RESUMEN

Abundant information exists on fluoride intake and excretion in populations exposed to fluoridated water, but not fluoridated salt, where fluoride is eaten through a combination of foods and beverages. This study assessed associations between dietary patterns, fluoride intake and excretion in Mexican women exposed to fluoridated salt. We estimated dietary fluoride intake and excretion (mg/day) from 31 women using 24-h recalls (ASA24) and 24-h urine collections (HDMS diffusion method) and assessed agreement among both estimates of exposure with a Bland-Altman plot. Dietary patterns among the sample were explored by Principal Component Analysis and associations between these patterns and both fluoride intake and excretion were estimated. using Quantile Regressions. Median dietary fluoride intake and excretion were 0.95 and 0.90 mg/day, respectively, with better agreement at values below 1.5 mg/day. We identified three dietary patterns: "Urban Convenience", "Plant-based" and "Egg-based". The "Urban Convenience" pattern, characterized by dairy and convenience foods was associated with an increase of 0.25 mg and 0.34 mg of F in the 25th and 50th percentiles of intake respectively, (p < 0.01), and a marginal 0.22 mg decrease in urinary fluoride (p = 0.06). In conclusion, in this sample of Mexican women, a dietary pattern rich in dairy and convenience foods, was associated with both fluoride intake and excretion.

Asunto(s)

Dieta , Fluoruración , Fluoruros , Cloruro de Sodio Dietético , Humanos , Femenino , Adulto , Fluoruros/orina , Fluoruros/administración & dosificación , México , Cloruro de Sodio Dietético/administración & dosificación , Dieta/estadística & datos numéricos , Persona de Mediana Edad , Adulto Joven , Conducta Alimentaria , Patrones Dietéticos

RESUMEN

BACKGROUND: Previous animal and ecological studies have provided evidence for an earlier sexual maturation in females in relation to fluoride exposure; however, no epidemiological studies have examined the association between fluoride exposure and pubertal development in both boys and girls using individual-level biomarkers of fluoride. Capitalizing on an ongoing Mexican birth cohort study, we examined the association between concurrent urinary fluoride levels and physical markers of pubertal development in children. METHODS: We conducted a cross-sectional study of 157 boys and 176 girls at age 10-17 years living in Mexico City. We used ion-selective electrode-based diffusion methods to assess fluoride levels in urine, adjusting for urinary specific gravity. Pubertal stages were evaluated by a trained physician. Associations of fluoride with pubertal stages and age at menarche were studied using ordinal regression and Cox proportional-hazard regression, respectively. RESULTS: In the entire sample, the geometric mean and interquartile range (IQR) of urinary fluoride (specific gravity adjusted) were 0.59 mg/L and 0.31 mg/L, respectively. In boys, our analysis showed that a one-IQR increase in urinary fluoride was associated with later pubic hair growth (OR = 0.71, 95% CI: 0.51-0.98, p = 0.03) and genital development (OR = 0.71, 95% CI: 0.53-0.95, p = 0.02). No significant associations were found in girls, although the direction was negative. CONCLUSIONS: Childhood fluoride exposure, at the levels observed in our study, was associated with later pubertal development among Mexican boys at age 10-17 years. Further research is needed to confirm these findings.

Asunto(s)

Exposición a Riesgos Ambientales , Fluoruros/orina , Pubertad , Adolescente , Niño , Ciudades/epidemiología , Estudios de Cohortes , Femenino , Genitales Masculinos/crecimiento & desarrollo , Humanos , Masculino , México/epidemiología , Oportunidad Relativa

RESUMEN

This study aimed to evaluate the gastrointestinal absorption and renal excretion of fluoride after the ingestion of high-fluoride dentifrice. Twelve volunteers participated in this in vivo, crossover, and blinded study. In three experimental phases, the volunteers were randomly assigned to one of three treatment groups, who ingested either the following: distilled and deionized water (control), conventional dentifrice (1100 µg/g), or high-fluoride dentifrice (5000 µg/g). Both dentifrices contained fluoride in the form of NaF/SiO2. To determine the rate of fluoride absorption, non-stimulated saliva was collected for up to 120 min after ingestion and the area under the curve of the salivary fluoride concentration was plotted as a function of time and the maximum concentration determined. All urine produced during the 24 h before and after ingestion was collected, and urinary excretion was calculated from the difference between the urinary fluoride concentrations in the two periods. A specific ion electrode coupled to an ion analyzer was used to measure fluoride concentrations. Statistical analysis was performed by ANOVA followed by Tukey's test with p set at 5%. All measured parameters were highest after the ingestion of the dentifrice with 5000 µg/g (p < 0.001), confirming that this has an increased level of bioavailable fluoride compared with the conventional dentifrice. The high-fluoride dentifrice increases the concentration of salivary fluoride, which may explain its greater anticaries effect. However, it poses a potential risk of causing dental fluorosis and so should not be used by children.

Asunto(s)

Dentífricos/química , Fluoruros/metabolismo , Fluoruros/orina , Absorción Gastrointestinal/fisiología , Riñón/metabolismo , Adulto , Estudios Cruzados , Humanos , Saliva/química , Adulto Joven

RESUMEN

BACKGROUND: Epidemiologic and animal-based studies have raised concern over the potential impact of fluoride exposure on neurobehavioral development as manifested by lower IQ and deficits in attention. To date, no prospective epidemiologic studies have examined the effects of prenatal fluoride exposure on behavioral outcomes using fluoride biomarkers and sensitive measures of attention. OBJECTIVE: We aimed to examine the association between prenatal fluoride exposure and symptoms associated with attention-deficit/hyperactivity disorder (ADHD). METHOD: 213 Mexican mother-children pairs of the Early Life Exposures to Environmental Toxicants (ELEMENT) birth cohort study had available maternal urinary samples during pregnancy and child assessments of ADHD-like behaviors at age 6-12. We measured urinary fluoride levels adjusted for creatinine (MUFcr) in spot urine samples collected during pregnancy. The Conners' Rating Scales-Revised (CRS-R) was completed by mothers, and the Conners' Continuous Performance Test (CPT-II) was administered to the children. RESULTS: Mean MUFcr was 0.85 mg/L (SD = 0.33) and the Interquartile Range (IQR) was 0.46 mg/L. In multivariable adjusted models using gamma regression, a 0.5 mg/L higher MUFcr (approximately one IQR higher) corresponded with significantly higher scores on the CRS-R for DSM-IV Inattention (2.84 points, 95% CI: 0.84, 4.84) and DSM-IV ADHD Total Index (2.38 points, 95% CI: 0.42, 4.34), as well as the following symptom scales: Cognitive Problems and Inattention (2.54 points, 95% CI: 0.44, 4.63) and ADHD Index (2.47 points; 95% CI: 0.43, 4.50). The shape of the associations suggested a possible celling effect of the exposure. No significant associations were found with outcomes on the CPT-II or on symptom scales assessing hyperactivity. CONCLUSION: Higher levels of fluoride exposure during pregnancy were associated with global measures of ADHD and more symptoms of inattention as measured by the CRS-R in the offspring.

Asunto(s)

Trastorno por Déficit de Atención con Hiperactividad/inducido químicamente , Fluoruros/efectos adversos , Efectos Tardíos de la Exposición Prenatal , Niño , Preescolar , Estudios de Cohortes , Femenino , Fluoruros/orina , Humanos , Estudios Longitudinales , Masculino , México , Embarazo , Estudios Prospectivos

RESUMEN

Fluoride (F) is a toxicant widely distributed in the environment. Experimental studies have shown kidney toxicity from F exposure. However, co-exposure to arsenic (As) has not been considered, and epidemiological information remains limited. We evaluated the association between F exposure and urinary kidney injury biomarkers and assessed As co-exposure interactions. A cross-sectional study was conducted in 239 adults (18-77 years old) from three communities in Chihuahua, Mexico. Exposure to F was assessed in urine and drinking water, and As in urine samples. We evaluated the urinary concentrations of albumin (ALB), cystatin-C (Cys-C), kidney injury molecule 1 (KIM-1), clusterin (CLU), osteopontin (OPN), and trefoil factor 3 (TFF-3). The estimated glomerular filtration rate (eGFR) was calculated using serum creatinine (Creat) levels. We observed a positive correlation between water and urine F concentrations (ρ = 0.7419, p < 0.0001), with median values of 1.5 mg/L and 2 µg/mL, respectively, suggesting that drinking water was the main source of F exposure. The geometric mean of urinary As was 18.55 ng/mL, approximately 39% of the urine samples had As concentrations above the human biomonitoring value (15 ng/mL). Multiple linear regression models demonstrated a positive association between urinary F and ALB (ß = 0.56, p < 0.001), Cys-C (ß = 0.022, p = 0.001), KIM-1 (ß = 0.048, p = 0.008), OPN (ß = 0.38, p = 0.041), and eGFR (ß = 0.49, p = 0.03); however, CLU (ß = 0.07, p = 0.100) and TFF-3 (ß = 1.14, p = 0.115) did not show significant associations. No interaction with As exposure was observed. In conclusion, F exposure was related to the urinary excretion of early kidney injury biomarkers, supporting the hypothesis of the nephrotoxic role of F exposure.

Asunto(s)

Arsénico/efectos adversos , Exposición a Riesgos Ambientales/efectos adversos , Fluoruros/efectos adversos , Enfermedades Renales/inducido químicamente , Riñón/efectos de los fármacos , Contaminantes Químicos del Agua/efectos adversos , Adolescente , Adulto , Anciano , Albuminuria/inducido químicamente , Albuminuria/diagnóstico , Albuminuria/orina , Arsénico/orina , Biomarcadores/orina , Clusterina/orina , Estudios Transversales , Cistatina C/orina , Monitoreo del Ambiente/métodos , Femenino , Fluoruros/orina , Tasa de Filtración Glomerular/efectos de los fármacos , Receptor Celular 1 del Virus de la Hepatitis A/análisis , Humanos , Riñón/metabolismo , Riñón/fisiopatología , Enfermedades Renales/diagnóstico , Enfermedades Renales/fisiopatología , Enfermedades Renales/orina , Masculino , México , Persona de Mediana Edad , Osteopontina/orina , Valor Predictivo de las Pruebas , Medición de Riesgo , Factor Trefoil-3/orina , Contaminantes Químicos del Agua/orina , Adulto Joven

RESUMEN

BACKGROUND: Mexico is included in the list of countries with concurrent arsenic and fluoride contamination in drinking water. Most of the studies have been carried out in the adult population and very few in the child population. Urinary arsenic and urinary fluoride levels have been accepted as good biomarkers of exposure dose. The Biomonitoring Equivalents (BE) values are useful tools for health assessment using human biomonitoring data in relation to the exposure guidance values, but BE information for children is limited. METHODS: We conducted a systematic review of the reported levels of arsenic and fluoride in drinking water, urinary quantification of speciated arsenic (inorganic arsenic and its methylated metabolites), and urinary fluoride levels in child populations. For BE values, urinary arsenic and fluoride concentrations reported in Mexican child populations were revised discussing the influence of factors such as diet, use of dental products, sex, and metabolism. RESULTS: Approximately 0.5 and 6 million Mexican children up to 14 years of age drink water with arsenic levels over 10 µg/L and fluoride over 1.5 mg/L, respectively. Moreover, 40% of localities with arsenic levels higher than 10 µg/L also present concurrent fluoride exposure higher than 1.5 mgF/L. BE values based in urinary arsenic of 15 µg/L and urinary fluoride of 1.2 mg/L for the environmentally exposed child population are suggested. CONCLUSIONS: An actual risk map of Mexican children exposed to high levels of arsenic, fluoride, and both arsenic and fluoride in drinking water was generated. Mexican normativity for maximum contaminant level for arsenic and fluoride in drinking water should be adjusted and enforced to preserve health. BE should be used in child populations to investigate exposure.

Asunto(s)

Arsénico/orina , Agua Potable , Fluoruros/orina , Calidad del Agua/normas , Niño , Agua Potable/efectos adversos , Agua Potable/análisis , Agua Potable/química , Exposición a Riesgos Ambientales/efectos adversos , Exposición a Riesgos Ambientales/análisis , Exposición a Riesgos Ambientales/prevención & control , Monitoreo del Ambiente/métodos , Monitoreo del Ambiente/normas , Humanos , México/epidemiología , Medición de Riesgo , Contaminantes Químicos del Agua/orina

RESUMEN

BACKGROUND: Some evidence suggests that fluoride may be neurotoxic to children. Few of the epidemiologic studies have been longitudinal, had individual measures of fluoride exposure, addressed the impact of prenatal exposures or involved more than 100 participants. OBJECTIVE: Our aim was to estimate the association of prenatal exposure to fluoride with offspring neurocognitive development. METHODS: We studied participants from the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) project. An ion-selective electrode technique was used to measure fluoride in archived urine samples taken from mothers during pregnancy and from their children when 6-12 y old, adjusted for urinary creatinine and specific gravity, respectively. Child intelligence was measured by the General Cognitive Index (GCI) of the McCarthy Scales of Children's Abilities at age 4 and full scale intelligence quotient (IQ) from the Wechsler Abbreviated Scale of Intelligence (WASI) at age 6-12. RESULTS: We had complete data on 299 mother-child pairs, of whom 287 and 211 had data for the GCI and IQ analyses, respectively. Mean (SD) values for urinary fluoride in all of the mothers (n=299) and children with available urine samples (n=211) were 0.90 (0.35) mg/L and 0.82 (0.38) mg/L, respectively. In multivariate models we found that an increase in maternal urine fluoride of 0.5mg/L (approximately the IQR) predicted 3.15 (95% CI: -5.42, -0.87) and 2.50 (95% CI -4.12, -0.59) lower offspring GCI and IQ scores, respectively. CONCLUSIONS: In this study, higher prenatal fluoride exposure, in the general range of exposures reported for other general population samples of pregnant women and nonpregnant adults, was associated with lower scores on tests of cognitive function in the offspring at age 4 and 6-12 y. https://doi.org/10.1289/EHP655.

Asunto(s)

Contaminantes Ambientales/toxicidad , Fluoruros/toxicidad , Inteligencia , Exposición Materna/estadística & datos numéricos , Efectos Tardíos de la Exposición Prenatal/epidemiología , Adulto , Niño , Desarrollo Infantil , Preescolar , Cognición , Contaminantes Ambientales/orina , Femenino , Fluoruros/orina , Humanos , Pruebas de Inteligencia , Masculino , México , Embarazo

RESUMEN

Fluoride is an important element for humans. It inhibits initiation and progression of dental caries and stimulates bone formation. However, excessive intake may lead to the appearance of dental and/or skeletal fluorosis and a decrease in intellectual coefficient in child populations. This study evaluates exposure to fluoride in the child population of Chaco province (Argentina) by analysis of drinking water, food and its bioaccessible fraction (quantity of fluoride solubilised by gastrointestinal digestion and available for intestinal absorption) and urine as a biomarker of internal dose. The concentration of fluoride in drinking water varied between 0.050 and 4.6 mg L-1, and 80% of the samples exceeded the WHO drinking-water guideline value (1.5 mg L-1). Fluoride concentrations in food ranged between 0.80 and 3.0 mg kg-1 fresh weight (fw), being lower in bioaccessible fraction (0.43-1.9 mg kg-1, fw). On the basis of the consumption data declared for the young child population, fluoride intake varies between 4.1 and 6.5 mg day-1, greater than the level recommended for this age group. Moreover, in some cases, concentrations of fluoride found in urine (0.62-8.9 mg L-1) exceeded those reported in areas with declared fluorosis. All data obtained show the worrying situation of child population in this area of Argentina.

Asunto(s)

Agua Potable/análisis , Exposición a Riesgos Ambientales , Fluoruros/orina , Análisis de los Alimentos , Agua Subterránea/análisis , Adolescente , Argentina , Disponibilidad Biológica , Biomarcadores/orina , Niño , Fluoruros/análisis , Humanos , Población Rural

RESUMEN

Environmental hazards from natural or anthropological sources are widespread, especially in the north-central region of Mexico. Children represent a susceptible population due to their unique routes of exposure and special vulnerabilities. In this study we evaluated the association of exposure to environmental kidney toxicants with kidney injury biomarkers in children living in San Luis Potosi (SLP), Mexico. A cross-sectional study was conducted with 83 children (5-12 years of age) residents of Villa de Reyes, SLP. Exposure to arsenic, cadmium, chromium, fluoride and lead was assessed in urine, blood and drinking water samples. Almost all tap and well water samples had levels of arsenic (81.5%) and fluoride (100%) above the permissible levels recommended by the World Health Organization. Mean urine arsenic (45.6ppb) and chromium (61.7ppb) were higher than the biological exposure index, a reference value in occupational settings. Using multivariate adjusted models, we found a dose-dependent association between kidney injury molecule-1 (KIM-1) across chromium exposure tertiles [(T1: reference, T2: 467pg/mL; T3: 615pg/mL) (p-trend=0.001)]. Chromium upper tertile was also associated with higher urinary miR-200c (500 copies/µl) and miR-423 (189 copies/µL). Arsenic upper tertile was also associated with higher urinary KIM-1 (372pg/mL). Other kidney injury/functional biomarkers such as serum creatinine, glomerular filtration rate, albuminuria, neutrophil gelatinase-associated lipocalin and miR-21 did not show any association with arsenic, chromium or any of the other toxicants evaluated. We conclude that KIM-1 might serve as a sensitive biomarker to screen children for kidney damage induced by environmental toxic agents.

Asunto(s)

Arsénico/orina , Cromo/orina , Contaminantes Ambientales/orina , Receptor Celular 1 del Virus de la Hepatitis A/metabolismo , Arsénico/análisis , Arsénico/sangre , Biomarcadores/orina , Niño , Preescolar , Cromo/análisis , Cromo/sangre , Creatinina/sangre , Agua Potable/análisis , Exposición a Riesgos Ambientales , Contaminantes Ambientales/análisis , Contaminantes Ambientales/sangre , Femenino , Fluoruros/análisis , Fluoruros/sangre , Fluoruros/orina , Tasa de Filtración Glomerular , Agua Subterránea/análisis , Humanos , Enfermedades Renales/sangre , Enfermedades Renales/orina , Plomo/análisis , Plomo/sangre , Plomo/orina , Lipocalina 2/orina , Masculino , México , MicroARNs/orina , Albúmina Sérica/análisis

RESUMEN

BACKGROUND: There is need to assess the developmental neurotoxicity of fluoride. Our knowledge of prenatal fluoride exposure is challenged as few population-based studies have been conducted and these generally date back several decades, provide incomplete data on sociodemographic variables, and have methodological limitations. OBJECTIVE: To measure urinary and plasma fluoride levels across three time points in pregnant mothers who were enrolled in the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) birth cohort study. METHODS: Fluoride levels were characterized in archived urine and plasma from 872 pregnant mothers sampled from the ELEMENT cohort. Various statistical methods were used to analyze the fluoride data with particular consideration for changes across three stages of pregnancy and against sociodemographic variables. RESULTS: All samples had detectable levels of fluoride. The mean urinary and plasma fluoride levels were 0.91 and 0.0221mg/L respectively, and these were not statistically different across three stages of pregnancy. Fluoride levels correlated across the stages of pregnancy studied, with stronger correlations between neighboring stages. Urinary fluoride changed as pregnancy progressed with levels increasing until ~23 weeks and then decreasing until the end of pregnancy. For plasma fluoride, there was a decreasing trend but this was not of statistical significance. Creatinine-adjusted urinary fluoride levels did not associate consistently with any of the sociodemographic variables studied. CONCLUSIONS: This study provides the most extensive characterization to date of fluoride exposure throughout pregnancy. These results provide the foundation to explore exposure-related health outcomes in the ELEMENT cohort and other studies.

Asunto(s)

Fluoruros/sangre , Fluoruros/orina , Embarazo/sangre , Embarazo/orina , Adulto , Estudios de Cohortes , Monitoreo del Ambiente , Femenino , Humanos , Recién Nacido , Masculino , Exposición Materna , Intercambio Materno-Fetal , México , Adulto Joven

RESUMEN

Inorganic arsenic (iAs) and fluoride (F-) are naturally occurring drinking water contaminants. However, co-exposure to these contaminants and its effects on human health are understudied. The goal of this study was examined exposures to iAs and F- in Chihuahua, Mexico, where exposure to iAs in drinking water has been associated with adverse health effects. All 1119 eligible Chihuahua residents (>18 years) provided a sample of drinking water and spot urine samples. iAs and F- concentrations in water samples ranged from 0.1 to 419.8 µg As/L and from 0.05 to 11.8 mg F-/L. Urinary arsenic (U-tAs) and urinary F- (U-F-) levels ranged from 0.5 to 467.9 ng As/mL and from 0.1 to 14.4 µg F-/mL. A strong positive correlation was found between iAs and F- concentrations in drinking water (rs = 0.741). Similarly, U-tAs levels correlated positively with U-F- concentrations (rs = 0.633). These results show that Chihuahua residents exposed to high iAs concentrations in drinking water are also exposed to high levels of F-, raising questions about possible contribution of F- exposure to the adverse effects that have so far been attributed only to iAs exposure. Thus, investigation of possible interactions between iAs and F- exposures and its related health risks deserves immediate attention.

Asunto(s)

Arsénico/orina , Agua Potable/análisis , Fluoruros/orina , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Agua Subterránea/análisis , Humanos , Masculino , México , Persona de Mediana Edad , Fosfatos , Adulto Joven

RESUMEN

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.

Asunto(s)

Fluoruros/orina , Fluorosis Dental/epidemiología , Población Rural , Niño , Humanos , México/epidemiología

RESUMEN

Humans may be exposed to arsenic (As) and fluoride (F) through water consumption. However, the interaction between these two elements and gene expression in apoptosis or inflammatory processes in children has not been thoroughly investigated. Herein, the expression of cIAP-1, XIAP, TNF-α, ENA-78, survivin, CD25, and CD40 was evaluated by RT-PCR. Additionally, the surface expression of CD25, CD40, and CD40L on peripheral blood mononuclear cells was analyzed by flow cytometry, and TNF-α was measured by Western blotting. This study examined 72 children aged 6-12 years who were chronically exposed to As (154.2µg/L) and F (5.3mg/L) in drinking water and in food cooked with the same water. The urine concentrations of As (6.9-122.4µg/L) were positively correlated with the urine concentrations of F (1.0-8.8mg/L) (r(2)=0.413, p<0.0001). The CD25 gene expression levels and urine concentrations of As and F were negatively correlated, though the CD40 expression levels were negatively correlated only with the As concentration. Age and height influenced the expression of cIAP-1, whereas XIAP expression was correlated only with age. Additionally, there was a lower percentage of CD25- and CD40-positive cells in the group of 6- to 8-year-old children exposed to the highest concentrations of both As and F when compared to the 9- to 12-year-old group (CD25: 0.7±0.8 vs. 1.1±0.9, p<0.0014; CD40: 16.0±7.0 vs. 21.8±5.8, p<0.0003). PHA-stimulated lymphocytes did not show any changes in the induction of CD25, CD69, or CD95. In summary, high concentrations of As and F alter the expression patterns of CD25 and CD40 at both the genetic and protein levels. These changes could decrease immune responses in children exposed to As and F.

Asunto(s)

Apoptosis/efectos de los fármacos , Arsénico/toxicidad , Exposición a Riesgos Ambientales , Fluoruros/toxicidad , Expresión Génica/efectos de los fármacos , Inmunidad Activa/efectos de los fármacos , Leucocitos Mononucleares/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/metabolismo , Arsénico/orina , Niño , Femenino , Fluoruros/orina , Humanos , Inflamación/genética , Inflamación/metabolismo , Leucocitos Mononucleares/metabolismo , Activación de Linfocitos/efectos de los fármacos , Masculino , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismo , Contaminantes Químicos del Agua/orina

RESUMEN

Depending on toothpaste formulation, part of the fluoride is insoluble and would not be totally absorbable in the gastrointestinal tract, thus changing dental fluorosis risk estimation. This hypothesis was tested with formulations with either all fluoride in a soluble form (NaF/SiO2-based toothpaste, 1,100 µg F/g as labeled, 1,129.7 ± 49.4 µg F/g soluble fluoride as analyzed) or with around 20% of insoluble fluoride (Na2FPO3/CaCO3-based toothpaste, 1,450 µg F/g as labeled, 1,122.4 ± 76.4 µg F/g soluble fluoride as analyzed). Toothpastes were evaluated either fresh or after accelerated aging, which increased insoluble fluoride to 40% in the Na2FPO3/CaCO3-based toothpaste. In a blind, crossover clinical trial conducted in five legs, 20 adult volunteers ingested 49.5 µg of total fluoride/kg body weight from each formulation or purified water (control). Whole saliva and urine were collected as bioavailability indicators, and pharmacokinetics parameters calculated showed significantly (p < 0.05) lower fluoride bioavailability for Na2FPO3/CaCO3 toothpaste, which was reduced further after aging. A significant correlation between the amount of soluble fluoride ingested, but not total fluoride, and fluoride bioavailability was found (r = 0.57, p < 0.0001). The findings suggest that the estimated fluorosis risk as a result of ingestion of Na2FPO3/CaCO3-based toothpastes should be calculated based on the toothpaste's soluble rather than total fluoride concentration.

Asunto(s)

Absorción Intestinal , Fluoruro de Sodio/metabolismo , Pastas de Dientes/química , Adolescente , Adulto , Análisis de Varianza , Disponibilidad Biológica , Carbonato de Calcio/metabolismo , Estudios Cruzados , Femenino , Fluoruros/metabolismo , Fluoruros/orina , Fluorosis Dental/etiología , Humanos , Modelos Lineales , Masculino , Fosfatos/metabolismo , Saliva/química , Silicatos/metabolismo , Método Simple Ciego , Fluoruro de Sodio/efectos adversos , Solubilidad , Estadísticas no Paramétricas , Pastas de Dientes/efectos adversos , Adulto Joven

RESUMEN

In this study, we evaluated apoptosis induction in human immune cells in children exposed to arsenic (As) and fluoride (F). Children living in two areas in Mexico (Soledad de Graciano Sanchez (SGS) in San Luis Potosí and Colonia 5 de Febrero in Durango) were studied. Water, urine and blood samples were collected. Approximately 90% of the water samples in 5 de Febrero had As and F levels above the World Health Organization intervention guideline (10 µg/L and 1.5mg/L, respectively). In SGS, 0% of the water samples exceeded Mexican guidelines. Urinary As and F levels in children living in 5 de Febrero were significantly higher than the levels found in children living in SGS. In addition, the level of apoptosis was higher in children from the 5 de Febrero community when compared with the level of apoptosis in children living in SGS. Thus, in a worldwide context, our study demonstrates the health risks to children living in these regions.

Asunto(s)

Apoptosis/efectos de los fármacos , Arsénico/toxicidad , Fluoruros/toxicidad , Leucocitos Mononucleares/efectos de los fármacos , Contaminantes Químicos del Agua/efectos adversos , Adolescente , Arsénico/sangre , Arsénico/orina , Niño , Agua Potable/química , Femenino , Fluoruros/sangre , Fluoruros/orina , Guías como Asunto , Humanos , Leucocitos Mononucleares/patología , Masculino , México , Contaminantes Químicos del Agua/sangre , Contaminantes Químicos del Agua/orina , Organización Mundial de la Salud

RESUMEN

As there is no homeostatic mechanism for maintaining circulating fluoride (F) in the human body, the concentration may decrease and increase again when intake is interrupted and re-started. The present study prospectively evaluated this process in children exposed to F intake from water and toothpaste, using F in urine as a biomarker. Eleven children from Ibiá, Brazil (with sub-optimally fluoridated water supply) aged two to four years who regularly used fluoridated toothpaste (1,100 ppm F) took part in the study. Twenty-four-hour urine was collected at baseline (Day 0, F exposure from water and toothpaste) as well as after the interruption of fluoride intake from water and dentifrice (Days 1 to 28) (F interruption) and after fluoride intake from these sources had been re-established (Days 29 to 34) (F re-exposure). Urinary volume was measured, fluoride concentration was determined and the amount of fluoride excreted was calculated and expressed in mg F/day. Urinary fluoride excretion (UFE) during the periods of fluoride exposure, interruption and re-exposure was analyzed using the Wilcoxon test. Mean UFE was 0.25 mg F/day (SD: 0.15) at baseline, dropped to a mean of 0.14 mg F/day during F interruption (SD: 0.07; range: 0.11 to 0.17 mg F/day) and rose to 0.21 (SD: 0.09) and 0.19 (SD: 0.08) following F re-exposure. The difference between baseline UFE and the period of F interruption was statistically significant (p<0.05), while the difference between baseline and the period of F re-exposure was non-significant (p>0.05). The findings suggest that circulating F in the body of young children rapidly decreases in the first 24 hours and again increases very fast after discontinuation and re-exposure of F from water and toothpaste.

Asunto(s)

Agua Potable/administración & dosificación , Fluoruros/administración & dosificación , Fluoruros/orina , Pastas de Dientes/administración & dosificación , Brasil , Preescolar , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Masculino

RESUMEN

OBJECTIVE: The purpose of this study was to evaluate caries and dental fluorosis among Mexican preschoolers and school-aged children in a non-endemic zone for fluorosis and to measure its biological indicators. METHODS: DMFT, DMFS, dmft, dmfs, and CDI indexes were applied. Fluoride urinary excretion and fluoride concentrations in home water, table salt, bottled water, bottled drinks, and toothpaste were determined. RESULTS: Schoolchildren presented fluorosis (CDI = 0.96) and dental caries (DMFT = 2.64 and DMFS = 3.97). Preschoolers presented dmft = 4.85 and dmfs = 8.80. DMFT and DMFS were lower in children with mild to moderate dental fluorosis (DF). Variable fluoride concentrations were found in the analyzed products (home water = 0.18-0.44 ppm F, table salt = 0-485 ppm F, bottled water = 0.18-0.47 ppm F, juices = 0.08-1.42 ppm F, nectars = 0.07-1.30 ppm F, bottled drinks = 0.10-1.70 ppm F, toothpaste = 0-2,053 ppm F). Mean daily fluoride excretion was 422 ± 176 µg/24 h for schoolchildren and 367 ± 150 µg/24 h for preschoolers. CONCLUSIONS: Data from our study show that, despite values of excretion within an optimal fluoride intake range, the prevalence of caries was significant in both groups, and 60% of the 11- to 12-year-old children presented with dental fluorosis. In addition, variable fluoride concentrations in products frequently consumed by children were found.

Asunto(s)

Caries Dental/epidemiología , Fluoruros/análisis , Fluorosis Dental/epidemiología , Bebidas/análisis , Niño , Preescolar , Índice CPO , Caries Dental/orina , Femenino , Fluoruros/orina , Fluorosis Dental/orina , Humanos , Masculino , México , Prevalencia , Cloruro de Sodio/química , Cloruro de Sodio Dietético/análisis , Encuestas y Cuestionarios , Pastas de Dientes/química , Agua/química

RESUMEN

There has been no comparison between fluoride concentrations in urine and nails of children exposed to different sources of systemic fluoride. The aim of this study was to compare the relationship between fluoride intake with urinary fluoride excretion and fluoride concentrations in fingernails and toenails of children receiving fluoride from artificially fluoridated water (0.6-0.8 mg F/L, n = 25), naturally fluoridated water (0.6-0.9 mg F/L, n = 21), fluoridated salt (180-200 mg F/Kg, n = 26), and fluoridated milk (0.25 mg F, n = 25). A control population was included (no systemic fluoride, n = 24). Fluoride intake from diet and dentifrice, urinary fluoride excretion, and fluoride concentrations in fingernails/toenails were evaluated. Fluoride was analyzed with an ion-selective electrode. Urinary fluoride excretion in the control community was significantly lower when compared with that in the fluoridated cities, except for the naturally fluoridated community. However, the same pattern was not as evident for nails. Both urinary fluoride output and fluoride concentrations in fingernails/toenails were significantly correlated to total fluoride intake. However, the correlation coefficients for fluoride intake and urinary fluoride output were lower (r = 0.28, p < 0.01) than those observed for fingernails/toenails (r = 0.36, p < 0.001), suggesting that nails might be slightly better indicators of fluoride intake at the individual level.

Asunto(s)

Fluoruros/análisis , Fluoruros/farmacocinética , Uñas/química , Análisis de Varianza , Animales , Biomarcadores , Estudios de Casos y Controles , Niño , Preescolar , Dentífricos , Fluoruros/orina , Humanos , Leche , Uñas/metabolismo , Cloruro de Sodio Dietético , Estadísticas no Paramétricas , Abastecimiento de Agua

RESUMEN

CONTEXT: T regulatory (Treg) cells play an important role in the modulation of the immune response, and are implicated in the pathogenesis of autoimmune diseases. Many people is exposed to fluoride (F), mainly through drinking water. OBJECTIVE: The aim of this work was to assess the possible effect of F exposure on different immune parameters, mainly Treg cells. MATERIALS AND METHODS: We studied 61 subjects from a community of the state of Durango, Mexico, where the population is exposed to F levels over 2.0 ppm in drinking water. Peripheral blood mononuclear cells (PBMC) were isolated and the level and function of Treg cells was analyzed by flow cytometry and cell proliferation assays. In addition, we detected the presence of apoptotic cells, the expression of TLR/CD14, and the in vitro synthesis of TNF-α by monocytes. RESULTS: We found a negative correlation between urinary F and percentage of CD4(+)CD25(+) Treg cells (r = -0.55, P < 0.001). Accordingly, a defective function of these cells was detected in 30% of individuals exposed to F. In contrast, a positive association between levels of CD4(+)TGF-ß(+) or CD4(+)IL-10(+) Treg lymphocytes and F urine concentrations was detected. In addition, a negative correlation was detected between the F urinary levels and the proportion of apoptotic cells, in PBMC or T cells or monocytes (P < 0.05 in all cases). Finally, no apparent association between F exposure and TLR4/CD14 expression or the synthesis of TNF-α was detected. CONCLUSION: Our data suggest that F exposure exerts a complex and relevant effect on Treg cells in humans.

Asunto(s)

Exposición a Riesgos Ambientales/efectos adversos , Fluoruros/efectos adversos , Linfocitos T Reguladores/efectos de los fármacos , Linfocitos T Reguladores/inmunología , Contaminantes Químicos del Agua/efectos adversos , Adolescente , Adulto , Anciano , Apoptosis/efectos de los fármacos , Apoptosis/inmunología , Recuento de Linfocito CD4 , Proliferación Celular/efectos de los fármacos , Estudios Transversales , Exposición a Riesgos Ambientales/análisis , Femenino , Citometría de Flujo , Fluoruros/orina , Humanos , Masculino , México , Persona de Mediana Edad , Vigilancia de la Población , Encuestas y Cuestionarios , Contaminantes Químicos del Agua/orina , Adulto Joven

RESUMEN

The aim of this study was to examine the relationship between total daily fluoride intake (TDFI), daily urinary fluoride excretion (DUFE) and fractional fluoride retention (FFR) using available data, in order to clarify the ability of DUFE to predict TDFI and, therefore, the risk of fluorosis development. Examination of published reports of simultaneous measurement of TDFI and DUFE, together with data from two unpublished Chilean studies, yielded data for 212 children aged less than 7 years and for 283 adults aged 18-75 years, providing a total of 212 and 269 data points, respectively. The relationship between DUFE and TDFI was studied for children and adults, separately. Daily fluoride retention (DFR) was estimated as a function of TDFI in children and adults assuming an average 90% fluoride absorption, and the numerical relationships between the estimated FFR and the TDFI were explored. Limiting FFR values of 0.55 and 0.36 were found for children and adults, respectively, above a threshold of TDFI of 0.5 and 2 mg, respectively. Neutral fluoride balances were predicted when the TDFI was equal to approximately 0.07 mg F/day for children and 0.8 mg F/day for adults. For children and adults, it is possible to obtain reasonably good estimations of community-based TDFI and DFR, using DUFE data. The advantages and limitations of these relationships, together with the need for future studies, are discussed.

Asunto(s)

Cariostáticos/administración & dosificación , Fluoruros/administración & dosificación , Absorción , Adolescente , Adulto , Anciano , Algoritmos , Cariostáticos/análisis , Cariostáticos/farmacocinética , Niño , Preescolar , Femenino , Fluoruros/farmacocinética , Fluoruros/orina , Fluorosis Dental/etiología , Predicción , Humanos , Lactante , Masculino , Persona de Mediana Edad , Adulto Joven