Urinary Excretion of Sodium, Potassium, and Chloride, but Not Iodine, Varies by Timing of Collection in a 24-Hour Calibration Study

Details

• Alternative Title:
  J Nutr
• Personal Author:
  Wang, Chia-Yih ; Cogswell, Mary E. ; Loria, Catherine M. ; Chen, Te-Ching ; Pfeiffer, Christine M. ; Swanson, Christine A. ; Caldwell, Kathleen L. ; Perrine, Cria G. ; Carriquiry, Alicia L. ; Liu, Kiang ; Sempos, Christopher T. ; Gillespie, Cathleen D. ; Burt, Vicki L.
• Description:
  Because of the logistic complexity, excessive respondent burden, and high cost of conducting 24-h urine collections in a national survey, alternative strategies to monitor sodium intake at the population level need to be evaluated. We conducted a calibration study to assess the ability to characterize sodium intake from timed-spot urine samples calibrated to a 24-h urine collection. In this report, we described the overall design and basic results of the study. Adults aged 18-39 y were recruited to collect urine for a 24-h period, placing each void in a separate container. Four timed-spot specimens (morning, afternoon, evening, and overnight) and the 24-h collection were analyzed for sodium, potassium, chloride, creatinine, and iodine. Of 481 eligible persons, 407 (54% female, 48% black) completed a 24-h urine collection. A subsample (n = 133) collected a second 24-h urine 4-11 d later. Mean sodium excretion was 3.54 ± 1.51 g/d for males and 3.09 ± 1.26 g/d for females. Sensitivity analysis excluding those who did not meet the expected creatinine excretion criterion showed the same results. Day-to-day variability for sodium, potassium, chloride, and iodine was observed among those collecting two 24-h urine samples (CV = 16-29% for 24-h urine samples and 21-41% for timed-spot specimens). Among all race-gender groups, overnight specimens had larger volumes (P < 0.01) and lower sodium (P < 0.01 to P = 0.26), potassium (P < 0.01), and chloride (P < 0.01) concentrations compared with other timed-spot urine samples, although the differences were not always significant. Urine creatinine and iodine concentrations did not differ by the timing of collection. The observed day-to-day and diurnal variations in sodium excretion illustrate the importance of accounting for these factors when developing calibration equations from this study.
• Subjects:
  Adolescent Adult Article Calibration Chlorides Circadian Rhythm Creatinine Cross-Sectional Studies Female Follow-Up Studies Humans Iodine Male Nutrition Surveys Potassium Sodium Surveys And Questionnaires Time Factors Urine Specimen Collection Young Adult

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• Source:
  J Nutr. 143(8):1276-1282
• Pubmed ID:
  23761643
• Pubmed Central ID:
  PMC6370020
• Document Type:
  Journal Article
• Funding:
  CC999999/Intramural CDC HHS/United States ; T32 DK007734/DK/NIDDK NIH HHS/United States
• Volume:
  143
• Issue:
  8
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:5cb6721606fc07d285bd24067db56fb86aaff74035d5c80d62466a76cd87e643
• Download URL:
  https://stacks.cdc.gov/view/cdc/75910/cdc_75910_DS1.pdf
• File Type:
  [PDF - 116.16 KB ]