Association between infant formula feeding and dental fluorosis and caries in Australian children

Objective: The objective of this study was to evaluate associations between patterns of infant formula feeding and dental fluorosis and caries in a representative sample of Australian children. Methods: A population-based study gathered information on fluoride exposure in early childhood. Information on infant formula feeding and fluoridation status was used to group children: three groups in nonfluoridated areas (formula nonuser, user for =6 months, and user for 6+ months) and four groups in fluoridated areas (nonuser, user with nonfluoridated water, user with fluoridated water for =6 months, and user with fluoridated water for 6+ months). Children aged 8-13 years were examined for fluorosis using the Thylstrup and Fejerskov (TF) Index. Primary tooth caries experience recorded at age 8-9 years was extracted from clinical records. Fluorosis cases were defined as having TF 1+ on maxillary incisors. Fluorosis prevalence and primary caries experience were compared across formula user groups in multivariable regression models adjusting for other factors. Results: Total sample was 588 children. Children in fluoridated areas had higher prevalence of very mild to mild fluorosis, but lower caries experience than those in nonfluoridated areas. Among children in nonfluoridated areas, formula users for 6+ months had significantly higher prevalence of fluorosis compared with nonusers. There was no significant difference in fluorosis prevalence among the formula users in fluoridated areas. Among children in fluoridated areas, formula users with nontap water had higher caries experience. Conclusion: Infant formula use was associated with higher prevalence of fluorosis in nonfluoridated areas but not in fluoridated areas. Type of water used for reconstituting infant formula in fluoridated areas was associated with caries experience.