A standard calculation methodology for human doubly labeled water studies.
Cell Rep Med
; 2(2): 100203, 2021 02 16.
Article
in En
| MEDLINE
| ID: mdl-33665639
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.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Oxygen Isotopes
/
Body Composition
/
Water
/
Energy Metabolism
Limits:
Humans
Language:
En
Journal:
Cell Rep Med
Year:
2021
Document type:
Article
Affiliation country: