Improving maternal folate status to prevent infant neural tube defects: working group conclusions and a framework for action

Comparative Scoping Review of Prenatal Care Resources for Families of Children With Spinal Dysraphism and Hydrocephalus in High-Income Countries and Low- and Middle-Income Countries

BACKGROUND AND OBJECTIVES

Low- and middle-income countries (LMICs) face higher incidences and burdens of care for neural tube defects (NTDs) and hydrocephalus compared with high-income countries (HICs), in part due to limited access to neurosurgical intervention. In this scoping review, we aim to integrate studies on prenatal care, counseling, and surgical management for families of children with spinal dysraphism and hydrocephalus in LMICs and HICs.

METHODS

PubMed, Embase, Global Index Medicus, and Web of Science electronic databases were searched for English language articles pertaining to prenatal care, counseling, and surgical management for families of children with spinal dysraphism and hydrocephalus in HICs and LMICs. Identified abstracts were screened for full-text review. Studies meeting inclusion criteria were reviewed in full and analyzed.

RESULTS

Seventy studies met the inclusion criteria. Twelve studies (16.9%) were conducted in HICs only, 50 studies (70.4%) were conducted in LMICs only, and 9 studies (12.7%) encompassed both. On thematic analysis, seven underlying topics were identified: epidemiology, folate deficiency and supplementation/fortification, risk factors other than folate deficiency, prenatal screening, attitudes and perceptions about NTDs and their care, surgical management, and recommendations for guideline implementation.

CONCLUSION

NTDs have become a widely acknowledged public health problem in many LMICs. Prenatal counseling and care and folate fortification are critical in the prevention of spinal dysraphism. However, high-quality, standardized studies reporting their epidemiology, prevention, and management remain scarce. Compared with NTDs, research on the prevention and screening of hydrocephalus is even further limited. Future studies are necessary to quantify the burden of disease and identify strategies for improving global outcomes in treating and reducing the prevalence of NTDs and hydrocephalus. Surgical management of NTDs in LMICs is currently limited, but pediatric neurosurgeons may be uniquely equipped to address disparities in the care and counseling of families of children with spinal dysraphism and hydrocephalus.

Integrated surveillance strategy to support the prevention of neural tube defects through food fortification with folic acid: the experience of Costa Rica

PURPOSE

(1) To describe how Costa Rica implemented an integrated surveillance strategy of folate deficiency, neural tube defects (NTDs) prevalence, NTDs-associated infant mortality rate (NTDs-IMR), and folic acid food fortification (FAFF), to support with evidence NTDs prevention policies; (2) to disseminate updated data from monitoring programs.

METHODS

We performed a cross-sectional analysis, using the databases of national surveillance systems for NTDs outcomes to compare NTDs-prevalence and NTDs-IMR observed in the pre-fortification (1987-1998) and post-fortification (2010-2020) periods. In addition, using data from FAFF monitoring program (2010-2020), means of folic acid concentration (mg/kg) and folic acid daily intake (μg/day) were calculated for each fortified food (corn and wheat flour, rice and milk), as well as its contribution to folic acid estimated average requirement (EAR).

RESULTS

After FAFF Costa Rica showed a decrease of 84% in folic acid deficiency in women of childbearing age, as well as a 53% decrease in the prevalence of NTDs, falling from 11.82/10,000 to 5.52/10,000 livebirths. In addition, there was a 76% reduction in the NTDs-IMR from 77.01/100,000 to 18.66/100,000 livebirths. Between 2010 and 2020, all fortified foods provided an average contribution of 119% of the EAR of folic acid in the population.

CONCLUSION

To reduce NTD risk, an integrated surveillance strategy is essential not only to base prevention strategies on evidence, but also to demonstrate their impact and improve interventions over time. The experience in Costa Rica provides evidence that this type of surveillance is feasible to be implemented in developing countries.

Global strategies for the prevention of neural tube defects through the improvement of folate status in women of reproductive age

INTRODUCTION

Neural tube defects represent a global public health problem, mainly in countries where effective prevention strategies are not yet in place. The global prevalence of neural tube defects is estimated at 18.6/10,000 (uncertainty interval: 15.3-23.0) live births, where ~ 75% of cases result in under-five mortality. Most of the mortality burden is in low- and middle-income countries. The main risk factor for this condition is insufficient folate levels in women of reproductive age.

METHODS

This paper reviews the extent of the problem, including the most recent global information on folate status in women of reproductive age and the most recent estimates of the prevalence of neural tube defects. Additionally, we provide an overview of the available interventions worldwide to reduce the risk of neural tube defects by improving folate status in the population, including dietary diversification, supplementation, education, and fortification.

RESULTS

Large-scale food fortification with folic acid is the most successful and effective intervention to reduce the prevalence of neural tube defects and associated infant mortality. This strategy requires the coordination of several sectors, including governments, the food industry, health services providers, the education sector, and entities that monitor the quality of the service processes. It also requires technical knowledge and political will. An international collaboration between governmental and non-governmental organizations is essential to succeed in saving thousands of children from a disabling but preventable condition.

DISCUSSION

We propose a logical model for building a national-level strategic plan for mandatory LSFF with folic acid and explain the actions needed for promoting sustainable system-level change.

Van der Wees P, Bocchino JM, Rosseau GL. Barriers and facilitators to the implementation of mandatory folate fortification as an evidence-based policy to prevent neural tube defects

BACKGROUND

Neural tube defects continue to be one of the main congenital malformations affecting the development of the nervous system and a significant cause of disability and disease burden to individuals living with these conditions. Mandatory food fortification with folic acid is, by far, one of the most efficacious, safe, and cost-effective interventions to prevent neural tube defects. However, most countries fail to effectively fortify staple foods with folic acid, impacting public health and healthcare systems and generating dismal disparities.

AIM

This article discusses the main barriers and facilitators for implementing mandatory food fortification as an evidence-based policy to prevent neural tube defects worldwide.

METHODS

A comprehensive review of the scientific literature allowed the identification of the determinant factors acting as barriers or facilitators for the reach, adoption, implementation, and scaling up of mandatory food fortification with folic acid as an evidence-based policy.

RESULTS

We identified eight barriers and seven facilitators as determinant factors for food fortification policies. The identified factors were classified as individual, contextual, and external, inspired by the Consolidated Framework for Implementation of Research (CFIR). We discuss mechanisms to overcome obstacles and seize the opportunities to approach this public health intervention safely and effectively.

CONCLUSIONS

Several determinant factors acting as barriers or facilitators influence the implementation of mandatory food fortification as an evidence-based policy worldwide. Notoriously, policymakers in many countries may lack knowledge of the benefits of scaling up their policies to prevent folic acid-sensitive neural tube defects, improve the health status of their communities, and promote the protection of many children from these disabling but preventable conditions. Not addressing this problem negatively affects four levels: public health, society, family, and individuals. Science-driven advocacy and partnerships with essential stakeholders can help overcome the barriers and leverage the facilitators for safe and effective food fortification.

Prenatal folic acid supplementation and folate status in early pregnancy: ECLIPSES study

This research evaluates the prevalence of inadequate folate status in early pregnancy, the pattern of prenatal folic acid (FA) supplementation and associated factors in Spanish pregnant women from the ECLIPSES study, which included 791 participants prior gestational week 12. A cross-sectional evaluation of erythrocyte folate levels was performed at recruitment and used to calculate the prevalence of folate deficiency (erythrocyte folate < 340 nmol/l) and insufficiency (erythrocyte folate < 906 nmol/l). Sociodemographic and lifestyle data as well as information on prenatal FA supplementation were recorded. Descriptive and multivariate statistical analyses were performed. The prevalence of folate deficiency and insufficiency were 9·6 % and 86·5 %, respectively. Most of women used prenatal FA supplements, but only 6·3 % did so as recommended. Supplementation with FA during the periconceptional period abolished folate deficiency and reduced folate insufficiency. Prenatal FA supplementation with ≥1000 µg/d in periconceptional time and pregnancy planning increased erythrocyte folate levels. The main risk factor for folate insufficiency in early pregnancy was getting prenatal FA supplementation out of the periconceptional time (OR 3·32, 95 % CI 1·02, 15·36), while for folate deficiency they were young age (OR 2·02, 95 % CI 1·05, 3·99), and smoking (OR 2·39, 95 % CI 1·30, 4·37). In addition, social and ethnic differences according to folate status were also identified. As conclusion, periconceptional FA use is crucial for achieving optimal folate levels in early pregnancy. Pregnancy planning should focus on young women, smokers, those with low consumption of folate-rich foods, low socio-economic status or from ethnic minorities.

Review of Existing Models to Predict Reductions in Neural Tube Defects Due to Folic Acid Fortification and Model Results Using Data from Cameroon

Several models have been developed to predict the effects of folic acid fortification programs on prevention of neural tube defects (NTDs), but each relies on different assumptions and data inputs. We identified and reviewed 7 models that predict the effects of folic acid intake or status on NTD risk. We applied 4 of these models [the original and a modified version of the Lives Saved Tool (LiST) and models developed by Arth et al. and Wald et al.] to predict the effect of folic acid fortification of wheat flour on reduction of NTDs using national survey data from Cameroon. The estimated percentage of NTDs averted due to fortified wheat flour (5.0 μg folic acid/g flour) varied by predictive model, with a 21-31% reduction in LiST to 83% in Arth's model, and 15% in Wald's model. As the simulated fortification level was increased from 1.0 to 7.0 μg folic acid/g flour, the pattern of change in estimated numbers of NTDs averted differed due to different model assumptions: the number of NTDs averted increased and then reached a plateau in the modified LiST model (as would be expected in real-world conditions), increased sharply in Arth's model, and increased continuously in Wald's model. This wide variation in predicted effects, and implausible results in some cases, undermines the models' utility for users of model outputs. Concurrent collection of dietary and biomarker data, including plasma and RBC folate concentrations, and NTD outcomes, is necessary to validate these models and monitor change in folic acid intake, folate-related biomarkers, and reduced NTD risk due to fortification. In the meantime, models based on erythrocyte folate concentration are recommended, based on biological plausibility and consistency with empirical evidence. Where erythrocyte folate data are unavailable, sensitivity analyses (using several models) could be conducted to examine the range of possible outcomes.

Provision of folic acid for reducing arsenic toxicity in arsenic-exposed children and adults

BACKGROUND

Arsenic is a common environmental toxin. Exposure to arsenic (particularly its inorganic form) through contaminated food and drinking water is an important public health burden worldwide, and is associated with increased risk of neurotoxicity, congenital anomalies, cancer, and adverse neurodevelopment in children. Arsenic is excreted following methylation reactions, which are mediated by folate. Provision of folate through folic acid supplements could facilitate arsenic methylation and excretion, thereby reducing arsenic toxicity.

OBJECTIVES

To assess the effects of provision of folic acid (through fortified foods or supplements), alone or in combination with other nutrients, in lessening the burden of arsenic-related health outcomes and reducing arsenic toxicity in arsenic-exposed populations.

SEARCH METHODS

In September 2020, we searched CENTRAL, MEDLINE, Embase, 10 other international databases, nine regional databases, and two trials registers.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing the provision of folic acid (at any dose or duration), alone or in combination with other nutrients or nutrient supplements, with no intervention, placebo, unfortified food, or the same nutrient or supplements without folic acid, in arsenic-exposed populations of all ages and genders.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included two RCTs with 822 adults exposed to arsenic-contaminated drinking water in Bangladesh. The RCTs compared 400 µg/d (FA400) or 800 µg/d (FA800) folic acid supplements, given for 12 or 24 weeks, with placebo. One RCT, a multi-armed trial, compared FA400 plus creatine (3 g/d) to creatine alone. We judged both RCTs at low risk of bias in all domains. Due to differences in co-intervention, arsenic exposure, and participants' nutritional status, we could not conduct meta-analyses, and therefore, provide a narrative description of the data. Neither RCT reported on cancer, all-cause mortality, neurocognitive function, or congenital anomalies. Folic acid supplements alone versus placebo Blood arsenic. In arsenic-exposed individuals, FA likely reduces blood arsenic concentrations compared to placebo (2 studies, 536 participants; moderate-certainty evidence). For folate-deficient and folate-replete participants who received arsenic-removal water filters as a co-intervention, FA800 reduced blood arsenic levels more than placebo (percentage change (%change) in geometric mean (GM) FA800 -17.8%, 95% confidence intervals (CI) -25.0 to -9.8; placebo GM -9.5%, 95% CI -16.5 to -1.8; 1 study, 406 participants). In one study with 130 participants with low baseline plasma folate, FA400 reduced total blood arsenic (%change FA400 mean (M) -13.62%, standard error (SE) ± 2.87; placebo M -2.49%, SE ± 3.25), and monomethylarsonic acid (MMA) concentrations (%change FA400 M -22.24%, SE ± 2.86; placebo M -1.24%, SE ± 3.59) more than placebo. Inorganic arsenic (InAs) concentrations reduced in both groups (%change FA400 M -18.54%, SE ± 3.60; placebo M -10.61%, SE ± 3.38). There was little to no change in dimethylarsinic acid (DMA) in either group. Urinary arsenic. In arsenic-exposed individuals, FA likely reduces the proportion of total urinary arsenic excreted as InAs (%InAs) and MMA (%MMA) and increases the proportion excreted as DMA (%DMA) to a greater extent than placebo (2 studies, 546 participants; moderate-certainty evidence), suggesting that FA enhances arsenic methylation. In a mixed folate-deficient and folate-replete population (1 study, 352 participants) receiving arsenic-removal water filters as a co-intervention, groups receiving FA had a greater decrease in %InAs (within-person change FA400 M -0.09%, 95% CI -0.17 to -0.01; FA800 M -0.14%, 95% CI -0.21 to -0.06; placebo M 0.05%, 95% CI 0.00 to 0.10), a greater decrease in %MMA (within-person change FA400 M -1.80%, 95% CI -2.53 to -1.07; FA800 M -2.60%, 95% CI -3.35 to -1.85; placebo M 0.15%, 95% CI -0.37 to 0.68), and a greater increase in %DMA (within-person change FA400 M 3.25%, 95% CI 1.81 to 4.68; FA800 M 4.57%, 95% CI 3.20 to 5.95; placebo M -1.17%, 95% CI -2.18 to -0.17), compared to placebo. In 194 participants with low baseline plasma folate, FA reduced %InAs (%change FA400 M -0.31%, SE ± 0.04; placebo M -0.13%, SE ± 0.04) and %MMA (%change FA400 M -2.6%, SE ± 0.37; placebo M -0.71%, SE ± 0.43), and increased %DMA (%change FA400 M 5.9%, SE ± 0.82; placebo M 2.14%, SE ± 0.71), more than placebo. Plasma homocysteine: In arsenic-exposed individuals, FA400 likely reduces homocysteine concentrations to a greater extent than placebo (2 studies, 448 participants; moderate-certainty evidence), in the mixed folate-deficient and folate-replete population receiving arsenic-removal water filters as a co-intervention (%change in GM FA400 -23.4%, 95% CI -27.1 to -19.5; placebo -1.3%, 95% CI -5.3 to 3.1; 1 study, 254 participants), and participants with low baseline plasma folate (within-person change FA400 M -3.06 µmol/L, SE ± 3.51; placebo M -0.05 µmol/L, SE ± 4.31; 1 study, 194 participants). FA supplements plus other nutrient supplements versus nutrient supplements alone In arsenic-exposed individuals who received arsenic-removal water filters as a co-intervention, FA400 plus creatine may reduce blood arsenic concentrations more than creatine alone (%change in GM FA400 + creatine -14%, 95% CI -22.2 to -5.0; creatine -7.0%, 95% CI -14.8 to 1.5; 1 study, 204 participants; low-certainty evidence); may not change urinary arsenic methylation indices (FA400 + creatine: %InAs M 13.2%, SE ± 7.0; %MMA M 10.8, SE ± 4.1; %DMA M 76, SE ± 7.8; creatine: %InAs M 14.8, SE ± 5.5; %MMA M 12.8, SE ± 4.0; %DMA M 72.4, SE ±7.6; 1 study, 190 participants; low-certainty evidence); and may reduce homocysteine concentrations to a greater extent (%change in GM FA400 + creatinine -21%, 95% CI -25.2 to -16.4; creatine -4.3%, 95% CI -9.0 to 0.7; 1 study, 204 participants; low-certainty evidence) than creatine alone.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that FA supplements may benefit blood arsenic concentration, urinary arsenic methylation profiles, and plasma homocysteine concentration versus placebo. There is low-certainty evidence that FA supplements plus other nutrients may benefit blood arsenic and plasma homocysteine concentrations versus nutrients alone. No studies reported on cancer, all-cause mortality, neurocognitive function, or congenital anomalies. Given the limited number of RCTs, more studies conducted in diverse settings are needed to assess the effects of FA on arsenic-related health outcomes and arsenic toxicity in arsenic-exposed adults and children.

Effects of vitamin and mineral supplementation during pregnancy on maternal, birth, child health and development outcomes in low- and middle-income countries: A systematic review

Background

Almost two billion people who are deficient in vitamins and minerals are women and children in low- and middle-income countries (LMIC). These deficiencies are worsened during pregnancy due to increased energy and nutritional demands, causing adverse outcomes in mother and child. To reduce micronutrient deficiencies, several strategies have been implemented, including diet diversification, large-scale and targeted fortification, staple crop bio-fortification and micronutrient supplementation.

Objectives

To evaluate and summarize the available evidence on the effects of micronutrient supplementation during pregnancy in LMIC on maternal, fetal, child health and child development outcomes. This review will assess the impact of single micronutrient supplementation (calcium, vitamin A, iron, vitamin D, iodine, zinc, vitamin B12), iron-folic acid (IFA) supplementation, multiple micronutrient (MMN) supplementation, and lipid-based nutrient supplementation (LNS) during pregnancy.

Search Methods

We searched papers published from 1995 to 31 October 2019 (related programmes and good quality studies pre-1995 were limited) in CAB Abstracts, CINAHL, Cochrane Central Register of Controlled Trials, Embase, International Initiative for Impact Evaluations, LILACS, Medline, POPLINE, Web of Science, WHOLIS, ProQuest Dissertations & Theses Global, R4D, WHO International Clinical Trials Registry Platform. Non-indexed grey literature searches were conducted using Google, Google Scholar, and web pages of key international nutrition agencies.

Selection Criteria

We included randomized controlled trials (individual and cluster-randomized) and quasi-experimental studies that evaluated micronutrient supplementation in healthy, pregnant women of any age and parity living in a LMIC. LMIC were defined by the World Bank Group at the time of the search for this review. While the aim was to include healthy pregnant women, it is likely that these populations had one or more micronutrient deficiencies at baseline; women were not excluded on this basis.

Data Collection and Analysis

Two authors independently assessed studies for inclusion and risk of bias, and conducted data extraction. Data were matched to check for accuracy. Quality of evidence was assessed using the GRADE approach.

Main Results

A total of 314 papers across 72 studies (451,723 women) were eligible for inclusion, of which 64 studies (439,649 women) contributed to meta-analyses. Seven studies assessed iron-folic acid (IFA) supplementation versus folic acid; 34 studies assessed MMN vs. IFA; 4 studies assessed LNS vs. MMN; 13 evaluated iron; 13 assessed zinc; 9 evaluated vitamin A; 11 assessed vitamin D; and 6 assessed calcium. Several studies were eligible for inclusion in multiple types of supplementation. IFA compared to folic acid showed a large and significant (48%) reduction in the risk of maternal anaemia (average risk ratio (RR) 0.52, 95% CI 0.41 to 0.66; studies = 5; participants = 15,540; moderate-quality evidence). As well, IFA supplementation demonstrated a smaller but significant, 12% reduction in risk of low birthweight (LBW) babies (average RR 0.88, 95% CI 0.78 to 0.99; studies = 4; participants = 17,257; high-quality evidence). MMN supplementation was defined as any supplement that contained at least 3 micronutrients. Post-hoc analyses were conducted, where possible, comparing the differences in effect of MMN with 4+ components and MMN with 3 or 4 components. When compared to iron with or without FA, MMN supplementation reduced the risk of LBW by 15% (average RR 0.85, 95% CI 0.77 to 0.93; studies = 28; participants = 79,972); this effect was greater in MMN with >4 micronutrients (average RR 0.79, 95% CI 0.71 to 0.88; studies = 19; participants = 68,138 versus average RR 1.01, 95% CI 0.92 to 1.11; studies = 9; participants = 11,834). There was a small and significant reduction in the risk of stillbirths (average RR 0.91; 95% CI 0.86 to 0.98; studies = 22; participants = 96,772) and a small and significant effect on the risk of small-for-gestational age (SGA) (average RR 0.93; 95% CI 0.88 to 0.98; studies = 19; participants = 52,965). For stillbirths and SGA, the effects were greater among those provided MMN with 4+ micronutrients. Children whose mothers had been supplemented with MMN, compared to IFA, demonstrated a 16% reduced risk of diarrhea (average RR 0.84; 95% CI 0.76 to 0.92; studies = 4; participants = 3,142). LNS supplementation, compared to MMN, made no difference to any outcome; however, the evidence is limited. Iron supplementation, when compared to no iron or placebo, showed a large and significant effect on maternal anaemia, a reduction of 47% (average RR 0.53, 95% CI 0.43 to 0.65; studies = 6; participants = 15,737; moderate-quality evidence) and a small and significant effect on LBW (average RR 0.88, 95% CI 0.78 to 0.99; studies = 4; participants = 17,257; high-quality evidence). Zinc and vitamin A supplementation, each both compared to placebo, had no impact on any outcome examined with the exception of potentially improving serum/plasma zinc (mean difference (MD) 0.43 umol/L; 95% CI -0.04 to 0.89; studies = 5; participants = 1,202) and serum/plasma retinol (MD 0.13 umol/L; 95% CI -0.03 to 0.30; studies = 6; participants = 1,654), respectively. When compared to placebo, vitamin D supplementation may have reduced the risk of preterm births (average RR 0.64; 95% CI 0.40 to 1.04; studies = 7; participants = 1,262), though the upper CI just crosses the line of no effect. Similarly, calcium supplementation versus placebo may have improved rates of pre-eclampsia/eclampsia (average RR 0.45; 95% CI 0.19 to 1.06; studies = 4; participants = 9,616), though the upper CI just crosses 1.

Authors' Conclusions

The findings suggest that MMN and vitamin supplementation improve maternal and child health outcomes, including maternal anaemia, LBW, preterm birth, SGA, stillbirths, micronutrient deficiencies, and morbidities, including pre-eclampsia/eclampsia and diarrhea among children. MMN supplementation demonstrated a beneficial impact on the most number of outcomes. In addition, MMN with >4 micronutrients appeared to be more impactful than MMN with only 3 or 4 micronutrients included in the tablet. Very few studies conducted longitudinal analysis on longer-term health outcomes for the child, such as anthropometric measures and developmental outcomes; this may be an important area for future research. This review may provide some basis to guide continual discourse around replacing IFA supplementation with MMN along with the use of single micronutrient supplementation programs for specific outcomes.

Reducing the Burden of Anemia and Neural Tube Defects in Low- and Middle-Income Countries: An Analysis to Identify Countries with an Immediate Potential to Benefit from Large-Scale Mandatory Fortification of Wheat Flour and Rice

Using a predetermined set of criteria, including burden of anemia and neural tube defects (NTDs) and an enabling environment for large-scale fortification, this paper identifies 18 low- and middle-income countries with the highest and most immediate potential for large-scale wheat flour and/or rice fortification in terms of health impact and economic benefit. Adequately fortified staples, delivered at estimated coverage rates in these countries, have the potential to avert 72.1 million cases of anemia among non-pregnant women of reproductive age; 51,636 live births associated with folic acid-preventable NTDs (i.e., spina bifida, anencephaly); and 46,378 child deaths associated with NTDs annually. This equates to a 34% reduction in the number of cases of anemia and 38% reduction in the number of NTDs in the 18 countries identified. An estimated 5.4 million disability-adjusted life years (DALYs) could be averted annually, and an economic value of 31.8 billion United States dollars (USD) generated from 1 year of fortification at scale in women and children beneficiaries. This paper presents a missed opportunity and warrants an urgent call to action for the countries identified to potentially avert a significant number of preventable birth defects, anemia, and under-five child mortality and move closer to achieving health equity by 2030 for the Sustainable Development Goals.

Folate intake, markers of folate status and oral clefts: An updated set of systematic reviews and meta-analyses

BACKGROUND

There has been a longstanding debate about the role of folate in the etiology of orofacial clefts (OFCs). Studies of different measures of nutritional intake or folate status have been done to investigate the possible role of folate in the prevention of OFC. Only one knowledge synthesis has attempted to bring together different types of evidence. The aim of the present work was to update it.

METHODS

Evidence for associations between OFC and dietary folate, supplement use, folic acid fortification, biomarkers of folate status, and variants of MTHFR (C677T and A1298C) were included. Potentially eligible articles were systematically identified from PubMed, Medline, Embase, and Web of Science (2007-2020) and combined using random-effects meta-analysis when appropriate. Quality assessments were conducted using the Newcastle-Ottawa scale and Cochrane's risk of bias tool.

RESULTS

Sixty-four studies published since the previous knowledge synthesis were identified, with eight of these identified through a supplementary search from October, 2018 to August, 2020. There was an inverse association between folic acid-containing supplement use before or during pregnancy and cleft lip with or without cleft palate (CL/P) (OR 0.60, 95% CI 0.51-0.69), with considerable between-study heterogeneity. The prevalence of CL/P showed a small decline post-folic acid fortification in seven studies (OR 0.94, 95% CI 0.86-1.02). No association was found between OFC and genetic markers of folate status. The coronavirus-19 pandemic has threatened food availability globally and therefore there is a need to maintain and even enhance surveillance concerning maternal intake of folate and related vitamins.

CONCLUSIONS

The risk of non-syndromic OFC was reduced among pregnant women with folic acid-containing supplements during the etiologically relevant period. However, high heterogeneity between included studies, incomplete reporting of population characteristics and variation in timing of exposure and supplement types mean that conclusions should be drawn with caution.

The Relationship Between Pregnancy Intentions and Diet or Physical Activity Behaviors in the Preconception and Antenatal Periods: A Systematic Review and Meta-Analysis

INTRODUCTION

Healthy preconception and antenatal diet and physical activity behaviors may optimize maternal and offspring outcomes. These behaviors are thought to be linked to pregnancy intentions. The aim of this study was to conduct a systematic review and meta-analysis to determine the association between women's pregnancy intentions and diet or physical activity behaviors in the preconception and antenatal periods.

METHODS

MEDLINE Complete, PsycINFO, CINAHL Complete, Global Health, Embase, and INFORMIT: Health Subset were searched in September 2018 for studies that evaluated relationships between pregnancy intentions and dietary and physical activity behaviors. Risk of bias was assessed, and random effects meta-analyses were conducted for dietary (food groups; energy and macronutrients; diet quality; and caffeine, iodine, and folate intake) and physical activity outcomes.

RESULTS

Of 2623 screened records, 19 eligible studies were identified. The overall risk of bias was moderate to high. Twelve studies measured diet and physical activity behaviors during preconception, 5 during pregnancy, and 2 across both periods. Eleven studies measured pregnancy intention retrospectively, and 8 prospectively measured pregnancy intention. The number of studies available for meta-analyses of individual dietary and physical activity outcomes ranged from 2 to 5. Pregnancy intentions were not associated with preconception fruit, vegetable, or caffeine intake or physical activity. Antenatally, women with intended pregnancies were more likely to report healthier diets, lower caffeine intake, and higher physical activity. Insufficient studies were available to conduct subgroup comparisons for prospective or retrospective assessment.

DISCUSSION

Pregnancy intentions were not associated with preconception diet or physical activity behaviors. In contrast, antenatally, women with intended pregnancies demonstrated better diet and physical activity behaviors. Given the small number of studies available for meta-analyses, further research is needed to consolidate our findings. Meanwhile, health professionals can assess women's pregnancy intentions during preconception and pregnancy and encourage a healthy lifestyle.

Cellular mechanisms underlying Pax3-related neural tube defects and their prevention by folic acid

Neural tube defects (NTDs), including spina bifida and anencephaly, are among the most common birth defects worldwide, but their underlying genetic and cellular causes are not well understood. Some NTDs are preventable by supplemental folic acid. However, despite widespread use of folic acid supplements and implementation of food fortification in many countries, the protective mechanism is unclear. Pax3 mutant (splotch; Sp2H ) mice provide a model in which NTDs are preventable by folic acid and exacerbated by maternal folate deficiency. Here, we found that cell proliferation was diminished in the dorsal neuroepithelium of mutant embryos, corresponding to the region of abolished Pax3 function. This was accompanied by premature neuronal differentiation in the prospective midbrain. Contrary to previous reports, we did not find evidence that increased apoptosis could underlie failed neural tube closure in Pax3 mutant embryos, nor that inhibition of apoptosis could prevent NTDs. These findings suggest that Pax3 functions to maintain the neuroepithelium in a proliferative, undifferentiated state, allowing neurulation to proceed. NTDs in Pax3 mutants were not associated with abnormal abundance of specific folates and were not prevented by formate, a one-carbon donor to folate metabolism. Supplemental folic acid restored proliferation in the cranial neuroepithelium. This effect was mediated by enhanced progression of the cell cycle from S to G2 phase, specifically in the Pax3 mutant dorsal neuroepithelium. We propose that the cell-cycle-promoting effect of folic acid compensates for the loss of Pax3 and thereby prevents cranial NTDs.

Scorecard for spina bifida research, prevention, and policy: Score analysis by Human Development Index and WHO region

The People and Organizations United for Spina Bifida and Hydrocephalus (PUSH!) Global Alliance created scorecards to rate country-level performance on spina bifida, including folate status among women of reproductive age; birth prevalence and mortality associated with spina bifida; prevention strategies; access to care; and the country's engagement in the UN Convention on the Rights of Persons with Disabilities. A total of 187 countries were examined based on a criteria-based scoring system represented by stars (http://www.pu-sh.org). This paper summarized scores by Human Development Index (HDI) classification spanning six World Health Organization (WHO) regions. For every indicator stratified by HDI classification, a greater proportion of 'Very High' and 'High' HDI countries scored a full star (highest performance) compared to countries in the 'Medium' and 'Low' HDI strata. A majority of countries in the South East Asia (SEARO) region received full stars for availability of published studies on folate status among women of reproductive age, and most countries in the European region scored full stars for surveying birth prevalence of spina bifida. Very few countries in the European (EURO) and SEARO region had full stars for prevention strategy for spina bifida through fortification. Overall, 90% of countries did not have published studies on spina bifida mortality. This is the first time country-level performance for spina bifida research, prevention and care, grouped by HDI and WHO region has been examined. Policy-makers and stakeholders can use our analyses as benchmarks in their efforts to improve spina bifida surveillance, prevention and care and to close gaps.

Excess micronutrient intake: defining toxic effects and upper limits in vulnerable populations

Excessive micronutrient intake causes a variety of adverse health effects, depending on dose and duration. The risk of excess intake carries significant implications for micronutrient delivery interventions, particularly when such programs are overlapping. To minimize risk and provide public health guidance, several countries and the Food and Agriculture Organization of the United Nations/World Health Organization have set upper intake levels (ULs) for various life-stage populations using the risk assessment framework. However, there is a lack of international consensus on the actual ULs due to variability in application of this framework and a scarcity of evidence from which to draw upon, especially for children. Often ULs for children are established through a downward weight-based extrapolation from adult ULs, which is not always appropriate. The published ULs of nine organizations are compared, recent population nutrient intake evidence is presented, and the toxic effects of key minerals and vitamins are reviewed. Finally, the evidence for toxicity and setting of ULs for each nutrient is discussed including a comment on our degree of confidence in the strength of existing individual ULs. Challenges with risk assessment and opportunities for strengthening the definition of ULs are discussed.

Global folate status in women of reproductive age: a systematic review with emphasis on methodological issues

Inadequate folate status in women of reproductive age (WRA) can lead to adverse health consequences of public health significance, such as megaloblastic anemia (folate deficiency) and an increased risk of neural tube defect (NTD)-affected pregnancies (folate insufficiency). Our review aims to evaluate current data on folate status of WRA. We queried eight databases and the World Health Organization Micronutrients Database, identifying 45 relevant surveys conducted between 2000 and 2014 in 39 countries. Several types of folate assays were used in the analysis of blood folate, and many surveys used folate cutoffs not matched to the assay. To allow better comparisons across surveys, we attempted to account for these differences. The prevalence of folate deficiency was >20% in many countries with lower income economies but was typically <5% in countries with higher income economies. Only 11 surveys reported the prevalence of folate insufficiency, which was >40% in most countries. Overall, folate status data for WRA globally are limited and must be carefully interpreted due to methodological issues. Future surveys would benefit from using the microbiologic assay to assess folate status, along with assay-matched cutoffs to improve monitoring and evaluation of folic acid interventions, thus informing global efforts to prevent NTDs.