Emulation of Community Water Fluoridation within America Counties

Objectives: Objective: This study aims to determine the extent to which an emulation model of community water fluoridation (CWF) diffusion explains variance in fluoridation coverage across U.S. counties, as modeled using supply side factors (neighboring fluoridation coverage) and demand side factors (health literacy, education, and population density.)

Methods: Methods: We employ a multilevel geographically weighted autoregressive model to analyze county level fluoridation from the 2014 Water Fluoridation Reporting Systems (WFRS) data set. We predicted fluoridation coverage as a function of neighboring fluoridation coverage, a county’s health literacy, population density, and socio-demographic population characteristics from the U.S. Census. Our modeling strategy permits us to model emulation as a function of successful implementation of fluoride by neighboring counties and the conductivity of a county to learn and implement lessons from neighboring experiences as a function of their knowledge levels and suitability to implement CWF.

Results: Results: Health literacy and neighboring fluoridation coverage were positively associated with fluoridation coverage within a county. Increasing the health literacy of a county from the first to third quartile increases fluoridation coverage by 25 percentage points, and increasing neighboring county fluoridation from the first to third quartiles increases fluoridation by approximately 30 percentage points.

Conclusions: Conclusion: There is strong reason to believe that counties emulate each other based upon the coverage of fluoridation practiced by their neighbors and their own health literacy. These results suggest that while fluoridation coverage expansion is prone to inertia, it appears possible to advance fluoridation through strategic efforts to share information of positive experiences from fluoridated counties with neighboring low fluoridated counties.