Urinary Fluoride Levels Research Articles

Safe use of fluoride-containing toothpastes for caries prevention in children

Relevance. Following environmental rehabilitation efforts in Chapayevsk, Samara Region, an increase in the prevalence and severity of dental caries has been observed, particularly among preschool-aged children.Objective. To evaluate the safety of fluoride use for preventing dental caries in children.Material and methods. A survey was conducted among 124 parents of children aged 5–6 years attending preschools and 361 adolescents aged 12 and 15 years, using the WHO questionnaire (2013). Responses regarding oral hygiene habits were analyzed. Fluoride ion concentrations were measured in drinking water using the potentiometric method (GOST 4386-89 S.6), in urine according to GOST 8.563-96, and in toothpastes following GOST 7983-2016. The availability and popularity of fluoride-containing toothpastes in pharmacies and supermarkets were also assessed. Statistical analysis was performed using IBM SPSS Statistics v.26 (IBM Corporation).Results. Over the past 15 years, the fluoride content in drinking water decreased from 0.78–0.91 mg/L to 0.49– 0.71 mg/L following the city’s environmental rehabilitation efforts, remaining suboptimal for caries prevention. Analysis of fluoride excretion via the kidneys indicated low overall fluoride intake from water, toothpaste, and food. A weak correlation was found between the DMFT (decayed, missing, and filled teeth) index and urinary fluoride levels (ρ = 0.35), as well as estimated systemic fluoride levels (ρ = 0.36). These results indicate low fluoride intake, eliminating concerns about toxic effects on health. An analysis of toothpaste preferences showed that the population primarily chooses fluoride-free toothpastes or those with fluoride levels below 1000 ppm. This trend is influenced by the product range available, low adherence to preventive dental care, and misinformation from online sources that often attribute negative effects to fluoridation or raise safety concerns. The actual fluoride content in toothpastes was found to be within acceptable technological limits.

Urinary Fluoride Levels Among Youth in the National Health and Nutrition Examination Survey (NHANES) 2015-2016: Potential Differences According to Race.

Urinary fluoride (UF) is the most well-established biomarker for fluoride exposure, and understanding its distribution can inform risk assessment for potential adverse systemic health effects. To our knowledge, this study is the first to report distributions of UF among youth according to sociodemographic factors in a nationally representative United States (US) sample. The study included 1191 children aged 6-11 years and 1217 adolescents aged 12-19 years from the National Health and Nutrition Examination Survey (NHANES) 2015-2016. We examined UF according to sociodemographic variables as well as Spearman correlations between UF and plasma fluoride. Survey-weighted quantile regression examined associations between tap water fluoride and UF levels adjusted for covariates. The average age of participants was 12.5 years. The median (IQR) UF and water fluoride concentrations were 0.52 (0.50) mg/L and 0.39 (0.54) mg/L, respectively. Children had higher UF levels than adolescents and males had higher UF levels than females. UF differed according to race/ethnicity among both children and adolescents. Specifically, non-Hispanic Black youth tended to have higher UF levels than all participants except for those classified as other race/multiracial. UF and plasma fluoride were moderately correlated for children and adolescents. Higher water fluoride levels were associated with higher UF levels, and the magnitudes of association were larger at higher quantiles of UF (β = 0.14, p < 0.001; β = 0.20, p< 0.001 at the 25th and 50th quantiles, respectively). The magnitude of association between water fluoride and UF was the largest for non-Hispanic Black participants (predictive margin = 0.3, p < 0.001). Non-Hispanic Black youth in the US may have greater fluoride exposure and receive more of their fluoride intake from tap water than youth of other races/ethnicities. Factors contributing to potential racial/ethnic disparities in fluoride exposure within the US warrant further investigation so that they can be mitigated to reduce the potential for harm.

Association between ESR1 and COL1A1 gene polymorphisms and skeletal fluorosis in Tibetan, Kazakh, Mongolian and Russian populations, China.

Skeletal fluorosis is a chronic metabolic bone disease caused by excessive accumulation of fluoride in the bones. Previous studies have found that when the intake of tea fluoride is similar, the prevalence of skeletal fluorosis varies greatly among different ethnic groups, which may be related to different genetic backgrounds. Single nucleotide polymorphisms (SNPs) of estrogen receptor 1 (ESR1) and collagen type 1 α1 (COL1A1) were strongly associated with bone metabolism as well as bone growth and development, but their association with the risk of skeletal fluorosis has not been reported. To explore the incidence of skeletal fluorosis in different nationalities in the endemic fluorosis area of brick-tea type. To study the relationship between 4 SNPS of ESR1 and COL1A1 gene and skeletal fluorosis METHODS: A cross-sectional study was conducted in Inner Mongolia, Qinghai and Xinjiang. By including exclusion criteria, a total of 989 people were included in the study, demographic data were collected, and physical examinations and laboratory biochemical tests were performed. The X-ray of the participants were diagnosed according to the diagnostic criteria of Chinese endemic skeletal fluorosis (WS192-2008). Fluoride levels in tea or urine were measured using fluoride ion electrodes. SNP was evaluated using Sequenom-MassARRAY system. The prevalence of skeletal fluorosis varies among different nationalities. Binary logistic regression found that carried the ESR1 Rs9340799 G allele played a protective role in brick-tea-type fluorosis (OR=0.673[95% CI, 0.495,0.914]). Russians carried the COL1A1 Rs1800012 T allele had a significantly higher risk of developing skeletal fluorosis (OR=6.370 [95% CI, 1.413,28.715]). When stratified by sex, carriage of the T allele in COL1A1 Rs1800012 significantly increased the risk of developing skeletal fluorosis in Russian men. At the same time, changes in tea fluoride intake and older age can affect the effect of genetic background differences on the risk of skeletal fluorosis. Our data suggested that there may be a genetic component to the risk of skeletal fluorosis in participants of different ethnicities and that this difference could modified by tea fluoride intake, sex or age.

Fluoride exposure, personal susceptibility and osteoarticular degeneration: Evidence from farmers in the Yellow River Basin of Henan Province

Osteoarticular degeneration (OAD) is an important issue. Excessive fluoride can damage osteoarticular health. Besides, personal susceptibility (including genetic factors, physiological characteristics, and lifestyle) also contributes to osteoarticular development significantly. However, little evidence focused on the comprehensive modification of fluoride exposure and personal susceptibility on osteoarticular health. Thus, this study explored the relationships among fluoride exposure, genetic factors, physiological characteristics, lifestyle, and OAD risk, as well as the potential interactions among contributors in 593 adults from a cross-sectional study conducted in 2017. We observed that the OAD (n=175) risk was increased with increasing urinary fluoride (UF) levels (OR=1.484; 95%CI: 1.043, 2.111), age (OR=1.065; 95%CI: 1.033, 1.098), and hip circumference (OR=1.069; 95%CI: 1.014, 1.127), as well as a poor night sleep quality (OR=1.818; 95%CI: 1.072, 3.084). More fruit consumption (>350g/d) was beneficial to OAD prevention (OR=0.102; 95%CI: 0.012, 0.850). Genetic susceptibility analysis showed that the CG genotype of calcitonin related polypeptide alpha (CALCA) rs1553005 loci was related to higher OAD risk (OR=1.959; 95%CI: 1.003, 3.825), whereas higher methylation status of GNAS complex locus (GNAS) (OR=0.617; 95%CI: 0.410, 0.929) and TC genotype of rs7121 loci (OR=0.569; 95%CI: 0.371, 0.871) showed protective effect on OAD. Additionally, OAD risk was related to the interaction of fluoride-rs1553005 polymorphism-rs7121 polymorphism-GNAS methylation, fluoride-age-fruits, age-fruits, and rs1553005 polymorphism-GNAS methylation-rs7121 polymorphism-age-hip circumference-fruits-UF. Findings suggested that the OAD susceptibility might be modified by the interactions between fluoride and personal susceptibility.

7002 Building Poor Bone, A Rare Presentation Of Skeletal Fluorosis

Abstract Disclosure: C. Pham: None. J.S. Lopresti: None. Skeletal fluorosis is a rare disease associated with osteosclerosis and fractures. Case: 26 year old male presented with a history of multiple traumatic fractures but no childhood or family history of fractures. Initial labs revealed a corrected calcium of 8.1 mg/dL (8.5-10.3), ALP 1,504 U/L (40-129), PTH 131 pg/ml (15-65), 25-OH D 14 ng/ml (30-100), PO4 3.7 mg/dl (2.5-4.5) and normal creatinine. X-Rays demonstrated osteosclerosis and cortical expansion of bone and nuclear bone scan demonstrated diffuse increased uptake. Further history revealed huffing of computer inhalants (10 cans daily) for years. Due to these findings, urine fluoride 16.88 mg/L (0.20-3.20 mg/L) and serum fluoride 0.40 mg/L (&amp;lt;0.05 mg/L) were obtained and vitamin D was started. 4 months later, his vitamin D level improved to 21 while calcium levels normalized despite ongoing inhalant use. ALP (878) and PTH (92) continued to be elevated albeit at improved levels. Conclusion: Exposure to fluoride leads to a rare condition called skeletal fluorosis causing accelerated osteogenesis and bone turnover leading to weak bone. Symptoms include bony pain, fractures, and osteosclerosis on radiographs. Differential diagnosis includes other conditions associated with osteosclerosis such as Paget’s disease and myelofibrosis. However, diffuse osteosclerosis and vertebral osteophytosis are noted only in skeletal fluorosis compared to other potential causes, though our patient did not have a CT spine done to assess for osteophytes. Biochemical studies can include hypocalcemia and hyperparathyroidism. It is thought that low calcium intake contributes to the hyperparathyroidism. Elevated serum and urine fluoride levels are also diagnostic and can persist for months after cessation of fluoride intake. Sodium fluoride has been posited as a treatment for osteoporosis due to its tremendous ability to build bone; however, the quality of bone made is poor leading to unacceptable fracture rates. Skeletal fluorosis should be suspected in any patient with history of diffuse osteosclerosis and hyperparathyroidism; and vitamin D supplementation should be initiated. In our case, hypocalcemia and PTH levels were improved despite active inhalant use after vitamin D supplementation. This suggests that Vitamin D deficiency and fluoride may be two independent driving factors in hyperparathyroidism in patients with fluorosis. Increased calcium absorption with vitamin D provides therapeutic benefit in both cases. Presentation: 6/1/2024

Fluorosis Masquerading as Compressive Myelopathy

A 60-year-old woman from Cuddalore presented with restricted neck movements, progressive difficulty in walking, and lower limb weakness, leading to bed confinement. Clinical examination revealed spastic paraparesis, brisk reflexes, and sensory deficits below the hips. Laboratory investigations indicated renal insufficiency and elevated urine fluoride levels. Imaging demonstrated calcifications of sacroiliac, sacrospinous ligaments, interosseous membrane, and posterior longitudinal ligament, with osteosclerosis and osteoporosis. Differential diagnoses included Ankylosing Spondylitis and Diffuse Idiopathic Skeletal Hyperostosis. However, the unique pattern of ligament calcification and elevated fluoride levels supported a diagnosis of fluorosis. This case underscores the importance of considering fluorosis in patients from endemic areas with spastic paraparesis and characteristic radiological findings. Posterior decompression via laminectomy was performed, emphasizing the need for awareness of fluorosis as a potential cause of cervical compressive myelopathy.

Kinetics of fluoride after brushing with the no-rinse method

BackgroundFluoride plays a vital role in preventing dental caries, with its addition to oral care products significantly promoting oral hygiene. A no-rinse brushing method aims to increase fluoride retention in the oral cavity, as rinsing with water decreases fluoride levels in saliva, which could affect remineralization. While the no-rinse brushing method holds promise for improving fluoride retention in the oral cavity, critical inquiries persist regarding its safety. This study investigated the kinetics of oral fluoride and potential risks to fully assess its effectiveness and implications for oral health.MethodsTen healthy adults participated in a crossover study comparing the no-rinse with the rinse method. All subjects followed American Dental Association (ADA) brushing guidelines. Levels of fluoride in saliva (supernatant and sediment) and urine were measured over time, and plasma fluoride was measured one hour after brushing. Pharmacokinetic parameters were also calculated from the data.ResultsParticipants using the no-rinse method had higher fluoride levels in supernatant immediately and up to 30 min post-brushing compared to the rinse method. Fluoride levels in sediment were higher only immediately after brushing. The total fluoride concentration in saliva remained elevated for up to 5 min with the no-rinse method. Systemic fluoride absorption showed no significant difference between the two methods based on blood and urine analysis.ConclusionThis research indicates that the no-rinse method can enhance fluoride retention in the oral cavity for up to 30 min after a single brushing. In addition, our findings suggest that this method does not significantly influence systemic fluoride levels or toxicity.RegistryThai Clinical Trials Registry, TCTR (http://thaiclinicaltrials.org). Clinical trial registration number: TCTR20231104001 (4/11/2023).

The Association between Fluoride and Bone Mineral Density in US Children and Adolescents: A Pilot Study.

The aim of this study was to examine the association between fluoride exposure and bone mineral density (BMD) in children and adolescents. We used data from the National Health and Nutrition Examination Survey (NHANES) 2015-2016. The fluoride concentrations in the water samples, plasma samples, and urine samples were measured electrometrically using an ion-specific electrode. Total body less head BMD (TBLH BMD) was measured using dual-energy X-ray absorptiometry (DXA). Weighted generalized linear regression models and restricted cubic splines (RCS) regression models were used to analyze the relationships between the three types of fluoride exposure and TBLH BMD. We performed subgroup analyses stratified by sex. A total of 1413 US children and adolescents were included in our study. In our linear regression models, we found inverse associations between fluoride concentrations in water and plasma and TBLH BMD. Additionally, we discovered a non-linear association between fluoride concentrations in water and plasma and TBLH BMD. No significant association or non-linear relationship was found between urine fluoride levels and TBLH BMD. This nationally representative sample study provides valuable insight into the intricate connection between fluoride exposure and skeletal health in children and adolescents.

The Impact of Exposure to Iodine and Fluorine in Drinking Water on Thyroid Health and Intelligence in School-Age Children: A Cross-Sectional Investigation.

Iodine and fluorine, as halogen elements, are often coexisting in water environments, with nearly 200 million people suffering from fluorosis globally, and, in 11 countries and territories, adolescents have iodine intakes higher than that required for the prevention of iodine deficiency disorders. It has been suggested that excess iodine and/or fluorine can affect thyroid health and intellectual development, especially in children, but their combined effect has been less studied in this population. This study investigated 399 school-age children in Tianjin, China, collected drinking water samples from areas where the school-age children lived, and grouped the respondents according to iodine and fluorine levels. Thyroid health was measured using thyroid hormone levels, thyroid volume, and the presence of thyroid nodules; intelligence quotient (IQ) was assessed using the Raven's Progressive Matrices (CRT) test; and monoamine neurotransmitter levels were used to explore the potential relationship between thyroid health and intelligence. Multiple linear regression and restricted cubic spline (RCS) analyses showed that iodine and fluorine were positively correlated with thyroid volume and the incidence of thyroid nodules in school-age children, and negatively correlated with IQ; similar results were obtained in the secondary subgroups based on urinary iodine and urinary fluoride levels. Interaction analyses revealed a synergistic effect of iodine and fluorine. A pathway analysis showed that iodine and fluorine were negatively associated with the secretion of free triiodothyronine (FT3) and free tetraiodothyronine (FT4), which in turn were negatively associated with the secretion of thyroid-stimulating hormone (TSH). Iodine and fluorine may affect IQ in school-aged children through the above pathways that affect thyroid hormone secretion; of these, FT3 and TSH were negatively correlated with IQ, whereas FT4 was positively correlated with IQ. The relationship between thyroid hormones and monoamine neurotransmitters may involve the hypothalamic-pituitary-thyroid axis, with FT4 hormone concentrations positively correlating with dopamine (DA), norepinephrine (NE), and 5-hydroxytryptophan (5-HT) concentrations, and FT3 hormone concentrations positively correlating with DA concentrations. Monoamine neurotransmitters may play a mediating role in the effects of iodine and fluoride on intelligence in schoolchildren. However, this study has some limitations, as the data were derived from a cross-sectional study in Tianjin, China, and no attention was paid to the reciprocal effects of iodine and fluorine at different doses on thyroid health and intelligence in schoolchildren in other regions.

Maternal prenatal urinary fluoride levels and internalizing and externalizing problems in 8- and 11-year-old children

Maternal prenatal urinary fluoride levels and internalizing and externalizing problems in 8- and 11-year-old children

Salivary proteomic signatures in severe dental fluorosis

The relationship between dental fluorosis and alterations in the salivary proteome remains inadequately elucidated. This study aimed to investigate the salivary proteome and fluoride concentrations in urine and drinking water among Thai individuals afflicted with severe dental fluorosis. Thirty-seven Thai schoolchildren, aged 6–16, were stratified based on Thylstrup and Fejerskov fluorosis index scores: 10 with scores ranging from 5 to 9 (SF) and 27 with a score of 0 (NF). Urinary and water fluoride levels were determined using an ion-selective fluoride electrode. Salivary proteomic profiling was conducted via LC–MS/MS, followed by comprehensive bioinformatic analysis. Results revealed significantly elevated urinary fluoride levels in the SF group (p = 0.007), whereas water fluoride levels did not significantly differ between the two cohorts. Both groups exhibited 104 detectable salivary proteins. The NF group demonstrated notable upregulation of LENG9, whereas the SF group displayed upregulation of LDHA, UBA1, S100A9, H4C3, and LCP1, all associated with the CFTR ion channel. Moreover, the NF group uniquely expressed 36 proteins, and Gene Ontology and pathway analyses suggested a link with various aspects of immune defense. In summary, the study hypothesized that the CFTR ion channel might play a predominant role in severe fluorosis and highlighted the depletion of immune-related salivary proteins, suggesting compromised immune defense in severe fluorosis. The utility of urinary fluoride might be a reliable indicator for assessing excessive fluoride exposure.

Organochlorine pesticide residues and urinary arsenic and fluoride levels in mothers and their newborns who are residents of rural areas in Durango State, Mexico

ABSTRACT Maternal and prenatal exposure to organochlorine pesticides (OCP), arsenic (As), and fluoride (F−) is a critical public health concern. The present study assessed serum OCP residues and urinary As and F− levels in mother and newborn pairs who are residents of rural areas of Durango State, Mexico, from August 2018 to February 2019. Levels of OCP, As, and F− were measured in serum and urine samples by Gas chromatography – Tandem mass spectrometry (GC – MS/MS), Hydride generation – Atomic fluorescent spectrometry (HG-AFS, and ion-selective electron analysis (ISE), respectively, in 60 binomial mothers – newborns. Dieldrin, endrin aldehyde, and endosulfan-II were significantly higher in newborns than in mothers (p ˂0.05). Meanwhile, no significant differences were observed for As and F− concentrations between mother – newborn pairs. Differences were observed in ∑Dienes and ∑DDTs comparing newborns with normal and low birth weights and a positive relationship in ƩDienes, ƩChlordanes, and ƩDDTs between mother and newborn pairs (p ˂ 0.05). These findings highlight the importance of extensive research regarding the influence of pollution.

Association between fluoride exposure and psychiatric disorders in adults

ABSTRACT To explore the association between fluoride exposure and depression / anxiety in adults, the 1,169 participants were recruited. The demographic information of participants was obtained through questionnaire survey and physical measurements. Morning urine samples were collected, and urinary fluoride (UF) level was determined. Changes in depression and anxiety levels were evaluated using the Patient Health Questionnaire-2 and General Anxiety Disorder-2 scales. The association between psychiatric disorders and UF levels was analyzed. In the total population, the prevalence of depression and anxiety were 3.17% and 4.19%, respectively. These results showed no significant association between depression / anxiety scale scores and UF levels. Logistic regression suggested no significant association between depression / anxiety levels, and UF levels, but there was an interaction between UF and income on depression. Our findings highlighted the interaction between fluoride exposure and monthly income, which may affect depression in adults.

Impaired neurogenesis induced by fluoride via the Notch1 signaling and effects of carvacrol intervention

The negative regulation on neurogenesis has been implicated in fluoride neurotoxicity, while the evidence is limited. To explore whether fluoride interferes with neurogenesis via the Notch1 signaling and the potential alleviation effects of carvacrol (CAR), we conducted in vivo and in vitro experiments, as well as epidemiological analyses in this study. The results showed that urinary fluoride levels and circulating Notch1 levels were associated with IQ levels in boys. NaF-treated rats had fewer neurons, lower densities of dendritic spines, depressed neurogenesis, and impaired learning and memory abilities. In vitro experiments using undifferentiated PC12 cells mimicking neurogenesis revealed that NaF suppressed differentiation and neurite outgrowth. Besides, Notch1 signaling activation was detected in vivo and in vitro. The latter was confirmed using an in vitro model supplemented with DAPT, a potent Notch1 inhibitor. Furthermore, CAR supplementation negatively regulated NICD1 and Hes1 expressions and promoted hippocampal neurogenesis, thereby improving neurological functions in NaF-treated rats. These findings indicated that the inhibition of neurogenesis in hippocampi induced by fluoride via Notch1 signaling activation may be one of the underlying mechanisms of its neurotoxicity, and that CAR significantly alleviated the neurotoxicity of NaF via the Notch1 signaling.

Effect of Groundwater Fluoride Concentration on Human Health: A Systematic Review

In studies conducted by various researchers it was observed that the groundwater is polluted by fluoride in most of the parts of World. Due to reported health related issues some workers carried out carcinogenic risk assessments and meta-analysis of fluoride exposure to humans. In this context, fluoride concentration data in groundwater across India by systematic searches conducted in various international search engines databases was collected. In some tests High water and urine fluoride levels in children indicated the chronic exposure to fluoride and suggested that the population is at high risk of developing chronic fluorosis in some regions of World. This paper highlighted the research work of various workers wherein Fluoride concentration risk factors related to human health are pointed and also discussed the steps to reduce fluoride in ground water. Keywords: Fluoride, Carcinogenic risk assessment, meta-analysis, ground water, chronic fluorosis.

Correlations between bone metabolism biomarkers and fluoride exposure in adults and children

Increased exposure to fluoride, which notably affects bone metabolism, is a global concern. However, the correlations and sensitivity of bone metabolism to fluoride remain controversial. In this cross-sectional study, 549 children (aged 7–12 years) and 504 adults (≥ 18 years old) were recruited in the high-fluoride areas of the Henan Province. Urinary fluoride (UF) level was determined using a fluoride electrode. Fasting venous blood serum was collected to measure bone metabolism biomarkers. The selected bone metabolism biomarkers for children included bone alkaline phosphatase (BALP), serum alkaline phosphatase (ALP), osteocalcin (OCN), calcitonin (CT), parathyroid hormone (PTH), phosphorus (P5+), and calcium (Ca2+). For adults, the biomarkers included ALP, CT, PTH, β-CrossLaps (β-CTX), P5+, and Ca2+. The correlations between UF and bone metabolism biomarkers were analyzed using binary logistic regression, a trend test, a generalized additive model, and threshold effect analysis. Regression analysis indicated a significant correlation between serum OCN, PTH, and UF levels in children aged 7–9 years. Serum OCN, PTH, and BALP contents were significantly correlated with UF in boys (P < 0.05). Furthermore, the interaction between age and UF affected serum P5+ and PTH (P < 0.05). The generalized additive model revealed nonlinear dose–response relationships between P5+, BALP, and UF contents in children (P < 0.05). Serum OCN level was linearly correlated with the UF concentration (P < 0.05). Similarly, a significant correlation was observed between β-CTX and UF levels in adults. In addition, significant correlations were observed between UF–age and serum Ca2+, β-CTX, and PTH contents. There was a non-linear correlation between serum Ca2+, P5+, and β- CTX and UF levels (P < 0.05). Overall, serum OCN, BALP, and P5+ levels can serve as sensitive bone metabolism biomarkers in children, while β-CTX, P5+, and Ca2+ can be considered fluoride-sensitive bone metabolism biomarkers in adults.

Correlation between dental fluorosis risk and bone-specific alkaline phosphatase, osteocalcin, matrix metalloproteinase and parathyroid hormone in children.

The aim of this study was to investigate the association between dental fluorosis occurrence in children and bone metabolism-related indicators, including bone-specific alkaline phosphatase (BALP), osteocalcin (OC), matrix metalloproteinase (MMP-2, MMP-9, MMP-20), and parathyroid hormone (PTH). A total of 189 cases of school-age children who underwent health examinations in our hospital were enrolled, according to the presence or absence of dental fluorosis. They were divided into the fluorosis group (n=97) and fluoride-free group (n=92), and the serum BALP, OC, MMP-2, MMP-9, MMP-20, and PTH levels of the two groups were compared and relevant clinical data were collected. This study employed multivariate logistic regression to examine the factors associated with the development of dental fluorosis in children. The urine fluoride levels, BALP, MMP-2, and MMP9 of the children in the fluorosis group were higher than fluoride-free group, and the mother's educational level, per capita annual household income, OC, and PTH were lower than fluoride-free group (P<0.05). Based on Spearman correlation analysis, a positive correlation was identified between the urinary fluoride level, the extent of dental fluorosis, and indicators such as BALP, MMP-2, and MMP-9. (r=0.618, 0.558, 0.567, 0.597, 0.602, 0.571, P<0.001), and negatively correlated with OC and PTH (r=-0.580, -0.603, -0.549, -0.515, P<0.001). As the urinary fluoride level and the extent of dental fluorosis increased, there was a gradual elevation in serum BALP, MMP-2, and MMP-9 levels in children, while OC and PTH levels gradually decreased (P<0.05). After adjusting for confounding factors, including urinary fluoride, maternal education level, and per capita annual household income, multivariate Logistic regression analysis showed that BALP, OC, MMP-2, MMP-9, and PTH were independently associated with the risk of dental fluorosis (P<0.05). High BALP, MMP-2, MMP-9, low OC, and PTH are independent factors affecting the occurrence of dental fluorosis and are related to the extent of dental fluorosis.

The effect of experimentally induced acute fluoride poisoning on the thyroid gland and hormones in geriatric rats.

The aim of this study was to investigate the effects of fluoride on the thyroid gland and hormones in rats with acute poisoning by different doses of fluoride. For this purpose, a total of 5 groups were formed, including a control (C) group of 8 rats and 4 test groups consisting of 10 rats each. Toxicity was induced with NaF at doses of 45, 60, 70, and 90 mg/kg/bw in the test groups F45, F60, F70, and F90, respectively. During the study, 2 rats died in F45, 3 in both F60 and F70, and 4 in F90. Surviving rats were euthanized 24 hours after poisoning, and blood samples were collected. Urine samples were also taken before and after poisoning. Urinary fluoride levels increased after intoxication and were found to be statistically significant. There were no significant differences in the levels of thyroid hormones TT3, TT4, and FT4 between the test groups and the control group. However, a significant decrease in FT3 levels was observed in the test groups compared to the control group. Although there were no significant changes in TSH hormone levels in the F45 and F90 groups compared to the control group, a significant decrease was observed in the F60 and F70 groups. Histopathological examination revealed follicular degeneration, a decrease in the volume of colloidal fluid, and atypical follicular epithelium in the thyroid glands of the test groups. In conclusion, abnormal changes in the thyroid gland and hormones were observed in rats with acute poisoning by different doses of fluoride.

Fluoride exposure and pediatric kidney health in dry, wet and intermediate climatic zone communities in Sri Lanka: Implications from urinary Cystatin-C, and albumin-creatinine ratio

BackgroundHigh fluoride exposure is increasingly discussed attributing to kidney injury as a causative factor. Depending on geochemistry, differential fluoride levels in drinking water are identified in different regions in Sri Lanka. However, the levels of fluoride exposure, and associations with kidney health has not been adequately studied in Sri Lanka, particularly in pediatric communities. Hence, the present study aimed to assess fluoride exposure in selected pediatric communities in the dry, wet and intermediate climatic zones in Sri Lanka, along with an assessment of renal health using urinary Cystatin-C (uCys-C), and albumin-creatinine ratio (uACR). MethodsWe conducted a cross-sectional study with school students in selected education zones representing dry (N = 331), wet (N = 152), and intermediate (N = 292) climatic zones in Sri Lanka. Fluoride contents in urine and drinking water were assessed as measures of fluoride exposure. ResultsThe median (interquartile distance) urinary fluoride levels of participants in the dry, wet and intermediate zones were 1.63(1.04–2.85), 1.29(0.85–2.21), and 1.07(0.61–1.98) mg/gCr while the fluoride contents of drinking water samples were 1.76(1.36–2.30), 0.25(0.18–0.37), and 0.43(0.26–0.63) ppm respectively with significant differences among the three groups. Median uCys-C level (ng/mgCr) of the participants in intermediate zone [30.26(8.49–71.44)] was significantly low (p < 0.05) compared to that of the participants in dry zone [56.19(7.08–211.8)], and wet zone [66.29(30.43–125.20)]. The incidences of elevated uCys-C levels above reference intervals in participants of dry zone (47.7%), and wet zone (50.0%) were significantly high (p < 0.001) compared to the intermediate zone (26.4%). ConclusionRelatively high fluoride exposure is likely in dry and wet zone communities compared to the intermediate zone along with significantly higher incidence of uCys-C levels above reference intervals in study groups with higher fluoride exposure. However, to conclude a clear link between fluoride exposure and kidney health we need in-depth studies.

Association between urinary fluoride concentrations and the prevalence of metabolic syndrome in adult individuals from the Central Region of Mexico

ABSTRACT Emerging scientific studies have supported the hypothesis that exposure to environmental chemicals increases the incidence of diverse human metabolic disorders. Therefore, this study aimed to evaluate the association between fluoride exposure and metabolic syndrome (MetS) prevalence in people from the Central Region of Mexico. This research included 575 adult individuals. Urinary fluoride concentrations were determined using a potentiometric method. Anthropometric measurements and blood pressure were also acquired. Serum fasting glucose and lipid levels were quantified. For the MetS screening, we used the International Diabetes Federation (IDF) and National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria. The mean urinary fluoride levels were 3.50 ± 2.50 mg/L. The prevalence of MetS was approximately 27 and 25% according to NCEP ATP III and IDF criteria, respectively. A multivariate logistic regression analysis showed significant associations (p < 0.05) between urinary fluoride concentrations and MetS occurrence using NCEP ATP III criteria (OR = 1.60; 95% CI 1.05–2.10) and IDF criteria (OR = 1.35; 95% CI 0.95–1.45). These findings emphasize the need to discover the underlying mechanisms that fluoride exposure has on MetS pathogenesis.