE Healthcare Lunar and Hologic DXA systems Journal Article

In: J Bone Miner Res, 27 (10), pp. 2208-16, 2012, ISSN: 1523-4681 (Electronic) 0884-0431 (Linking).

Links | BibTeX | Tags: 80 and over, Absorptiometry, Adiposity, Adolescent, Adult, Aged, Body Composition, Body Weight, Bone and Bones, Bone Density, Calibration, Child, Demography, diagnostic imaging, Female, Humans, Internationality, Male, methods, Middle Aged, Photon, physiology, Preschool, Reference Standards, Reproducibility of Results, standards, Young Adult

Shepherd, J A; Wang, L; Fan, B; Gilsanz, V; Kalkwarf, H J; Lappe, J; Lu, Y; Hangartner, T; Zemel, B S; Fredrick, M; Oberfield, S; Winer, K K

Optimal monitoring time interval between DXA measures in children Journal Article

In: J Bone Miner Res, 26 (11), pp. 2745-52, 2011, ISSN: 1523-4681 (Electronic) 0884-0431 (Linking).

Links | BibTeX | Tags: Absorptiometry, Adolescent, Bone and Bones, Bone Density, Child, diagnostic imaging, Female, Humans, Male, methods, monitoring, Photon, Physiologic, physiology, Time Factors

Kalkwarf, H J; Gilsanz, V; Lappe, J M; Oberfield, S; Shepherd, J A; Hangartner, T N; Huang, X; Frederick, M M; Winer, K K; Zemel, B S

Tracking of bone mass and density during childhood and adolescence Journal Article

In: Journal of Clinical Endocrinology & Metabolism, 95 (4), pp. 1690-8, 2010, ISSN: 1945-7197 (Electronic) 0021-972X (Linking).

Links | BibTeX | Tags: Absorptiometry, Adolescent, anatomy & histology, Body Height, Body Weight, Bone and Bones, Bone Density, Bone development, chemistry, Child, Female, Femur Neck, growth & development, Humans, Longitudinal Studies, Male, Organ Size, Photon, physiology, Radius, Regression Analysis, Sexual Maturation, Spine

Zemel, B S; Leonard, M B; Kelly, A; Lappe, J M; Gilsanz, V; Oberfield, S; Mahboubi, S; Shepherd, J A; Hangartner, T N; Frederick, M M; Winer, K K; Kalkwarf, H J

Height adjustment in assessing dual energy x-ray absorptiometry measurements of bone mass and density in children Journal Article

In: Journal of Clinical Endocrinology & Metabolism, 95 (3), pp. 1265-73, 2010, ISSN: 1945-7197 (Electronic) 0021-972X (Linking).

Links | BibTeX | Tags: Absorptiometry, Adolescent, Adolescent Development, Age Factors, Body Height, Bone and Bones, Bone Density, Child, Child Development, Cross-Sectional Studies, diagnostic imaging, Female, Humans, Male, methods, Photon, physiology, Reference Values, Regression Analysis, Sex Factors

Blake, G M; Shepherd, J A

Effect of random BMD measurement errors on diagnostic classification using T-scores Journal Article

In: J Clin Densitom, 10 (4), pp. 415-7; author reply 417-8, 2007, ISSN: 1094-6950 (Print) 1094-6950 (Linking).

Links | BibTeX | Tags: 80 and over, Absorptiometry, Adipose Tissue, Adult, Age Factors, Aged, Bone and Bones, Bone Density, Data Interpretation, diagnosis, Humans, instrumentation, metabolism, methods, Middle Aged, Models, Osteoporosis, pathology, Photon, Predictive Value of Tests, Reference Standards, Reproducibility of Results, Risk Factors, Spine, standards, Statistical

Shepherd, J A; Blake, G M

T-scores and Z-scores Journal Article

In: J Clin Densitom, 10 (4), pp. 349-50, 2007, ISSN: 1094-6950 (Print) 1094-6950 (Linking).

Links | BibTeX | Tags: Bone and Bones, Bone Density, Data Interpretation, Densitometry, diagnosis, Equipment Design, Humans, instrumentation, methods, Osteoporosis, pathology, physiology, Statistical, X-Rays

Binkley, N; Kiebzak, G M; Lewiecki, E M; Krueger, D; Gangnon, R E; Miller, P D; Shepherd, J A; Drezner, M K

Recalculation of the NHANES database SD improves T-score agreement and reduces osteoporosis prevalence Journal Article

In: J Bone Miner Res, 20 (2), pp. 195-201, 2005, ISSN: 0884-0431 (Print) 0884-0431 (Linking).

Links | BibTeX | Tags: Absorptiometry, Bone and Bones, Bone Density, Databases as Topic, Densitometry, diagnosis, DXA QA/QC, epidemiology, Female, Femur, Femur Neck, Humans, methods, Osteoporosis, pathology, Photon, Postmenopause, Prevalence, Software, standards, Time Factors

Njeh, C F; Saeed, I; Grigorian, M; Kendler, D L; Fan, B; Shepherd, J; McClung, M; Drake, W M; Genant, H K

Assessment of bone status using speed of sound at multiple anatomical sites Journal Article

In: Ultrasound Med Biol, 27 (10), pp. 1337-45, 2001, ISSN: 0301-5629 (Print) 0301-5629 (Linking).

Links | BibTeX | Tags: 80 and over, Adult, Aged, Anthropometry, Bone and Bones, Bone Density, diagnostic imaging, Female, Fingers, Humans, instrumentation, Metatarsus, methods, Middle Aged, Osteoporosis, Physical Phenomena, Physics, physiopathology, Radius, Reference Values, Sound, Tibia, Transducers, Ultrasonography