title: Sodium and potassium urinary excretion levels of preschool children: Individual, daily, and seasonal differences.
abstract: In this study, the authors measured sodium and potassium concentrations in spot urine samples of preschool children on multiple days, and evaluated individual, daily, and seasonal effects. A total of 104 healthy preschool children aged 4 to 5 years were studied. Urine samples were collected from the first urine of the day after waking for three consecutive days (Monday-Wednesday) four times a year (spring, summer, autumn, winter). The authors estimated the daily urine volume as 500 mL and daily creatinine excretion as 300 mg, and used these to calculate daily sodium and potassium excretion levels. Daily sodium and potassium excretion levels and sodium to potassium ratios were highly variable. The coefficient variant in the children's excretion levels were also high within and between individuals. Sodium excretion levels and sodium to potassium ratios were higher on Monday (weekend sodium intakes) than Tuesday. Season had no effect on sodium or potassium excretion levels, but the sodium to potassium ratio was higher in summer than in winter. In conclusion, levels of urinary sodium excretion are comparatively high and those of potassium are low in preschool students, with high variability within and between individuals.
authors.affiliation: Department of Nutritional Sciences, Faculty of Nutritional Sciences, Nakamura Gakuen University, Fukuoka, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Yasutake
authors.affiliation: Division of Early Childhood Care and Education, Nakamura Gakuen Junior College, Fukuoka, Japan.
authors.forename: Mikako
authors.initials: M
authors.lastname: Nagafuchi
authors.affiliation: Tensho Kindergarten, Koga, Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Izu
authors.affiliation: Department of Nutritional Sciences, Faculty of Nutritional Sciences, Nakamura Gakuen University, Fukuoka, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Kajiyama
authors.affiliation: Department of Nutritional Sciences, Faculty of Nutritional Sciences, Nakamura Gakuen University, Fukuoka, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Imai
authors.affiliation: Health Care Center, Fukuoka University, Fukuoka, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Murata
authors.affiliation: Health Care Center, Fukuoka University, Fukuoka, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ohe
authors.affiliation: Health Care Center, Fukuoka University, Fukuoka, Japan.
authors.forename: Munechika
authors.initials: M
authors.lastname: Enjoji
authors.affiliation: Hypertension Center, Steel Memorial Yawata Hospital, Kitakyushu, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Tsuchihashi
mesh_terms: D002675:Child, Preschool; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D011188:Potassium / Q000652:urine*; D064167:Recommended Dietary Allowances; D012621:Seasons; D012964:Sodium / Q000652:urine*; D016482:Urinalysis / Q000379:methods*; D059349:Urine Specimen Collection / Q000379:methods
chemical_list: D012964:Sodium; D003404:Creatinine; D011188:Potassium
keywords: Japanese children; between-individual variation; sodium intake; sodium to potassium ratio; within-individual variation