Signes-Pastor et al. 2022 — Dietary arsenic exposure and respiratory outcomes in Spanish children
This prospective cohort study from the INMA (Environment and Childhood) project explored the association between inorganic arsenic (iAs) exposure, quantified via urinary arsenic speciation at 4 years of age, and respiratory symptoms assessed at ages 4 and 7 years in 400 Spanish children. In this low-arsenic-water population, food (primarily rice and rice-based products) represents the dominant exposure pathway rather than drinking water. Urinary exposure biomarker: the summed concentration of iAs, MMA, and DMA (ΣAs), measured by IC-ICP-MS (LOD 0.011 µg/L) at Queen’s University Belfast. Median urinary ΣAs was 4.92 µg/L at 4 years. GEE-Poisson regression showed an increasing trend in expected counts of cumulative respiratory symptoms (wheeze, asthma, eczema, sneeze) with increasing urinary ΣAs. Adjusted expected counts at ln-ΣAs = 1.57 (average) and 4.00 (99th percentile) were 0.63 and 1.33 respiratory events, respectively. Findings are exploratory but suggest that even at low dietary iAs exposure levels, respiratory health effects may be detectable in young children.
Key numbers
- n = 400 children (INMA cohort), 339 with complete data for analysis.
- Urinary ΣAs median at 4 years: 4.92 µg/L (SG-corrected).
- LOD for arsenic speciation: 0.011 µg/L.
- Analytical method: IC-ICP-MS (ion chromatography-ICP-MS) for speciation; iAs, MMA, DMA, AsB measured.
- ΣAs = iAs + MMA + DMA (AsB excluded as non-toxic organic form from seafood).
- Adjusted expected respiratory symptom count at average exposure (ln-ΣAs = 1.57): 0.63 (95% CI 0.36–1.10).
- Adjusted expected count at 99th percentile exposure (ln-ΣAs = 4.00): 1.33 (95% CI 0.61–2.89).
- Exposure source in this population: primarily food (rice, rice-based products) given low-arsenic tap water (<10 µg/L).
- iAs regulatory context cited: EU/Codex maximum of 100 µg iAs/kg for infant rice cereal.
Methods (brief)
Urinary arsenic speciation by IC-ICP-MS; urine samples collected at 4-year pediatric follow-up. Respiratory outcomes assessed via validated ISAAC questionnaire at 4 and 7 years. Statistical analysis: Generalized Estimating Equations (GEE) with Poisson link, natural log-transformed urinary ΣAs; GEE splines used to visualize dose-response. Covariates: child sex, maternal smoking, maternal education, sub-cohort, dietary vegetable/fruit/seafood consumption. Limitations: cross-sectional exposure measurement (single 4-year timepoint); maternal urinary arsenic during pregnancy not directly studied here; small sample limits power for specific respiratory outcomes.
Implications
Certification: This paper establishes that low-level dietary iAs exposure in European children (primarily via rice) is detectable at the population level and associated with increased respiratory symptom burden. It strengthens the scientific case for iAs limits in rice products consumed by young children, including HMT&C certification thresholds for infant-relevant products. Courses: Illustrates the dietary iAs pathway in low-arsenic-water populations; demonstrates urinary biomarker methodology and the ISAAC questionnaire framework for respiratory outcomes in children. App: Dietary iAs exposure biomarker data for Spanish children; rice identified as primary iAs source in low-water-arsenic populations. Microbiome: not applicable directly, but respiratory outcomes from dietary arsenic exposure may involve indirect gut-lung axis mechanisms; flag for future cross-reference.