Trial reportThe American journal of clinical nutrition2019
Defining the plasma folate concentration associated with the red blood cell folate concentration threshold for optimal neural tube defects prevention: a population-based, randomized trial of folic acid supplementation.
Trial report in The American journal of clinical nutrition, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to 2 registered trials, which are not on this map. Cited by 58 papers, 3 of them syntheses that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Blood Folate and Homocysteine Levels Following Administration of Folic Acid According to Different Daily Dosing Schedules:a Simulation of Food Fortification
Feasibility, Acceptability and Directional Signal Effect on Blood Folate Levels of Iodized Salt Fortified With Folic Acid: Clinical Study
Who cites it
58 citing papers in PubMed, 3 syntheses or guidelines pooled it.
- Effects of maternal folate and vitamin B12 on gestational diabetes mellitus: a dose-response meta-analysis of observational studies.European journal of clinical nutrition · 2022Pooled it
- Folate Levels and Pregnancy Rate in Women Undergoing Assisted Reproductive Techniques: a Systematic Review and Meta-analysis.Reproductive sciences (Thousand Oaks, Calif.) · 2022Pooled it
- The Roles of Reduced Folate Carrier-1 (RFC1) A80G (rs1051266) Polymorphism in Congenital Heart Disease: A Meta-Analysis.Medical science monitor : international medical journal of experimental and clinical research · 2021Pooled it
- A Randomized Crossover Trial of Acceptability of Quadruple-Fortified Salt in Women and their Households in Southern India.The Journal of nutrition · 2025Trial
- Trial
- Impact of daily-supervised administration of a package of iron and folic acid and vitamin BEuropean journal of clinical nutrition · 2021Trial
- Population RBC folate concentrations can be accurately estimated from measured whole blood folate, measured hemoglobin, and predicted serum folate-cross-sectional data from the NHANES 1988-2010.The American journal of clinical nutrition · 2020Trial
- Maternal lifestyle risk factors and human embryonic morphologic development using 3D ultrasound: a population-based prospective cohort study.Human reproduction (Oxford, England) · 2026Article
- Folate Deficiency Alters microRNA Expression and Transcriptomic Networks in a Human Trophoblast Model.Nutrients · 2026Article
- Associations between Red Blood Cell Folate Forms and Demographic, Physiologic, and Lifestyle Factors in the United States Population: Cross-Sectional Data from the National Health and Nutrition Examination Survey August 2021-August 2023.Current developments in nutrition · 2026Article
- Choline and Its Companions: Inter-Related Roles of Choline and B Vitamins in Fetal Development and Offspring Health.Nutrients · 2026Review
- Air Pollution Mixture and Folate Status Indicators among Pregnant Women in Canada: Maternal-Infant Research on Environmental Chemicals (MIREC) Study, 2008 to 2011.Current developments in nutrition · 2026Article
- Prediabetes, diabetes, and folate status among United States women of reproductive age: NHANES 2011-March 2020.The American journal of clinical nutrition · 2026Article
- Reference intervals for blood concentrations of folate-related biomarkers in early pregnancy among pregnant women in Qingdao.BMC pregnancy and childbirth · 2026Article
- B Vitamin Deficiencies and Associated Neuropathies.Current nutrition reports · 2026Review
- Article
- Targeting Folate Receptors for the Detection and Selective Treatment of Cancer: Advanced Precision Oncology in Practice.International journal of biological sciences · 2026Review
- Nicotine consumption and folate insufficiency in pregnancy: a population-based cross-sectional study.The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians · 2025Article
- Association between gestational environmental chemical mixtures and folate exposures with autistic behaviors in a Canadian birth cohort.Environmental epidemiology (Philadelphia, Pa.) · 2025Article
- Vitamin BClinical nutrition ESPEN · 2025Observational
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Authors and funding
9 authors.
Funding
Abstract
backgroundFor women of reproductive age, a population-level red blood cell (RBC) folate concentration below the threshold 906 nmol/L or 400 ng/mL indicates folate insufficiency and suboptimal neural tube defect (NTD) prevention. A corresponding population plasma/serum folate concentration threshold for optimal NTD prevention has not been established.
objectiveThe aim of this study was to examine the association between plasma and RBC folate concentrations and estimated a population plasma folate insufficiency threshold (pf-IT) corresponding to the RBC folate insufficiency threshold (RBCf-IT) of 906 nmol/L.
methodsWe analyzed data on women of reproductive age (n = 1673) who participated in a population-based, randomized folic acid supplementation trial in northern China. Of these women, 565 women with anemia and/or vitamin B-12 deficiency were ineligible for folic acid intervention (nonintervention group); the other 1108 received folic acid supplementation for 6 mo (intervention group). We developed a Bayesian linear model to estimate the pf-IT corresponding to RBCf-IT by time from supplementation initiation, folic acid dosage, methyltetrahydrofolate reductase (MTHFR) genotype, body mass index (BMI), vitamin B-12 status, or anemia status.
resultsUsing plasma and RBC folate concentrations of the intervention group, the estimated median pf-IT was 25.5 nmol/L (95% credible interval: 24.6, 26.4). The median pf-ITs were similar between the baseline and postsupplementation samples (25.7 compared with 25.2 nmol/L) but differed moderately (±3-4 nmol/L) by MTHFR genotype and BMI. Using the full population-based baseline sample (intervention and nonintervention), the median pf-IT was higher for women with vitamin B-12 deficiency (34.6 nmol/L) and marginal deficiency (29.8 nmol/L) compared with the sufficient group (25.6 nmol/L).
conclusionsThe relation between RBC and plasma folate concentrations was modified by BMI and genotype and substantially by low plasma vitamin B-12. This suggests that the threshold of 25.5 nmol/L for optimal NTD prevention may be appropriate in populations with similar characteristics, but it should not be used in vitamin B-12 insufficient populations. This trial was registered at clinicaltrials.gov as NCT00207558.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.