Decline in Isotope Dilution Space Ratio Above Age 60 Could Affect Energy Estimates Using the Doubly Labeled Water Method

the IAEA DLW database consortium

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Abstract

Background: Doubly labeled water is gold standard for measuring total energy expenditure (TEE). Measurements using the method are sensitive to the isotope dilution space ratio (DSR). Accuracy and precision of the method might be improved if we could identify factors influencing DSR. Objectives: We evaluated the potential associations of age, sex, ethnicity, anthropometry, body composition, turnover rates of the isotopes, and geographical elevation with DSR. Methods: We used univariate regression analysis to explore the relationships between the continuous variables and analysis of variance to test the relationships between the categorical variables with DSR. Subsequently, we used general linear model (GLM) and 1-way analysis of variance to evaluate the simultaneous associations of age, sex, ethnicity, fat-free mass (FFM) and fat mass (FM) on DSR. Results: From 5678 measurements complied from studies around the world with diverse ethnicity and living at various elevations, the mean DSR was 1.0364 ± 0.0141. No meaningful physiologic effect of any of the continuous and categorical variable on DSR was detected. General linear model analysis revealed no effect of FFM and FM (P > 0.33) on DSR, but DSR decreased with age (P < 0.001) among those aged 60 y and older regardless of sex. Among the Whites who were younger than 60 y, DSR was not related to FFM and FM (P = 0.73) but was affected by both age and sex (P < 0.001). Conclusions: Previous estimates of age-related decline in TEE may have overestimated TEE at age 90 y. Validation studies on older participants are required to confirm this finding.

Original languageEnglish
JournalJournal of Nutrition
Volume154
Issue number12
Pages (from-to)3824-3831
ISSN0022-3166
DOIs
Publication statusPublished - 2024

Bibliographical note

Funding Information:
With support from the USDA/Agricultural Research Service grant 6250-51000-053, the DLW database, is supported by the International Atomic Energy Agency, Taiyo Nippon Sanso, and SERCON. The contents of this publication do not necessarily reflect the views or policies of the USDA nor does mention of trade names, commercial products, or organizations imply endorsement.

Funding Information:
1 With support from the USDA/Agricultural Research Service grant 6250-51000-053. The DLW database, is supported by the International Atomic Energy Agency, Taiyo Nippon Sanso and SERCON. The contents of this publication do not necessarily reflect the views or policies of the USDA nor does mention of trade names, commercial products, or organizations imply endorsement.

Publisher Copyright:
© 2024 American Society for Nutrition

Keywords

  • doubly labeled water
  • energy expenditure
  • isotope dilution space ratio

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