Date of Graduation


Document Type


Degree Name

Doctor of Philosophy in Kinesiology (PhD)

Degree Level



Health, Human Performance and Recreation


Stavros Kavouras

Committee Member

Nicholas Greene

Second Committee Member

Matthew Ganio

Third Committee Member

Andy Mauromoustakos


Children, Hydration, Parental Influence, Physical Activity, Water Intake


PURPOSE: The purpose of these studies was 1) to examine the factors that influence the water intake in children and 2) to identify the optimal time window to assess hydration status that would be equivalent to 24-hour urine sample in children. METHODS: Study 1: Data for 200 parents (age:3-13y, female:62%, BMI:28.4±7.0kg∙m-2) and 200 children (age:7.5±2.9y, female:44%, BMI:17.7±3.9kg∙m-2) were recruited. Subjects recorded their fluid and food consumption on the 2-day diary, and food data were analyzed by using the Nutrition Data System for Research (NDSR) program. Physical activity levels were assessed with the International Physical Activity Questionnaire (IPAQ). All urine samples were collected for 24-h. Study 2: Data for 541 children (age:3-13y, female:45%, BMI:17.7±4.0kg∙m-2) participated in the study. The equivalence of their mean of spot urine sample was tested compared to the 24-h urine sample to identify the optimal time window to measure the hydration status by using the mean of spot urine sample at specific time window [morning (0600-1159), early afternoon (1200-1559), late afternoon (1600-1959), evening (2000-2359), overnight (2400-0559), and first morning (0600-0959)]. RESULTS: In study 1, 59% of children did not meet the water intake guideline by Institute of Medicine (IOM) and 42% of them were underhydrated [24-h urine osmolality (UOsm):≥800mmol·kg-1]. Children’s age, BMI, total energy intake (TEI), total fat, total carbohydrate, total protein, and sodium intake were significantly associated with their water intake pattern, as well as parent’s BMI, marital status and education (P