Effect of altitude on urinary, plasma and nail fluoride levels in children and adults in Nepal

Sah, Om; Maguire, Anne; Zohoori, Fatemeh

doi:10.1016/j.jtemb.2019.09.003

Cited by 11 publications

(4 citation statements)

References 36 publications

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“…Although water F concentration has been reported to exert the most influence on F concentration of finger-and toenails, older age groups (≥30 years) and females have been found to have significantly higher nail F concentrations than younger age groups and males [Fukushima et al, 2009]. In contrast, a recent study [Sah et al, 2020] reported a statistically significantly higher F concentration in the fingernails of parents than of their children, whereas no statistically significant difference in toenail F concentration between parents and children was observed.…”

Section: Resultsmentioning

confidence: 82%

Biomarkers for the Assessment of Exposure to Fluoride in Adults

et al. 2021

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To monitor deficient or excessive intakes of biologically available fluoride (F), various biological samples have been tested for use as biomarkers of human exposure to F. Most such studies have concerned children and often have only involved measurement of F in 1 or 2 types of sample. The present study investigated the relationships of F concentrations in biomarkers of F exposure; including plasma, saliva, hair, finger- and toenails, and daily urinary F excretion (UFE) with the total daily F intake (TDFI) of adults. TDFI was assessed in 60 healthy adults, aged ≥20 years; 31 lived in a low-F water area (LFA, 0.04 mg F/L) and 29 in a high-F water area (HFA, 3.05 mg F/L) of Nigeria. All volunteers provided at least 1 biomarker sample from the above list and completed a questionnaire to evaluate F intake from the diet and toothpaste ingestion. TDFI, UFE and F concentrations of biomarkers were statistically significantly higher in the HFA than in the LFA. There were strong statistically significant positive correlations between TDFI and UFE (ρ = 0.730, p < 0.001); plasma F (ρ = 0.729, p < 0.001); fasting whole saliva F (ρ = 0.653, p < 0.001) and hair F (ρ = 0.603, p < 0.001). The statistically significant positive correlations between TDFI and fingernail F (ρ = 0.502, p < 0.001) and between TDFI and toenail F (ρ = 0.556, p < 0.001) were moderate. In conclusion, this study has indicated the usefulness of 24-h UFE as well as F concentration in plasma, fasting whole saliva and hair as biomarkers of contemporary or sub-chronic F exposure in groups of adults. However, they do not appear to have the necessary sensitivity to predict F exposure in individuals.

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Section: Resultsmentioning

confidence: 82%

Biomarkers for the Assessment of Exposure to Fluoride in Adults

et al. 2021

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“…Due to the scarcity of relevant studies on these relationships, the findings should be interpreted with caution. A study with 89 children and their parents [Sah et al, 2020], in which total daily fluoride intake and fluoride concentrations of toe-and finger-nails were assessed, found no significant differences in fingernail fluoride in both children and parents but a statistically significant difference in toenail fluoride concentration in parents. This study also found a statistically significant difference in toenail fluoride concentration in parents but not in children.…”

Section: Discussionmentioning

confidence: 96%

Fluoride Exposure in Community Prevention Programmes for Oral Health Using Nail Clippings and Spot Urine Samples: A Systematic Review and Meta-Analysis

Eskandari,

Kumah,

Azevedo

et al. 2023

Caries Res

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Due to practical difficulties in quantifying fluoride exposure in populations, practical and accurate biomarkers can play a major role in the surveillance of fluoride. Among different fluoride biomarkers, spot urine and nail clippings have gained more attention due to their ease of acquisition. However, there is no robust consensus about the accuracy of these biomarkers for the estimation of fluoride exposure. This systematic review and meta-analysis aimed to synthesise evidence on the association between fluoride exposure and the fluoride concentration of spot urine and nail clippings. This review was conducted and reported using the PRISMA Statement. Nine databases (Medline, CINAHL, Web of Science, Scopus, ScienceDirect, Sage Journals Online, Campbell Collaboration, Cochrane Collaboration, and Embase); search engines (Google and Google Scholar); and grey literature were searched up to September 2022. All screening, data extraction, and quality assessments were conducted in duplicate. All experimental and observational research studies that reported the correlation between fluoride exposure and fluoride concentrations of spot urine and/or nail clippings were included. The Mixed-Methods Appraisal tool was used to assess the methodological quality of the included studies. A random effect meta-analysis was carried out to determine the relationship between fluoride exposure and fluoride concentration of biomarkers (i.e., spot urine and nail clippings). Forty-four studies met the inclusion criteria. A total of 694,578 participants were included in this review. Twenty-five studies were included in the meta-analysis. The primary meta-analysis showed a moderate correlation of 0.674 (95% confidence interval [CI]: 0.623–0.725, n = 25) between fluoride intake and fluoride concentration of spot urine and a strong correlation of 0.938 (95% CI: 0.520–1.355, n = 11) between fluoride intake and the fluoride concentration of nail clippings in all age groups. The findings of secondary meta-analyses showed a strong positive correlation between fluoride intake and fluoride/creatinine ratio of spot urine in children (0.929; 95% CI: 0.502–0.991; n = 2). In conclusion, spot urine and nail clippings have the potential to be employed as non-invasively obtained biomarkers in populations. However, due to the scarcity of high quality, relevant studies, more research is needed to establish the validity of these biomarkers.

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“…Animal experiments have shown that under low oxygen conditions, mice ingested more fluoride, and their enamel formation was affected. Higher altitudes result in a lower oxygen concentration of the air and lower pH levels of the urine, and they affect the metabolism of fluoride and calcium and increase the reabsorption of fluoride by the kidneys (71)(72)(73). Changes in acid-base balance caused by high-altitude hypoxia may increase fluoride levels in organisms' internal environments by increasing the reabsorption of fluoride and reducing fluoride excretion in the urine.…”

Section: Relationship Between Fluorosis and Altitudementioning

confidence: 99%

Brick tea consumption and its relationship with fluorosis in Tibetan areas

et al. 2022

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Brick tea-type fluorosis (BTF) due to a high intake of brick tea is possible in Tibetan populations, and dental fluorosis (DF) and skeletal fluorosis (SF) are its primary manifestations. To determine the prevalence of DF and SF and their relationships with brick tea intake in Tibetan populations, a literature review was conducted for studies published between 1994 and 2021. The available evidence revealed that brick tea may be produced from older stems and leaves of the tea plant and that the fluoride content of brick tea exceeds the national standard. The harsh environment of the plateau has led to limited food sources for the local Tibetan people who form the habit of drinking tea leaves as a satiation solution to digest greasy food and replenish vitamins, and regular consumption of brick tea leads to excessive exposure of Tibetan residents to fluoride. Studies in Tibet showed that the prevalence of DF in children was 14.06–75.93% in different districts, and the overall pooled prevalence of DF was 26.08%. The prevalence of SF in adults was 19.90–74.77% in different Tibetan districts, and the overall pooled prevalence of SF was 33.84%. The analysis of risk factors showed that the prevalence of BTF may be related to high-altitude and different working and living conditions, and BTF in children may be associated with fluoride intake during mothers’ pregnancy and lactation. With the development of bioinformatics research, gene polymorphisms were suspected to be related to susceptibility to fluorosis in Tibetan populations. The study of BTF in Tibetan people needs to be further investigated and standardized, and additional studies evaluating the pathogenesis and preventive measures of BTF are warranted.

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Effect of altitude on urinary, plasma and nail fluoride levels in children and adults in Nepal

Cited by 11 publications

References 36 publications

Biomarkers for the Assessment of Exposure to Fluoride in Adults

Biomarkers for the Assessment of Exposure to Fluoride in Adults

Fluoride Exposure in Community Prevention Programmes for Oral Health Using Nail Clippings and Spot Urine Samples: A Systematic Review and Meta-Analysis

Brick tea consumption and its relationship with fluorosis in Tibetan areas

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