ArticleToxicology and environmental health sciences2026
Impact of sample mass on the reliability of toenail fluoride for exposure assessment.
Article in Toxicology and environmental health sciences, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
1 citing paper in PubMed.
- Relationships between Toenail, Urinary, and Drinking-water Fluoride Concentrations in a Pregnancy Cohort using Private Water Systems in the United States.Biological trace element research · 2026Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
12 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Objective: This study aimed to determine the minimum toenail mass needed for reliable fluoride analysis, and to compare fluoride extraction efficiency (%FE) using two protocols. Methods: Toenail samples (n = 98 from 11 participants) were grouped into masses ranging from 1.0 to 5.0 mg (± 0.5 mg). Fluoride content was analyzed using a hexamethyldisiloxane(HMDS)-facilitated diffusion method and a fluoride-ion selective electrode. Pooled toenail samples (3.0 ± 0.5 mg) from four participants were analyzed using two protocols: protocol-A used 1 mL of HMDS-saturated 3N sulfuric acid/2 mL DI water; and protocol-B used 3 mL/3 mL. Samples were re-analyzed twice to calculate %FE. Minimum mass-threshold was determined by intraclass correlation coefficients (ICC) with 95%-confidence intervals (CI) from linear mixed-effects models and change-point analysis, accounting for intra-participant variability. F-tests compared the variance in %FE between protocols. Results: Fluoride content ranged from 0.82 to 9.22 µg/g. Excellent reliability (ICC = 0.90, 95%CI:[0.71, 0.95]) was observed in samples ≥ 2.5 mg. A change-point was identified at 2.20 mg(95%CI:[1.70, 2.70 mg]). A less variable %FE was observed with protocol-A (43-58%) compared to protocol-B (38-80%) (F-ratio = 0.23, p = 0.02). Conclusion: Toenail sample mass affects the reliability of fluoride analysis. The use of a minimum toenail mass of about 2.2-2.5 mg increases the reliability of fluoride analysis at the participant level. Variability in %FE should be considered in future efforts to standardize analytical protocols. Supplementary Information: The online version contains supplementary material available at 10.1007/s13530-026-00321-y.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.