Return to baseline arsenic concentrations after 1 year on

Overview

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Key numbers

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Funding information After 12 months on a GFD, total median urinary arsenic concentration returned
National Institute of Diabetes and Digestive to baseline (3.42 vs. 4.93 μg/L, p = 0.17). The median total nail arsenic col-
the primary outcome measure given the lack of robust The study population (48% female) primarily self‐
normative data for the US population, but we were able identiﬁed as white (90%), which reﬂects the racial
majority (62%) had an annual household income >
2.6 | Statistical analysis (96%). More than half (52%) had a family history of a
Assuming a power of 80% and α of 0.05, a sample size of repeat transglutaminase immunoglobulin A (TTG IgA)
descriptive summaries were used to summarize data. GFD (mean value of TTG IgA was 7.4, with normal
Paired Wilcoxon signed rank test, analysis of variance, TTG IgA deﬁned as <10); 13 (87%) were within normal
als), we applied a conservative Bonferroni correction. All participants were following a GFD with 90% (19/21)
after 6 months on a GFD, 21 (60%) provided a follow‐ sources of dietary arsenic were chicken, apples,
rice‐containing sources of arsenic were gluten‐free concentration at 6 months was 12.8 μg/L, which was
vs. 4.93 μg/L, p = 0.17; Figure 1), and the maximum which may have lacked sufﬁcient statistical power to
was 34 μg/L, which is well below the threshold for be able to assess differences in toenail arsenic
arsenic toxicity in urine(100 μg/L) established by the concentrations.
For comparison, median measured total urinary arsenic a biomarker for exposure.19,20 After applying a
umes, vegetables, and animal organs.25 Urinary Mo 12 months of a GFD. This should provide solace to
intake.26,27 The mean urinary Mo concentrations in ﬂuctuations in arsenic exposure and explore prevention
elevated compared to baseline (130.4 vs. 57.1 μg/L). GFDs, nuances are important, and risk assessment
high with only 42% of those recruited at endoscopy The authors declare no conﬂicts of interest.

Methods (brief)

Results: Twenty‐one of the 35 (60%) participants provided a follow‐up sample.
T32DK007477, R01DK 97112, K23 119584; samples (p = 0.56). Only urinary molybdenum concentration was increased
children (between ages of 2–18 years) diagnosed with mass spectrometry (Agilent 8900 ICP‐MS; Agilent
samples along with a 3‐day dietary record. In this cohort, 2 × 250 mm column and a Thermo AG7, 2 × 50 guard
the current study, the 35 participants who had provided run after each calibration and every 20 samples.
samples after 6 months on a GFD were asked to submit
additional urine and toenail samples after 12 months on
12 months after GFD initiation as well as changes in ries were collected on paper during clinic visits or
samples collected 12 months after GFD initiation were lized previously in our prospective cohort, which had
−80° C.10 Urinary concentrations of arsenic and 22 Study.13 Urine was collected on Day 4.
Toenail samples were collected as a biomarker of long‐ submit a follow‐up sample after 12 months on a GFD.
binds to keratin. Toenail sample collection was per-
to compare to prior samples measured on the same composition of the CeD clinical population. All partici-
Assuming a power of 80% and α of 0.05, a sample size of repeat transglutaminase immunoglobulin A (TTG IgA)
Of the 35 participants who provided a urine sample consumed tap water. The most common non‐rice
up urine sample, and 20 provided a toenail sample after and brussels sprouts/broccoli/cauliﬂower. Common
12 months on a GFD samples(p = 0.565) (Figure 3A,B).
returned to baseline after 12 months on a GFD (3.42 the smaller sample size for the follow‐up collection,

Implications

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Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

Commit	Date	Change	Description
b01ec52c	2026-08-04	major	2 sections added
d49e450f	2026-08-03	major	5 sections added; narrative text revised