Patterns of Fluoride Intake from Birth to 36 Months

Authors


  • Portions of this paper were presented at the 1998 European Organization for Caries Research (ORCA) and 1999 American Association for Public Health Dentistry (AAPHD) annual meetings. This research was supported in part by grants from the National Institute of Dental and Craniofacial Research 2RO1-DE09551 and 2P30-DE10126. The authors thank Ms. Tina Craig for her assistance in manuscript preparation.

Send correspondence and reprint requests to Dr. Levy, N330 DSB, University of Iowa, Iowa City, Iowa 52242. E-mail: steven-Ievy@uiowa.edu. Dr. Warren is affiliated with the Department of Preventive and Community Dentistry, Dr. Davis is with the Department of Biostatistics, Dr. Kanellis is with the Department of Pediatric Dentistry, and Dr. Wefel is with the Department of Pediatric Dentistry and the Dows Institute for Dental Research, all at the University of Iowa. Dr. Kirchner is with the Department of Pediatrics, Case Western Reserve University, Cleveland, OH.

Abstract

Objectives: Dental fluorosis prevalence has increased in the United States, Canada, and other nations due to the widespread availability of fluoride in many forms, with fluoride ingestion during the first three years of life appearing most critical in fluorosis etiology. With few contemporary studies 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 of age from water, dentifrice, and dietary fluoride supplements and combined. Methods: Repeated responses to separate series of questions about water intake, use of fluoride dentifrice, and use of fluoride supplements were collected by questionnaire as part of the longitudinal Iowa Fluoride Study and used to estimate fluoride intake. Estimated intake is reported by source and combined at different ages. Effects of subject age and other covariates on fluoride intake were assessed using regression methods appropriate for the analysis of correlated data. Results: For most children, water fluoride intake was the predominant source, especially through age 12 months. Combined 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 from 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 percentages greatest during the first 9 months. Regression analyses showed fluoride intake (mg F/kg bw) from 1.5–9 months to decrease with increasing child's age, mother's age, and mother's education, with a complex three-way interaction among these factors. From 12–20 months, fluoride intake increased with increasing child age and decreased with increasing mother's age. No statistically significant relation-ships were found for fluoride intake from 24–36 months. Conclusions: There is considerable variation in fluoride intake across ages and among individuals. Longitudinal studies may be necessary to fully understand the relationships between fluoride ingestion over time and development of fluorosis.

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