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Research: Iowa Fluoride Study

The Iowa Fluoride Study (IFS) is a longitudinal study of children designed to quantify fluoride exposures from both dietary and non-dietary sources and to associate longitudinal fluoride exposures with dental fluorosis (spots on teeth) and dental caries (cavities). Mothers of newborns were recruited from 8 Iowa hospital postpartum units between 1992 and 1995. These hospitals were responsible for the large majority of all births in the area that they served, with a combined total of about 8,000 births per year, or approximately 20 percent of all births in Iowa.

At recruitment, detailed information was obtained on items of interest such as demographics, water sources, and infant feeding plans. Thereafter, questionnaires were mailed to the participants’ homes at scheduled intervals (every few months) and parents provided information about the children’s water sources, beverage and selected food intake, use of dietary fluoride supplements, and tooth brushing habits. Approximately 50 percent of those invited to participate elected to do so. Overall, 1385 mothers participated in some portion of the IFS, and approximately 580 children continue to be followed at 19 to 21 years of age.

Dental examinations were conducted by trained dentist examiners to assess dental fluorosis and caries. Primary (baby) teeth were examined at approximately age 5, remaining primary teeth and early-erupting permanent teeth (mixed dentition) were examined at approximately age 9, and permanent teeth were examined at about age 13 and 17.