Relationships between fluoride intake, urinary fluoride excretion and fluoride retention in children and adults: an analysis of available data.

The aim of this study was to examine the relationship between total daily fluoride intake (TDFI), daily urinary fluoride excretion (DUFE) and fractional fluoride retention (FFR) using available data, in order to clarify the ability of DUFE to predict TDFI and, therefore, the risk of fluorosis development. Examination of published reports of simultaneous measurement of TDFI and DUFE, together with data from two unpublished Chilean studies, yielded data for 212 children aged less than 7 years and for 283 adults aged 18-75 years, providing a total of 212 and 269 data points, respectively. The relationship between DUFE and TDFI was studied for children and adults, separately. Daily fluoride retention (DFR) was estimated as a function of TDFI in children and adults assuming an average 90% fluoride absorption, and the numerical relationships between the estimated FFR and the TDFI were explored. Limiting FFR values of 0.55 and 0.36 were found for children and adults, respectively, above a threshold of TDFI of 0.5 and 2 mg, respectively. Neutral fluoride balances were predicted when the TDFI was equal to approximately 0.07 mg F/day for children and 0.8 mg F/day for adults. For children and adults, it is possible to obtain reasonably good estimations of community-based TDFI and DFR, using DUFE data. The advantages and limitations of these relationships, together with the need for future studies, are discussed.

The fractional urinary fluoride excretion of adults consuming naturally and artificially fluoridated water and the influence of water hardness: a randomized trial.

AIMS: To assess whether there was any significant difference in the average fractional urinary fluoride excretion (FUFE) values among adults consuming (NaF) fluoridated Ca-free water (reference water), naturally fluoridated hard water and an artificially (H2SiF6) fluoridated soft water. DESIGN: Sixty adult females (N=20 for each treatment) participated in this randomized, double-blind trial. The experimental design of this study provided an indirect estimation of the fluoride absorption in different types of water through the assessment of the fractional urinary fluoride excretion of volunteers. RESULTS: Average daily FUFE values (daily amount of fluoride excreted in urine/daily total fluoride intake) were not significantly different between the three treatments (Kruskal-Wallis; p = 0.62). The average 24-hour FUFE value (n=60) was 0.69; 95% C.I. 0.65-0.73. CONCLUSIONS: The results of this study suggest that the absorption of fluoride is not affected by water hardness.

Fractional urinary fluoride excretion of young female adults during the diurnal and nocturnal periods.

OBJECTIVES: This study aimed to confirm a previously obtained value for the fractional urinary fluoride excretion (FUFE) over a 24-hour period in adults and to assess whether there are significant differences between FUFE measured during the diurnal (7 a.m. and 6 p.m.) and the subsequent nocturnal (6 p.m. until 7 a.m. of the following day) periods. METHODS: Urine was collected over 24 h from 60 healthy female volunteers residing in Santiago, Chile. The individuals' fluoride intakes over the diurnal and nocturnal periods were calculated from their corresponding F ingestion, measured by dietary analysis. Separate urine collections during both periods were obtained from each volunteer. The fluoride concentrations were measured with a fluoride-ion-selective electrode either directly (urine, water and beverages) or after sample treatment with the microdiffusion technique (food). RESULTS: The average 24-hour FUFE value was 0.69, with a 95% CI of 0.65-0.72, while the average FUFE for the diurnal period was 0.46 (95% CI: 0.42-0.50), and the corresponding result for the nocturnal period showed a significantly higher (paired t test, p < 0.0001) amount of 1.09 (95% CI: 0.97-1.22). CONCLUSIONS: A recently published result for the daily FUFE value (0.71) in adults was confirmed. The diurnal average FUFE value is significantly lower than the average nocturnal one. Accepting that approximately 10% of the fluoride intake is not absorbed, the daily fluoride retention can be preliminarily estimated as 20% of the ingested fluoride.

Congenital idiopathic growth hormone deficiency associated with prenatal and early postnatal growth failure. The International Board of the Kabi Pharmacia International Growth Study.

To assess the role of growth hormone in fetal and infant growth, we analyzed the pretreatment data on 52 patients with a diagnosis of congenital growth hormone deficiency before 2 years of age, obtained from the Kabi Pharmacia International Growth Study. These infants had reduced birth-length standard deviation scores, an excess of birth weight relative to length, and progressive growth failure. We conclude that congenital growth hormone deficiency may cause impaired growth in utero and early infancy, and that growth hormone plays an important role in perinatal and infantile growth.