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Release: Dec. 11, 2001

Iowa Fluoride Study marks 10 years of studying children's dental health

IOWA CITY, Iowa -- For the past decade, researchers at the University of Iowa College of Dentistry and UI Hospitals and Clinics have been assessing the dental and bone health of Iowa children.

Initiated in 1991 by Steven Levy, D.D.S., professor of preventive and community dentistry at the UI College of Dentistry and professor of epidemiology at the UI College of Public Health, and colleagues, the Iowa Fluoride Study began with an overall goal of examining how fluoride exposures and ingestion beginning at birth relate to the occurrence of dental fluorosis (cosmetic changes in the teeth) and cavities.

The study began by recruiting newborn babies from eight different hospitals in Iowa City, Cedar Rapids, Waterloo, Des Moines and Muscatine between 1992 and 1995. Parents of the children participating in the study are contacted several times a year and asked to complete questionnaires as to what foods and beverages their children consume, the sources of water they drink, their dental health habits, their use of fluoride toothpaste and tablets, and other information. The participants are also given dental examinations every few years. Approximately 700 families are still actively participating in the study.

Currently, the participants are ages 6 to 9, and the focus now is on completing examinations of children at ages 8.5 to 9. The study is also looking at the relationship between children's sucking on pacifiers and fingers and the need for orthodontic treatment.

Levy noted that so far, findings from the Iowa Fluoride Study suggest that fluoride exposure and intake vary even more than researchers expected. Levy and his colleagues also found that cavities in primary teeth are still a problem, even though average rates today are lower than in the past.

The Iowa Fluoride Study has also led to other studies, including the Iowa Bone Development Study. This project involves the same children as the Iowa Fluoride Study and looks at dietary, genetic and physical activity factors and how these affect bone growth. Parents are asked to complete other questionnaires about the amount of physical activity their children are getting, and the children's diets are analyzed to see how much calcium, vitamin D, phosphorus and fluoride they are ingesting. Children also wear motion sensors so the researchers can assess how much physical activity they are getting.

The bone density study involves specialized, very low-radiation X-rays of developing bones when participants arrive at the UI for their dental screenings. A small blood draw allows investigators to look at genes believed to be related to bone development, such as vitamin D receptor, that have been studied very little in children.

Based on findings from the Iowa Bone Development Study, UI researchers recently reported that children could improve bone health by increasing physical activity.

Funded initially by two five-year grants from the National Institute for Dental and Craniofacial Research, Levy notes that these studies are uniquely appropriate for Iowa.

"Because of the stability of the population and cooperation in Iowa, this is a perfect state in which to do a study like this," Levy said. "Our staff is very appreciative of the families that have remained with us for this long."

The current dental grant extends for three more years. Additional funding has been received from the National Dairy Council and the U.S. Centers for Disease Control and Prevention to relate dietary patterns to both dental cavities and general growth patterns.

Co-investigators for the Iowa Fluoride Study include Jim Wefel, Ph.D., John Warren, D.D.S., Rebecca Slayton, Ph.D., D.D.S., Mike Kanellis, D.D.S., and Teresa Marshall, Ph.D., all professors in the UI College of Dentistry; Steve Hillis, Ph.D., assistant research scientist in the UI Department of Statistics and Actuarial Science; Jim Torner, Ph.D., professor and head of the UI Department of Epidemiology, Trudy Burns, Ph.D., professor in the UI Department of Biostatistics; Marcia Willing, Ph.D., M.D., associate professor in the UI Department of Pediatrics, and Kathy Janz, Ph.D., associate professor in the UI Department of Health, Leisure and Sport Studies.