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Hierarchical Modeling and Aggregation
Published in Song S. Qian, Mark R. DuFour, Ibrahim Alameddine, Bayesian Applications in Environmental and Ecological Studies with R and Stan, 2023
Song S. Qian, Mark R. DuFour, Ibrahim Alameddine
Fluoride can help reduce dental caries. As a result, some U.S. cities started adding fluoride to community drinking water in the 1940s. In the 1960s, the U.S. government recommended fluoridation of drinking water to prevent tooth decay. Currently, the U.S. Public Health Service has recommended a concentration of 0.7 mg/L in drinking water. Long-term exposure to high levels of fluoride, however, can cause a condition called skeletal fluorosis, the buildup of fluoride in the bones. This can eventually result in joint stiffness and pain, and can also lead to weak bones or fractures in older adults. As a result, government agencies and health organizations established legal or recommended limits for fluoride in drinking water. For example, EPA set a legally enforceable MCL at 4 mg/L and a secondary (recommended) MCL at 2 mg/L to help protect children (under the age of 9) from dental fluorosis (fluoride build-up in developing teeth, preventing tooth enamel from forming normally); the World Health Organization has a fluoride guideline of 1.5 mg/L in drinking water [U.S. EPA, 2016a].
Pathophysiology of Fluorosis and Calcium Dose Prediction for Its Reversal in Children: Mathematical Modeling, Analysis, and Simulation of Three Clinical Case Studies
Published in P. Mereena Luke, K. R. Dhanya, Didier Rouxel, Nandakumar Kalarikkal, Sabu Thomas, Advanced Studies in Experimental and Clinical Medicine, 2021
Suja George, A. B. Gupta, Mayank Mehta, Akshara Goyal
Only few clinical studies have been reported on the treatment and reversal of skeletal fluorosis, even though the problem has been recognized in India since 1937 [11]. In the present study, data derived from two clinical case studies from the villages of Jaipur, Rajasthan, India carried out by Gupta et al. [2, 12] and one from Delhi, India reported by Susheela and Bhatnagar [13] abridged in Table 11.1, were used for development of mathematical model to estimate calcium requirement for excess fluoride ingestion.
Ultratrace Minerals
Published in Luke R. Bucci, Nutrition Applied to Injury Rehabilitation and Sports Medicine, 2020
Because most fluoride intake is derived from water intake, local geographic influences and addition of fluoride to municipal supplies of tap water largely determine fluoride intake. As a result, fluoride deficiencies severe enough to affect dental enamel and bone density appear to be isolated and uncommon. However, fluoride toxicity is an increasing concern.1046 Acute lethal doses of fluoride in man are 32 to 64 mg/kg, an extremely high dose. Nevertheless, accidental acute fluoride poisoning has resulted in at least 45 deaths (43 from an accidental poisoning in a single hospital in the early 1940s).1046 Of more practical concern is chronic fluoride toxicity, manifested as dental and skeletal fluorosis.1046 Dental fluorosis (ranging in severity from white spots on teeth to hypomineralization with staining and pitting of enamel) is increasing in frequency in the U.S. but, overall, is usually mild with no aesthetic changes. Skeletal fluorosis results from chronic ingestion of 10 to 25 mg of fluoride per day for years. Skeletal hypermineralization, soft tissue calcification (especially tendons and ligaments), and exostosis formation are apparent and may progress to crippling.1046 Thus, fluoride exhibits a narrow window of safe and adequate intake. Bone defects are manifested during both deficiency and toxicity of fluoride.
Thoracic spine ossified ligamentum flavum: single-surgeon experience of fifteen cases and a new MRI finding for preoperative diagnosis of dural ossification
Published in British Journal of Neurosurgery, 2020
The exact causative factors for OLF remain unclear. Both intrinsic and extrinsic factors have been proposed.24,26 These include mechanical stress, transformation of elastic fibers into ossified tissue involving genetic cellular properties, inflammation and angiogenesis, TGF-beta, BMP-2, MMPs and interleukins.7–10,26,29 Skeletal fluorosis has also been reported as an etiological factor.16,30 It is generally believed that ossification is a bilateral process.24,31,32 However, the lesion may be asymmetric, wherein ossification on one side is more prominent than the other (Figure 2). A significant proportion may also have concomitant spinal disorders such as OPLL and disc herniations or coexistent cervical/lumbar pathologies.3,7,10,22,24 In this series, eight cases had associated spinal pathologies. On many occasions, it was intraoperatively observed that the ossification was not uniform, with areas of non-ossified flavum being interspersed with the ossified one (Figure 6). The author hypothesizes that the hypertrophied and ossified flava are two ends of a spectrum with the interspersing of the two being in the intermediate stage, and if left untreated, there would occur ossification of the remaining hypertrophied flavum in due course of time.
Skeletal fluorosis secondary to harmful inhalant use
Published in Clinical Toxicology, 2022
Derek J. Fikse, Danny Le, Ryan M. Surmaitis
Skeletal fluorosis is rare in the United States due to the regulations set in place by the United States Public Health Service, which set a maximum allowable fluoride concentration in drinking water [3]. It is common in endemic countries due to high concentrations of fluoride in water supplies, teas, and chemicals used in certain occupations [4]. The effective treatment for skeletal fluorosis is to stop the offending agent and prevent further exposure [5]. Vitamin C, vitamin D, and calcium may aid in bone repair in affected individuals. Vitamin E and methionine may reduce bone accumulation of fluoride [5]. This is especially important as about 9% of the US population has experimented with inhalants at least once with 58% of said group starting as early as 9th grade [1].
Borassus flabellifer Linn haustorium methanol extract mitigates fluoride-induced apoptosis by enhancing Nrf2/Haeme oxygenase 1 –dependent glutathione metabolism in intestinal epithelial cells
Published in Drug and Chemical Toxicology, 2022
Joice Tom Job, Rajakrishnan Rajagopal, Ahmed Alfarhan, Arunaksharan Narayanankutty
Fluoride is a trace element that is commonly known for its toxic impacts, especially on teeth, bone, and soft tissues. Drinking water is the primary source of fluoride ion and several countries in the world are having a fluoride level above 1.5 ppm (Tkachenko et al.2021). Fluoride ions are absorbed partly in the stomach and prominent portion in the small intestine (Villa et al.1993). As the intestine is the major site of fluoride absorption, high intake of fluoride has been associated with alterations in the gut microbiota, redox imbalance in intestinal cells, and thereby resulting in rectal barrier damages (Fu et al.2020, Wang et al.2020b). It has also been proposed that increased fluoride intake may be associated with the risk of inflammatory bowel diseases (IBD), however, no specific dose-limit was reported for the same (Follin-Arbelet and Moum 2016). Besides, the risk of various cancers including that of the colon has been associated with increased water fluoride (Yang et al.2000, Takahashi et al.2001). Fluoride intake has been shown to inhibit the activity of Na/K + dependent ATPase activity in multiple cell types (A and G 2015, Waugh 2019). Subsequently, the absorption of glucose in intestinal cells also gets reduced upon exposure to fluoride (Chen et al.2016). The health impact associated with fluoride toxicity is usually observed as dental and skeletal fluorosis (Shankar et al.2021). Together with this, the fluoride ions are also known to induce enzyme inactivation, redox imbalance, and DNA damage (Zhong et al.2021). It has been proposed that dietary intake of essential nutrients and antioxidants are possible ways to limit the fluoride-induced toxic health impacts (Susheela and Bhatnagar 2002).