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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 teacher head, 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".