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Natural abundance deuterium and 18-oxygen effects on the precision of the doubly labeled water methodThe doubly labeled water method for measuring total energy expenditure is subject to error from natural variations in the background 2H and 18O in body water. There is disagreement as to whether the variations in background abundances of the two stable isotopes covary and what relative doses of 2H and 18O minimize the impact of variation on the precision of the method. We have performed two studies to investigate the amount and covariance of the background variations. These were a study of urine collected weekly from eight subjects who remained in the Madison, WI locale for 6 wk and frequent urine samples from 14 subjects during round-trip travel to a locale > or = 500 miles from Madison, WI. Background variation in excess of analytical error was detected in six of the eight nontravelers, and covariance was demonstrated in four subjects. Background variation was detected in all 14 travelers, and covariance was demonstrated in 11 subjects. The median slopes of the regression lines of delta2H vs. delta18O were 6 and 7, respectively. Modeling indicated that 2H and 18O doses yielding a 6:1 ratio of final enrichments should minimize this error introduced to the doubly labeled water method.
Document ID
20040112447
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Horvitz, M. A.
(University of Wisconsin-Madison Madison, Wisconsin 53706, United States)
Schoeller, D. A.
Date Acquired
August 21, 2013
Publication Date
June 1, 2001
Publication Information
Publication: American journal of physiology. Endocrinology and metabolism
Volume: 280
Issue: 6
ISSN: 0193-1849
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Regulatory Physiology
Non-NASA Center

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