Signes-Pastor et al. 2022 — Dietary exposure to toxic elements during infants’ first year, NH Birth Cohort
This longitudinal biomonitoring study tracked urinary concentrations of 17 elements (8 essential, 9 non-essential) in US infants at 6 weeks of age (exclusively breastfed baseline) and at 1 year of age following weaning in the New Hampshire Birth Cohort Study. Several non-essential elements increased markedly between the two time points: urinary As increased from a median of 0.20 µg/L at 6 weeks to 2.31 µg/L at 1 year, representing an 11-fold increase; Mo increased from 1.02 to 45.36 µg/L (44-fold). Rice consumption at 1 year was significantly associated with increased urinary As and Mo concentrations, extending the established rice-arsenic link specifically to the US infant weaning context. Pb, Cd, Hg, Al, Sb, Sn, and V also showed higher concentrations at 1 year than at 6 weeks, consistent with weaning-related dietary expansion driving non-essential element exposure.
Key numbers
- Urinary As median: 0.20 µg/L at 6 weeks → 2.31 µg/L at 1 year (11-fold increase); as-consumed basis via urine
- Urinary Mo: 1.02 µg/L at 6 weeks → 45.36 µg/L at 1 year (44-fold increase)
- Urinary Pb, Cd, Hg, Al, Sb, Sn, V all higher at 1 year vs 6 weeks (magnitudes in supplemental tables)
- Rice consumption at 1 year significantly associated with urinary As (regression coefficient positive, p < 0.05)
- n = 187 paired urine samples; independent rice subgroup n = 147
- Analytes: Al, As, Cd, Hg, Pb, Sb, Sn, U, V (non-essential) and Co, Cr, Cu, Fe, Mn, Mo, Ni, Se (essential)
- As speciation by HPLC-ICP-MS (Dartmouth Trace Element Analysis Core); speciation data available for urinary As species
- Urine analyzed by ICP-MS (Agilent 8900)
Methods (brief)
Longitudinal cohort study (NHBCS, New Hampshire, USA). Spot urine samples collected at ~6 weeks and ~1 year of age. Urinary specific gravity measured; concentrations specific-gravity-corrected. As speciation: HPLC-ICP-MS with Thermo AS7 anion-exchange column. Food diary collected over 3 days prior to urine collection at 1 year. LOD values not reported in abstract; full analytical metadata in supplemental.
Implications
Certification: Demonstrates that infant dietary exposure to As, Pb, Cd, and multiple other toxic metals increases sharply at weaning and is directly driven by rice and rice-based food introduction; strongest evidence base for targeting rice in infant food certification. Courses: Canonical NHBCS study linking rice weaning foods to urinary arsenic in US infants. App: Supports rice-based infant food as high-priority risk category; multi-metal simultaneous exposure framework (Al, Sb, Sn, U alongside As) relevant to mixture considerations. Microbiome: Not directly applicable.