Hoen et al. 2018 - Infant urinary arsenic and gut microbiome
Hoen and colleagues examined whether urinary arsenic at 6 weeks of age related to infant gut-microbiome composition in the New Hampshire Birth Cohort Study. This is a4 biomonitoring and microbiome evidence: it does not report infant-formula product concentrations, but it does provide human infant exposure-biomarker data and sex-specific microbiome associations in a formula-relevant early-life population.
Key numbers
The study analyzed 204 infants with both 6-week urine and stool samples. Table 1 reports urinary arsenic concentrations in infants of median 0.4 micrograms/L, mean 0.63 micrograms/L, and range <0.05-4.8 micrograms/L. Home tap-water arsenic had mean 1.5 micrograms/L and range <0.05-57.0 micrograms/L.
Feeding-stratified urinary arsenic means reported in the Results were 0.5 micrograms/L for exclusively breastfed infants, 0.9 micrograms/L for mixed-fed infants, and 1.2 micrograms/L for formula-only infants.
Overall microbiome composition at 6 weeks was marginally associated with natural-log urinary arsenic after adjustment for feeding and urine specific gravity (pseudo-F 1.85, p = 0.05). The authors identified 8 OTUs positively associated with urinary arsenic and 14 OTUs negatively associated with urinary arsenic. Positively associated taxa included a strong positive association with Ruminococcus; negatively associated taxa included OTUs assigned to Bacteroides, Bifidobacterium, and Clostridiaceae.
Sex- and feeding-stratified analysis found the strongest association in formula-fed males. Among exclusively or partially formula-fed males (n = 33), overall microbiome composition was associated with urinary arsenic after adjustment for formula exclusivity and urine specific gravity (pseudo-F 2.30, p = 0.008). No such association was observed in formula-fed females (n = 23, pseudo-F 0.54, p = 0.93), exclusively breastfed males (n = 85, pseudo-F 0.58, p = 0.83), or exclusively breastfed females (n = 58, pseudo-F 1.14, p = 0.39).
Among formula-fed males, urinary arsenic was associated with 9 OTUs after adjustment, with 2 positively associated and 7 negatively associated. Negatively associated taxa included Bifidobacterium, Bacteroides, and Lactobacillus; positively associated taxa included a Lachnospiraceae OTU and a Streptococcus OTU.
The cohort discussion notes that popular infant-formula brands in prior work by the same group contained 2.2-12.6 ng/g arsenic, most of it inorganic, and that drinking water used to mix formula contributed additional infant exposure.
Methods (brief)
Infant urine at 6 weeks was analyzed for total arsenic concentration, and stool microbiome composition was measured by sequencing of bacterial 16S rRNA gene regions from DNA extracted from stool. The current-study inclusion set came from the New Hampshire Birth Cohort Study and required urine, stool, and feeding data at 6 weeks. Statistical models used natural-log urinary arsenic, generalized UniFrac distance, feeding adjustment, and urine specific gravity adjustment; subgroup analyses were stratified by sex and feeding mode.
Implications
Certification: Do not use this source as product-occurrence evidence for infant formula. It provides infant urinary biomonitoring and microbiome-association evidence rather than formula-powder or ready-to-feed concentrations.
Courses: Useful for showing that early-life arsenic exposure can be detected at low urinary concentrations in a US cohort and that formula-fed male infants showed the clearest microbiome signal.
App: Context only. This paper supports infant exposure and microbiome-risk framing, not contamination profiling of a specific market product.
Microbiome: Primary human infant source for arsenic-gut-microbiome association, with strongest signal in formula-fed males.
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Verification notes
Recovered under the 2026-06-10 inclusion-by-default rule from a prior skip:not-food-occurrence disposition. The old skip was too narrow because the paper is direct a4 biomonitoring and microbiome evidence in a formula-relevant infant population.
Products and ingredients are intentionally empty. The paper does not assay market infant-formula products directly in this dataset; it measures infant urinary arsenic and stool microbiome composition. Arsenic is tagged as tAs because the infant biomarker in this paper is total urinary arsenic, not speciated inorganic arsenic.
Page history
The five most recent substantive edits to this page. 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 | Description |
|---|---|---|
| b1a5e1e | 2026-06-13 | recovery | hoen2018 infant arsenic microbiome |