Association between gestational environmental chemical mixtures and folate exposures with autistic behaviors in a Canadian birth cohort
Bibliographic record
Abstract
Background: Prenatal exposure to environmental chemicals may be associated with autism or autistic-like behaviors. Previous studies suggest that these associations are stronger when folic acid (FA) supplementation is lower. Methods: We used data from the Maternal-Infant Research on Environmental Chemicals study, a Canadian pregnancy and birth cohort (2008-2011). We considered five separate chemical mixtures (measured during the first trimester of pregnancy): metals, organochlorine pesticides, per- and polyfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), and persistent organic pollutants (POPs; including organochlorine pesticides, PFAS, PCBs, and one polybrominated diphenyl ether congener). Autistic-like behaviors were documented in 601 3-4-year-old children with the social responsiveness scale-2 (SRS-2), where higher T-scores denote more behaviors. We used quantile g-computation to estimate the mixture-SRS-2 associations and assessed whether gestational FA supplementation and plasma total folate concentrations modified these associations. Results: The PFAS mixture was associated with decreased SRS-2 T-scores (Ψ = -0.5; 95% confidence interval [CI] = -1.1, 0.1). The metal-SRS-2 associations were stronger in the positive direction among participants with high (>1,000 μg/d) FA supplementation (Ψ = 2.4; 95% CI = 0.8, 3.9) versus those with adequate (400-1,000 μg/d) supplementation (Ψ = -0.2; 95% CI = -1.1, 0.7) (p-interaction = 0.003). Plasma total folate concentrations similarly modified these associations (p-interaction = 0.01). The associations between the PFAS, PCB, and POP mixtures and SRS-2 T-scores were stronger in the positive direction among participants with low (<400 μg/d) versus adequate FA supplementation. This was not observed when assessing modification by plasma total folate concentrations. Conclusion: Our results suggest that the metal mixture is more strongly associated with autistic-like behaviors among participants with higher folate exposure, and the PFAS, PCB, and POP mixtures are more strongly associated with autistic-like behaviors among participants with low FA supplementation.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".