Doubly labelled water: Multi-point and two-point methods in pre-school children.
OBJECTIVE
We compared the multi-sample and two-sample methods for measuring total energy expenditure (TEE) using doubly labelled water (DLW) in pre-school children to establish whether taking multiple samples provides any advantage in free-living conditions.


METHODS
Sixty-five children (32 boys; aged 2-6 years) were recruited from Aberdeen, UK. TEE was measured over 7 and 14 days using the multi-point and two-point methods by DLW. Total body composition was measured using dual-energy X-ray absorptiometry.


RESULTS
There was no significant difference between the mean TEE estimated using the multi-point and two-point methods. Independent of sampling technique, there was no significant difference in the TEE estimated over 7 and 14 days. Correlation of the deviations of the day-to-day enrichments suggests that the major factors driving isotope affected both isotopes. Association between fat-free mass (FFM) and TEE over 14 days was higher when using the multi-point method (r(2)=57.7%, P<0.001) compared with the two-point method (r(2)=41.1%, P < 0.001). There was no systematic bias in the difference between the two methods.


CONCLUSIONS
Multi- and two-point approaches give similar results for calculation of daily TEE in pre-school children. For studies aiming to establish a population level of TEE the two-sample method is a cost effective approach. However, the multi-point method appears to have greater accuracy and precision based on the better relationship to FFM (or FFM and FM combined). Consequently where maximum precision is required, in particular when energy expenditure of individual subjects is needed, this approach may be more appropriate.
Djafarian
Kurosh
K
Aberdeen Centre for Energy Regulation and Obesity, Rowett Research Institute, Bucksburn, Aberdeen, United Kingdom.
Jackson
Diane M
DM
Milne
Eric
E
Roger
Paula
P
Speakman
John R
JR
D015502:Absorptiometry, Photon; D001823:Body Composition; D002245:Carbon Dioxide / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D017666:Deuterium Oxide; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011865:Radioisotope Dilution Technique; D013997:Time Factors
D002245:Carbon Dioxide; D017666:Deuterium Oxide