Patterns of fluoride intake from birth to 36 months

Objectives: Dental fluorosis prevalence has increased in the United States, Canada, and other nations due to the widespread availability of fluoride i n many forms, with fluoride ingestion during the first three years of life appearing most critical in fluorosis etiology. With few contemporary studie s of fluoride ingestion in this age group, the purpose of this paper is to describe patterns of estimated fluoride ingestion from birth to 36 months o f age from water, dentifrice, and dietary fluoride supplements and combined . Methods: Repeated responses to separate series of questions about water i ntake, use of fluoride dentifrice, and use of fluoride supplements were col lected by questionnaire as part of the longitudinal Iowa Fluoride Study and used to estimate fluoride intake. Estimated intake is reported by source a nd combined at different ages. Effects of subject age and other covariates on fluoride intake were assessed using regression methods appropriate far t he analysis of correlated data. Results: For most children, water fluoride intake was the predominant source, especially through age 12 months. Combin ed daily fluoride intake increased through 9 months, was lower at 12 and 16 months, and increased again thereafter. Mean intake per unit body weight ( bw) was about 0.075 mg F/kg bw through 3 months of age, 0.06 mg F/kg bw at 6 and 9 months, 0.035 mg F/kg bw at 12 and 16 months and 0.043 mg F/kg bw f rom 20-36 months. Depending on the threshold chosen (e.g., 0.05 or 0.07 mg F/kg bw), variable percentages of the children exceeded the levels, with pe rcentages greatest during the first 9 months. Regression analyses showed fl uoride intake (mg F/kg bw) from 1.5-9 months to decrease with increasing ch ild's age, mothers age, and mother's education, with a complex three-way in teraction among these factors. From 12-20 months fluoride intake increased with increasing child age and decreased with increasing mother's age. No st atistically significant relationships were found for fluoride intake from 2 4-36 months Conclusions: There is considerable variation in fluoride intake across ages and among individuals. Longitudinal studies may be necessary t o fully understand the relationships between fluoride ingestion over time a nd development of fluorosis.