Carignan et al. (2015)
Early-life arsenic exposure assessment in a birth cohort comparing infant feeding modes. Measured urinary and breast milk arsenic in 72 infants at 6 weeks of age, plus tap water from 874 maternal homes. Formula-fed infants had 7.5-fold higher urinary arsenic than breastfed infants; formula powder estimated as the primary dietary source.
Key numbers
| Measurement | Median | Max | N |
|---|---|---|---|
| Infant urine As (all) | 0.17 μg/L | 2.9 μg/L | 72 |
| Breast milk As | 0.31 μg/L | 1.94 μg/L | 9 |
| Maternal tap water As | 0.44 μg/L | 4.2 μg/L | 874 |
Feeding mode comparison: Formula-fed infants: 0.32 μg/L median urinary As (range 0.02–1.49). Breastfed infants: 0.04 μg/L median urinary As (range <0.01–0.38). Difference: 8-fold median, β=2.02 (95% CI 1.21–2.83, p<0.0001).
Exposure attribution: Estimated median daily arsenic exposure in formula-fed infants approximately 70% attributable to formula powder (~0.13 μg/day), remainder to tap water (~0.06 μg/day). Breastfed infants received ~0.03 μg/day primarily via breast milk.
Methods
Inductively coupled plasma mass spectrometry (ICP-MS) with collision cell for total arsenic quantification. Arsenic speciation (inorganic iAs vs dimethylarsinic acid DMA, monomethylarsonic acid MMA) performed via high-performance liquid chromatography (HPLC) coupled to ICP-MS. Infant exposure calculated from measured concentrations and typical intake volumes (formula reconstitution, breast milk volumes, tap water ingestion). Body weight normalization used for dose comparison.
Implications
Formula powder represents a substantial arsenic exposure pathway for formula-fed infants in this US cohort, with urinary biomarkers indicating systemic absorption. The 7-fold difference between feeding modes was statistically robust and driven primarily by water-As in reconstituted formula rather than contaminants in the powder itself. Breastfeeding substantially reduces early-life arsenic exposure compared to formula-feeding when formula is reconstituted with As-contaminated tap water.
Wiki pages updated
- infant-formula → contamination_profile[iAs]
- breast-milk → contamination_profile[iAs]
- arsenic-inorganic → source references
- infant-formula-powder-non-soy → routing [direct_evidence]
- infant-rtf-non-soy → routing [broad_context]
---
**Git commit message:**
ingest: carignan2015-arsenic-breastfed-formula [peer-reviewed, A-tier]
Source: Estimated Exposure to Arsenic in Breastfed and Formula-Fed Infants in a United States Cohort
Raw handle: FM_4421773 Cite key: estimated2015-estimated-exposure-arsenic-breastfed
Cohort study (NHBCS): 72 infants at 6 weeks, iAs measured in urine, breast milk, maternal tap water. Formula-fed infants: 7.5× higher urinary As than breastfed (0.32 vs 0.04 μg/L, p<0.0001). ~70% of formula-fed exposure from formula powder. Breastfed exposure minimal (~0.03 μg/day).
Frontmatter: iAs metal, breast milk + infant formula ingredients, infant urine + breast milk + tap water matrices, US jurisdiction, 72 infants, A-tier peer-reviewed.
Body: summary, key numbers table, methods (ICP-MS + HPLC-ICP-MS speciation), implications, wiki pages updated.
Routing: infant-formula-powder-non-soy (direct), infant-rtf-non-soy (broad context), breast-milk (direct), arsenic-inorganic (reference).
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