Fluorosis Areas Research Articles

Fluoride Exposure from Drinking Water Increases the Risk of Stroke: An Ecological Study in Changwu Town, China.

Stroke is a major cause of death globally and the leading cause in China. Excessive fluoride exposure has been linked to cardiovascular conditions related to stroke risk factors such as hypertension, atherosclerosis, dyslipidemia, and cardiomyopathy. However, evidence supporting the association between fluoride exposure and stroke risk is limited. We constructed an ecological study in Changwu Town, Heilongjiang Province, China, a typical endemic fluorosis area caused by excessive fluoride exposure from drinking water. We collected demographic data, stroke prevalence, and mortality information from 2017 to 2021. Fluoride exposure data were obtained from the national monitoring project on endemic fluorosis. Water fluoride concentrations were measured using the standardized methods. Trend changes in stroke rates were assessed using annual percentage change (APC). Differences in stroke rates among fluoride exposure groups were analyzed using chi-square tests. From 2017 to 2021, the all-ages and age-standardized stroke prevalence rates of permanent residents in Changwu Town increased year by year, while the all-ages and age-standardized mortality rates did not change significantly. The prevalence rates of stroke were significantly higher in endemic fluorosis areas compared to non-endemic areas (p < 0.001). Stratifying the population into tertile groups based on the water fluoride cumulative exposure index (WFCEI) revealed statistically significant differences in stroke prevalence rates (p < 0.001), showing a dose-response relationship with the WFCEI. However, the all-ages and age-standardized mortality rates of stroke were not found to be related to fluoride exposure. Long-term excessive fluoride exposure from drinking water may increase the risk of stroke prevalence, indicating fluoride overexposure as a potential risk factor for stroke.

Interventional clinical trial on mitigating endemic fluorosis in pregnant and lactating eweswith Spirulina platensis and its impact onlamb production traits.

This interventional clinical trial aimed to assess the potential impact of Spirulina platensis supplementation on pregnant and lactating ewes living in a Moroccan endemic fluorosis area. Forty-eight ewes were divided into four equal groups: Groups I and II served as controls belonging respectively to fluorosis-free and endemic fluorosis areas, Groups III and IV received respectively 250 and 500 mg*kg-1 BW/day of S. platensis, during late pregnancy and early lactation. The results revealed that ewes reared in fluorosis-free areas exhibited significantly lower plasma fluoride and significantly higher haemoglobin levels compared to endemic fluorosis areas (P < 0.0001). However, supplementation with 500 mg*kg-1 BW*day-1 of S. platensis significantly improved these two parameters compared to Group II (P < 0.0001). Ewes in the endemic area also displayed increased oxidative stress (P < 0.05), characterized by decreased ascorbic acid levels and catalase activity, as well as elevated levels of reduced glutathione and malondialdehyde. Supplementation with 500 mg*kg-1 BW*day-1 of S. platensis enhanced the antioxidant status (P < 0.05) by increasing ascorbic acid levels and catalase activity and decreasing levels of reduced glutathione and malondialdehyde. Moreover, this dose yielded similar average daily gains compared to lambs of ewes living in fluorosis-free area. In conclusion, S. platensis may serve as a promising solution for addressing endemic fluorosis in pregnant and lactating ewes.

Water pollution with fluoride in the Republic of Moldova and its impact on oral health

Water quality, especially drinking water quality, is one of the most essential requirements for the survival of not only mankind but all terrestrial life on Earth. As a determining factor of health, the quality of drinking water must correspond to sanitary regulations, and the violation of the water protection regime results in pollution. Water pollution is one of the major threats to public health in the Republic of Moldova. According to data compiled by the Yale Center for Environmental Law and Policy, globally, the Republic of Moldova was placed 83rd out of 180 countries in terms of drinking water quality, the first place being occupied by the countries with the highest drinking water quality. The „age-standardized life-years lost per 100,000 people due to exposure to unsafe drinking water (Daily rate)” is a measure used to evaluate the quality of water. The Daly score for the Republic of Moldova in 2022 was 50.0. The Republic of Moldova is considered a biogeochemical zone with regard to some chemical elements in the environment, including the content of fluorine in groundwater, soil, and subsequently in food products. The analysis of water samples taken by the National Public Health Center of the Republic of Moldova demonstrated that in 90% of cases, water sources subjected to laboratory investigations for microbiological and chemical parameters (boron, fluorine, and nitrates) do not meet the requirements. The present study was a prospective, observational one, the main objective of which was to evaluate the epidemiological dental characteristics of children from the fluorosis-endemic area of the Republic of Moldova. The study targeted 520 12- and 15-year-old children from Fălești district, where the fluoride concentration in drinking water exceeds 16 times the permissible norm of 16.2 ppm/l. Thus, the prevalence of dental fluorosis in this locality (Dean index ≥1) was 98.7 for 12-year-old children and 100% for 15-year-old adolescents. The prevalence of dental caries was 51.2% with an intensity of 2.1 for 12-year-old children, and for 15-year-old children, the prevalence was 67.1% with an intensity of 3.5. Children’s age and severity of dental fluorosis were independent predictors of dental caries intensity. Thus, a positive correlation was established between the severity of dental fluorosis and the intensity of dental caries in both study groups and in all groups of teeth. The percentage of children with a COAD index (decayed, filled, or absent teeth) ≥1 was higher in those whose Dean index was ≥ 5 in the second molar compared to other groups of teeth. Conclusion. Dental fluorosis remains the most common dental disease in fluorosis-endemic areas, and the severity of fluorosis increases with increasing fluoride concentrations in drinking water. Contrary to the previously established opinion, tooth decay also develops in children from endemic areas of fluorosis, and its frequency and intensity are directly correlated with the concentration of fluoride in drinking water. The higher the concentration of fluoride, the higher the values of the prevalence indices and intensity of dental caries. Republic of Moldova performs suboptimally in the prevention of oral diseases in the pediatric population, and the implementation of dental disease prevention programs would have major implications for improving dental morbidity.

العلاقة بين سمية الفلوريد والإجهاد التأكسدي ومضاعفات الحمل لدى النساء اللواتي يعشن في مناطق التسمم بالفلور

كان الهدف من هذه الدراسة هو التحقيق من العلاقة بين مستويات فلوريد البلازما المرتفعة، والإجهاد التأكسدي، ومضاعفات الحمل (الإجهاض، وموت الجنين داخل الرحم، والولادة المبكرة، وتسمم الحمل) لدى النساء اللواتي يعشن في إقليم سطات بالمغرب. تم جمع عينات الدم من النساء الحوامل ذوات الحمل الطبيعي (عدد = 60)، والإجهاض (عدد = 20)، وموت الجنين داخل الرحم (عدد = 10)، والولادة المبكرة (عدد = 20)، وتسمم الحمل (عدد = 20). بعد ذلك، تم تحديد مستويات فلوريد البلازما والأنشطة الأنزيمية لخلايا الدم الحمراء من superoxide dismutase (SOD)، catalase (CAT)، glutathione peroxidase (GPx). أظهرت النتائج أن مستويات الفلوريد في البلازما أقل بشكل ملحوظ عند النساء ذوات الحمل الطبيعي بتركيز 0.030 ± 0.003 ملغم / لتر مقارنة بالنساء اللائي تعرضن للإجهاض وموت الجنين داخل الرحم والولادة المبكرة وتسمم الحمل، بتركيزات 0.040 ± 0.002، 0.037 ± 0.002، 0.034 ± 0.004 و0.034 ± 0.003 ملغم / لتر، على التوالي. بالإضافة إلى ذلك، زاد نشاط SOD بشكل ملحوظ عند النساء اللواتي يعانين من مضاعفات الحمل، بينما انخفضت أنشطة CAT وGPx مقارنة بالنساء ذوات الحمل الطبيعي. علاوة على ذلك، لوحظ وجود علاقة قوية بين مستويات فلوريد البلازما وأنشطة مضادات الأكسدة ومضاعفات الحمل. قد يؤدي وجود مستويات عالية من فلوريد البلازما إلى زيادة انتشار الإجهاض ووفاة الجنين داخل الرحم والولادة المبكرة وتسمم الحمل، عبر مسار الإجهاد التأكسدي لدى النساء الحوامل اللواتي يعشن في إقليم سطات بالمغرب.

Identifying the oral microbiome of adolescents with and without dental fluorosis based on full-length 16S rRNA gene sequencing.

Dental fluorosis, resulting from long-term environmental exposure to fluoride, is prevalent among diverse populations worldwide. Severe fluorosis not only compromises the aesthetic appeal of teeth but also impairs their functionality. This study aims to investigate the oral microbiome in dental fluorosis and the health individuals of adolescents living in the endemic fluorosis area of Guizhou, China through full-length 16S rDNA sequencing. Fourty-six individuals meet the sampling criteria, and we divided these samples into the following groups: a healthy group (H = 23) and a dental fluorosis group (F = 23), and two subgroups of Miao ethnicity: a healthy Miao group (Hm = 13) and a dental fluorosis Miao group (Fm = 15). A total of 660,389 high-quality sequences were obtained, and 12,007 Amplicon Sequence Variants (ASVs) were identified, revealing significant variations in oral microbiome between Fm and Hm groups. The composition of oral microbiota was similar between the H and F groups. At the genus level, Pseudopropionibacterium and at the species level, Streptococcus oralis_subsp.dentisani_clade_058 were less abundant in group F than in group H (P < 0.05). Further analysis revealed that the abundance of Capnocytophaga gingivalis and Kingella denitrificans was significantly lower in Fm fluorosis patients than in the Hm group (P < 0.05). Based on the LEfSe analysis, the potential core biomarkers in the oral of Fm fluorosis patients were identified at different taxonomic levels, ranging from phylum to species. These include Gammaproteobacteria, Prevotella sp_HMT_304, Gemella sanguinis, and Gracilibacteria_(GN02). Network analysis revealed that the microbiota in the fluorosis group exhibited more complex interactions with each other than the healthy group. Notably, within the Hm group, the potential biomarkers Capnocytophaga gingivalis and Kingella denitrificans exhibited a positive correlation. Finally, we employed PICRUSt2 analysis to explore the abundance clustering of the top 30 functional units in each sample, and we found that the metabolic pathway compositions of the four groups were similar. In summary, our findings suggest that the microbial composition of plaque in Hm patients with dental fluorosis is significantly altered, and we identified the potential marker microorganisms that contribute to these changes.

Fluorine pollution in a sheep fluorosis area of the northern Helan Mountains, Ningxia, China

The relationship between endemic sheep fluorosis and coal mining and combustion in Helan Mountain, Ningxia, China, is lacking clear research and understanding.

Spatial-Temporal Analysis of Drinking Water Type of Endemic Fluorosis - China, 2009-2022.

Endemic fluorosis, caused by high fluoride levels in drinking water, has been a significant health issue in rural areas of China for many decades. There has been a notable decline in the detection rate of dental fluorosis in children aged 8-12 years in drinking water fluorosis areas across the country from 2009 to 2022. While 14 provincial-level administrative divisions are classified as low-probability clusters, Tianjin remains classified as a high-probability cluster. The current policy for preventing and controlling endemic fluorosis in China needs adjustment. Rather than focusing solely on regions with high incidence, there should be a shift towards monitoring and early warning of fluoride exposure. Additionally, local containment measures should be intensified.

Exposure to fluoride exacerbates the cognitive deficit of diabetic patients living in areas with endemic fluorosis, as well as of rats with type 2 diabetes induced by streptozotocin via a mechanism that may involve excessive activation of the poly(ADP ribose) polymerase-1/P53 pathway

Epidemiology has shown that fluoride exposure is associated with the occurrence of diabetes. However, whether fluoride affects diabetic encephalopathy is unclear. Elderly diabetic patients in areas with endemic (n = 169) or no fluorosis (108) and controls (85) underwent Montreal Cognitive Assessment. Sprague-Dawley rats receiving streptozotocin and/or different fluoride doses were examined for spatial learning and memory, brain morphology, blood-brain barrier, fasting blood glucose and insulin. Cultured SH-SY5Y cells were treated with 50 mM glucose and/or low- or high-dose fluoride, and P53-knockdown or poly-ADP-ribose polymerase-1 (PARP-1) inhibition. The levels of PARP-1, P53, poly-ADP-ribose (PAR), apoptosis-inducing factor (AIF), and phosphorylated-histone H2A.X (ser139) were measured by Western blotting. Reactive oxygen species (ROS), 8-hydroxydeguanosine (8-OHdG), PARP-1 activity, acetyl-P53, nicotinamide adenine dinucleotide (NAD+), activities of mitochondrial hexokinase1 (HK1) and citrate synthase (CS), mitochondrial membrane potential and apoptosis were assessed biochemically. Cognition of diabetic patients in endemic fluorosis areas was poorer than in other regions. In diabetic rats, fasting blood glucose, insulin resistance and blood-brain barrier permeability were elevated, while spatial learning and memory and Nissl body numbers in neurons declined. In these animals, expression and activity of P53 and PARP-1 and levels of NAD+, PAR, ROS, 8-OHdG, p-histone H2A.X (ser139), AIF and apoptosis content increased; whereas mitochondrial HK1 and CS activities and membrane potential decreased. SH-SY5Y cells exposed to glucose exhibited changes identical to diabetic rats. The changes in diabetic rats and cells treated with glucose were aggravated by fluoride. P53-knockout or PARP-1 inhibition mitigated the effects of glucose with/without low-dose fluoride. Elevation of diabetic encephalopathy was induced by exposure to fluoride and the underlying mechanism may involve overactivation of the PARP-1/P53 pathway.

Fluoride exposure and prevalence of osteochondroma in drinking water Endemic fluorosis areas of Heilongjiang Province, China: a cross-sectional study

ABSTRACT To investigate the relationship between fluoride exposure and Osteochondroma (OC) prevalence, a cross-sectional study was conducted in drinking water endemic fluorosis areas of Heilongjiang Province, China. Our study first reported that the prevalence of OC was 2.3% in drinking water endemic fluorosis areas of Heilongjiang Province, China, and no difference in gender. Logistic regression analysis found that compared to 1st quartile participants, the prevalence of OC was 73% lower in the 2nd quartile participants of WF (Water fluoride), and 3.4 times higher among the 2nd quartile UF (Urinary fluoride) participants. Our study suggests that 0.259–0.420 mg/L of WF may be considered an appropriate level for reducing OC prevalence, while UF (≥0.750 mg/L) could slightly increase the prevalence of OC. In summary, the link between fluoride and OC prevalence is complicated and needs to be further investigated in a cohort population.

Epidemiological analysis of drinking water-type fluorosis areas and the impact of fluorosis on children’s health in the past 40 years in China

This study analyzed the effect of China’s fluorosis prevention and control program, which has been in effect for more than 40 years, and the impact of fluorosis on children’s health. Relevant research studies were retrieved from the following online databases from the time of their inception to May 2022: PubMed, ScienceDirect, Embase, Cochrane, China National Knowledge Infrastructure, and Wanfang. The Review Manager 5.3 software was used in statistical analyses. This article included seventy studies: Thirty-eight studies reported the effect of improving water quality and reducing fluoride content, the incidence rate of dental fluorosis in children, and the level of urinary fluoride, and thirty-two studies reported the intelligence quotient (IQ) and health status of children. Following water improvement strategies, the fluoride levels in drinking water decreased significantly; urinary fluoride levels and dental fluorosis decreased significantly in children. With regard to the effect of fluorosis on the IQ of children, the results showed that the IQ of children in areas with a high fluoride of fluorosis was lesser than that in areas with a low fluoride, and this difference was significant. Based on the prevalence of dental fluorosis and its effect on the intelligence of children, it appears that reducing fluoride levels in drinking water and monitoring water quality are important strategies for the prevention and treatment of fluorosis.Graphical abstract

An interventional clinical trial investigating the effects of Spirulina platensis on dental fluorosis and antioxidant system in lambs reared in endemic areas

This study aimed to evaluate the protective effect of Spirulina platensis primary against dental fluorosis and secondary against oxidative stress in lambs reared in endemic fluorosis areas. Forty-eight lambs aged 5 months were divided into four equal groups (each one including 6 males and 6 females). Groups I and II served as controls belonging respectively to fluorosis-free (Settat) and endemic fluorosis (El Fokra) areas, while the other two Groups III and IV (belonging to El Fokra) received respectively a fixed daily intake of 250 and 500 mg/kg bodyweight (BW) of Spirulina platensis. The experiment was carried out for 13 months until the adult incisors appeared for all animals. According to the Dean’s Fluorosis Index (DFI), 500 mg/kg BW/day of Spirulina platensis (Group IV) protected against dental fluorosis. Moreover, in both male and female lambs, this dose significantly (p < 0.0001) reduced the plasmatic levels of fluoride, proteins, GSH, and MDA compared to the Group II. Furthermore, enzymatic activities of catalase and SOD increased significantly (p < 0.0001) in male and female lambs of the Group IV as compared to Group II. In conclusion, our findings support the potential use of Spirulina platensis as a valuable solution for addressing fluorosis in sheep, warranting further clinical trials.

Association between mtDNA haplogroups and skeletal fluorosis in Han population residing in drinking water endemic fluorosis area of northern China

ABSTRACT To investigate the association between mtDNA genetic information and the risk of SF, individuals were conducted in the drinking water endemic fluorosis area in northern China, sequenced the whole genome of mtDNA, identified the SNPs and SNVs, analyzed the haplogroups, and diagnosed SF, and then, the effect of mtDNA genetic information on the risk of SF was evaluated. We find that, D5 haplogroup and its specific SNPs reduced the risk, while the D4 haplogroup and its specific SNPs increased the risk of SF. The number of SNVs in coding regions of mitochondrial respiratory chain (MRC) is different between the controls and cases. This suggests that D5 haplogroup may play a protective role in the risk of SF, while the opposite is observed for the D4 haplogroup, this may relate to their specific SNPs. And SNVs that encode the MRC complex may also be associated with the risk of SF.

Spatial correlation between the prevalence of dental fluorosis and the chemical elemental composition of drinking water sources in a typical coal-fired pollution fluorosis area

Objective: To investigate the spatial distribution characteristics and correlation between the prevalence of dental fluorosis and the chemical elemental composition of drinking water sources in coal-fired fluorosis areas. Methods: Based on the survey data on the prevalence of dental fluorosis at CDC in Guizhou Province in 2022, 274 original surface drinking water sources were collected in typical coal-fired fluorosis areas, and fluoride (F), calcium (Ca), magnesium (Mg), aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), cadmium (Cd), barium (Ba), lead (Pb) 17 elements; apply Moran's I index, Getis-Ord Gi* hotspot analysis of the global spatial autocorrelation of chemical elements in drinking water and the degree of aggregation of each element on the local area, and correlation analysis with the prevalence of dental fluorosis in the region. Results: Except for Cu, Zn, and Cd, global spatial autocorrelation Moran's I was negative, and all other elements were positive. F, Ca, Al, Ti, As, Mo, Cd, and Cu elements showed high values of aggregation in the southeastern low-altitude area; Mg, Ba, Pb, Cr, Mn, and Fe elements were mainly aggregated in the central altitude terrain transition area, Zn and Se elements in water sources are significantly positively correlated with the prevalence of dental fluorosis (P<0.05). In contrast, F, Mg, Al, Ti, As, Mo, Cd, Ba, and Pb elements negatively correlate (P<0.05). Elements in the central region were high-high aggregation, as a hot spot aggregation area with high disease incidence, while F, Al, Mn, Mo, Cd, and Ba elements in the western region were low-low aggregation, as a cold spot aggregation area with a low incidence of fluorosis. Conclusions: The risk of population fluoride exposure in surface drinking water sources is shallow. However, the chemical element content of drinking water sources in coal-fired polluted endemic fluorosis areas has prominent spatial geographical distribution characteristics. There is a significant spatial aggregation effect with the prevalence of dental fluorosis, which may play a synergistic or antagonistic effect on the occurrence and prevalence of dental fluorosis.

Association of Dental Fluorosis and Urinary Fluoride with Intelligence among Schoolchildren.

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.

Association between low fluoride exposure and children's intelligence: a meta-analysis relevant to community water fluoridation

ObjectivesPrevious meta-analyses have mainly focused on studies conducted in endemic fluorosis areas with relatively high fluoride concentrations. These are impoverished rural communities in China, India, and Iran, and the findings cannot be generalised to developed countries. Therefore, we investigated the association between fluoride concentrations relevant to community water fluoridation and children's cognition measured with IQ scores by synthesising effect sizes reported in observational studies. MethodsA previous meta-analysis and the National Toxicology Program database that included a search of multiple databases and the authors' search of PubMed, Google Scholar, and Mendeley provided the data. Cross-sectional and cohort studies examining the association between fluoride and children's cognition and intelligence scores were selected. Two reviewers abstracted data using standard procedures. We performed three meta-analyses to synthesise the effects using the random effects models. ResultsEight studies of standardized mean difference in IQ scores from non-endemic fluorosis areas found no statistically significant difference between recommended and lower levels of fluoride (standardized mean difference = 0.07; 95% confidence interval: −0.02, 0.17; I2 = 0%), and no significant fluctuation in IQ scores across the differences in fluoride concentrations by non-linear modeling with restricted cubic spline (P = 0.21). Meta-analyses of children's and maternal spot urinary fluoride associated pooled regression coefficients (Betachildren = 0.16; 95% confidence interval: −0.40, 0.73; P = 0.57; I2 = 0%, Betamaternal = −0.92; 95% CI: −3.29, 1.46; P = 0.45; I2 = 72%) were not statistically significant. Further regression analysis by standardizing absolute mean IQ scores from lower fluoride areas did not show a relationship between F concentration and IQ scores (Model Likelihood-ratio test: P-value = 0.34.) ConclusionsThese meta-analyses show that fluoride exposure relevant to community water fluoridation is not associated with lower IQ scores in children. However, the reported association observed at higher fluoride levels in endemic areas requires further investigation.

Analysis of multiple pathways and levels of fluoride intake in fluorosis areas of Southwest China

In the coal-burning fluorosis areas of China, over 10 million people suffer from dental fluorosis caused by multiple pathways of fluoride intake. However, the link between dental fluorosis prevalence, the geochemical distribution of fluoride, and contributions of different exposure pathways remain unclear. Here, we aimed to quantify the various fluoride exposure pathways and establish the association between dental fluorosis and fluoride intake in Southwest China. Epidemiological data on the peak time of fluorosis prevalence were combined with geochemical analyses of the fluoride content in coal and clay over a large scale, the amounts and ratios of fluoride intake through different exposure pathways were calculated, and the association between the total daily fluoride intake (TDFI) and dental fluorosis severity was analyzed. The prevalence of dental fluorosis was not significantly correlated with the fluoride geo-background of coal and clay on a large scale (P > 0.05). The co-combustion of coal and clay contained in hand-made briquettes is the main pathway of fluoride contamination, which occurs through the inhalation of polluted air and consumption of contaminated roasted products. Furthermore, the TDFI per person ranged from 2.78 to 17.32 mg, and it was significantly positively correlated with the prevalence of dental fluorosis (P < 0.05). The TDFI from breathing and eating was 1.1–3.2 mg and 1.1–15.1 mg, which accounted for 9%–54% and 40%–90% of the total TDFI, respectively. The combination of living habits and soil geochemical fluoride anomalies resulted in the higher prevalence of fluorosis in rural areas of Southwest China.

Iodine Status in Pregnant Women Having Urinary Fluoride in Contaminated Areas: A Case Study of Phayao Province.

Fluoride naturally occurs in the Earth's crust and is widely dispersed in groundwater. The high consumption of fluoride can inhibit iodine metabolism in the human body, especially in the thyroid gland. This study assessed iodine knowledge, iodine consumption behavior, urinary iodine (UI), thyroid stimulating hormone (serum TSH), and free triiodothyronine3 (serum FT3) and examined the connection between fluoride exposure and UI and thyroid function as serum concentrations of TSH and FT3 in pregnant women dwelling in an area of endemic fluorosis. This was a cross-sectional study. The population included 152 pregnant women within the 1st trimester of pregnancy, during which they were provided antenatal care (ANC) in seven public community hospitals in Phayao province, Thailand. The study consisted of two components. First, the study consisted of a questionnaire in which we evaluated the iodine knowledge and iodine consumptive behaviors in subjects. Second, biochemical data were investigated to evaluate thyroid function in the subjects. The gestational age of most subjects was 8-12 weeks. The study population has lived in fluoride-contaminated areas since birth (76.97%). The iodine and iodine consumption levels were moderate (50.00%). Their food iodine consumption was 3-4 days/week, and the top five consumption ranks were iodized salt, cooked pork, eggs, sticky rice, and iodine fish sauce. In terms of biochemical parameters, 63.16% of respondents had UI levels below 150.00 g/L, which is below the normal reference range of 150.00-249.00 g/L. 89.47% of the risk of hypothyroidism was associated with serum TSH levels below 2.50 g/L. In 38.16% of the samples, normal levels of serum FT3 (2.00-4.40 pg/L) were identified in the subjects. In addition, 61.84% of the samples had FT3 concentrations greater than 4.40 pg/L (high intake of iodine). The approved association between positive serum FT3 data and serum TSH was positive (r = 260 and p < 0.05). These studies imply that these elevated levels of TSH and FT3 place pregnant women in their first trimester at risk for hypothyroidism.

Geo-Environmental Factors’ Influence on the Prevalence and Distribution of Dental Fluorosis: Evidence from Dali County, Northwest China

Residents living in areas with high fluorine environmental background will ingest excessive fluorine from the atmosphere, drinking water, food and other ways. Long-term effects of fluorine on the human body could cause people suffering from dental fluorosis and influence the sustainable development of the severe fluorosis areas. Previous studies have independently discussed the high fluoride environment in Dali County from the aspects of natural environment, drinking water quality and endemic fluorosis. This study carried out a detail investigation on dental fluorosis population in seven selected villages of Dali County, Shaanxi province, northwest China. The highest dental fluorosis index of 1.9 was found in Lianjia village located near the Anren depression, while the lowest dental fluorosis index of 0.0 was found in Jiaxi village near the Yellow River alluvium. Groundwater fluorine contents the range was 0.01 mg/L to 11.80 mg/L, with the highest value (2.6 mg/L) being observed in the 2nd terrace of Weihe River. The lowest groundwater fluorine content (0.8 mg/L) was observed in the Yellow River alluvium. Soil fluorine contents ranged from 1.18 mg/kg to 13.70 mg/kg, with its highest value (13.70 mg/kg) observed in Xinfeng village near the Anren depression. The lowest value of fluorine (1.18 mg/kg) was found in soil from the 1st terrace of Weihe River. As for the fluorine contents of corn, they ranged from 4.04 mg/kg to 7.72 mg/kg. The highest value (7.72 mg/kg) appeared in the 3rd terrace of Weihe River and the lowest value (4.04 mg/kg) in the 2nd terrace of Weihe River. The soil leaching was the dominant fluorine source of groundwater environment. Areas with severe dental fluorosis are located at the edge of the depression and the conjunction between steep slope and gentle slope. A poor correlation was found between the dental fluorosis index from the seven investigated villages and the corn fluorine content contrarily to the groundwater fluorine content, which positively correlated to the dental fluorosis index. Based on the obtained results, two recommendations were done to prevent and control dental fluorosis and accelerate the sustainable development in Dali County: to strengthen the use of low fluorine groundwater for drinking water supply, and to widely install the public water purifiers in the rural communities for purifying high-fluorine water to reduce the incidence of dental fluorosis in the population.

Weathering of Clay-Pyrite of Coal-Bearing Formation in the Endemic Fluorosis Area of Southwest China

Weathering of Clay-Pyrite of Coal-Bearing Formation in the Endemic Fluorosis Area of Southwest China

Association between dietary intake of one-carbon metabolism nutrients and hyperglycemia in coal-burning fluorosis areas of Guizhou, China.

Background and aimsThere are limited studies describing the association between dietary intake of one-carbon metabolism nutrients and hyperglycemia. The present study aimed to investigate the association of habitual dietary intake of one-carbon metabolism nutrients with hyperglycemia in a fluorosis area in China, and explored the interaction between these nutrients and fluorosis related to hyperglycemia.MethodIn a cross-sectional study, we recruited 901 villagers, ages ranging from 18–75, in Guizhou Province. Dietary data and other covariate data were obtained through an interviewer-administered questionnaire. We collected venous blood samples from participants who had fasted for one night to obtain fasting blood glucose levels and we categorized dietary intake of betaine, total choline, methionine, folate, vitamins B6 and B12, and choline subclasses into quartiles (Q1–Q4). The lowest quartile (Q1) served as the reference group. An unconditional logistic regression model was used to evaluate the protective effects of a dietary intake of one-carbon nutrients against hyperglycemia. We calculated Odds Ratios (ORs) with 95% confidence intervals (CIs). A presence or absence of fluorosis subgroup analysis was performed to determine the potential effect of fluorosis on hyperglycemia.ResultAfter adjusting for potential confounding factors, we found that a greater intake of dietary vitamin B6, total choline and methyl-donor index was inversely associated with the occurrence of hyperglycemia (P-trend <0.05). However, there were no significant associations between hyperglycemia and the dietary intake of folate, vitamin B12, methionine, and betaine. As for the choline subgroups, it showed that the dietary intake of free choline, phosphatidylcholine, and glycerol phosphatidylcholine was negatively correlated with the occurrence of hyperglycemia (P < 0.05). In contrast, there was no statistical association between dietary phosphatidylcholine and sphingomyelin and hyperglycemia (all P > 0.05). The results of subgroup analysis showed that dietary intake of folate, vitamin B6, total choline, free choline, glycerol phosphorylcholine, and phosphocholine had a protective effect against the occurrence of hyperglycemia in the non-fluorosis subgroup, although no effects were observed in the fluorosis subgroup. There were significant interactions between these nutrients and fluorosis (P = 0.010–0.048).ConclusionThe study demonstrated that higher dietary intake of vitamin B6, total choline, methyl-donor index, free choline, glycerol phosphorylcholine, and phosphocholine in choline compounds were associated with a lower incidence of hyperglycemia. Moreover, the associations were modified by the presence or absence of fluorosis. Further investigation is needed to test the association in large-scale follow-up studies.