Criterion values for urine-specific gravity and urine color representing adequate water intake in healthy adults

Growing evidence suggests a distinction between water intake necessary for maintaining a euhydrated state, and water intake considered to be adequate from a perspective of long-term health. Previously, we have proposed that maintaining a 24-h urine osmolality (U[sub.Osm]) of [precedes/equal to]500 mOsm/kg is a desirable target for urine concentration to ensure sufficient urinary output to reduce renal health risk and circulating vasopressin. In clinical practice and field monitoring, the measurement of U[sub.Osm] is not practical. In this analysis, we calculate criterion values for urine-specific gravity (U[sub.SG]) and urine color (U[sub.Col]), two measures which have broad applicability in clinical and field settings. A receiver operating characteristic curve analysis performed on 817 urine samples demonstrates that a U[sub.SG] [succeeds/equal to]1.013 detects U[sub.Osm] [greater than] 500 mOsm/kg with very high accuracy (AUC 0.984), whereas a subject-assessed U[sub.Col][succeeds/equal to]4 offers high sensitivity and moderate specificity (AUC 0.831) for detecting U[sub.Osm] [greater than] 500 m Osm/kg. European Journal of Clinical Nutrition (2017) 71, 561-563; doi: 10.1038/ejcn.2016.269; published online 1 February 2017
Author(s): E T Perrier [1]; J H Bottin [1]; M Vecchio [1]; G Lemetais [1] Introduction Water is essential to life, represents the largest single nutrient in terms of intake, [...]