Prevention of neural-tube defects with folic acid in China. China-U.S. Collaborative Project for Neural Tube Defect Prevention

Fertility and pregnancy-related events in women with celiac disease: a population-based cohort study

BACKGROUND & AIMS

Previous studies have raised concern about reduced fertility and increased adverse pregnancy-related events in women with celiac disease, but none has estimated overall fertility compared with the general female population.

METHODS

We compared computerized primary care data for 1521 women with celiac disease with data for 7732 age- and practice-matched women without celiac disease. We estimated population-based rates of fertility and adverse pregnancy outcomes.

RESULTS

Crude fertility rates were 48.2 and 47.7 live births per 1000 person-years for women with and without celiac disease, respectively (rate ratio, 1.01; 95% confidence interval, 0.90-1.14). Age-specific fertility rates showed that women with celiac disease had lower fertility when younger but higher fertility when older compared with women without celiac disease. This increase in relative fertility with increasing age held whether women had treated or untreated celiac disease. Risks of cesarean section (odds ratio, 1.33; 95% confidence interval, 1.03-1.70) and miscarriage (rate ratio, 1.31; 95% confidence interval, 1.06-1.61) were moderately higher in women with celiac disease, but risks of assisted birth, breech birth, preeclampsia, postpartum hemorrhage, ectopic pregnancy, stillbirth, and termination were similar.

CONCLUSIONS

Overall, women with celiac disease have fertility similar to that of the general female population, but they have their babies at an older age. Although our findings may reflect a disease effect, the age shift in fertility rates and the increase in cesarean section risk is consistent with socioeconomic or educational advantages of women with celiac disease.

Brain tissue fragments in the amniotic fluid of rats with neural tube defect

AIMS

Brain tissue nodules are occasionally seen in the lungs of neural tube defect (NTD) cases. We looked for brain tissue fragments in amniotic fluid of rats with NTD as it is the basis for the aspiration hypothesis.

METHODS

Eighty-seven pregnant rats were randomly divided into experimental (n=58) and control (n=29) groups. Experimental rats received 100,000 U of vitamin A in 1 mL of corn oil on gestational days 8, 9 and 10, while control rats received corn oil. On gestational days 15, 18, 19, 20 and 21, amniotic fluid was drawn from three control animals and five experimental animals and analysed.

RESULTS

NTD was found in 22.75% of experimental fetuses and in no control fetuses. Brain tissue fragment number and volume fraction increased between gestational days 18 and 20, falling on day 21.

CONCLUSIONS

Excessive doses of vitamin A induce a high rate of early fetal death and development of NTD. Brain tissue fragments in the amniotic fluid reflect the evolution from exencephaly to anencephaly and could support the aspiration hypothesis. However, as it is a late event in the rat, this model may not reproduce the brain tissue nodules in the lung.

Awareness of the role of folic acid, dietary folate intake and plasma folate concentration in Japan

AIM

To investigate awareness of the role of folic acid in the prevention of neural tube defects, dietary intake of folate, and plasma folate concentration.

METHODS

Postal questionnaires were collected from 1190 lay female subjects in three different groups and from seven groups of 3067 health-care providers. Dietary folate was investigated by assessing food frequency charts that were kept for 3 days by 245 women, and plasma folate was assessed by analyzing the blood serum of 194 women.

RESULTS

Less than 15% of citizens and mothers who had live births knew that there was a link between folic acid and neural tube defects. The exception was with myelodysplastic families, in which awareness was 92%. Awareness among health-care professionals was generally low. The highest level was found in obstetricians-gynecologists (76%) and the lowest in nurses (12%). Dietary folate intake and plasma concentration were highest in pregnant women (356 microg/day and 11.9 ng/mL) and the lowest in student nurses (217 microg/day and 6.8 ng/mL). When the recommended dietary allowance of folate in Japan is taken into consideration, 22% of the non-pregnant women and 71% of the pregnant women did not fulfill the recommended dietary allowance.

CONCLUSIONS

Information on the role of periconceptional intake of folic acid is not sufficiently disseminated to young women and health-care professionals alike. Pregnant women should be repeatedly recommended to take folic acid supplements of 400 microg/day.

International retrospective cohort study of neural tube defects in relation to folic acid recommendations: are the recommendations working?

OBJECTIVES

To evaluate the effectiveness of policies and recommendations on folic acid aimed at reducing the occurrence of neural tube defects.

DESIGN

Retrospective cohort study of births monitored by birth defect registries.

SETTING

13 birth defects registries monitoring rates of neural tube defects from 1988 to 1998 in Norway, Finland, Northern Netherlands, England and Wales, Ireland, France (Paris, Strasbourg, and Central East), Hungary, Italy (Emilia Romagna and Campania), Portugal, and Israel. Cases of neural tube defects were ascertained among liveborn infants, stillbirths, and pregnancy terminations (where legal). Policies and recommendations were ascertained by interview and literature review.

MAIN OUTCOME MEASURES

Incidences and trends in rates of neural tube defects before and after 1992 (the year of the first recommendations) and before and after the year of local recommendations (when applicable).

RESULTS

The issuing of recommendations on folic acid was followed by no detectable improvement in the trends of incidence of neural tube defects.

CONCLUSIONS

Recommendations alone did not seem to influence trends in neural tube defects up to six years after the confirmation of the effectiveness of folic acid in clinical trials. New cases of neural tube defects preventable by folic acid continue to accumulate. A reasonable strategy would be to quickly integrate food fortification with fuller implementation of recommendations on supplements.

Folate Supplementation and Twin Pregnancies

BACKGROUND

Women in many countries are advised to increase their folate intake to lower the risk of neural tube defects. For this purpose several countries add folate to the flour. Therefore, it is important to monitor possible adverse effects of this B vitamin. We have assessed the effect of folate on twin pregnancies.

METHODS

We conducted a retrospective, population-register based study of 176,042 women who gave birth from December 1998 through the end of 2001. Use of folate and multivitamin supplements was recorded on the mandatory birth notification form of the Medical Birth Registry of Norway. Pregnancies after in vitro fertilization (IVF) were reported separately.

RESULTS

With adjustment for maternal age and parity, we observed an increased risk of twin pregnancies associated with preconceptional use of folate (odds ratio = 1.59; 95% confidence interval = 1.41-1.78). This association was largely explained by confounding with IVF pregnancies, which were strongly associated both with twin pregnancies and folate use. After exclusion of known IVF pregnancies, and accounting for underreporting of both IVF pregnancies and folate use, the risk was no longer elevated (1.02; 0.85-1.24). Weak associations with twin pregnancies were observed for use of multivitamins and folate during pregnancy, but could be due to increased use of vitamins after a recognized twin pregnancy.

CONCLUSIONS

The association between preconceptional folate use and twin pregnancies was strongly confounded by IVF. After accounting for IVF pregnancies and underreporting, we found no evidence for an association between preconceptional folate supplements and twinning.

Methylenetetrahydrofolate reductase 677C-->T polymorphism affects DNA methylation in response to controlled folate intake in young women

DNA methylation is critical for normal genomic structure and function and is dependent on adequate folate status. A polymorphism (677C-->T) in a key folate enzyme, methylenetetrahydrofolate reductase (MTHFR), may impair DNA methylation when folate intake is inadequate and may increase the risk of reproductive abnormalities. The present study was designed to evaluate the effect of the MTHFR 677C-->T polymorphism on changes in global DNA methylation in young women consuming a low folate diet followed by repletion with the current Recommended Dietary Allowance (RDA). Women (age 20-30 years) with the TT (variant; n = 19) or CC (n = 22) genotype for the MTHFR 677C-->T polymorphism participated in a folate depletion-repletion study (7 weeks, 115 microg DFE/day; 7 weeks, 400 microg DFE/day). DNA methylation was measured at baseline, week 7, and week 14 using a [3H]methyl acceptance assay and a novel liquid chromatography tandem mass spectrometry assay of the DNA bases methylcytosine and cytosine. [3H]Methyl group acceptance tended to increase (P = 0.08) during depletion in all subjects, indicative of a decrease in global DNA methylation. During repletion, the raw change and the percent change in the methylcytosine/total cytosine ratio increased (P = 0.03 and P = 0.04, respectively) only in the subjects with the TT genotype. Moderate folate depletion in young women may cause a decrease in overall DNA methylation. The response to folate repletion suggests that following folate depletion women with the MTHFR 677 TT genotype have a greater increase in DNA methylation with folate repletion than women with the CC genotype.

Community-based interventions for improving perinatal and neonatal health outcomes in developing countries: a review of the evidence

BACKGROUND

Infant and under-5 childhood mortality rates in developing countries have declined significantly in the past 2 to 3 decades. However, 2 critical indicators, maternal and newborn mortality, have hardly changed. World leaders at the United Nations Millennium Summit in September 2000 agreed on a critical goal to reduce deaths of children <5 years by two thirds, but this may be unattainable without halving newborn deaths, which now comprise 40% of all under-5 deaths. Greater emphasis on wide-scale implementation of proven, cost-effective measures is required to save women's and newborns' lives. Approximately 99% of neonatal deaths take place in developing countries, mostly in homes and communities. A comprehensive review of the evidence base for impact of interventions on neonatal health and survival in developing-country communities has not been reported.

OBJECTIVE

This review of community-based antenatal, intrapartum, and postnatal intervention trials in developing countries aimed to identify (1) key behaviors and interventions for which the weight of evidence is sufficient to recommend their inclusion in community-based neonatal care programs and (2) key gaps in knowledge and priority areas for future research and program learning.

METHODS

Available published and unpublished data on the impact of community-based strategies and interventions on perinatal and neonatal health status outcomes were reviewed. Evidence was summarized systematically and categorized into 4 levels of evidence based on study size, location, design, and reported impact, particularly on perinatal or neonatal mortality. The evidence was placed in the context of biological plausibility of the intervention; evidence from relevant developed-country studies; health care program experience in implementation; and recommendations from the World Health Organization and other leading agencies.

RESULTS

A paucity of community-based data was found from developing-country studies on health status impact for many interventions currently being considered for inclusion in neonatal health programs. However, review of the evidence and consideration of the broader context of knowledge, experience, and recommendations regarding these interventions enabled us to categorize them according to the strength of the evidence base and confidence regarding their inclusion now in programs. This article identifies a package of priority interventions to include in programs and formulates research priorities for advancing the state of the art in neonatal health care.

CONCLUSIONS

This review emphasizes some new findings while recommending an integrated approach to safe motherhood and newborn health. The results of this study provide a foundation for policies and programs related to maternal and newborn health and emphasizes the importance of health systems research and evaluation of interventions. The review offers compelling support for using research to identify the most effective measures to save newborn lives. It also may facilitate dialogue with policy makers about the importance of investing in neonatal health.

Embryonic development of folate binding protein-1 (Folbp1) knockout mice: Effects of the chemical form, dose, and timing of maternal folate supplementation

Inactivation of folate binding protein-1 (Folbp1) adversely impacts murine embryonic development, as nullizygous embryos (Folbp1(-/-)) die in utero. Administration of folinic acid (N5-formyl-tetrahydrofolate) to Folbp1-deficient dams before and throughout gestation rescues the majority of embryos from premature death; however, a portion of surviving embryos develop structural malformations, including neural tube defects. We examined whether maternal supplementation with L-N5-methyl-tetrahydrofolate (L-5M-THF) has superior protective effects on embryonic development of Folbp1(-/-) fetuses compared with L-N5-formyl-tetrahydrofolate (L-5F-THF). We also examined the critical period during gestation when folate supplementation is most beneficial to the developing Folbp1(-/-) embryos. Folbp1(-/-) pups presented with a range of malformations involving the neural tube, craniofacies, eyes, and abdominal wall. The frequencies of these malformations decreased with increasing folate dose, regardless of the form used. There was no additional benefit provided by L-5M-THF compared with L-5F-THF. Despite rescuing the phenotype in Folbp1(-/-) embryos, no significant elevation of Folbp1(-/-) maternal folate levels was observed with supplementation.

Are the betaine-homocysteine methyltransferase (BHMT andBHMT2) genes risk factors for spina bifida and orofacial clefts?

Abnormalities in folate and/or homocysteine metabolism may adversely influence embryonic development, leading to the birth of infants with a variety of congenital malformations, including neural tube defects (NTDs) and craniofacial abnormalities. Based upon suggestive evidence that periconceptional folic acid supplementation is effective in preventing a significant proportion of the aforementioned birth defects, genetic variation in the folate biosynthetic pathways may influence the infant's susceptibility to these birth defects. The goal of our study was to investigate sequence variations in the betaine-homocysteine methyltransferase (BHMT) and betaine-homocysteine methyltransferase (BHMT2) genes as modifiers of risk of spina bifida, cleft palate, and cleft lip and palate. The results of this study indicated that individuals homozygous for the single nucleotide polymorphism R239Q in BHMT did not have elevated risks for spina bifida. Genotype frequencies for the BHMT2 rs626105 polymorphism also did not reveal any elevated risks for spina bifida, and only a modest, imprecise elevation of risk for orofacial clefts. The results of these experiments suggest that variants of the BHMT/BHMT2 genes in infants do not substantially contribute to the risk of spina bifida or orofacial clefts in our study population.

An intervention study to increase knowledge and use of folic acid among relatives in neural tube defect-affected families in Washington, D.C

BACKGROUND

Little is known about the level of knowledge and use of folic acid among near relatives in U.S. families of a child with spina bifida. We hypothesized that relatives would be more knowledgeable than the general population and more likely to take folic acid. Further, we hypothesized that relatives would be more motivated by an intervention to increase their use of folic acid.

METHODS

We conducted an intervention study among females in families attending a hospital spina bifida clinic in Washington, DC.

RESULTS

The 231 subjects consisted of the affected individuals, mothers, sisters, and aunts. The average age was 34 years. At baseline, most (87.4%) reported that they had heard of folic acid; 37.6% were currently taking multivitamins with folic acid and 6.9% were taking folic acid tablets. The intervention significantly increased both knowledge (to 99%) and intake of folic acid from 41.9 to 48.5%. Folic acid intake increased significantly among African-American women and women with less education, women who were older, married, with children, and nonsmokers.

CONCLUSIONS

This intervention was successful in increasing folic acid intake among female relatives in spina bifida-affected families. By the end of the study, almost all women had heard of folic acid and folic acid use had increased by 16%. Among these women at higher than expected risk for having an affected child, this rate of intake, while more than the general population, still falls short of optimum. Fortification of food with folic acid may be the only way to ensure increased folic acid intake.

An Exploration of Health Effects of Folic Acid in Pregnancy Beyond Reducing Neural Tube Defects

OBJECTIVES

First, to examine the biological basis of why folic acid may have health effects beyond its proven effect of reducing neural tube defects; and second, to explore current controversial policies of folic acid supplementation and food fortification.

METHODS

We searched MEDLINE for English-language papers published from 1991 to 2003, using the key words "folic acid" and "folate." The literature search was restricted to human studies. Of 8986 publications identified, 65 were relevant to the objectives of this paper.

RESULTS

Analysis of the literature revealed that a major mechanism of folic acid in improving infant health may be related to its effect in correcting maternal folate-homocysteine-methylenetetrahydrofolate reductase metabolic defects. Conversely, exposure to high levels of folic acid may have such adverse health effects as increased risk of neurologic disorders in the general population.

CONCLUSIONS

Randomized trials or well-designed prospective cohort studies are needed to assess the effects of folic acid on various pregnancy outcomes. To enable an examination of the association between folic acid and rare outcomes, such as a specific category of birth defects and fetal and neonatal deaths, it is necessary to recruit a large number of pregnant women to participate in such studies.

Trends and predictors of folic acid awareness and periconceptional use in pregnant women

OBJECTIVE

The purpose of this study was to describe recent trends in folic acid awareness and use in the periconceptional period among pregnant women in relation to maternal sociodemographic and other relevant factors.

STUDY DESIGN

From 1988 to 2002, 16,555 women from the Slone Epidemiology Center Birth Defects Study were interviewed about medication use before and during pregnancy (which included multivitamins and folic acid), about whether they were aware of any vitamins that might decrease the risk of birth defects, and about sociodemographic and medical factors.

RESULTS

Awareness of folic acid benefits increased from 0 in 1988 to 50% in 1996 and thereafter. The use of folic acid in the periconceptional period increased from 15% in 1988 to 40% in the last few years. Maternal education was a strong independent predictor of both awareness and use as were ethnicity, whether the pregnancy was wanted, family income, and whether a health care provider was consulted before planning.

CONCLUSION

Promoting the use of folic acid supplements, particularly among these disadvantaged groups, is essential to further decrease the prevalence of neural tube defects.

Reduced folate carrier gene is a risk factor for neural tube defects in a Chinese population

BACKGROUND

There is a considerable body of data demonstrating that periconceptional supplementation of folic acid can prevent a significant proportion of neural tube defects (NTDs). At present, the mechanism by which folic acid exerts its beneficial effect remains unknown. Folate transporter genes, including the reduced folate carrier gene (RFC1), have been proposed as NTD risk factors.

METHODS

The study population included 104 nuclear families with NTDs and 100 nonmalformed control families. We investigated the possible association between a common RFC1 polymorphism (A80G) and NTD risk among offspring, as well as potential gene-environment interactions between the infant RFC1 genotype and maternal periconceptional use of folic acid through a population-based case-control study.

RESULTS

We observed that the infants of the GG genotype were associated with a 2.56-fold increased risk of NTDs when compared to the AA genotype (odds ratio [OR], 2.56; 95% confidence interval [CI], 1.04-6.36) in our study population. Among mothers who did not utilize folic acid supplements, the risk for having a child with an NTD was 3.30 (95% CI, 1.15-9.65) for offspring with the GG genotype, compared to the reference (AA) genotype. Children who had the GG genotype and whose mothers did not take folic acid had an elevated risk for NTDs (OR, 8.80; 95% CI, 2.83-28.69), compared to offspring with the AA and GA genotypes whose mothers utilized folic acid supplements.

CONCLUSIONS

Our findings suggest that the RFC1 G allele is likely to be an important genetic factor in determining folate transport and subsequently may be a risk factor for NTDs in this Chinese population.

Epidemiology of neural tube defects and folic acid

This review article combines four disparate observations about Neural Tube Defects (NTDs). They are the worldwide decline in the birth incidence that began prior to prenatal diagnosis; family recurrence risks; the effect of prenatal diagnosis and termination of affected pregnancies; and the effect of folic acid.

Spina bifida

Spina bifida results from failure of fusion of the caudal neural tube, and is one of the most common malformations of human structure. The causes of this disorder are heterogeneous and include chromosome abnormalities, single gene disorders, and teratogenic exposures. However, the cause is not known in most cases. Up to 70% of spina bifida cases can be prevented by maternal, periconceptional folic acid supplementation. The mechanism underlying this protective effect is unknown, but it is likely to include genes that regulate folate transport and metabolism. Individuals with spina bifida need both surgical and medical management. Although surgical closure of the malformation is generally done in the neonatal period, a randomised clinical trial to assess in utero closure of spina bifida has been initiated in the USA. Medical management is a lifelong necessity for individuals with spina bifida, and should be provided by a multidisciplinary team.

Evidence that the risk of spina bifida is influenced by genetic variation at the NOS3 locus

BACKGROUND

There is substantial evidence that the risk of spina bifida, a malformation of the caudal neural tube, may be associated with maternal or embryonic disturbances in the folate-homocysteine metabolic axis. Hence, variants of genes that influence this pathway represent an intriguing group of candidate genes for spina bifida and other neural tube defects (NTD). A common variant of the gene for endothelial nitric oxide synthase (NOS3 G894T) was recently added to this group of NTD candidate genes, based on a report demonstrating that homozygosity for the T allele of this variant is associated with increased homocysteine levels in normal adult populations.

METHODS

The association between the risk of spina bifida and both the maternal and embryonic genotype for the NOS3 G894T variant was evaluated in data from 301 families by using the transmission disequilibrium test (TDT) and log-linear modeling.

RESULTS

Analyses of these data using the TDT provided no evidence that the risk of spina bifida was significantly related to either the maternal or embryonic NOS3 genotype. However, the log-linear analyses indicated that the risk of spina bifida was significantly associated with the embryonic, but not the maternal, genotype for the NOS3 G894T variant.

CONCLUSIONS

The results of the present analyses suggest that the embryonic NOS3 G894T genotype is associated with the risk of spina bifida. Moreover, these analyses highlight the importance of a detailed examination of the study data. Had these analyses been restricted to the methodologically simpler TDT, the association between the NOS3 G894T genotype and risk of spina bifida may well have been overlooked.

Will mandatory folic acid fortification prevent or promote cancer?

An overwhelming body of evidence for a protective effect of periconceptional folic acid supplementation against neural tube defects (NTDs) led to mandatory folic acid fortification in the United States. The effectiveness of folic acid fortification in improving folate status has already been shown to be quite striking, with a dramatic increase in blood measurements of folate in the United States. Preliminary reports also suggest a significant reduction ( approximately 15-50%) in NTDs in the United States. The success of folic acid fortification in improving folate status and in reducing NTD rates is truly a public health triumph and provides a paradigm of collaboration between science and public health policy. Although folic acid is generally regarded as safe, there continues to be concern that folic acid fortification may have adverse effects in subpopulation groups not originally targeted for fortification. In this regard, an emerging body of evidence suggests that folic acid supplementation may enhance the development and progression of already existing, undiagnosed premalignant and malignant lesions. Over the past few years, the US population has been exposed to a significant increase in folate intake, for which essentially no data on safety exist. The potential cancer-promoting effect of folic acid supplementation needs to be considered in carefully monitoring the long-term effect of folic acid fortification on the vast majority of the US population, who are not at risk of NTDs.

Micronutrient fortification of foods--rationale, application and impact

Deficiencies in intake of essential vitamins and minerals (commonly referred to as micronutrients) that are essential for efficient energy metabolism and other functions of the human body (commonly termed as micronutrients) are severe and widespread in many parts of the world. They cause an immeasurable burden on individuals, on health services, education systems and families caring for children who are disabled or mentally impaired. Studies by World Bank have shown that countries whose populations suffer from micronutrient deficiencies encounter economic losses as high as 5% of gross domestic product (GDP). The solution to control and prevent micronutrient deficiencies is available and affordable. At a national level, micronutrient malnutrition can be addressed by implementing programmes designed to educate people to diversify their diets (where appropriate foods are available), or by fortifying commonly eaten foods with the missing micronutrients or providing nutrient supplements through targeted distribution programmes. Food fortification is increasingly recognized as an effective means of delivering micronutrients. Fortification of foods can provide meaningful amounts of the nutrient at normal consumption of the food vehicle. Proper choice of fortificant and processing methods could ensure the stability and bioavailability of the nutrient. The level of fortification should take into account variations in food consumption to ensure safety for those at the higher end of the scale and impact for those at the lower end. Fortification needs to be supported by adequate food regulations and labeling, quality assurance and monitoring to ensure compliance and desired impact. In industrialized countries food fortification has played a major role in the substantial reduction and elimination of a number of micronutrient deficiencies. Although a growing number of large scale fortification programmes in different parts of the world are beginning to demonstrate impact at the biochemical level and are leading to the elimination of several nutrient deficiencies, food fortification remains an underutilized opportunity in many developing countries where micronutrient malnutrition remains a public health problem.

Folate content in commercial white and whole wheat sandwich breads

After the U.S. mandate of folic acid fortification of enriched grain products, a report indicated higher than expected fortification. Limited information is available on folic acid in enriched products. We measured the folate content in 92 sandwich breads (46 white breads and 46 whole wheat breads) in Birmingham, Alabama, during 2001-2003. The mean folate content in white bread declined significantly from 2001 to 2002 or 2003, whereas the decline in folate content in whole wheat bread containing enriched flour was not significant. White bread contained significantly more folate than whole wheat bread containing enriched flour in 2001 and 2003. In 2002 and 2003, >40% of breads made of enriched flour contained <115 microg of folate/100 g and >70% contained <160 microg/100 g. These percentages were markedly higher than those in 2001. Our data suggest that folic acid in breads containing enriched flour declined after 2001 and monitoring of fortification may be necessary.

The human T locus and spina bifida risk

The transcription factor T is essential for mesoderm formation and axial development during embryogenesis. Embryonic genotype for a single-nucleotide polymorphism in intron 7 of T ( TIVS7 T/C) has been associated with the risk of spina bifida in some but not all studies. We developed a novel genotyping assay for the TIVS7 polymorphism using heteroduplex generator methodology. This assay was used to genotype spina bifida case-parent trios and the resulting data were analyzed using the transmission disequilibrium test and log-linear analyses. Analyses of these data demonstrated that heterozygous parents transmit the TIVS7-C allele to their offspring with spina bifida significantly more frequently than expected under the assumption of Mendelian inheritance (63 vs 50%, P=0.02). Moreover, these analyses suggest that the TIVS7-C allele acts in a dominant fashion, such that individuals carrying one or more copies of this allele have a 1.6-fold increased risk of spina bifida compared with individuals with zero copies. In silico analysis of the sequence surrounding this polymorphism revealed a potential target site for olfactory neuron-specific factor-1, a transcription factor expressed in the neural tube during development, spanning the polymorphic site. Several other putative, developmentally important and/or environmentally responsive transcription factor-binding sites were also identified close to the TIVS7 polymorphism. The TIVS7 polymorphism or a variant that is in linkage disequilibrium with the TIVS7 polymorphism may, therefore, play a role in T gene expression and influence the risk of spina bifida.

A comprehensive evaluation of food fortification with folic acid for the primary prevention of neural tube defects

BACKGROUND: Periconceptional use of vitamin supplements containing folic acid reduces the risk of a neural tube defect (NTD). In November 1998, food fortification with folic acid was mandated in Canada, as a public health strategy to increase the folic acid intake of all women of childbearing age. We undertook a comprehensive population based study in Newfoundland to assess the benefits and possible adverse effects of this intervention. METHODS: This study was carried out in women aged 19-44 years and in seniors from November 1997 to March 1998, and from November 2000 to March 2001. The evaluation was comprised of four components: I) Determination of rates of NTDs; II) Dietary assessment; III) Blood analysis; IV) Assessment of knowledge and use of folic acid supplements. RESULTS: The annual rates of NTDs in Newfoundland varied greatly between 1976 and 1997, with a mean rate of 3.40 per 1,000 births. There was no significant change in the average rates between 1991-93 and 1994-97 (relative risk [RR] 1.01, 95% confidence interval [CI] 0.76-1.34). The rates of NTDs fell by 78% (95% CI 65%-86%) after the implementation of folic acid fortification, from an average of 4.36 per 1,000 births during 1991-1997 to 0.96 per 1,000 births during 1998-2001 (RR 0.22, 95% CI 0.14-0.35). The average dietary intake of folic acid due to fortification was 70 μg/day in women aged 19-44 years and 74 μg/day in seniors. There were significant increases in serum and RBC folate levels for women and seniors after mandatory fortification. Among seniors, there were no significant changes in indices typical of vitamin B12 deficiencies, and no evidence of improved folate status masking haematological manifestations of vitamin B12 deficiency. The proportion of women aged 19-44 years taking a vitamin supplement containing folic acid increased from 17% to 28%. CONCLUSIONS: Based on these findings, mandatory food fortification in Canada should continue at the current levels. Public education regarding folic acid supplement use by women of childbearing age should also continue.

Omphalocele and gastroschisis: Black-White disparity in infant survival

BACKGROUND

Racial/ethnic variations in the occurrence of abdominal wall defects have been previously noted but it remains poorly understood whether race/ethnicity is a determinant of survival among affected infants.

METHODS

Study was conducted on cases of gastroschisis and omphalocele recorded for the years 1983-1999 at the New York Congenital Malformation Registry. Adjusted and unadjusted hazard ratios were generated from a Proportional Hazards Regression model to compare survival among affected Blacks, Hispanics and Whites. The major end point of analysis was differences in all cause mortality among infants with abdominal wall birth defects across different racial/ethnic groups.

RESULTS

Among the three racial/ethnic groups, 1481 infants were diagnosed with either omphalocele (978 or 66%) or gastroschisis (503 or 34%). Overall infant mortality rate (IMR) was 182 per 1000, with 74% of the deaths occurring within the first 28 days of life. Omphalocele infants had significantly higher infant mortality (IMR = 215 per 1000) than infants with gastroschisis (IMR = 118 per 1000)[p < 0.0001]. Overall, Black infants with abdominal wall defects had lower mortality indices than Whites and Hispanics. However, when considered as separate disease entities, Black infants were twice as likely to survive as compared to Whites if they had omphalocele [Adjusted Hazard Ratio (AHR) = 0.52; 95% Confidence Interval (CI) = 0.37-0.74], and twice as likely to die as Whites if they had gastroschisis instead (AHR = 2.23; 95% CI = 1.16-4.28). For both defect subtypes, Hispanics have risks for infant mortality comparable to Whites.

CONCLUSIONS

The natural history of omphalocele and gastroschisis co-varies with race. Black infants with gastroschisis have worse survival outcomes while those with omphalocele have better chances of survival than their White or Hispanic counterparts.

Geographical, seasonal and gender differences in folate status among Chinese adults

Low blood folate concentrations have been associated with cardiovascular disease, neural tube defects and selected cancers, but little is known about folate status in Chinese adults. In a cross-sectional study we measured the plasma and red blood cell folate concentrations in 2422 Chinese men and women aged 35 to 64 y, living in the North and South of China, who provided blood samples either in March or September of 2001. The geometric mean concentrations of plasma and red blood cell folate were lower among Northerners than Southerners (adjusted geometric means, 8.4 and 502, and 16.7 and 811 nmol/L, respectively) controlling for age, gender, season (spring and fall), area (urban and rural), BMI, multivitamin use, alcohol intake and current smoking status. We estimated that approximately 40% of the Northerners and approximately 6% of the Southerners had plasma folate concentrations lower than the 6.8 nmol/L (3 microg/L), and approximately 30% of the Northerners and approximately 4% of the Southerners had red blood cell folate concentrations lower than the 363 nmol/L (160 microg/L), levels used to define folate deficiency. Within each region, men had lower plasma folate concentrations than women (6.9 versus 9.8 nmol/L in the North, and 14.5 versus 19.6 nmol/L in the South). In men, current smokers had a higher risk of folate deficiency compared with nonsmokers [adjusted odds ratios, 1.9 (95% CI, 1.4-2.6) for plasma folate deficiency and 2.5 (95% CI, 1.7-3.6) for red blood cell folate deficiency (P < 0.001)]. Our findings suggest that a large proportion of Chinese adults have a low folate status, especially those living in northern China where 60% of the men are plasma folate deficient in the spring. Further studies are needed to elucidate the factors that influence folate concentrations among middle-aged Chinese and to evaluate possible intervention strategies.

Awareness of the use of folic acid to prevent neural tube defects in a Mediterranean area

OBJECTIVES

The risk of neural tube defects (NTDs) is decreased in women who take folic acid during the periconceptional period. The main objective of our study was to evaluate the awareness of the need for folic acid supplementation and also the actual intake during the periconceptional period to prevent neural tube defects in a Mediterranean area.

STUDY DESIGN

A retrospective study was performed from 1 July to 30 November 2000. One thousand consecutive women who delivered in our hospital were interviewed during the immediate postpartum period about their knowledge of neural tube defects and folic acid intake before and during pregnancy.

RESULTS

Most women (85.7%) referred not having been specifically informed about the need to take folic acid to prevent neural tube defects although approximately half of the women (50.6%) were in fact, aware of the need for folic acid intake. Eight percent (8.1%) of the women took folic acid before conception but only 6.9% did so during the effective period from 4 weeks before conception to 4 weeks after conception. Logistic regression analysis showed that awareness of the need to take folic acid together with having had preconceptional counselling and knowledge of NTDs were the strongest variables related to the fact of having taken folic acid during the correct period.

CONCLUSIONS

Although the population is aware of the need to take folic acid, the real impact of the present recommendations is almost negligible. Information in primary care and preconceptional counselling to specifically inform patients about the need to take folic acid to prevent NTDs seem to be crucial to improve the final intake of folic acid during the protective period.

Folic acid supplementation enhances repair of the adult central nervous system

Folic acid supplementation has proved to be extremely effective in reducing the occurrence of neural tube defects (NTDs) and other congenital abnormalities in humans, suggesting that folic acid can modulate key mechanisms for growth and differentiation in the central nervous system (CNS). To prevent NTDs, however, supplemental folate must be provided early in gestation. This suggests that the ability of folic acid to activate growth and differentiation mechanisms may be confined to the early embryonic period. Here, we show that folic acid can enhance growth and repair mechanisms even in the adult CNS. Using lesion models of CNS injury, we found that intraperitoneal treatment of adult rats with folic acid significantly improves the regrowth of sensory spinal axons into a grafted segment of peripheral nerve in vivo. Regrowth of retinal ganglion cell (RGC) axons into a similar graft also was enhanced, although to a smaller extent than spinal axons. Furthermore, folic acid supplementation enhances neurological recovery from a spinal cord contusion injury, showing its potential clinical impact. The results show that the effects of folic acid supplementation on CNS growth processes are not restricted to the embryonic period, but can also be effective for enhancing growth, repair, and recovery in the injured adult CNS.

Method of weighted proportion of reproductive-aged women taking folic acid supplements to predict a neural tube defect rate decline

BACKGROUND

Neural tube defect (NTD) rates can be lowered by increased consumption of folic acid (FA) by women before and during early pregnancy. The crude proportion of reproductive-aged women taking FA supplements has been used to predict a decline of the NTD rate in the general population. In this study we examine the potential error in using the crude proportion to predict NTD risk reduction, and offer an alternative method.

METHODS

The crude proportion measures the number of women taking FA. It ignores the substantial variability by maternal age in the probability of giving birth. Age-specific fertility rates (ASFRs) reflect the probability that a woman in a specific age group will give birth in a given year. In this study, we show how to calculate a proportion weighted by ASFRs to predict a decline in the NTD rate, and to assess the effectiveness of FA consumption in preventing NTDs.

RESULTS

Our results show that a crude proportion of 50% of women (15-49 years old) taking FA is associated with a range of 24-77% in weighted proportions. Assuming a 40% risk reduction from taking 400 microg of FA daily, the expected NTD rate decline could vary from 9.6% to 30.6%, depending on the age distribution of women taking FA.

CONCLUSIONS

The ASFR-weighted proportion estimates the proportion of babies born to women taking FA, as opposed to the crude proportion of women taking FA. We recommend using the ASFR-weighted proportion to predict an NTD rate decline and measure the success of FA education campaigns. We found that when women in high-fertility age groups increased their FA consumption, the decline in the NTD rate was greater than when women in low-fertility age groups did so. Our findings suggest that the more efficient approach to NTD prevention is to focus on women with a higher probability of giving birth. For example, by focusing on <50% of women of childbearing age (20-34 years), as much as 76% of the maximum NTD rate reduction can be achieved.

Phenotype of the neural tube defect mouse model bent tail is not sensitive to maternal folinic acid, myo-inositol, or zinc supplementation

BACKGROUND

Bent tail is a mouse model for X-linked neural tube defects (NTDs) that is characterized by the presence of exencephaly, a delayed posterior neuropore closure, and a tail phenotype. In addition, Bent tail shows laterality defects and increased prenatal mortality. The congenital malformations of this mouse are caused by a submicroscopic deletion that completely encompasses the gene coding for the zinc finger transcription factor Zic3. In this study we investigated the sensitivity of the phenotype of Bent tail to the nutrients folinic acid, myo-inositol, and zinc. These nutrients are thought to be involved in the etiology of NTDs, in combination with a genetic predisposition.

METHODS

The most penetrant phenotype of the Bent tail mouse, the tail malformation, was used as a marker for the nutrient sensitivity of the neural phenotype. The size of the litters and the survival of the offspring, subdivided according to genotype, were analyzed as markers for the nutrient sensitivity of other phenotypic features of Bent tail.

RESULTS

In confirmation of earlier studies, we observed the prenatal loss of a number of homozygous females and hemizygous males, as well as the effect of genotype on the tail phenotype of Bent tail. However, periconceptional supplementation of the maternal diet with folinic acid, myo-inositol, or zinc produced no significant effects on either the tail phenotype of the offspring or the size and genotypic composition of the litters.

CONCLUSIONS

Bent tail appears to be a folinic acid-, myo-inositol-, and zinc-insensitive mouse model for NTDs.

Trend in prevalence of neural tube defects in Quebec

BACKGROUND

In Canada, the first recommendations on the use of folic acid (FA) supplements by women planning a pregnancy or capable of becoming pregnant were issued in 1993. In 1998, fortification of flour with FA became mandatory. The objective of this study was to assess the impact of these measures on the prevalence of neural tube defects (NTDs) in the province of Quebec.

METHODS

The study population included stillbirths, live births, and elective terminations for fetal malformations that were reported in 1992-2000 for women residing in the province of Quebec. NTD cases were identified from stillbirth certificates and hospital discharge summaries.

RESULTS

There was a marked decrease in the total NTD rate after 1997. The average NTD rate was 1.89 per 1000 total births during the period of 1992-1997, and 1.28 per 1000 in 1998-2000, a 32% reduction (p < 0.001).

CONCLUSIONS

Fortification of flour, which began in early 1997 and gradually became widespread, is a very plausible explanation for the timing, shape, and magnitude of the decrease in NTD prevalence observed in Quebec and other Canadian provinces. An increase in FA supplement use may have played only a minor role. Birth Defects Research (Part A) 67:000-000, 2003.

Describing a folic acid intervention for health care providers: implications for professional practice and continuing education

The purpose of this article is to, first, describe the content of a folic acid professional education intervention that was developed and implemented as a result of a collaborative effort between an academic institution and a nonprofit organization-the Pittsburgh, Pennsylvania, chapter of the March of Dimes-and the process by which it was developed; second, report the results of an evaluation of the impact of this intervention on knowledge and recommendation behaviors of health care providers; and third, discuss the implications for professional practice and continuing education. We developed a novel presentation that had practical utility for practitioners that could be implemented in either a classroom or continuing education setting.

Marginal maternal vitamin B12 status increases the risk of offspring with spina bifida

OBJECTIVE

The purpose of this study was to investigate B vitamins and homocysteine as risk factor for offspring with spina bifida.

STUDY DESIGN

Blood samples from 45 mothers and their children with spina bifida and from 83 control mothers and their children were obtained to determine the levels of serum and red blood cell folate, serum vitamin B(12), whole blood vitamin B(6), and total plasma homocysteine.

RESULTS

In the case mothers, the vitamin B(12) concentration was 21% lower (95% CI, 8%-33%) compared with control mothers. Unlike folate, vitamin B(6,) and homocysteine, a vitamin B(12) concentration of <or=185 pmol/L was associated with a 3.5-fold (95% CI, 1.3- 8.9) spina bifida risk. In children, no differences in folate, vitamin B(6), vitamin B(12), and homocysteine concentrations were observed after adjustment for the child's age.

CONCLUSION

A marginal maternal vitamin B(12) status increases the risk of an offspring with spina bifida.

Gene–nutrient interactions: importance of folates and retinoids during early embryogenesis

The role that nutritional factors play in mammalian development has received renewed attention over the past two decades, as the scientific literature exploded with reports of retinoid compounds disrupting craniofacial development, and with other reports that folic acid supplementation in the periconceptional period can protect embryos from highly significant malformations. As was often the case, the situation became far more complicated, as the interaction between nutritional factors with selected genes was recognized. In this review, we attempt to summarize a complex clinical and experimental literature of nutritional factors, their biological transport mechanisms, and the impact that they have during early embryogenesis. Although not exhaustive, our goal was to provide an overview of important gene-nutrient interactions and a framework for their investigation.

Metabolic effects and the methylenetetrahydrofolate reductase (MTHFR) polymorphism associated with neural tube defects in southern Brazil

BACKGROUND

The importance of metabolic factors in neural tube defects (NTDs) has been the focus of many investigations. Several authors have suggested that abnormalities in homocysteine metabolism, such as hyperhomocysteinemia, folate deficiency, and low vitamin B12, may be responsible for these malformations and that both nutritional factors and genetic abnormalities are associated with them.

METHODS

We conducted a case-control study to investigate the influence of biochemical and genetic factors in NTDs in infants in southern Brazil. Levels of folate, vitamin B12, total homocysteine (t-Hcy) and the 677C>T and 1298A>C polymorphisms of the MTHFR gene were analyzed in 41 NTD child-mother pairs and 44 normal child-mother control pairs.

RESULTS

Subjects in the case group had a higher mean blood folate level than those in the control group. The level of vitamin B12 was lower in mothers in the NTD group than in control mothers (p = 0.004). The level of t-Hcy was not different in the two groups, but t-Hcy and vitamin B12 were correlated (p = 0.002). There was no difference in the genotype distribution for 677C>T and 1298A>C polymorphisms of MTHFR in the case and control pairs. The level of t-Hcy was correlated with 677TT.

CONCLUSIONS

Despite the small sample in this study, we suggest that low vitamin B12 and, consequently, hyperhomocysteinemia are important risk factors for NTDs in our population.

Evidence for suboptimal use of periconceptional folic acid supplements globally

OBJECTIVE

To systematically summarise the available evidence concerning the rate of folic acid supplement use pre- and periconceptionally, to identify those characteristics associated with low rates of use and to assess whether folic acid public awareness campaigns are associated with higher folic acid use.

DESIGN

Systematic overview.

SETTING

Survey studies.

POPULATION

Women of reproductive age, most of whom were currently or recently pregnant.

METHODS

Two investigators searched MEDLINE, Embase and Nutriotiongate databases between 1990 and 2003. Bibliographies of retrieved references were scanned for other relevant publications, and authors were contacted if necessary. Studies were included that evaluated the rate of folic acid supplement use either before conception or in early pregnancy.

MAIN OUTCOME MEASURES

Rate of preconceptional and/or periconceptional folic acid use, rate of planned pregnancy in each study, as well as significant characteristics differentiating non-users from users of folic acid, including the effect of folic acid awareness campaigns.

RESULTS

A total of 52 studies were included. In 34 studies, reported preconceptional folic acid use varied from 0.9% to 50%. In 49 studies, the reported rate of periconceptional supplement use ranged from 0.5% to 52%. Significant predictors of reduced periconceptional folic acid use were a low level of formal education, immigrant status, young maternal age, lack of a partner and an unplanned pregnancy. Four studies examined the effect of mass media campaigns on periconceptional folic acid use; the reported rates increased significantly, by a factor of 1.7 to 7.2, but in no study was the post-campaign rate above 50%.

CONCLUSIONS

In many countries, fewer than 50% of women take periconceptional folic acid supplements. Consideration should be given to the practical advantages of folic acid fortification of centrally processed foods, such as wheat, corn and rice flour, while further promoting vitamin tablet supplement use and planned pregnancy.

Oral Synthetic Folic Acid and Vitamin B12Supplements Work-If One Consumes Them

Oral supplements of synthetic folic acid and vitamin B12 are very effective in increasing blood levels of the vitamins and are known to prevent birth defects and cardiovascular diseases.

A commonABCC2 promoter polymorphism is not a determinant of the risk of spina bifida

BACKGROUND

There is compelling evidence that the risk of spina bifida, a malformation of the caudal neural tube, is associated with maternal and/or embryonic disturbances in folate/homocysteine metabolism. Hence, functional variants of genes that influence folate/homocysteine metabolism constitute a biologically plausible group of candidate risk factors for spina bifida and other neural tube defects. One such candidate is ABCC2, the gene encoding ABCC2, (a.k.a. canalicular multispecific organic anion transporter [cMOAT], multidrug resistance related protein 2 [MRP2]), a member of the ABC transporter family that effluxes natural folates and anti-folate drugs such as methotrexate.

METHODS

The association between the risk of spina bifida and both the maternal and embryonic ABCC2 C(-24)T genotype was evaluated by using the transmission disequilibrium test and log-linear modeling.

RESULTS

These analyses provided no evidence that the risk of spina bifida was significantly related to either the maternal or embryonic ABCC2 C(-24)T genotype.

CONCLUSIONS

The results of the present analyses suggest that the C(-24)T variant of the ABCC2 gene is not a major determinant of spina bifida risk.

High rates of neural tube defects in Ukraine

BACKGROUND

Oral consumption of synthetic folic acid can prevent neural tube defects (NTDs), which are some of the most severe congenital anomalies. The prevalence of NTDs in Ukraine and other countries of the former U.S.S.R. has not been well studied. We determined the prevalence of NTD-affected pregnancies in Northwestern Ukraine as background for policy decisions related to flour fortification in this country.

METHODS

The Ukrainian-American Birth Defects Program was established in 1999 and conducts population- based surveillance of birth defects in several oblasts (states) of Ukraine. We determined the prevalence of NTDs in the Volyn and Rivne oblasts of Northwestern Ukraine for three years, 2000-2002.

RESULTS

There were 75,928 births in the two oblasts in 2000-2002. There were 159 cases of NTDs among live births, stillbirths, and induced abortions. The prevalence of NTDs in the two oblasts in Northwestern Ukraine is 2.1 per 1000 births.

CONCLUSIONS

The prevalence of NTD-affected pregnancies we found in Northwestern Ukraine is almost four times what it should be. This prevalence suggests that population folate deficiency is widespread in Ukraine. Universal folic acid fortification of flour milled in Ukraine is urgently needed to end this epidemic of birth defects. Such fortification would be expected to prevent folate deficiency anemia, heart attacks, and strokes.

The Metropolitan Atlanta Congenital Defects Program: 35 years of birth defects surveillance at the Centers for Disease Control and Prevention

BACKGROUND

The Metropolitan Atlanta Congenital Defects Program (MACDP) is a population-based birth defects surveillance program administered by the Centers for Disease Control and Prevention (CDC) that has been collecting, analyzing, and interpreting birth defects surveillance data since 1967. This paper presents an overview of MACDP current methods and accomplishments over the past 35 years.

METHODS

MACDP actively monitors major birth defects among infants born to residents of five counties of metropolitan Atlanta, an area with approximately 50,000 annual births. Cases are ascertained from multiple sources, coded using a modified British Pediatric Association six-digit code, and reviewed and classified by clinical geneticists.

RESULTS

MACDP has monitored trends in birth defects rates and has served as a case registry for descriptive, risk factor, and prognostic studies of birth defects, including studies of Agent Orange exposure among Vietnam War veterans, maternal use of multivitamins, diabetes, febrile illnesses, and survival of children with neural tube defects. MACDP has served as a data source for one of the centers participating in the National Birth Defects Prevention Study, and for developing and evaluating neural tube defects prevention strategies related to the periconceptional use of folic acid supplements.

CONCLUSIONS

Since its inception, MACDP has served as a resource for the development of uniform methods and approaches to birth defect surveillance across the United States and in many other countries, monitoring birth defects rates, and as a case registry for various descriptive, etiologic, and survival studies of birth defects. MACDP has also served as a training ground for a large number of professionals active in birth defects epidemiology.

NTP-CERHR Expert Panel report on the reproductive and developmental toxicity of methanol

The National Toxicology Program (NTP) and the National Institute of Environmental Health Sciences (NIEHS) established the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) in June 1998. The purpose of the Center is to provide timely, unbiased, scientifically sound evaluations of human and experimental evidence for adverse effects on reproduction, including development, caused by agents to which humans may be exposed. Methanol was selected for evaluation by the CERHR based on high production volume, extent of human exposure, and published evidence of reproductive or developmental toxicity. Methanol is used in chemical syntheses and as an industrial solvent. It is a natural component of the human diet and is found in consumer products such as paints, antifreeze, cleaning solutions, and adhesives. It is used in race car fuels and there is potential for expanded use as an automobile fuel. This evaluation is the result of a 10-month effort by a 12-member panel of government and non-government scientists that culminated in a public Expert Panel meeting. This report has been reviewed by CERHR staff scientists, and by members of the Methanol Expert Panel. Copies have been provided to the CERHR Core Committee, which is made up of representatives of NTP-participating agencies. This report is a product of the Expert Panel and is intended to (1). interpret the strength of scientific evidence that a given exposure or exposure circumstance may pose a hazard to reproduction and the health and welfare of children; (2). provide objective and scientifically thorough assessments of the scientific evidence that adverse reproductive/development health effects are associated with exposure to specific chemicals or classes of chemicals, including descriptions of any uncertainties that would diminish confidence in assessment of risks; and (3). identify knowledge gaps to help establish research and testing priorities. The expert panel report becomes a central part of the subsequent NTP-CERHR Monograph. Each monograph includes the NTP Brief on the chemical under evaluation, the expert panel report, and all public comments on the expert panel report. The NTP Brief contains the NTP's conclusions on the potential for exposure to result in adverse effects on human development and reproduction. It is based on the expert panel report, public comments on the report, and relevant data published after the expert panel report was completed. NTP-CERHR Monographs are publicly available and are transmitted to appropriate health and regulatory agencies.

Impact of folic acid fortification in the United States: markedly diminished high maternal serum alpha-fetoprotein values

OBJECTIVE

Folic acid fortification of breads and grains was implemented in the United States in 1998 in an attempt to reduce the incidence of neural tube defects. Outcome data from birth registries have shown a 20% drop-less than originally predicted. In this study, we ascertain if the impact of folic acid fortification is better seen at the time of midtrimester prenatal diagnosis by looking at incidence of high maternal serum alpha-fetoprotein (MSAFP) values.

METHODS

Data regarding MSAFP levels in 61,119 patients undergoing maternal serum screening at a large commercial laboratory were categorized by multiples of the median (MoM). The data were compared between 2 groups: before mandatory supplementation in the United States in 1997 and after mandatory supplementation in 2000. High MSAFP values were further categorized as high (2.75-4.00 MoM) or very high (more than 4.00 MoM). Data were analyzed by chi(2) analysis.

RESULTS

Comparative data showed a 32% decrease of patients with MoM greater than 2.75 + (2.5% -1.7%). Further categorizations revealed similar decreases.

CONCLUSION

The introduction of folic acid fortification has produced a profound decrease in the number of high MSAFP values, reflective of a decreased incidence of neural tube defects. Our results help to validate the decision to fortify food with folic acid, which represents a highly successful public health policy for primary prevention of birth defects.

LEVEL OF EVIDENCE

II-2

Preventing congenital anomalies in developing countries

The birth prevalence of congenital anomalies in developing countries is similar to that observed in developed countries. However, the health impact of birth defects is higher because of a lack of adequate services for the care of affected infants and a higher rate of exposures to infections and malnutrition. A number of successful measures for the prevention of congenital anomalies are being taken in a number of developing nations. Primary prevention programs are based on public education about preconceptional and prenatal risks. Prevention based on reproduction options includes teratogen information services and prenatal screening for fetal anomalies. In addition, programs for the detection of congenital malformations at birth, followed by early treatment, are contributing to secondary prevention. Prevention of congenital anomalies in the developing world requires: (a) good epidemiological data on the prevalence and types of birth defects and genetic disorders; (b) educating health professionals in the goals and methods of preventing birth defects at low cost but with high impact, and (c) expansion of family planning and improvement of antenatal care combined with educational campaigns to avoid the risks for birth defects. The basis for public health preventive measures should be the primary health care level. In a sizable proportion of developing countries, the stage is already set for these measures to be implemented. Required are education, political will, and proper organization and allocation of resources.

Effects of once-a-week or daily folic acid supplementation on red blood cell folate concentrations in women

OBJECTIVE

Our aim was to determine if a once-a-week folic acid supplement increases women's red blood cell folate to concentrations (>905 nmol/l) that are associated with a low risk of bearing a child with a neural tube defect.

DESIGN

Randomized control trial.

SETTING

General community.

SUBJECTS

In total, 114 nonpregnant women (18-40 y) volunteers, with red blood cell folate concentrations between 295 and 905 nmol/l at screening.

INTERVENTION

Women were randomized to receive a once-a-week 2800 microg folic acid supplement, a daily 400 microg folic acid supplement or a daily placebo for 12 weeks.

RESULTS

The mean (95% CI) red blood cell folate concentrations increased during the 12-week intervention from 608 (553-668) to 900 (828-978) in the weekly folic acid group (P<0.05) and from 615 (560-677) to 1053 (957-1158) nmol/l in the daily group (P<0.05) during the trial. At week 12, 49% of women ingesting the weekly folic acid supplement had red blood cell folate concentrations greater than 905 nmol/l compared to 74% of women ingesting the daily supplement.

CONCLUSION

A once-a-week 2800 microg folic acid supplement can increase women's red blood cell folate to concentrations associated with a reduced risk of bearing a child with a neural tube defect, but is less effective than a 400 microg daily supplement. Use of a weekly folic acid supplement over at least 12 weeks before conception by women of child-bearing age may prevent neural tube defects.

FUNDING

The Otago Medical Research Foundation (Laurenson Award). Healtheries (New Zealand) provided the supplements.

Promoter haplotype combinations for the human PDGFRA gene are associated with risk of neural tube defects

Recent animal studies suggested that deregulated expression of the platelet-derived growth factor receptor alpha (PDGFRalpha) may contribute to the failure of normal neural tube closure (NTC). There is also suggestive evidence that the promoter haplotype of the PDGFRA is associated with genetic susceptibility in human neural tube defects (NTDs). The purpose of our study was to investigate the association between promoter haplotype combinations of the human PDGFRA gene and risk for NTDs in a Hispanic population from the Texas-Mexico border region. This population has a considerably higher prevalence of NTDs (16/10,000 live births) than that generally reported in the United States (8-10/10,000 live births). In the present study, NTDs were defined as spina bifida or anencephaly. The haplotype of PDGFRA gene promoter was determined by direct DNA sequence analysis. Two novel haplotypes, H2epsilon and H1beta, were found. We observed significant differences among variable haplotype groups from in vitro transient transfection studies in U2-OS osteosarcoma cell and two other cell lines (HeLa cell and MCF7 cell). Result from our case-control study demonstrated that the frequencies of haplotypes with low transcription activity were significantly higher in NTD mothers than that observed in control mothers (odds ratio=2.2, 95% CI=1.0-4.6). Infants with at least one low activity allele showed slightly higher risk (odds ratio=1.5, 95%=0.8-3.1). Our study suggests that the reduced transcriptional activity of PDGFRA gene could increase the risk of having an NTD-affected pregnancy.

Recommendations for accelerating global action to prevent folic acid-preventable birth defects and other folate-deficiency diseases: Meeting of experts on preventing folic acid-preventable neural tube defects

BACKGROUND

In April of 2003, The Micronutrient Initiative, in collaboration with several other organizations, convened a group of knowledgeable scientists and policy experts to discuss ways to accelerate the global pace at which countries implement effective and sustainable programs to prevent folic acid-preventable birth defects and other folate-deficiency diseases. Programs implemented to date by fewer than 40 countries have prevented only 10% of the estimated 240,000 annual cases of folic acid-preventable spina bifida and anencephaly.

METHODS

Participants in this meeting summarized and presented scientific evidence showing that increased consumption of synthetic folic acid prevents a large proportion of spina bifida and anencephaly cases. They also reviewed related guidance and endorsement issued by national professional societies and advisory bodies as well as policies and programs implemented by some countries that have already demonstrated successful results in terms of reduced rates of neural tube defects and improved folate nutrition.

CONCLUSIONS

The group formulated and discussed recommendations and strategies for increasing the pace of neural tube defect prevention globally. The recommendations and strategies are published here.

Folate, colorectal carcinogenesis, and DNA methylation: lessons from animal studies

Folate, a water-soluble B vitamin and cofactor in one-carbon transfer, is an important nutritional factor that may modulate the development of colorectal cancer (CRC). Epidemiologic and clinical studies indicate that dietary folate intake and blood folate levels are inversely associated with CRC risk. Collectively, these studies suggest an approximately 40% reduction in the risk of CRC in individuals with the highest dietary folate intake compared with those with the lowest intake. Animal studies using chemical and genetically predisposed rodent models have provided considerable support for a causal relationship between folate depletion and colorectal carcinogenesis as well as a dose-dependent protective effect of folate supplementation. However, animal studies also have shown that the dose and timing of folate intervention are critical in providing safe and effective chemoprevention; exceptionally high supplemental folate levels and folate intervention after microscopic neoplastic foci are established in the colorectal mucosa promote, rather than suppress, colorectal carcinogenesis. These animal studies, in conjunction with clinical observations, suggest that folate possesses dual modulatory effects on carcinogenesis depending on the timing and dose of folate intervention. Folate deficiency has an inhibitory effect, whereas folate supplementation has a promoting effect on the progression of established neoplasms. In contrast, folate deficiency in normal epithelial tissues appears to predispose them to neoplastic transformation, and modest levels of folate supplementation suppress the development of tumors in normal tissues. Notwithstanding the limitations associated with animal models, these studies suggest that the optimal timing and dose of folate intervention must be established for safe and effective chemoprevention in humans. Folate is an important factor in DNA synthesis, stability, and integrity, the repair aberrations of which have been implicated in colorectal carcinogenesis. Folate may also modulate DNA methylation, which is an important epigenetic determinant in gene expression (an inverse relationship), in the maintenance of DNA integrity and stability, in chromosomal modifications, and in the development of mutations. A mechanistic understanding of how folate status modulates colorectal carcinogenesis further strengthens the case for a causal relationship and provides insight into a possible chemopreventive role of folate.

Scientific evidence supporting folic acid fortification of flour in Australia and New Zealand

BACKGROUND

Fortification of flour with folic acid is a safe, sustainable, and cost-effective approach for preventing spina bifida and anencephaly, and it is likely to confer multiple health benefits to the adult population. Scientists and advocates are bringing this intervention to the attention of policymakers in countries around the world, and consequently the demand for sound, science-backed policy rationale is increasing.

METHODS

We recently prepared this scientific review for scientists, physicians, and advocates who were promoting mandatory folic acid fortification of flour in Australia and New Zealand. This short document references the most relevant published scientific data and national and international recommendations from other countries and presents an argument for fortification based on demonstrated need, proven effectiveness, safety, and multiple health benefits.

CONCLUSIONS

With some modifications, this document could be utilized in other countries considering fortification of flour or other staple products with folic acid.