Low-dose fluoride and lead co-exposure alters bone mineral density in youth: A nationally representative cross-sectional study.

Fluorine is a ubiquitous non-metallic trace element found in nature, typically in the form of compounds. It is essential for human health; an appropriate amount of fluorine contributes to maintaining bone health, while both insufficient and excessive doses can cause significant harm to the body. A deficiency of fluorine often leads to dental and bone lesions, and other related symptoms. To prevent diseases such as dental caries, public health strategies have been implemented in the United States, providing drinking water containing silicofluorides, fluorosilicic acid, and its salt-sodium fluorosilicate, to over 200 million people across 17,558 communities [1]. Since the introduction of this measure, local diseases such as dental caries and osteoporosis have been effectively prevented and controlled, resulting in an overall improvement in the population’s health. However, the use of fluoridated drinking water can sometimes lead to excessive fluoride intake [2]. Due to the dual nature of fluoride, excessive consumption can disrupt the balance of calcium and phosphorus metabolism in the body, causing significant damage to the shape, structure, and function of bones and joints. Consequently, the issue of fluorosis resulting from fluoridated drinking water in the United States has garnered considerable attention.

In addition to causing fluorosis, the fluorinated substances added to community drinking water also possess certain acidic properties that can promote the dissolution of lead in water pipe, thereby exacerbating the health risks associated with lead exposure in the population [3].Furthermore, the use of lead-based paint, lead pipes, and lead welding materials in the drinking water supply systems of American households has significantly increased the risk of lead exposure among the population [4], [5]. The skeletal system, which serves as the largest reservoir of lead in the human body, can be compromised during lead exposure. This can lead to damage to bone structure, malformations in bone development, and a reduction in bone mass [6], [7], [8].

To our knowledge, the effects of co-exposure to low concentrations of fluoride and lead on skeletal development in children and adolescents have not received the attention they deserve. Given the severe toxicity of fluoride and lead, as well as the higher vulnerability of children and adolescents to toxicant, it is crucial to study the effects of fluoride and lead co-exposure on bone mineral density (BMD) in the local residents.

Based on the above analysis, this study aimed to investigate the relationship between fluoride exposure, lead exposure, and BMD in children and adolescents, as well as the interaction between the two contributor’s co-exposure on BMD. This will provide valuable clues about the effects of co-exposure to low-dose fluoride and lead on bone health of the local child and adolescent in the United States.