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Precision of DLW energy expenditure measurements: contribution of natural abundance variations

1996; American Physiological Society; Volume: 270; Issue: 1 Linguagem: Inglês

10.1152/ajpendo.1996.270.1.e164

1522-1555

Patrick Ritz, Tim Cole, C. Couet, W. A. Coward,

Economic and Environmental Valuation

Accuracy and precision of the the doubly labeled water (DLW) measurements of energy expenditure are commonly estimated with models that do not account for 2H and 18O natural abundance variation. A new and simple treatment that completes the ratio-product model is derived in the present study. It uses both linear regression of multipoint data with time and information on within-subject 2H and 18O natural abundance variation. Use of this treatment is demonstrated in a group of seven subjects in whom 2H and 18O natural abundance variation was assessed by collecting predose samples for 6-8 days before dosing. In this set of 16 measurements, the precision (coefficient of variation) of individual DLW estimates of CO2 production was 4.90 +/- 2.14%, of which 3.23 +/- 1.20% arose from natural abundance variation.