Urinary and plasma fluoride levels in pregnant women from Mexico City

Thomas, Deena; Basu, Niladri; Martínez-Mier, E. Ángeles; Sánchez, Brisa N.; Zhang, Zhenzhen; Liu, Yun; Parajuli, Rajendra Prasad; Peterson, Karen E.; Mercado‐García, Adriana; Bashash, Morteza; Hernández-Ávila, Mauricio; Hu, Howard; Téllez-Rojo, Martha M.

doi:10.1016/j.envres.2016.06.046

Cited by 38 publications

(51 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A number of recent studies, mainly conducted in adults [Bashash et al, 2017[Bashash et al, , 2018Thomas et al, 2016] used spot urine samples to estimate fluoride exposure and its link with several health outcomes. Although the potential of spot urine samples to predict fluoride exposure has been examined in young children [Zohouri et al, 2006;Zohoori and Maguire, 2017], its appropriateness to estimate fluoride exposure in adults has not been examined and validated.…”

Section: Discussionmentioning

confidence: 99%

Biomarkers for the Assessment of Fluoride Exposure in Children

et al. 2020

View full text Add to dashboard Cite

Due to practical difficulties in quantifying fluoride exposure, the ability of various biomarkers to predict it has been investigated previously. However, the results are inadequate for validation of their application and usefulness. This study aimed to investigate the association between contemporary/recent biomarkers of fluoride exposure and total daily fluoride intake (TDFI) of children with large differences in fluoride exposure through drinking water. TDFI was assessed in 61 healthy 4 to 5 years old children who provided at least one biomarker sample; 32 lived in a low-fluoride area (0.04 mgF/L) and 29 lived in a high-fluoride area (3.05 mgF/L). Validated questionnaires were administered to evaluate fluoride intake from diets (including water) and toothpaste ingestion. Daily urinary fluoride excretion (UFE) as well as fluoride concentrations in plasma, fasting whole saliva, hair and nails (toenails/fingernails) were evaluated and related to total fluoride exposure. TDFI, UFE and fluoride concentration of biomarkers were statistically significantly higher in the high-fluoride area than in the low-fluoride area. There was a strong statistically significant positive correlation between TDFI and: UFE (ρ=0.756, p<0.001); plasma fluoride concentration (ρ=0.770, p<0.001); toenail fluoride concentration (ρ=0.604, p<0.001). The statistically significant positive correlation between TDFI and fingernail fluoride concentration (ρ=470, p<0.001) as well as between TDFI and fasting whole saliva fluoride concentration (ρ=0.453, p=0.001) was moderate, whereas it was weak between TDFI and hair fluoride concentration (ρ=0.306, p=0.027). In conclusion, the current study confirmed the suitability of 24h urine samples for estimating F exposure in children. The strong correlations between TDFI and F in plasma and toenails also suggest these biomarkers may be considered for health risk assessments of fluoride in children who are susceptible to development of dental fluorosis. Sample preparation and analysis Urine samples collected over the 24h period were pooled for each participant, and the total volume was measured. Saliva samples were centrifuged at 1000 rpm (MSE Harrier 18/80, UK) for 2 min to separate any food debris [Martínez-Mier et al., 2011]. Each blood sample was centrifuged for 10 min at 1500 rpm and the plasma collected. Nail samples from each participant (finger-and toenails , separately) were weighed, and then surface contamination from the nail clippings was removed by sonication in distilled water for 15 min [Whitford, 2005]. The cleaned samples were dried at 95ºC and weighed again. Food samples were weighed and then homogenised using an industrial blender (Cookwork BL9292, UK). Water and urine samples were analysed directly using a F ion selective electrode (ISE, 720A series; Orion Research Inc., Boston, MA, USA) after addition of TISAB III [Martínez-Mier et al., 2011]. Food, toothpaste, plasma, whole saliva, hair and nail samples were analysed after overnight hexamethyldisiloxane-acid diffusion [Martínez-Mier et a...

show abstract

Section: Discussionmentioning

confidence: 99%

Biomarkers for the Assessment of Fluoride Exposure in Children

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Quality control measures included daily instrument calibration, procedural blanks, replicate runs, and the use of certified reference materials (Institut National de Santé Publique du Québec, Cat #s 0910 and 1007; NIST3183, Fluoride Anion Standard). Urinary fluoride concentrations were measured at the UMSPH and the Indiana University Oral Health Research Institute (OHRI) as previously described ( Thomas et al 2016 ). A validation study comparing measures taken by the two labs in the same samples revealed a between-lab correlation of 0.92 ( Thomas et al 2016 ).…”

Section: Methodsmentioning

confidence: 99%

“…Urinary fluoride concentrations were measured at the UMSPH and the Indiana University Oral Health Research Institute (OHRI) as previously described ( Thomas et al 2016 ). A validation study comparing measures taken by the two labs in the same samples revealed a between-lab correlation of 0.92 ( Thomas et al 2016 ).…”

Section: Methodsmentioning

confidence: 99%

) using the formula:

. The values of average creatinine concentration used for the

at each trimester were derived from the larger pool of trimester-1, -2, and -3 samples from Cohorts 2A and 3 examined in our previous report on maternal fluoride biomarker levels ( Thomas et al 2016 ): 100.81, 81.60, and 72.41 (mg/L), respectively. For each woman, an average of all her available creatinine-adjusted urinary fluoride concentrations during pregnancy (maximum three samples and minimum one sample) was computed and used as the exposure measure (

).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6–12 Years of Age in Mexico

Bashash

Thomas

et al. 2017

Environ Health Perspect

Self Cite

169

152

View full text Add to dashboard Cite

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

show abstract

“…Creatinine-adjusted urinary fluoride concentrations were obtained for each maternally derived sample by dividing the fluoride concentration (MUF) in the sample by the sample's creatinine concentration (MUC), and multiplying by the average creatinine concentration of samples available at each trimester (MUC average ) using the formula: ðMUF=MUCÞ × MUC average . The values of average creatinine concentration used for the MUC average at each trimester were derived from the larger pool of trimester-1, -2, and -3 samples from Cohorts 2A and 3 examined in our previous report on maternal fluoride biomarker levels (Thomas et al 2016): 100.81, 81.60, and 72.41 (mg/L), respectively. For each woman, an average of all her available creatinine-adjusted urinary fluoride concentrations during pregnancy (maximum three samples and minimum one sample) was computed and used as the exposure measure (MUF cr ).…”

Section: Exposure Assessmentmentioning

confidence: 99%

Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6-12 Years of Age in Mexico

Hu¹,

Bashash²,

Thomas³

et al. 2018

ISEE Conference Abstracts

Self Cite

View full text Add to dashboard Cite

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 ð0:35Þ mg=L and 0:82 ð0:38Þ mg=L, respectively. In multivariate models we found that an increase in maternal urine fluoride of 0:5 mg=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.

show abstract

Urinary and plasma fluoride levels in pregnant women from Mexico City

Abstract: Background: There is need to assess the developmental neurotoxicity of fluoride. Our

Cited by 38 publications

References 22 publications

Biomarkers for the Assessment of Fluoride Exposure in Children

Biomarkers for the Assessment of Fluoride Exposure in Children

Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6–12 Years of Age in Mexico

Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6-12 Years of Age in Mexico

Contact Info

Product

Resources

About