Fluoride Content In Urine Research Articles

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.

Downregulation of miR-4755-5p promotes fluoride-induced osteoblast activation via tageting Cyclin D1

BackgroundEndemic fluorosis remains a major public health issue in many countries. Fluoride can cause abnormalities in osteoblast proliferation and activation, leading to skeletal fluorosis. However, its detailed molecular mechanism remains unclear. Based on a previous study, the aim of this study is to explore the role of miRNA in osteoblast activation of skeletal fluorosis via targeting of Cyclin D1. MethodsA population study of coal-burning fluorosis and in vitro experiments were performed in this study. Urine fluoride (UF) concentrations of the participants were determined using a national standardized ion selective electrode approach. Based on our previous miRNA sequence results, bioinformatic analysis was used to predict miR-4755-5p targeting Cyclin D1. Quantitative real-time PCR (qRT-PCR) was used to verify the expression of miR-4755-5p. The expression of Cyclin D1 mRNA was detected by qRT-PCR. The expression of Cyclin D1 protein was detected by enzyme-linked immunosorbent assay (ELISA) and Western blotting, respectively. Cell viability was detected by CCK-8 method. The distribution of the cell cycle was analyzed by flow cytometry. The alkaline phosphatase (ALP) activity and bone Gla protein (BGP) content were detected by micronutrient enzymes standard method and ELISA. The target binding between miR-4755-5p and Cyclin D1 was verified using dual-luciferase reporter assay. ResultsIn the fluoride-exposed population, the results showed that with the increase in UF content, the expression of miR-4755-5p decreased gradually, while the mRNA transcription and protein expression of Cyclin D1 increased gradually. The relative miR-4755-5p expression showed a negative correlation with Cyclin D1 expression. Subsequently, in human osteoblasts treated with sodium fluoride (NaF), the results also showed that NaF caused low expression of miR-4755-5p and increased expression of Cyclin D1. Further, the results of miR-4755-5p mimic transfection confirmed that under the action of NaF, miR-4755-5p overexpression reduced Cyclin D1 protein expression within osteoblasts and further inhibited cell proliferation and activation. Simultaneously, luciferase reporter assays verified that Cyclin D1 was the miR-4755-5p direct target. ConclusionThe results demonstrate that fluoride exposure induced the downregulation of miR-4755-5p and downregulated miR-4755-5p promoted fluoride-induced osteoblast activation by increasing Cyclin D1 protein expression. This study sheds new light on biomarkers and potential treatment for endemic fluorosis.

Sensitivity of two biomarkers for biomonitoring exposure to fluoride in children and women: A study in a volcanic area

The natural enrichment of water with fluoride is related to natural sources such as volcanic activity, with it being documented that fluorosis, an endemic and widespread disease in volcanic areas, is associated to the ingestion of high levels of fluoride through water. Thus, in this study, we aimed to define the fluoride concentration in drinking waters of volcanic origin and compare the sensitivity of urine and nail clippings as biomarkers for fluoride exposure in adults and children.Samples of drinking water from four villages in São Miguel Island (Azores) were used and the fluoride concentration was determined, as well the fluoride content in urine and toenails clippings from 66 children and 63 adults from these villages. A validated diet questionnaire, assessing sources of fluoride, was recorded for each participant. The fluoride determination in urine and nail clipping samples was made using a fluoride-specific electrode.A positive correlation was found between the fluoride daily intake and fluoride content in children urine (rs = 0.475; p < 0.001) and in their nail clippings (rs = 0.475; p < 0.001), while in adult women, the fluoride daily intake correlated positively with fluoride content nail clippings (rs = 0.495, p < 0.001).This reveals that nail clippings are more reliable as biomarkers of chronic exposure to fluoride than urine for populations of different ages (children vs. adults). Furthermore, nail clippings are more suitable than urine fluoride levels to assess long term exposure to fluoride in areas where the exposure to fluoride in drinking water is considered within, or slightly above, the recommended legal values.

Dental fluorosis, fluoride in urine, and nutritional status in adolescent students living in the rural areas of Guanajuato, Mexico.

Objective:The aim of this study was to assess urine fluoride concentration, nutritional status, and dental fluorosis in adolescent students living in the rural areas of Guanajuato, Mexico.Materials and Methods:A cross-sectional study was conducted including participants aged 11–20 years. The presence and severity of dental fluorosis was registered according to the Thylstrup and Fejerskov index (TFI) criteria. Anthropometric measures were also recorded. Urine sample of the first morning spot was recollected to assess urine fluoride concentration by using the potentiometric method with an ion-selective electrode. Water samples were also recollected and analyzed. Bivariate tests were performed to compare urine fluoride concentration according to different variables such as sex, body mass index, and TFI. Nonparametric tests were used. A logistic regression model was performed (SPSS® 21.0).Results:This study included 307 participants with a mean age of 15.6 ± 1.6; 62.5% of the participants showed normal weight. A total of 91.9% of the participants had dental fluorosis, and 61.6% had TFI > 4. Mean fluoride content in urine ranged between 0.5 and 6.65 mg/L, with a mean of 1.27 ± 1.2 mg/L. Underweight children showed greater urine fluoride concentration. The increment of urine fluoride was a related (OR = 1.40) to having severe dental fluorosis.Conclusions:Most of the studied population had moderate or severe dental fluorosis. Urine fluoride concentration was related to fluorosis severity and nutritional status. Underweight children showed greater urine fluoride concentration as well as severe dental fluorosis.

Association between urine fluoride and dental fluorosis as a toxicity factor in a rural community in the state of San Luis Potosi.

Objective. The aim of this study is to investigate urine fluoride concentration as a toxicity factor in a rural community in the state of San Luis Potosi, Mexico. Materials and Methods. A sample of 111 children exposed to high concentrations of fluoride in drinking water (4.13 mg/L) was evaluated. Fluoride exposure was determined by measuring urine fluoride concentration using the potentiometric method with an ion selective electrode. The diagnosis of dental fluorosis was performed by clinical examination, and the severity of damage was determined using Dean's index and the Thylstrup-Fejerskov (TF) index. Results. The range of exposure in the study population, evaluated through the fluoride content in urine, was 1.1 to 5.9 mg/L, with a mean of 3.14 ± 1.09 mg/L. Dental fluorosis was present in all subjects, of which 95% had severe cases. Higher urine fluoride levels and greater degrees of severity occurred in older children. Conclusions. The results show that dental fluorosis was determined by the presence of fluoride exposure finding a high positive correlation between the severity of fluorosis and urine fluoride concentration and the years of exposure suggested a cumulative effect.

Expression of sonic hedgehog signaling pathw ay and its inhibition by cyclopamine in rat liver with chronic fluorosis

To investigate the expression of sonic hedgehog (Shh) signaling pathway in liver fluorosis and to explore related mechanism. To establish animal model, 48 normal SD rats (aged 4-5 weeks) were randomly divided into 4 groups (12 each): control group, fluoriosis group, blocking group and blocking control group. After 6 months, the blocking group and blocking control group were injected intraperitoneally once every 2 days for 3 times with 10 mg/kg cyclopamine or dimethysulfoxide, respectively. Rats were sacrificed at the end of the experiment and the fluoride content in urine and liver function was determined. The expression of Shh and Gli1 protein and mRNA in hepatocytes was detected by immunohistochemistry and real-time fluorescence quantitative PCR, respectively. The fluoride contents in the urine and the incidence of dental fluorosis increased in the fluoride and blocking control groups as compared with those in the control group, but decreased in the blocking group compared with those of the fluoride and blocking control group. Compared with the control group, the titers of aspartate transaminase (AST) and alanine transaminase (ALT) significantly increased, while the activity of total protein and albumin decreased in the fluoride and blocking control groups. Compared with the fluoride and blocking control groups, the activity of the ALT slightly declined and the AST, total protein and albumin slightly increased in the blocking group. Histologically, the cells were disorganized and swollen with cytoplasmic clearing (balloon cells), compared with the control group. The expression of Shh and Gli1 significantly increased in all but the control group. Compared with the fluoride and blocking control groups, the expression of Shh and Gli1 declined in the blocking group. The overexpression and cyclopamine inhibition of the Shh signaling pathway are closely related to the content of fluoride in the liver. The Shh signaling pathway plays an important role in the pathogenesis of liver injury caused by fluorosis, suggesting a preventive and therapeutic target of the disease.

Changes of blood zinc content in patients with coal-burning endemic fluorosis and its implication

Objective To assess the association of zinc(Zn) with coal-burning endemic fluorosis(coal-burning fluorosis),so as to provide an evidence for the role of Zn in preventing coal-burning fluorosis.Methods Fifty children with dental fluorosis and 100 healthy controls were selected from Wushan County by stratified sampling,and the same number of children and controls were also selected from Fengjie County.Thirty adults were selected from skeletal fluorosis patients in Duping Township of Wushan County,and 60 healthy controls were selected in the same township.Fasting blood samples were collected from all the participants for Zn determination.Urine samples were collected to examine urine fluoride content.Wilcoxon rank sum test was used to analyze the differences in Zn and fluoride contents between cases and controls and between the two counties.The association between blood Zn and urine fluoride was examined by Pearson linear correlation/Spearman rank correlation.Results The average urine fluoride contents were significantly higher in the child fluorosis cases than in the controls from both counties(P0.01);and the average blood Zn contents were significantly lower in the fluorosis cases than in the controls from both counties(P0.01).Moreover,the child cases and controls from Wushan County had significantly lower average blood Zn contents compared with those from Fengjie County(P0.05);the child fluorosis cases in Wushan County had a significantly lower urine fluoride content compared with those from Fengjie County(P0.05).The average urine fluoride content of skeletal fluorosis adults from Wushan County was significantly higher than that of controls,and the average blood Zn content was significantly lower than that of controls(P0.01).In addition,Pearson linear correlation/Spearman rank correlation showed a weak positive relationship between blood Zn and urine fluoride in both children and adults(P0.05,P0.01).Conclusion It is indicated that patients with fluorosis are generally Zn deficient,suggesting Zn deficiency might be a risk factor for fluorosis.

Expression of mRNA and protein of p38, Osx, PI3K and Akt1 in rat bone with chronic fluorosis

To investigate the expressions of mRNA and protein of p38, Osx, PI3K, Akt1 in the rats bone with chronic fluorosis. Dental fluorosis were observed and the fluoride contents in the urine and bone were detected by fluorin-ion selective electrode. The morphologic changes and ultrastructure of rats' bone were observed by light and electronic microscopy. The expressions of protein and mRNA of p38, Osx, PI3K and Akt1 were detected by immunohistochemistry and real-time PCR, respectively. The contents of BALP and BGP in serum were detected by ELISA. The rates of dental fluorosis in the fluorosis rats were increased, and the fluoride contents in bone and urine of the fluorosis rats were increased compared to the control group, the difference was statistically significant (P < 0.05). The bone trabeculae thickness and density and the thickness of bone cortex in fluorosis rats were remarkably increased, the space of bone trabeculae was reduced, and in accordance with the matching morphometrical indices, the difference was statistically significant (P < 0.05) as compared with the control rats. The contents of BALP [(54.61 ± 2.27) U/L] and BGP [(2.38 ± 0.16) µg/L]in the fluoride groups were higher than those in the control group, the difference was statistically significant (P < 0.05). Ultrastructurally, the broadening of the osseouslacuna was observed. The reduced protuberances of the osteocytes, the unclear organelle structure, pyknosis, karyotheca increasation and edged chromatin were also observed. Compared to the control group, the expressions of protein and its mRNA of p38, Osx, PI3K and Akt1 were higher in the fluorosis rats than those in the control rats, and the difference was statistically significant (P < 0.05). There is no any expression of p38, Osx, PI3K and Akt1 in the osteocytes in fluorosis rats. The over-expression of p38, Osx, PI3K and Akt1 in bone tissue of fluorosis rats may relate to the accumulation of fluorine in the body. The bone injury mainly occur in the stage of the differentiation and proliferation. The upregulation of P38MARK signal path and PI3K/Akt1 signal path may be involved in the pathogenesis of bone injury caused by fluoride.

Alteration of mitochondrial distribution and gene expression of fission 1 protein in cortical neurons of rats with chronic fluorosis

To investigate the changes of mitochondrial distribution in axon/soma and the expression of mitochondrial fission 1 (Fis1) protein in the cortical neurons of rats with chronic fluorosis. Sixty SD rats were divided into 3 groups (20 each) according to weight hierarchy and fed with different concentrations of fluoride in drinking water (0, 10 and 50 mg/L, respectively) for 6 months. Images of mitochondria and tubulin labeled by immunofluorescence COXIV and tubulin-α were captured with fluorescence microscope. Fis1 protein expression in cortical neurons was analyzed with immunohistochemistry and Western blot. The expression of Fis1 mRNA was detected with real-time PCR. Varying degrees of dental fluorosis and increased fluoride contents in urine were observed in the rats receiving additional fluoride in drinking water. In the cortical neurons of rats fed with 10 mg/L and 50 mg/L fluoride, the numbers of neuronal soma stained with COXIV(34.8 ± 4.7 and 39.3 ± 3.0, respectively), and the expression of Fis1 protein (immunohistochemistry: 54.0 ± 3.6 and 51.3 ± 4.1, respectively; Western blot: 2.9 ± 0.4 and 2.6 ± 0.6, respectively) and mRNA (3773 ± 1292 and 1274 ± 162, respectively) was markedly increased as compared with controls (4.4 ± 2.3, 25.2 ± 2.5, 1.8 ± 0.2 and 277 ± 73) over the experimental period of 6 months. Excessive intake of fluoride results in an altered mitochondrial distribution in axon and soma in cortical neurons (i.e., the increase in soma and the decrease in axon), increased expression of Fis1 gene and enhanced mitochondrial fission. The altered mitochondrial distribution may be related to the high expression level of Fis1 and a functional disorder of mitochondria.

The Relationship of PTH Bst BI Polymorphism, Calciotropic Hormone Levels, and Dental Fluorosis of Children in China

The aim of this study was to explore the association of parathyroid hormone (PTH) gene Bst BI polymorphism, calciotropic hormone levels, and dental fluorosis of children. A case-control study was conducted in two counties (Kaifeng and Tongxu) in Henan Province, China in 2005-2006. Two hundred and twenty-five children were recruited and divided into three groups including dental fluorosis group (DFG), non-dental fluorosis group (NDFG) from high fluoride areas, and control group (CG). Urine fluoride content was determined using fluoride ion selective electrode; PTH Bst BI were genotyped using PCR-RFLP; osteocalcin (OC) and calcitonin (CT) levels in serum were detected using radioimmunoassay. Genotype distributions were BB 85.3% (58/68), Bb 14.7% (10/68) for DFG; BB 77.6% (52/67), Bb 22.4% (15/67) for NDFG; and BB 73.3% (66/90), Bb 27.7% (24/90) for CG. No significant difference of Bst BI genotypes was observed among three groups (P > 0.05). Serum OC and urine fluoride of children were both significantly higher in DFG and NDFG than in CG (P < 0.05, respectively), while a similar situation was not observed between DFG and NDFG in high fluoride areas (P > 0.05). Serum OC level of children with BB genotype was significantly higher compared to those with Bb genotype in high fluoride areas (P < 0.05). However, no significant difference of serum CT or calcium (Ca) was observed. In conclusion, there is no correlation between dental fluorosis and PTH Bst BI polymorphism. Serum OC might be a more sensitive biomarker for detecting early stages of dental fluorosis, and further studies are needed.

The influence of fluoride on expression of OPGL and M-CSF genes and their proteins in rats with experimental fluorosis and the therapeutic effect of Danlan Xianpeng Liaofu caspule

To investigate mRNA and protein expressions of OPGL and M-CSF mRNA in bones of rats with experimental fluorosis induced by intake of fluoride in the drinking water, and to study the antagonizing effects of Danlan Xianpeng Liaofu capsules on the gene expression. Totally 72 SD rats were randomly assorted into 6 groups including the control group, the fluoride group, the high-dosage (0.8 g/kg×d), mid-dosage (0.4 g/kg×d) and low dosage (0.2 g/kg×d) medication groups and the borax group (borax, 0.8 g/kg×d). The distribution of female and male rats in each group was divided up on a fifty-fifty basis. Except the control group, a NaF containing water (NaF 50 mg/L in concentration) was supplied as the drinking water for all the experimental rats in order to establish experimental fluorosis. The thickness and density of trabecula and the thickness of bone cortex were measured by light microscopy. The fluoride content in urine and bone were analyzed by using fluoride ion selective electrode method. Expressions of OPGL and M-CSF mRNA and protein were studied using RT-PCR and immuno-histochemistry, respectively. (1) 10/12 of the experimental fluorosis rats developed dental fluorosis, and 2/12 of dental fluorosis rats occurred in the low-dosage medication group. Fluoride content in urine and bone of the fluorosis rats increased (P<0.05). (2) Compared with that of the control rats, the bone trabecular depth, cortical thickness and trabecular density in experimental fluorosis rats were remarkably reduced. (3) Compared with that of the control group, mRNA expression of both OPGL and M-CSF was increased in the fluoride group rats. The difference was statistically significant (P<0.05). (4) Compared with that of the fluoride group animals, the expression intensity of OPGL mRNA decreased in animals of the control group, the high, mid- and low- dosage medication groups and the borax group. Among them, except the low-dosage group, the difference between all the other groups and the fluoride group was statistically significant, respectively (P<0.05). There was also a decrease of M-CSF mRNA in all the 3 medication groups and the borax group animals in comparing with that of the fluoride group and the difference was also statistically significant (P<0.05), respectively. (5) Compared with that of the control group. There were an increase of OPGL and a decrease of M-CSF protein expression; and in addition, there were a decrease of OPGL and an increase of M-CSF protein expression in all 3 medication groups and the borax group in comparing with that of the fluoride group anima (P < 0.05). Excessive fluoride induces an accelerated bone turnover and may promote the absorption activity of osteoclasts by increasing the expression of OPGL and M-CSF. Danlan Xianpeng Liaofu capsule may be capable of regulating bone remodeling through a down-regulation on OPGL and M-CSF expression.

Differences in exposure and biological markers of fluoride among White and African American children

To determine differences in self-reported fluoride exposure and fluoride exposure biomarkers between two racial groups. Questionnaires regarding fluoride exposure, urine and water collection kits were distributed to African American and White 7-14-year-old children. Children received a dental exam for fluorosis. Water, urine, and saliva were analyzed for fluoride content. Questionnaire responses and results of sample analyses were compared and observed differences were analyzed. 83 African American and 109 White children completed the study. Dental fluorosis was observed in 62.5 percent White and 80.1 percent African American children. Significant differences were found for fluorosis prevalence and severity between the groups (P < 0.05). Less African American children reported having used fluoride supplements in the past. White children began brushing their teeth at an earlier age. More White children visited a dentist for the first time before age 3. African American children reported currently using larger amounts of toothpaste. More Whites than African Americans had received topical fluoride treatments over the previous year. All of these differences were significant. Multivariate models showed that supplement use and amount of toothpaste used for brushing had significant associations to a child's fluorosis scores. Fluoride concentration of water and saliva was not different for the two groups; however, the fluoride content in urine was significantly higher in African Americans than in Whites [P < 0.05; 1.40 +/- standard deviation (SD) 0.65 ppm versus 1.08 +/- SD 0.28 ppm]. Differences in fluoride exposure between two racial groups were observed. These differences are complex and need to be better defined.

Study on relationship between drinking water endemic fluorosis and urine fluorine in Linyi county, Shanxi province

Objective To investigate the prevalence for endemic fluorosis of drinking water type and to discuss the relationship between endemic fluorosis and urinary fluorine in Linyi county, Shanxi province. Methods In 2006, three counties were selected as heavy, medium and control areas according to the distributing feature of the disease. The dental fluorosis in each spots was examined by Dean method. The levels of urinary fluorine were determined by fluorine selective ion electrode. The skeletal fluorosis of adults were examined by X-ray. Results There was evident differences of dental fluorosis and skeletal fluoresis among the heavy and the medium endemic fluorosis and control areas(X~2 = 410.945, P < 0.01 ), the prevalence of dental fluoresis in the medium area and the heavy area were 92.34% (253/274), 90.09% ( 291/323), significantly higher than in the control area[23.27% (64/275), X~2 = 274.927,268.287, all P < 0.01]. The heavy area had the highest rate of the skeletal fluorosis rate [59.75% (141/236) ], the medium area had the middle-level of the skeletal fluorosis rate[24.76%(52/210), X~2 = 183.578, P< 0.01]. Urine fluorine contents in both beavy[ (4.69 ± 0.17)mg/L] and medium areal (4.86 ± 0.13)mg/L] were higher than that in the control areas[ (1.75 ± 0.04)mg/L, H = 411.197, P< 0.01], and there was linear relevance between the different degree of skeletal fluorosis and urine fluorine contents (r = 0.508, P < 0.01). Conclusions The local fluoresis condition of Linyi county in Shanxi province was serious. The degree of skeletal fluorosis is associated with the fluoride content in urine. Key words: Fluoride poisoning; Fluorosis, dental; Osteofluorosis; Urine

Outcome analysis on drinking-water type endemic fluorosis in Qinghai in 2008

Objective To observe the state of endemic flurosis in Qinghai province in 2008 and to provide scientific basis for endemic flurosis control and prevention. Methods All the endemic fluorosis villages in Qinghai province was divided into slight,medium and heavy degree according to the water fluoride content before improving water,and 2,4,4 villages were collected from each degree,respectively. Water samples were collected from each direction of east,west,south,north and centre,and fluoride concentration were determined from each surveyed villages with unimproved-water. At the same time,3 copies of the peripheral water samples and a sample of source water were collected to determine fluoride concentration. In all the village children aged 8 to 12 were tested for dental fluorosis by Dean method. Six copies of the urinary fluoride were randomly sampled in different age groups. The fluorine content in urine was determined with F-ion selective electrode. The situation of clinical skeletal fluorosis of adults over 16 years of age was examined,and 20 adults in the villages of medium and heavy levels were filmed for skeletal fluorosis. Results The detectable rate of dental fluorosis of children aged 8-12 years old was 43.59% (245/562),that of skeletal flurosis of adults aged above 16 years was 50.32% (1582/3144) and detectable rate of X-ray was 29.45% (48/163). Fluoride content in urine was 1.52 mg/L. Conclusions Endemic fluorosis is still very serious in Qiaghai province in a rising trend,so the control measures need to be strengthen. Key words: Fluoride poisoning; Data collection ; Fluorosis,dental; Osteofluorosis

Intervened observation of low-fluoride brick-tea on the population in drinking-tea type fluorosis areas in Akesai County of Gansu Province

Objective To evaluate the intervention effects of low-fluoride brick tea in the population, and to provide data for the prevention and control of the brick-tea type fluorosis. Methods Eighty-six Kazakh families with 5-12 years old children were selected and divided into two groups in the severe brick-tea type fluorosis areas of Akesai County of Gansu Province. Forty-six households were intervened by drinking low-fluoride brick tea as intervention group and another 40 households drank general brick tea as control group. The fluoride content in water, tea and urine was monitored and the total daily fluoride intake of adults and children was calculated by the fluoride content of the tea before and during intervention. The baseline prevalence of dental fluorosis was surveyed in all Kazakh school students aged 5 - 12 years before intervention, dental fluorosis prevalence were surveyed in two groups after the intervention. The fluoride content in water, urine,tea, and brick-tea samples was detected by iron electrode method, and dental fluorosis was diagnosed by Dean's method. Results The fluoride content of water were 0.36,0.50 mg/L respectively before and 42 months after intervention. The total daily fluoride intake of adults and children in the intervention group (being 4.39,5.12,5.38,4.49 mg in adults and 1.90,2.33 in children, 2.33, 1.94 mg for four calculations) were lower than those in control group (8.42,9.07,8.35,7.92 and 3.65,3.93, 3.62,3.43 mg). Except the second batch (530.4 mg/kg), the average fluoride content of the other 3 batches of low-fluoride brick tea(239.3,222.88,154.7 mg/kg) was lower than that of 4 batches of market brick tea(366.9,412.2, 286.0,379.6 mg/kg). The fluoride content of low-fluoride brick tea samples was in accordance with the national standard(< 300 mg/kg) in 16 of 21 samples in 4 the batches, and the qualifying rate was 76.19%(16/21). Only 5 of 21 market brick tea samples in 4 batches was qualified, accounting for 23.80%(5/21), both were significantly different(χ2= 11.52, P < 0.01). In 12, 36, 42 months after intervention, urine fluoride content in the intervention group of adult(1.84,1.23,1.77 mg/L) and children(1.55,0.65,1.10 mg/L) was less than that of the control group (adults: 3.37,3.68,3.02 mg/L, children: 2.64,1.64,2.62 mg/L), both being statistically significant (t value were 2.94,2.43,3.91,3.29,2.31,4.42, P < 0.01 or 0.05). The detective rate of dental fluorosis was 69.02%(127/184)at baseline among children. After the intervention, it lowered to [44.83% (13/29) in the intervention group, significantly lower than that in the control group[71.88%(23/32), χ2 = 4.60, P < 0.05]. Conclusion Low-fluoride brick tea can reduce the fluoride intake of the residents who drink brick tea, and alleviate excessive fluoride and the damage of high-fluoride. Key words: Fluoride poisoning; Tea; Intervention studies; Outcome assessment

Report on the surveillance results of endemic fluorosis in Qinghai Province in 2007

Objective To investigate the fulfillment of improved water measures for endemic fluomsis and to find out the trend of prevalence in Qinghai Province in order to provide scientific basis and technical support for the government to formulate control strategies for endemic fluorosis.Methods Usage and management of reforming water facilities in Huzhu County were generally surveyed.Yanya Village,Caijiabu Town,Huzhu County was chosen as the surveillance spot.The household drinking water was surveyed.The dental fluorosis and urine fluoride content of children aged 8-12 years and adult above 16 years were examined.Skeletal fluorosis of adult was checked.The fluomsis content in drinking water and urine was determined with F-ion selective electrode method.The dental fluowsis was examined with Dean index.Skeletal fluorosis was diagnosed according to eountry standard(GB 16396-1996.WS 192-1999).Results The rate of water-improving was 60%(36/60)in Huzhu County.The mean of fluoride content in drinking water Was 1.25 mg/L The prevalence rate of dental fluorosis of children aged 8-12 years was 90.20%(46/51);that of adult was 88.89%(48/54).The dental fluorosis index of children was 1.77,that of adult was 2.95.The prevalence rate of skeletal fluorosis was 98.15% indicated by clinical data,18.87% by X-ray.The ufine fluorosis content of children was 2.27 mg/L,that of adult was 2.00 mg/L.Conclusion The disease condition of endemic fluorosis in Qinshai is serious,defluofidation is slow in effect. Key words: Endemic disease; Fhioresis; Epidemioiogieal surveiHance; Outcome assessment

Correlative study of fluoride content in urine, serum and urinary calculi

Fluoride content was measured in 100 urinary stones retrieved by open surgery of stone formers admitted at PGIMS Rohtak and their respective urine and serum and compared with those of healthy individuals. The concentration of fluoride was also measured in the sources of drinking water of these stone formers. The concentration of fluoride was definitely significantly higher in serum (p>0.01) and highly significantly higher in urine (p>-0.001) of stone formers compared to those of healthy individuals. The content of oxalate in serum and 24 h urine of the stone formers was also measured, which was increased significantly (p<0.005 and p<0.001) compared to healthy individuals. The concentration of fluoride was probably significantly higher in drinking water of these stone formers than the normal ones. There was a positive correlation between the content of fluoride of urinary stones and urine of stone patients (r=.88); stone and serum (r=.62); drinking water and stone (r=.85) and their urine and serum (r=.54); urine and drinking water (r=.83) and serum and water (r=.51). These results indicate a definite role of fluoride in urinary stone formation.

A biogeochemical study of the Podili and Tirupati area of Andhra Pradesh, India

The fluoride content of dung, urine and milk of grazing animals, for example cow, she-buffalo, doe and ewe, was studied in the Podili area, India, (endemic fluorosis) and also in Tirupati (non-fluorosis) for the purpose of comparison. The data reveal that the fluoride content of the urine of animals is suitable for the preparation of biogeochemical atlases studying the environmental effect in relation to health.