Assessing Disparities in Community Water Fluoridation Across US States: A Spectral Clustering Approach

Community water fluoridation (CWF) adjusts fluoride levels in public water supplies to prevent tooth decay and promote dental health, irrespective of socioeconomic status or dental care access. Regular sampling by community water systems (CWS) ensures compliance with regulations and standards. Centers for Disease Control and Prevention (CDC) provide biennial reports for health statistics surveillance by monitoring CWF status in US water systems. It’s important to note that specific policies and practices related to CWF can vary between countries. Therefore, this re- search applies the spectral clustering method to group and analyse the reception of fluorinated wa- ter by CWS between populations of US countries. The data from the National Water Fluoridation Statistics (2016-2018-2020) reported by the CDC have been considered. The spectral clustering ap- proach identified five clusters of US countries, which represent the different percentages of the pop- ulation served by CWS receiving fluorinated water. Among the results, one cluster has the lowest value of the percentage (33.3%) and it includes Hawaii, New Jersey, Oregon, Idaho, Montana, Lou- isiana, New Hampshire, Alaska, and Utah. Conversely, the cluster of countries Ohio, Indiana, Mar- yland, South Dakota, Georgia, Virginia, North Dakota, Illinois, Minnesota, Kentucky, District of Co- lumbia had the highest percentage (96.1%). These findings reveal relevant variations in the imple- mentation of CWF across different US countries, with some states having a notably lower percent- age of their population receiving fluorinated water than others. This could inform policy and public health efforts to improve access to fluoridated water and enhance dental health outcomes in areas with lower coverage.