# The Study of Muscle and Physical Performance in African Caribbeans

> **NIH NIH R01** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 2022 · $55,970

## Abstract

Project Summary/Abstract:
Supplemental funding is requesting to purchase a preowned Hologic Horizon Dual X-ray Absorptiometry (DXA)
Machine for the Tobago Health Studies (THS) Clinic. We have collected serial DXA images to measure body
composition in the THS for 20 years (4 visits), and the Hologic 4500W DXA machine we have malfunctioned
during the review process of the parent grant (R01AG074956) and is no longer in working order. The machine
was manufactured in 2000 and has been discontinued by Hologic and the parts required to repair the machine
are no longer available. The QDR 4500W is an FDA approved system and must be calibrated to factory
standards and validated by a medical physicist – which is not possible. We did not budget for this in
R01AG074956, as the machine was in good working order at the time of submission and during most of the
review period. The primary purpose of DXA for this proposal was to measure total body and appendicular fat
mass and using DXA as originally proposed has several advantages over less expensive methods of fat mass.
First, switching to BIA will mean the end of the serial DXA measures that have been ongoing since 2000, and
used to calculate invaluable longitudinal change data. Second, despite recent scrutiny, DXA is still considered
a “gold standard” for measuring lean and fat mass and is included in just about all definitions of “sarcopenia”.
For this reason, DXA has been and is being used by many studies to segment lean and fat mass. Thus, the
continued use of DXA would provide the invaluable opportunity for direct comparisons with other populations.
Third, DXA is more accurate than BIA for measuring fat mass and has been used to evaluate BIA's accuracy.
Finally, the primary measure of total body skeletal muscle mass in this study is D3Cr, and while this method
has shown to have stronger relationships with physical function in the MrOS study, these comparisons have
not been made in other populations. Thus, the inclusion of DXA, as originally proposed, would significantly
enhance the aims and scientific contributions of the parent R01.

## Key facts

- **NIH application ID:** 10669932
- **Project number:** 3R01AG074956-01S1
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **Principal Investigator:** Adam J Santanasto
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $55,970
- **Award type:** 3
- **Project period:** 2022-04-01 → 2026-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10669932

## Citation

> US National Institutes of Health, RePORTER application 10669932, The Study of Muscle and Physical Performance in African Caribbeans (3R01AG074956-01S1). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10669932. Licensed CC0.

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