Spina Bifida Phenotypes and Sex‐Specific Prevalence Among Offspring of Folic Acid Users
Bibliographic record
Abstract
Background Periconceptional consumption of folic acid can reduce a woman's risk of having a neural tube defect (NTD)‐affected pregnancy, particularly in high‐prevalence areas such as northern China; however, information about the effect of folic acid on sex‐specific or phenotype‐specific spina bifida prevalence is lacking. Methods We used data from the China‐U.S. NTD Prevention Project during which women were asked to take a daily pill containing 400 μg of folic acid without other vitamins to reduce their risk of having an NTD‐affected pregnancy. We used data from birth defect surveillance and births from 1993 through 1996 from a high‐prevalence region located in five counties in northern China to evaluate these effects. We also examined the distribution of spina bifida phenotypes‐‐categorizing lesions in the cervicothoracic region as high lesions and those in the lumbosacral region as low lesions. Results Among 21,536 women who took folic acid at any time before and during early pregnancy and 56,541 women who did not take folic acid, we identified 18 and 115 women, respectively, with spina bifida‐affected pregnancies of ≥ 20 weeks’ gestation. Among the women who did and did not take any folic acid, the prevalences of spina bifida were 8.4 per 10,000 pregnancies and 20.3 per 10,000, respectively (risk reduction ~59%). Among women who did and did not take any folic acid as part of the prevention project, the spina bifida prevalences among female offspring were 8.8 and 24.2 per 10,000 pregnancies, respectively (risk reduction ~64%), and the prevalences among male offspring were 8.0 and 17.0 per 10,000, respectively (risk reduction ~53%). Among women who did and did not take any folic acid, the prevalences of high spina bifida lesions among offspring were 3.3 and 11.0 per 10,000 pregnancies, respectively (risk reduction ~70%), and prevalences of low spina bifida lesions among offspring were 4.6 and 8.5 per 10,000 pregnancies, respectively (risk reduction ~45%). This difference was statistically significant at p<0.01 and among women with female offspring, the risk reduction was even greater for high lesions vs. low lesions. Discussion and Conclusions These findings suggest that the folic acid effect on neural tube closure is not limited to any one spina bifida phenotype; however, it appears that the effect may differ by level of lesion and offspring sex. Among women who consumed 400 μg of folic acid daily, compared with those with male offspring those with female offspring experienced a greater reduction in risk of spina bifida this reduction in risk among female offspring was greater for high lesions than for low lesions. The findings are also consistent with observations in seven Canadian provinces where the proportion of cervicothoracic lesions decreased in all regions after fortification. Examination of these variations in folic acid effects may be helpful in identifying factors important in the pathogenesis of spina bifida and other neural tube defects. Support or Funding Information CDC internal funding only
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.001 | 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".