A standard calculation methodology for human doubly labeled water studies

John R Speakman*, Yosuke Yamada*, Hiroyuki Sagayama, Anders Mikael Sjödin, the IAEA DLW database group

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

77 Citations (Scopus)
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Abstract

The doubly labeled water (DLW) method measures total energy expenditure (TEE) in free-living subjects. Several equations are used to convert isotopic data into TEE. Using the International Atomic Energy Agency (IAEA) DLW database (5,756 measurements of adults and children), we show considerable variability is introduced by different equations. The estimated rCO2 is sensitive to the dilution space ratio (DSR) of the two isotopes. Based on performance in validation studies, we propose a new equation based on a new estimate of the mean DSR. The DSR is lower at low body masses (<10 kg). Using data for 1,021 babies and infants, we show that the DSR varies non-linearly with body mass between 0 and 10 kg. Using this relationship to predict DSR from weight provides an equation for rCO2 over this size range that agrees well with indirect calorimetry (average difference 0.64%; SD = 12.2%). We propose adoption of these equations in future studies.

Original languageEnglish
Article number100203
JournalCell Reports Medicine
Volume2
Issue number2
Number of pages13
DOIs
Publication statusPublished - 2021

Keywords

  • Doubly labeled water
  • Free-living
  • Total energy expenditure
  • Validation

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