WATER INTAKE AND URINARY HYDRATION BIOMARKERS IN CHILDREN

Lisa T. Jansen1, Dimitris Bougatsas2, Evan C. Johnson3, Giannis Arnaoutis2, Spiridoula Tsipouridi2, Demosthenes B. Panagiotakos2, Stavros A. Kavouras FACSM1 1 University of Arkansas, Fayetteville, AR; 2 Harokopio University, Athens, Greece; 3 University of Wyoming, Laramie, WY Guidelines for adequate water intake for children (0-18 y) are outlined by the Institute of Medicine (IOM) and the European Food Safety Authority (EFSA). While the human body safeguards against dehydration via physiological pathways, the state of active total body water conservation is manifested by excretion of small volumes of highly concentrated urine. Recent research has shown detrimental health effects in adults reporting with chronically elevated markers for total body water conservation. This suggests a potential for preventative measures for health when implementing adequate hydration habits in children. However, studies report that up to 50% of children are voluntarily hypohydrated. It is unclear if this is due to the pediatric population struggling to meet hydration guidelines or due to inadequacy of the current guidelines. PURPOSE: The aims of the study were threefold. 1) Assess fluid intake and hydration biomarkers in Greek children. 2) Determine relative risk for hypohydration in children not meeting daily water intake recommendations compared to those that do. 3) Analyze current guidelines for efficacy to meet euhydration in children. METHODS: 150 boys and girls (9-13y) recorded their fluid intake for 2 consecutive days, with 24h urine samples being collected on day 2. Fluid intake records were analyzed for total water intake from fluids (TWI-F). Urine samples were analyzed for osmolality, color, specific gravity, and volume. Urine Osmolality ≥ 800 mmol∙kg-1 H2O was defined as hypohydration. RESULTS: Water intake from fluids was 1729(1555-1905) and 1550(1406-1686)mL∙d-1 for boys and girls. Prevalence of hypohydration was 33% (44% boys, 23% girls). Children that failed to meet TWI-F recommendations demonstrated a risk that was 1.99-2.12 times higher than in those meeting recommendations (P≤0.01). Boys aged 9-13y displayed urine osmolality of 777(725-830) mmol∙kg-1 and urine specific gravity of 1.021(1.019-1.022), higher values than reported in the 9-13y girls (P≤0.015), with \u3e27% classifying as hypohydrated despite meeting fluid intake recommendations. CONCLUSION: Failure to meet TWI-F guidelines doubled risk of hypohydration in children. While 23% of Boys 9-13y reported hypohydrated despite satisfying current guidelines and therefore may require greater water intake to achieve adequate hydration avoiding hyper concentration of urine. (The study was supported by a grant by Danone Research, Palaiseau, France