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Taher MK, Momoli F, Go J, Hagiwara S, Ramoju S, Hu X, Jensen N, Terrell R, Hemmerich A, Krewski D. Systematic review of epidemiological and toxicological evidence on health effects of fluoride in drinking water. Crit Rev Toxicol 2024; 54:2-34. [PMID: 38318766 DOI: 10.1080/10408444.2023.2295338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 11/27/2023] [Indexed: 02/07/2024]
Abstract
INTRODUCTION Fluoride is a naturally occurring substance that is also added to drinking water, dental hygiene products, and food supplements for preventing dental caries. Concerns have been raised about several other potential health risks of fluoride. OBJECTIVE To conduct a robust synthesis of evidence regarding human health risks due to exposure to fluoride in drinking water, and to develop a point of departure (POD) for setting a health-based value (HBV) for fluoride in drinking water. METHODS A systematic review of evidence published since recent reviews of human, animal, and in vitro data was carried out. Bradford Hill considerations were used to weigh the evidence for causality. Several key studies were considered for deriving PODs. RESULTS The current review identified 89 human studies, 199 animal studies, and 10 major in vitro reviews. The weight of evidence on 39 health endpoints was presented. In addition to dental fluorosis, evidence was considered strong for reduction in IQ scores in children, moderate for thyroid dysfunction, weak for kidney dysfunction, and limited for sex hormone disruptions. CONCLUSION The current review identified moderate dental fluorosis and reduction in IQ scores in children as the most relevant endpoints for establishing an HBV for fluoride in drinking water. PODs were derived for these two endpoints, although there is still some uncertainty in the causal weight of evidence for causality for reducing IQ scores in children and considerable uncertainty in the derivation of its POD. Given our evaluation of the overall weight of evidence, moderate dental fluorosis is suggested as the key endpoint until more evidence is accumulated on possible reduction of IQ scores effects. A POD of 1.56 mg fluoride/L for moderate dental fluorosis may be preferred as a starting point for setting an HBV for fluoride in drinking water to protect against moderate and severe dental fluorosis. Although outside the scope of the current review, precautionary concerns for potential neurodevelopmental cognitive effects may warrant special consideration in the derivation of the HBV for fluoride in drinking water.
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Affiliation(s)
- Mohamed Kadry Taher
- McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
- School of Mathematics and Statistics, Carleton University, Ottawa, ON, Canada
| | - Franco Momoli
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
- Risk Sciences International, Ottawa, ON, Canada
| | - Jennifer Go
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
- Risk Sciences International, Ottawa, ON, Canada
| | - Shintaro Hagiwara
- School of Mathematics and Statistics, Carleton University, Ottawa, ON, Canada
- Risk Sciences International, Ottawa, ON, Canada
| | - Siva Ramoju
- Risk Sciences International, Ottawa, ON, Canada
| | - Xuefeng Hu
- Department of Biology, Faculty of Science, University of Ottawa, Ottawa, ON, Canada
| | - Natalie Jensen
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
- Risk Sciences International, Ottawa, ON, Canada
| | - Rowan Terrell
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
- Risk Sciences International, Ottawa, ON, Canada
| | - Alex Hemmerich
- Risk Sciences International, Ottawa, ON, Canada
- Faculty of Education, Queen's University, Kingston, ON, Canada
| | - Daniel Krewski
- McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
- School of Mathematics and Statistics, Carleton University, Ottawa, ON, Canada
- Risk Sciences International, Ottawa, ON, Canada
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Baj J, Kowalska B, Flieger W, Radzikowska-Büchner E, Forma A, Czeczelewski M, Kędzierawski P, Karakuła K, Flieger M, Majerek D, Teresiński G, Maciejewski R, Flieger J. Assessment of the Concentration of 51 Elements in the Liver and in Various Parts of the Human Brain-Profiling of the Mineral Status. Nutrients 2023; 15:2799. [PMID: 37375704 DOI: 10.3390/nu15122799] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023] Open
Abstract
The anthropogenic environment and diet introduce many metals into the human body, both essential and toxic. Absorption leads to systemic exposure and accumulation in body fluids and tissues. Both excess and deficiency of trace elements are health hazards. The primary aim of the present study was to evaluate the concentration of 51 elements in liver samples and 11 selected brain regions obtained at post-mortem examination from a population of adults living in south-eastern Poland (n = 15). A total of 180 analyses were performed by inductively coupled plasma mass spectrometry in two independent replicates. The collected data show very high individual variability in the content of the investigated elements. Macroelements such as sodium, magnesium, phosphorus, potassium, calcium, iron, and zinc occurred in the highest concentrations and with the greatest statistically significant variations. Although the elemental content of the brain and liver differed significantly, the strongest positive correlation between liver and polus frontalis was observed for the essential element selenium (0.9338) and the strongest negative one for manganese (-0.4316) and lanthanum (-0.5110). The brain areas studied have different requirements for phosphorus, manganese, iron, and molybdenum. In addition, males had a significantly (p < 0.05) higher brain content of lanthanides and actinides than females. The results of this study show that the inhabitants of south-eastern Poland are exposed to a fairly uniform accumulation of aluminum and vanadium in the brain, which have the highest affinity to the thalamus dorsalis. This result proves that there is environmental exposure to these elements.
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Affiliation(s)
- Jacek Baj
- Department of Anatomy, Medical University of Lublin, 20-090 Lublin, Poland
| | - Beata Kowalska
- Department of Water Supply and Wastewater Disposal, Lublin University of Technology, 20-618 Lublin, Poland
| | - Wojciech Flieger
- Department of Anatomy, Medical University of Lublin, 20-090 Lublin, Poland
| | | | - Alicja Forma
- Department of Anatomy, Medical University of Lublin, 20-090 Lublin, Poland
| | - Marcin Czeczelewski
- Department of Forensic Medicine, Medical University of Lublin, 20-090 Lublin, Poland
| | - Paweł Kędzierawski
- Department of Forensic Medicine, Medical University of Lublin, 20-090 Lublin, Poland
| | - Kaja Karakuła
- I Department of Psychiatry, Psychotherapy, and Early Intervention, Medical University of Lublin, 20-439 Lublin, Poland
| | - Michał Flieger
- Department of Forensic Medicine, Medical University of Lublin, 20-090 Lublin, Poland
| | - Dariusz Majerek
- Department of Applied Mathematics, University of Technology, 20-618 Lublin, Poland
| | - Grzegorz Teresiński
- Department of Forensic Medicine, Medical University of Lublin, 20-090 Lublin, Poland
| | | | - Jolanta Flieger
- Department of Analytical Chemistry, Medical University of Lublin, 20-093 Lublin, Poland
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Gopnar VV, Rakshit D, Bandakinda M, Kulhari U, Sahu BD, Mishra A. Fisetin attenuates arsenic and fluoride subacute co-exposure induced neurotoxicity via regulating TNF-α mediated activation of NLRP3 inflammasome. Neurotoxicology 2023:S0161-813X(23)00086-4. [PMID: 37331635 DOI: 10.1016/j.neuro.2023.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/29/2023] [Accepted: 06/14/2023] [Indexed: 06/20/2023]
Abstract
Groundwater is considered safe, however, the occurrence of contaminants like arsenic and fluoride has raised a major healthcare concern. Clinical studies suggested that arsenic and fluoride co-exposure induced neurotoxicity, however efforts to explore safe and effective management of such neurotoxicity are limited. Therefore, we investigated the ameliorative effect of Fisetin against arsenic and fluoride subacute co-exposure-induced neurotoxicity, and associated biochemical and molecular changes. Male BALB/c mice Arsenic (NaAsO2: 50mg/L) and fluoride (NaF: 50mg/L) were exposed to drinking water and fisetin (5, 10, and 20mg/kg/day) was administered orally for 28 days. The neurobehavioral changes were recorded in the open field, rotarod, grip strength, tail suspension, forced swim, and novel object recognition test. The co-exposure resulted in anxiety-like behaviour, loss of motor coordination, depression-like behaviour, and loss of novelty-based memory, along with enhanced prooxidant, inflammatory markers and loss of cortical and hippocampal neurons. The treatment with fisetin reversed the co-exposure-induced neurobehavioral deficit along with restoration of redox & inflammatory milieu, and cortical and hippocampal neuronal density. Apart from antioxidants, inhibition of TNF-α/ NLRP3 expression has been suggested as one of the plausible neuroprotective mechanisms of Fisetin in this study.
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Affiliation(s)
- Vitthal V Gopnar
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER) - Guwahati, Changsari, Kamrup, Assam - 781101, India
| | - Debarati Rakshit
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER) - Guwahati, Changsari, Kamrup, Assam - 781101, India
| | - Mounisha Bandakinda
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER) - Guwahati, Changsari, Kamrup, Assam - 781101, India
| | - Uttam Kulhari
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER) - Guwahati, Changsari, Kamrup, Assam - 781101, India
| | - Bidya Dhar Sahu
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER) - Guwahati, Changsari, Kamrup, Assam - 781101, India
| | - Awanish Mishra
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER) - Guwahati, Changsari, Kamrup, Assam - 781101, India.
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Lin YY, Hsu WY, Yen CE, Hu SW. Association of Dental Fluorosis and Urinary Fluoride with Intelligence among Schoolchildren. CHILDREN (BASEL, SWITZERLAND) 2023; 10:987. [PMID: 37371219 DOI: 10.3390/children10060987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/24/2023] [Accepted: 05/30/2023] [Indexed: 06/29/2023]
Abstract
Fluoride is present naturally in water and has been used worldwide for the prevention of caries. Several studies conducted in high water fluoride or endemic fluorosis areas reported that fluoride adversely affected children's cognitive function, but some studies had negative findings. This study aimed to assess the relationship between urinary fluoride, dental fluorosis, and intelligence among schoolchildren living in communities with non-fluoridated drinking water. This cross-sectional study was conducted on 562 children aged 6-12 years in Taichung, Taiwan. Each child's urinary fluoride level was determined by a fluoride-ion-selective electrode, and the dental fluorosis condition was evaluated according to the criteria of Dean's Index. The Raven's Colored Progressive Matrices-Parallel and Standard Progressive Matrices-Parallel were used to assess children's intelligence. The results showed that the mean (±standard deviation) urinary fluoride concentrations were 0.40 ± 0.27 mg/L (0.43 ± 0.23 mg/g creatinine) among participants. The prevalence of dental fluorosis was 23.67%. After extensive evaluation of potential confounders, dental fluorosis and urinary fluoride were not associated with intelligence quotient (IQ) scores or grades in the regression models. In conclusion, dental fluorosis and urinary fluoride levels were not significantly related to the IQ of schoolchildren living in areas with low drinking water fluoride.
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Affiliation(s)
- Yuh-Yih Lin
- Institute of Oral Sciences, Chung Shan Medical University, Taichung 40201, Taiwan
| | - Wen-Yu Hsu
- Department of Psychology, Chung Shan Medical University, Taichung 40201, Taiwan
| | - Chin-En Yen
- Department of Early Childhood Development and Education, Chaoyang University of Technology, Taichung 41349, Taiwan
| | - Suh-Woan Hu
- Institute of Oral Sciences, Chung Shan Medical University, Taichung 40201, Taiwan
- Department of Dentistry, Chung Shan Medical University Hospital, Taichung 40201, Taiwan
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Knappett PSK, Farias P, Miller GR, Hoogesteger J, Li Y, Mendoza‐Sanchez I, Woodward RT, Hernandez H, Loza‐Aguirre I, Datta S, Huang Y, Carrillo G, Roh T, Terrell D. A Systems Approach to Remediating Human Exposure to Arsenic and Fluoride From Overexploited Aquifers. GEOHEALTH 2022; 6:e2022GH000592. [PMID: 35799913 PMCID: PMC9250112 DOI: 10.1029/2022gh000592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 05/25/2022] [Accepted: 05/31/2022] [Indexed: 05/14/2023]
Abstract
In semiarid agricultural regions, aquifers have watered widespread economic development. Falling water tables, however, drive up energy costs and can make the water toxic for human consumption. The study area is located in central Mexico, where arsenic and fluoride are widely present at toxic concentrations in well water. We simulated the holistic outcomes from three pumping scenarios over 100 years (2020-2120); (S1) pumping rates increase at a similar rate to the past 40 years, (S2) remain constant, or (S3) decrease. Under scenario S1, by 2120, the depth to water table increased to 426 m and energy consumption for irrigation increased to 4 × 109 kWh/yr. Arsenic and fluoride concentrations increased from 14 to 46 μg/L and 1.0 to 3.6 mg/L, respectively. The combined estimated IQ point decrements from drinking untreated well water lowered expected incomes in 2120 by 27% compared to what they would be with negligible exposure levels. We calculated the 100-year Net Present Value (NPV) of each scenario assuming the 2020 average crop value to water footprint ratio of 0.12 USD/m3. Without drinking water mitigation, S1 and S3 yielded relative NPVs of -5.96 × 109 and 1.51 × 109 USD, respectively, compared to the base case (S2). The relative NPV of providing blanket reverse osmosis treatment, while keeping pumping constant (S2), was 11.55 × 109 USD and this gain increased when combined with decreased pumping (S3). If a high value, low water footprint crop was substituted (broccoli, 1.51 USD/m3), the net gains from increasing pumping were similar in size to those of implementing blanket drinking water treatment.
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Affiliation(s)
| | - P. Farias
- Environmental HealthInstituto Nacional de Salud PúblicaCuernavacaMéxico
| | - G. R. Miller
- Civil & Environmental EngineeringTexas A&M UniversityCollege StationTXUSA
| | - J. Hoogesteger
- Water Resources ManagementWageningen UniversityWageningenThe Netherlands
| | - Y. Li
- Mines, Metallurgy and Geology EngineeringUniversity of GuanajuatoGuanajuatoMéxico
| | | | - R. T. Woodward
- Agricultural EconomicsTexas A&M UniversityCollege StationTXUSA
| | - H. Hernandez
- Geomatic and Hydraulic EngineeringUniversity of GuanajuatoGuanajuatoMéxico
| | - I. Loza‐Aguirre
- Mines, Metallurgy and Geology EngineeringUniversity of GuanajuatoGuanajuatoMéxico
| | - S. Datta
- Geological SciencesUniversity of Texas at San AntonioSan AntonioTXUSA
| | - Y. Huang
- Geology & GeophysicsTexas A&M UniversityCollege StationTXUSA
| | - G. Carrillo
- Public HealthTexas A&M UniversityCollege StationTXUSA
| | - T. Roh
- Public HealthTexas A&M UniversityCollege StationTXUSA
| | - D. Terrell
- Caminos de AguaSan Miguel de AllendeMéxico
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