European Journal of Clinical Nutrition· 2013Q1
Relation between urinary hydration biomarkers and total fluid intake in healthy adults
- 118citations
- Q1SCImago
- 2013year
Short summary
Total fluid intake in sedentary adults is strongly associated with 24-hour urine biomarkers like osmolality, color, and specific gravity (|r| ≥ 0.6, P<0.001), but models estimating intake from these biomarkers have high error and limited applicability.
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Key points
- Total fluid intake showed strong associations (|r| ≥ 0.6, P<0.001) with 24-hour urine osmolality, color, specific gravity, volume, and solute concentrations in 82 sedentary adults.
- Multiple 24-hour urine biomarkers were collinear, with high correlations observed between osmolality and specific gravity (r=0.86-0.97).
- First morning void urine samples did not show strong correlations with fluid intake.
- Models using urine volume explained over 50% of the variance in fluid intake (r²=0.59 for PLS, r²=0.52 for linear regression), but exhibited high error and large limits of agreement.
AI-generated from the title and abstract; the full text is not read.
Abstract
BACKGROUND/OBJECTIVES: In sedentary adults, hydration is mostly influenced by total fluid intake and not by sweat losses; moreover, low daily fluid intake is associated with adverse health outcomes. This study aimed to model the relation between total fluid intake and urinary hydration biomarkers. SUBJECTS/METHODS: During 4 consecutive weekdays, 82 adults (age, 31.6±4.3 years; body mass index, 23.2±2.7 kg/m(2); 52% female) recorded food and fluid consumed, collected one first morning urine (FMU) void and three 24-h (24hU) samples. The strength of linear association between urinary hydration biomarkers and fluid intake volume was evaluated using simple linear regression and Pearson's correlation. Multivariate partial least squares (PLS) modeled the association between fluid intake and 24hU hydration biomarkers. RESULTS: Strong associations (|r| ≥ 0.6; P<0.001) were found between total fluid intake volume and 24hU osmolality, color, specific gravity (USG), volume and solute concentrations. Many 24hU biomarkers were collinear (osmolality versus color: r=0.49-0.76; USG versus color: r=0.46-0.78; osmolality versus USG: 0.86-0.97; P<0.001). Measures in FMU were not strongly correlated to intake. Multivariate PLS and simple linear regression using urine volume explained >50% of the variance in fluid intake volume (r(2)=0.59 and 0.52, respectively); however the error in both models was high and the limits of agreement very large. CONCLUSIONS: Hydration biomarkers in 24hU are strongly correlated with daily total fluid intake volume in sedentary adults in free-living conditions; however, the margin of error in the present models limits the applicability of estimating fluid intake from urinary biomarkers.
The authors' abstract, as published at the source. European Journal of Clinical Nutrition, 2013 · DOI ↗
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Field: Physiology
PhysiologyMedicine