(LB02-16-25) Water Intake and Hydration Status in Children

Objectives: The current study assessed the relationship between children’s water intake and 24-hour urinary hydration biomarkers in a large US-based sample.

Methods: We collected data on 729 healthy children (3-13 y; 46% female) from Northwest Arkansas and Phoenix, Arizona. Total water intake (TWI) from beverages and food was assessed based on a two-day food and beverage diary. Adequate intake of TWI was dichotomized based on meeting vs. not meeting the National Academy of Medicine (NAM) TWI guidelines. Hydration was assessed via 24-hour urine osmolality (UOsm) during the 2^nd day of the two-day dietary records.

Results: Over half of the children (57.7%) did not meet the NAM TWI guidelines. More than two-thirds of children were not optimally hydrated ( >500 mmol/kg, 77%), while one-third of children were underhydrated based on 24-h UOsm (≥800 mmol/kg, 36.8%. Children not meeting NAM TWI guidelines had a 1.5 times higher risk of being underhydrated (24-h UOsm ≥800 mmol/kg). Children who consumed less than three cups (237 mL) of plain water intake (PWI) per day (56%) had a 2.4 times higher risk of not meeting the NAM TWI guidelines and a 1.4 times higher risk of being underhydrated. TWI was significantly associated with PWI, sugar-sweetened beverages, TWI from food, total energy intake, sodium intake, and ambient temperature (F_13,681 = 436, R² = 0.89, P < 0.0001). Specifically, higher TWI in children was related to higher consumption of plain water (β = 0.74, P < 0.0001), higher consumption of SSB (β = 0.35, p< 0.0001), greater TWI-f (β = 0.23, P < 0.0001), higher energy intake (β = 0.25, p< 0.0001), lower sodium intake (β = -0.11, P < 0.0001), higher protein intake (β = 0.09, P < 0.0001), and higher max temperatures (β = 0.03, P = 0.008) Twenty-four-hour UOsm was significantly associated with PWI (F_13,681 = 3.4, R² = 0.06; P</em> < 0.0001). Specifically, lower 24-h UOsm in children was related to higher PWI (β = -0.21, P < 0.0001), lower sodium intake (β = 0.14, P=0.0249), higher energy intake (β = -0.17, P=0.0267), and sex (female, β = -0.07, P=0.03).

Conclusions: Two-thirds of the children were not optimally hydrated, while children who consume less than three cups of plain water daily are less likely to meet the NAM water guidelines and more likely to be underhydrated.

Funding Sources: Danone Research & Innovation, Gif-sur-Yvette, France