Urinary fluoride excretion by preschool children in six European countries

Objective: To measure and compare 24-h urinary fluoride excretion in children aged 1.5-3.5 years from European study sites and to use these data to estimate the 24-h fluoride intake. Method: Twenty-four-hour urine samples were collected from 3-year-old children (n = 86) who were already participating in a European multicentre study. Samples were collected from Cork, Ireland (n = 19) where the water is fluoridated to a concentration between 0.8 and 1.0 ppm and from five sites with a water fluoride concentration <0.15 ppm: Knowsley, England (n = 18); Oulu, Finland (n = 18); Reykjavik, Iceland (n = 4); Haarlem, the Netherlands (n = 6); Almada/Setubal, Portugal (n = 21). The volume of the samples was measured; they were analysed for fluoride concentration and the 24-h urinary fluoride excretion was calculated. From this an estimate of the daily fluoride intake was made. Results: It was found that the mean fluoride excretion in response to the usual conditions of fluoride intake in the children in the nonfluoridated areas ranged from 0.16 mg (±0.08) in Oulu to 0.33 mg (±0.27) in Almada/Setubal with an overall mean of 0.23 mg (±0.19). The mean 24-h fluoride excretion in fluoridated Cork was 0.37 mg (±0.11). There was a significant difference between the fluoride excretion in the nonfluoridated areas and that in the fluoridated areas, and the data were broadly in agreement with WHO standards. Conclusions: The daily urinary fluoride excretion and estimated fluoride intake in these children appeared to be within acceptable limits.