Fluoride Action Network

Abstract

Background

Environmental chemical exposures have been implicated in pediatric kidney disease. No appraisal of the available evidence has been conducted on this topic.

Methods

We performed a systematic review of the epidemiologic studies that assessed association of environmental exposures with measures of kidney function and disease in pediatric populations. The search period went through July 2016.

Results

We found 50 studies that met the search criteria and were included in this systematic review. Environmental exposures reviewed herein included lead, cadmium, mercury, arsenic, fluoride, aflatoxin, melamine, environmental tobacco, bisphenol A, dental procedures, phthalates, ferfluorooctanoic acid, triclosan, and thallium/uranium. Most studies assessed environmental chemical exposure via biomarkers but four studies assessed exposure via proximity to emission source. There was mixed evidence of association between metal exposures, and other non-metal environmental exposures and pediatric kidney disease and other kidney disease biomarkers. The evaluation of causality is hampered by the small numbers of studies for each type of environmental exposure, as well as lack of study quality and limited prospective evidence.

Conclusion

There is a need for well-designed epidemiologic studies of environmental chemical exposures and kidney disease outcomes.


*Free full-text study online at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5821495/

Excerpt:

Two studies investigated the association of fluoride exposure, including 1 cross-sectional and 1 case-control. In a cross-sectional study of fluoride exposure in 210 children in China, the investigators found increases of urine NAG and urine ?-GT levels (). In case-control study of fluoride levels in 210 children in China, slightly higher urine NAG levels were found in participants with higher serum fluoride levels (). While both studies were from China, the first study did not offer adjustment for confounders while the second study matched on age, sex, and nutritional status.

… We identified two studies that showed a positive association between fluoride levels and urine NAG levels. This suggests that there is a possible association between fluoride and kidney function. We identified 2 studies that showed an association between Bisphenol A compounds and urine albumin levels. However, the literature on both fluoride and Bisphenol A and kidney function remains limited.

5. Gaps and limitations of existing research

Our review identified several gaps in scientific knowledge. These include a critical need for additional studies of environment chemicals exposures and renal health, including but not limited to lead, arsenic, manganese, cadmium, fluoride, Bisphenol A, PFOA, and PAH compounds.

… Children are particularly susceptible to environmental exposures compared to adults (). Firstly, children consume more food, water, and air per pound of body weight compared to adults and therefore are proportionally exposed to more environmental toxicants (, , ). Moreover, an individual’s susceptibiliy to environmental chemical exposure is greatest during “:windows of vulnerability,” the specific time periods when complex organs, pathways, and connections are being established (i.e. prenatal and early life development) (). Exposure to environmental chemicals during these periods can impact cell signaling and alter development. Due to physiological differences between children and adults, children more easily absorb toxicants such as lead, and have decreased elimination abilities. The blood-brain barrier is not fully developed for the first 36 months of life, leaving young children more susceptible to neruotoxicants (). Taken together, these facts suggest that environmental chemical exposure in childhood poses substantial public health concern.