Urinary fluoride excretion (UFE) in 6-7y olds using F milk

Effectiveness of 0.5mgF milk has been termed “moderate” in the UK. It is unclear whether this is due to sub-optimal compliance, or whether its F concentration is too low to achieve the WHO recommended UFE for optimal F exposure. Objectives: i) to measure UFE before and after receiving 0.5mgF and 0.9mgF in 189ml milks; ii) to compare UFE with WHO guidelines. Methods: 6-7y olds in 13 schools in a non F area of the UK were recruited. Children maintained usual dietary and oral hygiene habits. Following a 2 week “wash-in” with non F milk, 24h urine was collected on Day 4 of daily consumption of; i) non F milk (Week 1; baseline), ii) milk containing either 0.5mg or 0.9mgF (Week 2). Urine samples were analysed for F by a direct method. UFE was estimated from corrected 24h urine volume and F concentration. Results: For the 25 children providing a valid 24h urine sample, mean compliance with milk consumption was 99% (+2%). Mean (+SD) corrected baseline UFE for 0.5 mgF and 0.9mgF milk groups was 0.33 (+ 0.12)mg/day and 0.27 (+ 0.16)mg/day, baseline UFE in mg/kg bw/day was 0.014 (+ 0.005) and 0.011 (+ 0.007)respectively. For Week 2, UFE was 0.45 (+ 0.17) mg/day and 0.019 (+ 0.009)mg/kgbw/day for the 0.5mgF group; 0.42 (+ 0.19)mg/day and 0.017 (+ 0.009)mg/kg bw/day for the 0.9mgF group. Change in UFE (Week 1 to 2) was 0.12 (+0.14)mg/day and 0.005(+ 0.006)mg/kg bw/day for 0.5mgF and 0.15(+0.12)mg/day and 0.006(+ 0.005)mg/kg bw/day for 0.9mgF milk. Mean UFEs after both interventions were lower than WHO recommended standards for optimal F usage in 6-7y olds (UFE 0.48-0.6mgF/day). Conclusions: F concentration of 0.5mgF and 0.9mgF milks may be too low to achieve WHO recommended UFEs concomitant with optimal F exposure for children > 6y. Study funded by The Borrow Foundation