The Fluoride in Schoolchildren Study [FLOSS]

Abstract

Background: Fluoride plays a beneficial role in the prevention and repair of dental caries across all ages. In New Zealand, fluoride is found naturally in low concentrations in the water, soil and air. As a public health initiative, Community Water Fluoridation (CWF) and fluoride containing dentifrices were made available to increase fluoride exposure. There is currently a lack of data directly measuring fluoride intake within the population, particularly over the age of five years. Objective: To compare fluoride intake of children aged 9-11 years living in fluoridated and non-fluoridated regions within New Zealand. Design: A cross-sectional study was designed to measure total fluoride ingestion in children living in the Dunedin (fluoridated) and Waitaki (non-fluoridated) regions of the lower South Island of New Zealand. Dietary fluoride consumption was measured by 24-hr Weighed Diet Records (WDR). Expectorated toothpaste and toothbrush rinsed in deionised water samples were collected to calculate fluoride ingested from toothpaste. Fluoride excretion was analysed in 24-hr urine samples. Results: The mean ± standard deviation (SD) fluoride ingested from the diet and toothpaste in Dunedin (n=48) and the Waitaki District (n=16) was 1.546 ± 0.947 and 1.040 ± 0.853 mg/day, respectively; the Adequate Intake (AI) of fluoride is 2 mg/day. When only the diet (including fluoridated water) was considered, children from the fluoridated area consumed over twice as much fluoride as children from the non-fluoridated area, 0.730 ± 0.372 and 0.293 ± 0.281 mg/day, respectively. Toothpaste contributed 52 and 67% of the total fluoride intake in Dunedin and Waitaki, respectively. On average, Dunedin and the Waitaki District excreted 0.55 ± 0.46 and 0.24 ± 0.15 mg/day of fluoride, equivalent to 42 and 31% of the total fluoride ingested, respectively. Conclusion: Water and toothpaste were the primary factors contributing to total fluoride intakes in 9-11-year-old children living in two South Island regions. However, regardless of whether children lived in an area with or without CWF, on average, the total fluoride intakes of these children did not exceed the AI of 2.0 mg/day.