Variables Related to Urinary Calcium Excretion in Young Girls

• Published in: Journal of pediatric gastroenterology and nutrition Vol. 23; no. 1; pp. 8 - 12
• Main Authors: O'Brien, Kimberly O, Abrams, Steven A, Stuff, Janice E, Liang, Lily K, Welch, Thomas R
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott-Raven Publishers 01.07.1996; Lippincott
• Subjects: Absorption; Adolescent; Age Factors; Biological and medical sciences; Black or African American; Black People; Bone and Bones - metabolism; Calcium - urine; Calcium Isotopes; Calcium, Dietary - administration & dosage; Calcium, Dietary - pharmacokinetics; Child; Child, Preschool; Cohort Studies; Female; Fundamental and applied biological sciences. Psychology; Humans; Metabolisms and neurohumoral controls; Minerals - metabolism; Minerals - urine; Puberty - urine; Regression Analysis; Sodium - metabolism; Sodium - urine; Texas; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Water and mineral metabolism. Osmoregulation. Acidobasic balance; White People; Texas; Human; Radionuclide study; Urine; Excretion; Calcium; Female; Bone; Metabolism; Experimental study; Child; Uptake
• ISSN: 0277-2116; 1536-4801
• DOI: 10.1097/00005176-199607000-00002

SUMMARYThe relations among dietary and calcium kinetic factors and 24-h urinary mineral excretion were evaluated in a group of 89 healthy girls (51 white and 38 black) aged 4.9-16.7 years. Nutrient intakes were calculated for each participant using a weighed intake of all food and beverage on the day of the 24-h urine collection study and two subsequent 24-h food records. A significant relation was noted between urinary calcium and sodium excretion (r = 0.55; p < 0.0001). No significant relations were found between urinary calcium and (a) calcium intake (r = 0.08), (b) protein intake (r = 0.14), or (c) phosphorus intake (r = 0.11). Urinary calcium was not significantly related to fractional calcium absorption (r = 0.03) or net calcium absorption (r = 0.11), but was significantly associated with the bone calcium deposition rate (r = 0.24; p < 0.03). Using a multiple regression model, both urinary sodium and the bone calcium deposition rate were independent predictors of urinary calcium excretion in this population (r = 0.57; p = 0.0001). A substantial number of the children in this population had urinary calcium excretion >4 mg/kg/day (12%). The incidence of hypercalciuria differed between the racial groups and was markedly higher in the white than in the black children (17.6 vs. 5.3%). Over a range of usual calcium intakes, during the rapid-bone-growth period in childhood and early adolescence, urinary calcium appears relatively unaffected by calcium intake and is most strongly associated with urinary sodium levels.