Is Fluoride the Culprit? Revisiting Evidence on Environmental Origins of Chronic Kidney Disease of Uncertain Etiology (CKDu): A Narrative Review.

Fluoride is increasingly discussed as a geogenic risk factor for chronic kidney disease of uncertain etiology (CKDu); an epidemic of kidney disease is affecting hot tropical farming communities worldwide. Emerging evidence continues to support the association between high-fluoride exposure and kidney injury, particularly in regions with high fluoride levels. However, while fluoride's geogenic nature leads to prolonged exposure through water and food sources, the direct impact on kidney health remains incompletely understood. This review explores the relationship between fluoride exposure and adverse kidney health outcomes, especially in the context of CKDu, synthesizing findings from epidemiological studies conducted worldwide. While a broad range of studies show widespread dental fluorosis prevalence in regions with high environmental fluoride levels in Sri Lanka, India, China, and Mexico, such correlation was not evident for CKDu and environmental fluoride levels. Notably, the spatial distribution patterns of CKDu and exposure risk through high fluoride levels in drinking water exhibit some inconsistencies, suggesting fluoride alone may not be the sole driver of CKDu. This review underscores the kidney health risks of fluoride exposure while emphasizing the need for further studies that consider multiple interacting factors beyond fluoride exposure in examination of environmental triggers of CKDu.