Urinary fluoride excretion in small children following short-term fluoride supply with tablets or domestic salt.

Urinary fluoride (F) excretion has been studied in small children, with some comparisons with adults, following ingestion of F tablets or fluoridated salt (F-salt) containing 500 mg F/kg NaCl. 24-h urinary F in 7- to 8-year-old children in an institution and in 2- to 12-year-old children in families rapidly increased to average levels of about 0.85 and 0.55 parts/10(6), respectively, when the children had their meals spiced with F-salt. Children in families also showed significantly elevated urinary F excretion with two F-salted meals a day but not with one a day. After taking 0.5 mg F in the form of NaF tablets a group of children without previous F supply attained within 1 d a 24-h urinary F concentration which was about the same as that in children who had been taking caries-preventive tablet doses for years. The percentage of a single F dose excreted in the urine within 4 h after the ingestion of F tablets or an F-salted standard meal was about the same in preschool children and middle-aged adults. F quantities of the order 1.5-2 mg could be ingested by a child eating a meal comprising strongly F-salted dishes, and the urine could reach concentrations around 3 parts/10(6) F during the following 2-4 h. The results obtained support the concept that domestic salt containing about 500 parts/10(6) F is suitable for clinical testing on a larger scale under Swedish conditions. Calculations of F supplies to children aged 2 months-7 years with different diets and water and salt F contents are presented as diagrams.