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Article
Validity of predictive equations for 24-h urinary sodium excretion in adults aged 18–39 y1–5
American Journal of Clinical Nutrition
  • Mary E. Cogswell, Centers for Disease Control and Prevention
  • Chia-Yih Wang, Centers for Disease Control and Prevention
  • Te-Ching Chen, Centers for Disease Control and Prevention
  • Christine M. Pfeiffer, Centers for Disease Control and Prevention
  • Paul Elliott, Centre for Environment and Health
  • Cathleen Gillespie, Centers for Disease Control and Prevention
  • Alicia L. Carriquiry, Iowa State University
  • Christopher T. Sempos, National Institutes of Health
  • Kiang Liu, Northwestern University
  • Cria G. Perrine, Centers for Disease Control and Prevention
  • Christine A. Swanson, National Institutes of Health
  • Kathleen L. Caldwell, Centers for Disease Control and Prevention
  • Catherine M. Loria, Centers for Disease Control and Prevention
Document Type
Article
Publication Version
Published Version
Publication Date
1-1-2013
DOI
10.3945/ajcn.113.059436
Abstract

Background: Collecting a 24-h urine sample is recommended for monitoring the mean population sodium intake, but implementation can be difficult. Objective: The objective was to assess the validity of published equations by using spot urinary sodium concentrations to predict 24-h sodium excretion. Design: This was a cross-sectional study, conducted from June to August 2011 in metropolitan Washington, DC, of 407 adults aged 18–39 y, 48% black, who collected each urine void in a separate container for 24 h. Four timed voids (morning, afternoon, evening, and overnight) were selected from each 24-h collection. Published equations were used to predict 24-h sodium excretion with spot urine by specimen timing and race-sex subgroups. We examined mean differences with measured 24-h sodium excretion (bias) and individual differences with the use of Bland-Altman plots. Results: Across equations and specimens, mean bias in predicting 24-h sodium excretion for all participants ranged from2267 to 1300mg (Kawasaki equation). Bias was least with International Cooperative Study on Salt, Other Factors, and Blood Pressure (INTERSALT) equations with morning (2165 mg; 95% CI: 2295, 36 mg), afternoon (290 mg; 2208, 28 mg), and evening (2120 mg; 2230, 211 mg) specimens. With overnight specimens, mean bias was least when the Tanaka (223 mg; 95% CI: 2141, 95 mg) or Mage (2145 mg; 2314, 25 mg) equations were used but was statistically significant when using the Tanaka equations among females (216 to 243 mg) and the Mage equations among races other than black (2554 to 2372 mg). Significant over- and underprediction occurred across individual sodium excretion concentrations. Conclusions: Using a single spot urine, INTERSALT equations may provide the least biased information about population mean sodium intakes among young US adults. None of the equations evaluated provided unbiased estimates of individual 24-h sodium excretion. This trial was registered at clinicaltrials.gov as NCT01631240.

Comments

This article is from American Journal of Clinical Nutrition 98 (2013): 1502, doi: 10.3945/ajcn.113.059436.

Rights
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
Language
en
File Format
application/pdf
Citation Information
Mary E. Cogswell, Chia-Yih Wang, Te-Ching Chen, Christine M. Pfeiffer, et al.. "Validity of predictive equations for 24-h urinary sodium excretion in adults aged 18–39 y1–5" American Journal of Clinical Nutrition Vol. 98 Iss. 6 (2013) p. 1502 - 1513
Available at: http://works.bepress.com/alicia_carriquiry/32/