Prevalence of trisomy 21 following folic acid food fortification
Bibliographic record
Abstract
Polymorphisms of maternal genes responsible for normal folate metabolism may be associated with an increased risk of fetal trisomy 21. By January 1998, most of Canada's flour was being fortified with folic acid. We investigated whether the prevalence of antenatally and postnatally detected trisomy 21 changed before and after folic acid food fortification. A total of 218,977 women underwent second trimester maternal serum screening for trisomy 21 in the 48 months before fortification and 117,986 women were screened in the 29 months after fortification. There were 375 identified cases of trisomy 21 before fortification (1.71 per 1,000), compared to 201 cases thereafter (1.70 per 1,000) for a crude prevalence ratio (PR) of 0.99 (95% confidence interval [CI] 0.84-1.18). The associated risk of trisomy 21 did not change after adjustment for mean maternal age (adjusted PR 0.99 [95% CI 0.82-1.19]). Similarly, no significant decline in the monthly prevalence of trisomy 21 was observed using autoregressive integrated moving average time series analysis (P = 0.24). In conclusion, we failed to observe a decline in the occurrence of trisomy 21 following folic acid food fortification.
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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 | 0.001 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".