title: Total daily fluoride intake and fractional urinary fluoride excretion in 4- to 6-year-old children living in a fluoridated area: weekly variation?
abstract: OBJECTIVE
  Risk of development of dental fluorosis may increase with even a short-term increase in fluoride (F) intake during tooth formation. Considering the wide variations in F concentrations of different food and drinks, it is important to assess short-term differences in F intake and consequently fractional urinary F excretion (FUFE) in children, which provide an indication of F body burden. Therefore, the aim of this study was to investigate weekly variation in total daily F intake (TDFI) and its sources and fractional urinary F excretion (FUFE) in 4- to 6-year-olds living in a fluoridated area in the UK.
  
  
  METHODS
  Sixty-one children were surveyed twice with a 1-week gap between surveys. Dietary F intake was assessed by 'food-diary' and 'duplicate-plate collection'. Toothbrushing expectorate (saliva/toothpaste) was collected to estimate F intake from toothpaste ingestion. TDFI was calculated from dietary F intake and toothpaste ingestion. Daily urinary F excretion (DUFE) was estimated by collecting 24-h urine samples and FUFE was calculated from DUFE and TDFI [FUFE = (DUFE/TDFI) × 100].
  
  
  RESULTS
  The overall mean TDFI, DUFE and FUFE for all children were 0.056 (SD 0.036) mg/kgbw/day, 0.018 (SD 0.007) mg/kgbw/day and 39 (SD 20)%, respectively. The mean (95% CI) difference between the 2 weeks studied was 0.004 (-0.004, 0.011) mg/kgbw/day for TDFI, 0.002 (-0.001, 0.004) mg/kgbw/day for DUFE and 1 (-6, 8)% for FUFE.
  
  
  CONCLUSIONS
  Mean TDFI and FUFE did not vary statistically significantly with week and therefore one set of data collection from a group of children living in a temperate climate could be sufficient to monitor F exposure and F body burden in community prevention programmes for oral health.
authors.affiliation: Health and Social Care Institute, Teesside University, Middlesbrough, UK.
authors.forename: Narges
authors.initials: N
authors.lastname: Omid
authors.affiliation: Centre for Oral Health Research, School of Dental Sciences, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Anne
authors.initials: A
authors.lastname: Maguire
authors.affiliation: School of Science and Engineering, Teesside University, Middlesbrough, UK.
authors.forename: William T
authors.initials: WT
authors.lastname: O'Hare
authors.affiliation: Health and Social Care Institute, Teesside University, Middlesbrough, UK.
authors.forename: Fatemeh V
authors.initials: FV
authors.lastname: Zohoori
keywords: excretion; fluoride; intake; urine