title: The fractional urinary fluoride excretion of adolescents and adults under customary fluoride intake conditions, in a community with 0.6-mg F/L in its drinking water.
abstract: OBJECTIVE
  To assess the fractional urinary fluoride excretion (FUFE) relative to the customary daily fluoride (F) ingestion in adolescents and adults aged 11-75 years, and to explore the influence that some metabolic variables, such as the F-dose (mg F/kg body weight), rate of urinary fluoride excretion, age and body weight, might have on FUFE values.
  
  
  METHODS
  The fluoride ingestion and urinary excretion of 92 volunteers aged 11-75 years, resident in Santiago, Chile, were measured. In Santiago, the water is fluoridated to a concentration of between 0.5 and 0.6 mg/l. Individual FUFE values were calculated as the ratio between the total amount of F excreted with the urine and the total amount of F ingested, over a 24-hour period.
  
  
  RESULTS
  The average FUFE values did not differ significantly among adults (ANOVA; p > 0.31). The average 24-hour FUFE value for adults was 0.75; 95% C.I. = 0.70-0.80, while the corresponding value for adolescents was 0.35; 95% C.I. = 0.30-0.40. Individual FUFE values were fitted by a multiple regression model using the rate of F urinary excretion and the inverse of the F dose as significant predictors (R2 = 0.79).
  
  
  CONCLUSIONS
  Results obtained suggest that among adults residing in an area with an intermediate F-exposure, FUFE values do not depend on age. A relatively simple multiple regression model appears to explain 79% of the variability of the individually measured FUFE values. Further studies in areas with different F exposures are needed to refine the proposed model.
authors.affiliation: Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile. avilla@uec.inta.uchile.cl
authors.forename: Alberto
authors.initials: A
authors.lastname: Villa
authors.forename: Lorena
authors.initials: L
authors.lastname: Cabezas
authors.forename: Mireya
authors.initials: M
authors.lastname: Anabalón
authors.forename: Enrique
authors.initials: E
authors.lastname: Garza
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D001835:Body Weight; D002327:Cariostatic Agents / Q000008:administration & dosage / Q000032:analysis*; D002648:Child; D002677:Chile; D003802:Dentifrices / Q000032:analysis; D004326:Drinking; D005260:Female; D005459:Fluorides / Q000008:administration & dosage / Q000032:analysis / Q000652:urine*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D013997:Time Factors; D014881:Water Supply / Q000032:analysis
chemical_list: D002327:Cariostatic Agents; D003802:Dentifrices; D005459:Fluorides