TY - JOUR
T1 - Afternoon urine osmolality is equivalent to 24 h for hydration assessment in healthy children
AU - Suh, Hyun Gyu
AU - Summers, Lynn Dee G.
AU - Seal, Adam D.
AU - Colburn, Abigail T.
AU - Mauromoustakos, Andy
AU - Perrier, Erica T.
AU - Bottin, Jeanne H.
AU - Kavouras, Stavros A.
N1 - Publisher Copyright:
© 2019, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2020/6/1
Y1 - 2020/6/1
N2 - Background/Objectives: While daily hydration is best assessed in 24-h urine sample, spot sample is often used by health care professionals and researchers due to its practicality. However, urine output is subject to circadian variation, with urine being more concentrated in the morning. It has been demonstrated that afternoon spot urine samples are most likely to provide equivalent urine concentration to 24-h urine samples in adults. The aim of the present study was to examine whether urine osmolality (UOsm) assessed from a spot urine sample in specific time-windows was equivalent to 24-h UOsm in free-living healthy children. Subjects/Methods: Among 541 healthy children (age: 3–13 years, female: 45%, 77% non-Hispanic white, BMI:17.7 ± 4.0 kg m−2), UOsm at specific time-windows [morning (0600–1159), early afternoon (1200–1559), late afternoon (1600–1959), evening (2000–2359), overnight (2400–0559), and first morning] was compared with UOsm from the corresponding pooled 24-h urine sample using an equivalence test. Results: Late afternoon (1600–1959) spot urine sample UOsm value was equivalent to the 24-h UOsm value in children (P < 0.05; mean difference: 62 mmol kg−1; 95% CI: 45–78 mmol kg−1). The overall diagnostic ability of urine osmolality assessed at late afternoon (1600–1959) to diagnose elevated urine osmolality on the 24-h sample was good for both cutoffs of 800 mmol kg−1 [area under the curve (AUC): 87.4%; sensitivity: 72.6%; specificity: 90.5%; threshold: 814 mmol kg−1] and 500 mmol kg−1 (AUC: 83.5%; sensitivity: 75.0%; specificity: 80.0%; threshold: 633 mmol kg−1). Conclusion: These data suggest that in free-living healthy children, 24-h urine concentration may be approximated from a late afternoon spot urine sample. This data will have practical implication for health care professionals and researchers.
AB - Background/Objectives: While daily hydration is best assessed in 24-h urine sample, spot sample is often used by health care professionals and researchers due to its practicality. However, urine output is subject to circadian variation, with urine being more concentrated in the morning. It has been demonstrated that afternoon spot urine samples are most likely to provide equivalent urine concentration to 24-h urine samples in adults. The aim of the present study was to examine whether urine osmolality (UOsm) assessed from a spot urine sample in specific time-windows was equivalent to 24-h UOsm in free-living healthy children. Subjects/Methods: Among 541 healthy children (age: 3–13 years, female: 45%, 77% non-Hispanic white, BMI:17.7 ± 4.0 kg m−2), UOsm at specific time-windows [morning (0600–1159), early afternoon (1200–1559), late afternoon (1600–1959), evening (2000–2359), overnight (2400–0559), and first morning] was compared with UOsm from the corresponding pooled 24-h urine sample using an equivalence test. Results: Late afternoon (1600–1959) spot urine sample UOsm value was equivalent to the 24-h UOsm value in children (P < 0.05; mean difference: 62 mmol kg−1; 95% CI: 45–78 mmol kg−1). The overall diagnostic ability of urine osmolality assessed at late afternoon (1600–1959) to diagnose elevated urine osmolality on the 24-h sample was good for both cutoffs of 800 mmol kg−1 [area under the curve (AUC): 87.4%; sensitivity: 72.6%; specificity: 90.5%; threshold: 814 mmol kg−1] and 500 mmol kg−1 (AUC: 83.5%; sensitivity: 75.0%; specificity: 80.0%; threshold: 633 mmol kg−1). Conclusion: These data suggest that in free-living healthy children, 24-h urine concentration may be approximated from a late afternoon spot urine sample. This data will have practical implication for health care professionals and researchers.
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U2 - 10.1038/s41430-019-0519-5
DO - 10.1038/s41430-019-0519-5
M3 - Article
C2 - 31624367
AN - SCOPUS:85074526648
SN - 0954-3007
VL - 74
SP - 884
EP - 890
JO - European Journal of Clinical Nutrition
JF - European Journal of Clinical Nutrition
IS - 6
ER -