title: The fractional urinary fluoride excretion in young children under stable fluoride intake conditions.
abstract: The purpose of this study was to determine the fraction of the total daily fluoride intake that is excreted through the urine (FUEF) of children aged 3-5 years under usual intake conditions. Participating children were residents of an area with a fluoride (F) concentration of 0.5-0.6 mg/L in their drinking water. Assessments were made on two successive 24-h periods on 20 children, measuring the total amount of fluoride ingested through liquid and food consumption, and from ingestion of fluoridated toothpaste (500 microg F/g), together with the determination of the amount of fluoride excreted through urine. Fluoride retention was also estimated assuming a constant average F fraction of 10% excreted through faeces. It was found that the average proportion of liquids, solid foods, and toothpaste to the daily fluoride intake (1.02-mg F/day on average) were 40.8, 34.6, and 24.5%, respectively. The average FUEF value was 35.5% (95% C.I.=31.7-39.3%), and the estimated fractional F retention was 54.5%. The present data suggest a slight relationship between FUEF values and the inverse of the daily fluoride dose (1/dose) (r=0.513; P=0.021). When the present results are combined with those from previous studies on F-retention and urinary excretion, the correlation between both FUEF and fractional retention and 1/dose are very strong and highly significant (r=0.98, P<0.0001, and r=-0.986, P<0.0001, respectively). A possible mechanism is suggested in order to explain this latter finding. The potential usefulness of the current FUEF value for the estimation of daily F intake (or dose) from urinary F excretion data is also discussed.
authors.affiliation: Institute of Nutrition and Food Technology, University of Chile, Santiago. avilla@uec.inta.uchile.cl
authors.forename: A
authors.initials: A
authors.lastname: Villa
authors.forename: M
authors.initials: M
authors.lastname: Anabalón
authors.forename: L
authors.initials: L
authors.lastname: Cabezas
mesh_terms: D001682:Biological Availability; D002675:Child, Preschool; D002677:Chile; D005243:Feces / Q000737:chemistry; D005457:Fluoridation; D005459:Fluorides / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000652:urine*; D005502:Food; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008657:Metabolic Clearance Rate; D012044:Regression Analysis
chemical_list: D005459:Fluorides