Patterns of fluoride intake from 6 to 17 years of age: The Iowa Fluoride Study.

OBJECTIVES: This article reports on estimated daily fluoride intake from water, other beverages and selected foods, dentifrice, and dietary fluoride supplements by both individual sources, and all sources combined, among 787 children participating in the Iowa Fluoride Study (IFS) from 6 to 17 years of age. METHODS: Total daily fluoride intake (mg F) and fluoride intake per kilogram bodyweight (mg F/kg bw) were estimated using responses to questionnaires sent every 3-6 months. Dietary assessments included frequencies and amounts of beverage intake for the previous week from water, milk, ready-to-drink beverages, beverages made by adding water to concentrate or powder, and selected foods with substantial water content. Descriptive statistics and bivariate and multivariable analyses with linear mixed models were used to assess associations with each of mg F and mg F/kg bw. RESULTS: Mean combined dietary fluoride (mg F) from all sources examined in the study increased slightly with age, whereas the fluoride intake per kg bw decreased with age. Age, sex, and socioeconomic status were significantly associated with fluoride intake (mg F and mg F/kg bw). Each year increase in age was associated with a 0.02-mg increase in fluoride consumption, on average, after adjusting for the effects of covariates. CONCLUSIONS: Daily mean fluoride intakes from single and combined sources were relatively stable, while the intake of fluoride per kg bw decreased from 6 to 17 years of age. Fluoridated water was the major source of ingested fluoride, contributing over 50% of total daily intake at all ages.

Dietary Fluoride Intake by Children: When to Use a Fluoride Toothpaste?

Fluoride is recommended for its cariostatic effect, but excessive fluoride intake may have health risks. Increased prevalence of dental fluorosis in areas with low fluoride content in drinking water has been attributed to the inappropriate excessive intake of fluoride supplements (tablets and drops) and toothpaste ingestion. The aim of the present study was to estimate the fluoride intake and the risk of fluorosis in children (6 months-6 years) in the Castelli Romani area (province of Rome, Italy), which is volcanic, therefore with a higher concentration of fluorine. Measurements of the fluoride content in drinking water, mineral waters, vegetables and commercial toothpaste for children were performed. The fluoride concentrations of all samples were determined using a Fluoride Ion Selective Electrode (GLP 22, Crison, Esp). Data were analyzed by descriptive statistics. Differences between samples were determined by Student's t-test. The fluoride content in tap water samples collected from public sources averaged from 0.35 to 1.11 ppm. The Pavona area showed the highest content of fluoride with respect to the others (p ≤ 0.05). The fluoride content in mineral water samples averaged from 0.07 to 1.50 ppm. The fluoride content of some vegetables showed increased mean values when compared to control vegetables (p ≤ 0.05). Within the limitations of the present study, considerations should be made when prescribing fluoride toothpaste for infants (6 months-4 years) in the areas with high fluoride content, because involuntary ingestion is consistent.

sKlotho is associated with the severity of brick tea-type skeletal fluorosis in China.

The change of serum soluble Klotho (sKlotho) content is related to a variety of osteoarthropathy. However, its association with the severity of skeletal fluorosis (SF) is not clear. Here, the association of tea fluoride exposure with serum sKlotho levels and the severity of SF were investigated and further verified in a rat model of fluorosis. A cross sectional case control study was conducted in residents over 50 years old from brick-tea drinking areas in Qinghai and Xinjiang Provinces, China. Concentrations of fluoride in brick tea water and urine were determined by ion selective electrode method, and the levels of serum sKlotho were determined by ELISA method. Linear regression and ordered logistic regression models were constructed to examine the relationship among fluoride exposure, serum sKlotho levels and the severity of SF. The kidney and small intestine of Wistar rats were isolated for detection of Klotho by immunohistochemistry (IHC), and femoral artery blood was sampled to measure the serum levels of sKlotho. An increase of 1 mg/day in tea fluoride intake (TFI) was associated with a 12.070 pg/mL (95% CI: 0.452-23.689) increase in serum sKlotho levels and a 1.163-fold (95% CI: 1.007-1.342) increase in the severity of SF after adjusting for age, gender, and ethnicity. Serum sKlotho levels were also positively associated with the severity of SF (P < 0.05). The mediation analysis showed that serum sKlotho levels mediated 17.76% of the increase in the severity of SF caused by an increase of 1 mg/day of TFI. Moreover, a significant increase of serum sKlotho levels in fluoride-exposed groups was also seen in the rat model. The present study suggests that serum sKlotho may be a potential mediator of SF in brick tea-type fluorosis endemic areas.