Total daily fluoride intake and fractional urinary fluoride excretion in 4- to 6-year-old children living in a fluoridated area: weekly variation?

Abstract

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. 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]. 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. 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.