Govarts et al. 2016 - Prenatal chemical mixtures and birth weight

Govarts and colleagues analyzed 248 Flemish mother-child pairs to test whether prenatal chemical exposures, singly and in mixtures, were associated with birth weight. This is primary human biomonitoring and epidemiology evidence. It is not product occurrence evidence: metals were measured in cord blood, maternal blood, and maternal hair, while the outcome was birth weight.

Key numbers

Table 2 reports exposure biomarkers for the cohort. Metal and metalloid measures are listed below using the source’s units and biological matrices.

The cohort’s median birth weight was 3540 g, with a range of 2175-4950 g. Of the 16 exposure parameters studied in single-pollutant models, only cord-blood arsenic had a statistically significant negative association with birth weight: an interquartile-range increase in arsenic Z-score corresponded to a 91 g decrease in birth weight (95% CI: 17-164 g; p = 0.016) after adjustment for gestational age, child sex, maternal smoking, parity, and maternal prepregnancy BMI.

The principal-component regression sensitivity analysis identified a component constituted by arsenic and cadmium that was negatively associated with birth weight (p = 0.009; 209 complete cases). The mixture exploration found that arsenic, cadmium, lead, PFOA, and MECPP together strengthened the association relative to arsenic alone; one five-chemical mixture had an estimate of -135 g for an interquartile-range increase in the average mixture Z-score (p = 0.0019). In girls, the strongest reported mixture included PFOS, lead, cadmium, manganese, thallium, and methylmercury, with an estimate of -235 g (p = 0.0006).

Methods (brief)

The study used data from the FLEHS II mother-child cohort, recruited across Flanders from August 2008 to July 2009. Lead, manganese, copper, thallium, and arsenic were measured in cord blood; cadmium was measured in maternal whole blood collected after birth; total mercury and methylmercury were measured in maternal hair, with methylmercury used in the data analysis. Metals were measured by high-resolution ICP-MS after microwave acid digestion. Methylmercury was measured by headspace injection-gas chromatography-atomic fluorescence spectrometry.

Regression models related exposure biomarkers and mixtures to birth weight, with adjustment for gestational age, child sex, maternal smoking during pregnancy, parity, and maternal prepregnancy BMI. The authors also applied principal component analysis and an iterative mixture Z-score approach.

Implications

Certification: Do not admit this source into product or ingredient benchmark pools. The reported concentrations are human biomonitoring values in blood or hair, not concentrations in a commercial product, food, supplement, cosmetic, toy, or ingredient.

App: Use as prenatal health-context evidence for arsenic, cadmium, lead, manganese, methylmercury, and thallium mixture effects. Keep the arsenic result as total arsenic in cord blood; the paper explicitly states that arsenic speciation was not available in cord blood samples.

Courses: Useful for teaching the distinction between biomarker concentration, product concentration, and modeled health outcome; mixture modeling; and why total arsenic cannot be converted into inorganic arsenic without speciation.

Wiki pages this source may touch

• index
• index
• arsenic
• cadmium
• lead
• manganese
• mercury
• thallium
• copper

Verification notes

This page was built from the full PDF, including the exposure-methods section, Table 1, Table 2, the single-pollutant regression results, the mixture-model results, and the conclusions. The source is primary data, but it is context-only for HMI product routing because all routeable concentration values are biological biomarkers. The authors note that cord-blood arsenic speciation was not available; this page therefore records the arsenic biomarker as total arsenic and does not infer 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.