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)


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


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

Show all

Distinct phenotypic characteristics of normal-weight adults at risk of developing cardiovascular and metabolic diseases

Stanley, A; Schuna, J; Yang, S; Kennedy, S; Heo, M; Wong, M; Shepherd, J; Heymsfield, S B

Distinct phenotypic characteristics of normal-weight adults at risk of developing cardiovascular and metabolic diseases Journal Article

In: Am J Clin Nutr, 112 (4), pp. 967-978, 2020, ISSN: 1938-3207 (Electronic) 0002-9165 (Linking).

Links | BibTeX | Tags: body shape, Chronic Disease, composition, Obesity, Shape Up, Waist Circumference

Predicting 3D body shape and body composition from conventional 2D photography

Tian, I Y; Ng, B K; Wong, M C; Kennedy, S; Hwaung, P; Kelly, N; Liu, E; Garber, A K; Curless, B; Heymsfield, S B; Shepherd, J A

Predicting 3D body shape and body composition from conventional 2D photography Journal Article

In: Medical Physics, n/a (n/a), pp. 6232-6245, 2020, ISSN: 2473-4209 (Electronic) 0094-2405 (Linking).

Links | BibTeX | Tags: Body Composition, Dual-energy X-ray absorptiometry, nutritional assessment, Obesity, principal components analysis, Shape Up, silhouette

Dhaliwal, R; Shepherd, J A; Ghormli, L El; Copeland, K C; Geffner, M E; Higgins, J; Levitsky, L L; Nadeau, K J; Weinstock, R S; White, N H; Group, Today Study

Changes in Visceral and Subcutaneous Fat in Youth With Type 2 Diabetes in the TODAY Study Journal Article

In: Diabetes Care, 42 (8), pp. 1549-1559, 2019, ISSN: 1935-5548 (Electronic) 0149-5992 (Linking).

Links | BibTeX | Tags: Adiposity, administration & dosage, Adolescent, Blood Glucose, Body Fat Distribution, Child, Combined Modality Therapy, complications, Diabetes Mellitus, Drug Combinations, drug effects, Exercise Therapy, Female, Humans, Insulin Resistance, Intra-Abdominal Fat, Life Style, Male, metabolism, Metformin, Obesity, pathology, physiology, Sex Factors, Subcutaneous Fat, therapy, Thiazoles, Type 2

Detailed 3-dimensional body shape features predict body composition, blood metabolites, and functional strength: the Shape Up! studies

Ng, B K; Sommer, M J; Wong, M C; Pagano, I; Nie, Y; Fan, B; Kennedy, S; Bourgeois, B; Kelly, N; Liu, Y E; Hwaung, P; Garber, A K; Chow, D; Vaisse, C; Curless, B; Heymsfield, S B; Shepherd, J A

Detailed 3-dimensional body shape features predict body composition, blood metabolites, and functional strength: the Shape Up! studies Journal Article

In: Am J Clin Nutr, 110 (6), pp. 1316-1326, 2019, ISSN: 1938-3207 (Electronic) 0002-9165 (Linking).

Links | BibTeX | Tags: Absorptiometry, Adipose Tissue, Adolescent, Adult, Anthropometry, blood, Body Composition, Cross-Sectional Studies, diabetes, diagnostic imaging, Female, HDL, Humans, Imaging, Insulin, Knee, Lipoproteins, Male, Middle Aged, Obesity, Photon, physiology, Principal Component Analysis, Shape Up, Strength, Three-Dimensional, Triglycerides, Young Adult

Panizza, C E; Lim, U; Yonemori, K M; Cassel, K D; Wilkens, L R; Harvie, M N; Maskarinec, G; Delp, E J; Lampe, J W; Shepherd, J A; Marchand, L Le; Boushey, C J

Effects of Intermittent Energy Restriction Combined with a Mediterranean Diet on Reducing Visceral Adiposity: A Randomized Active Comparator Pilot Study Journal Article

In: Nutrients, 11 (6), 2019, ISSN: 2072-6643 (Electronic) 2072-6643 (Linking).

Links | BibTeX | Tags: Abdominal, Adiposity, Adult, Aged, Asian Americans, Caloric Restriction, Dash, Diet, diet therapy, East Asian American, Female, Hawaii, Humans, intermittent energy restriction, Intra-Abdominal Fat, Male, Mediterranean, Mediterranean diet, methods, Middle Aged, Obesity, physiopathology, Pilot Projects, randomized trial, Reducing, total adiposity, Treatment Outcome, visceral adipose tissue

Alba, D L; Farooq, J A; Lin, M Y C; Schafer, A L; Shepherd, J; Koliwad, S K

Subcutaneous Fat Fibrosis Links Obesity to Insulin Resistance in Chinese Americans Journal Article

In: Journal of Clinical Endocrinology & Metabolism, 103 (9), pp. 3194-3204, 2018, ISSN: 1945-7197 (Electronic) 0021-972X (Linking).

Links | BibTeX | Tags: Abdominal, Adiposity, Adult, Aged, Anthropometry, Asian Americans, blood, Blood Glucose, Body Composition, Body Mass Index, ethnology, European Continental Ancestry Group, Female, Fibrosis, Humans, Hydroxyproline, Insulin Resistance, Male, metabolism, methods, Middle Aged, Obesity, pathology, physiology, physiopathology, statistics & numerical data, Subcutaneous Fat

Hinton, B J; Fan, B; Ng, B K; Shepherd, J A

Dual energy X-ray absorptiometry body composition reference values of limbs and trunk from NHANES 1999-2004 with additional visualization methods Journal Article

In: PLoS One, 12 (3), pp. e0174180, 2017, ISSN: 1932-6203 (Electronic) 1932-6203 (Linking).

Links | BibTeX | Tags: 80 and over, Absorptiometry, Adolescent, Adult, Age Factors, Aged, Body Composition, Child, diagnostic imaging, Extremities, Female, Humans, Male, methods, Middle Aged, Obesity, Photon, Reference Values, Sarcopenia, Sex Factors, Sexual Maturation, Shape Up, Torso, Young Adult

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

Relative Skeletal Maturation and Population Ancestry in Nonobese Children and Adolescents Journal Article

In: J Bone Miner Res, 32 (1), pp. 115-124, 2017, ISSN: 1523-4681 (Electronic) 0884-0431 (Linking).

Links | BibTeX | Tags: Adolescent, Age Determination by Skeleton, Age Distribution, Body Composition, Body Height, Body Mass Index, bone age, Bone development, Child, Continental Population Groups, epidemiology, Female, genetics, growth, Humans, Male, Obesity, pediatric endocrinology, Population, population ancestry, Preschool, Regression Analysis, Sexual Maturation, skeletal maturation, Young Adult

Setiawan, V W; Lim, U; Lipworth, L; Lu, S C; Shepherd, J; Ernst, T; Wilkens, L R; Henderson, B E; Marchand, L Le

Sex and Ethnic Differences in the Association of Obesity With Risk of Hepatocellular Carcinoma Journal Article

In: Clin Gastroenterol Hepatol, 14 (2), pp. 309-16, 2016, ISSN: 1542-7714 (Electronic) 1542-3565 (Linking).

Links | BibTeX | Tags: Aged, Body Mass Index, California, Carcinoma, Case-Control Studies, complications, epidemiology, Ethnic Groups, Female, Hawaii, Hepatocellular, Humans, Incidence, Liver Cancer, Male, MEC Study, Middle Aged, Obesity, Prospective Studies, Risk Factors, Sex Factors, Visceral Adiposity

Kendler, D L; Borges, J L; Fielding, R A; Itabashi, A; Krueger, D; Mulligan, K; Camargos, B M; Sabowitz, B; Wu, C H; Yu, E W; Shepherd, J

The Official Positions of the International Society for Clinical Densitometry: Indications of Use and Reporting of DXA for Body Composition Journal Article

In: J Clin Densitom, 16 (4), pp. 496-507, 2013, ISSN: 1094-6950 (Print) 1094-6950 (Linking).

Links | BibTeX | Tags: Absorptiometry, Algorithms, Body Composition, Bone Density, Congresses as Topic, diagnostic imaging, dxa, Humans, Medical, metabolism, methods, Obesity, Osteoporosis, Photon, Practice Guidelines as Topic, Sarcopenia, Societies

Shepherd, J A

Is osteoporosis an obesity paradox? Journal Article

In: J Clin Densitom, 16 (2), pp. 131-2, 2013, ISSN: 1094-6950 (Print) 1094-6950 (Linking).

Links | BibTeX | Tags: Abdominal, epidemiology, Female, Humans, Male, Obesity, Osteoporosis

Wilson, J P; Fan, B; Shepherd, J A

Total and regional body volumes derived from dual-energy X-ray absorptiometry output Journal Article

In: J Clin Densitom, 16 (3), pp. 368-373, 2013, ISSN: 1094-6950 (Print) 1094-6950 (Linking).

Links | BibTeX | Tags: 4-Compartment body composition, Absorptiometry, Adp, Adult, BodPod, Body Composition, Bone Density, diagnosis, dxa, Female, Humans, Impedance, Male, methods, Obesity, Photon, physiology, Plethysmography, Retrospective Studies, volume

Morimoto, Y; Maskarinec, G; Conroy, S M; Lim, U; Shepherd, J; Novotny, R

Asian ethnicity is associated with a higher trunk/peripheral fat ratio in women and adolescent girls Journal Article

In: J Epidemiol, 22 (2), pp. 130-5, 2012, ISSN: 1349-9092 (Electronic) 0917-5040 (Linking).

Links | BibTeX | Tags: Abdominal, Absorptiometry, Adiposity, Adolescent, Adult, Asian Continental Ancestry Group, Child, ethnology, European Continental Ancestry Group, Female, Humans, Linear Models, Obesity, Photon, statistics & numerical data, Torso

Wilson, J P; Mulligan, K; Fan, B; Sherman, J L; Murphy, E J; Tai, V W; Powers, C L; Marquez, L; Ruiz-Barros, V; Shepherd, J A

Dual-energy X-ray absorptiometry-based body volume measurement for 4-compartment body composition Journal Article

In: Am J Clin Nutr, 95 (1), pp. 25-31, 2012, ISSN: 1938-3207 (Electronic) 0002-9165 (Linking).

Links | BibTeX | Tags: Absorptiometry, Adipose Tissue, Adult, Biological, Body Composition, Body Size, diagnosis, diagnostic imaging, Female, Humans, Male, methods, Middle Aged, Models, Obesity, Photon, Plethysmography, Reproducibility of Results

Novotny, R; Daida, Y; Morimoto, Y; Shepherd, J; Maskarinec, G

Puberty, body fat, and breast density in girls of several ethnic groups Journal Article

In: Am J Hum Biol, 23 (3), pp. 359-65, 2011, ISSN: 1520-6300 (Electronic) 1042-0533 (Linking).

Links | BibTeX | Tags: Absorptiometry, Adipose Tissue, Adolescent, anatomy & histology, Body Mass Index, Breast, Breast Neoplasms, Child, cytology, diagnostic imaging, epidemiology, Ethnic Groups, ethnology, Female, growth & development, Hawaii, Humans, Mammography, Obesity, Photon, Puberty, Risk Factors

Flegal, K M; Ogden, C L; Yanovski, J A; Freedman, D S; Shepherd, J A; Graubard, B I; Borrud, L G

High adiposity and high body mass index-for-age in US children and adolescents overall and by race-ethnic group Journal Article

In: Am J Clin Nutr, 91 (4), pp. 1020-6, 2010, ISSN: 1938-3207 (Electronic) 0002-9165 (Linking).

Links | BibTeX | Tags: Absorptiometry, Adiposity, Adolescent, Adult, Body Mass Index, Child, diagnosis, epidemiology, ethnology, Female, Hispanic Americans, Humans, Male, Mass Screening, methods, Obesity, Photon, Prevalence, Reference Values, United States, Young Adult

Flegal, K M; Shepherd, J A; Looker, A C; Graubard, B I; Borrud, L G; Ogden, C L; Harris, T B; Everhart, J E; Schenker, N

Comparisons of percentage body fat, body mass index, waist circumference, and waist-stature ratio in adults Journal Article

In: Am J Clin Nutr, 89 (2), pp. 500-8, 2009, ISSN: 1938-3207 (Electronic) 0002-9165 (Linking).

Links | BibTeX | Tags: 80 and over, Absorptiometry, Adipose Tissue, Adiposity, Adult, Aged, Body Composition, Body Mass Index, Cross-Sectional Studies, diagnosis, DXA QA/QC, epidemiology, Female, Health Surveys, Humans, Male, metabolism, methods, Middle Aged, Obesity, Photon, physiology, Predictive Value of Tests, United States, Waist Circumference, Waist-Hip Ratio, Young Adult