Urinary fluoride concentration in children with disabilities following long-term fluoride tablet ingestion

Urine is the most commonly utilized biomarker for fluoride excretion in public health and epidemiological studies. Approximately 30-50% of fluoride is excreted from urine in children. Urinary fluoride excretion reflects the total fluoride intake from multiple sources. After administering fluoride tablets to children with disabilities, urinary fluctuation patterns should be investigated. The purpose of this study was to monitor the short and long term fluctuating patterns of urinary fluoride concentration after fluoride tablets were ingested by children with disabilities. Children with disabilities aged 6-12 years old were selected randomly and were divided into three groups: Group A, 1.0mg fluoride tablet, Group B, 0.5mg fluoride tablet, and Group C, control group. The urine samples were collected in the morning (MU) and 2h after fluoride tablets were ingested (AU). Urine was collected on the day prior to fluoride intake (baseline), the first, the third, the fifth and the eighth day of fluoride ingestion for a short term, and once every 6 months for a total of 18 months for long-term observation. The AU sample showed statistically significantly higher concentrations of urine fluoride than those of the MU samples, and no statistically significant difference was noticed in the MU samples among the three groups. Group A showed the highest urinary fluoride concentration (UFC) among the three groups. UFC increased as ingested fluoride tablet dosage increased, and it returned to the baseline level on the following day and persisted throughout the study period.