Prevention of neural tube defects with folic acid: The Chinese experience

Preconceptional and Periconceptional Folic Acid Supplementation in the Visegrad Group Countries for the Prevention of Neural Tube Defects

Neural tube defects (NTDs) are malformations of the central nervous system that represent the second most common cause of congenital morbidity and mortality, following cardiovascular abnormalities. Maternal nutrition, particularly folic acid, a B vitamin, is crucial in the etiology of NTDs. FA plays a key role in DNA methylation, synthesis, and repair, acting as a cofactor in one-carbon transfer reactions essential for neural tube development. Randomized trials have shown that FA supplementation during preconceptional and periconceptional periods reduces the incidence of NTDs by nearly 80%. Consequently, it is recommended that all women of reproductive age take 400 µg of FA daily. Many countries have introduced FA fortification of staple foods to prevent NTDs, addressing the high rate of unplanned pregnancies. These policies have increased FA intake and decreased NTD incidence. Although the precise mechanisms by which FA protects against NTDs remain unclear, compelling evidence supports its efficacy in preventing most NTDs, leading to national recommendations for FA supplementation in women. This review focuses on preconceptional and periconceptional FA supplementation in the female population of the Visegrad Group countries (Slovakia, Czech Republic, Poland, and Hungary). Our findings emphasize the need for a comprehensive approach to NTDs, including FA supplementation programs, tailored counseling, and effective national-level policies.

Maternal periconceptional folic acid supplementation and risk for fetal congenital genitourinary system defects

BACKGROUND

Taking folic acid supplementation could reduce the risk of neural tube defects for offspring in the maternal periconceptional period, but the relationship between folic acid use and other birth defects remains unclear, such as genitourinary system birth defects.

METHODS

The data from a Prenatal Health Care System and Birth Defects Surveillance System in Tongzhou, Beijing, China, were collected from 2013 to 2018. We adjusted for differences in characteristics between comparison groups using propensity score inverse probability weighting and assessed associations with Poisson regression modeling.

RESULTS

A total of 65,418 live births and stillbirths were included, and there were 194 cases with congenital genitourinary defects among them. The prevalence of genitourinary system birth defects was 29.2 (34.9) per 10,000 for FA/MMFA users (nonusers). Compared to nonusers, FA/MMFA users had a lower risk for genitourinary system birth defects (adjusted risk ratio [aRR] 0.81, 95% confidence interval [CI] 0.67, 0.98), and for hypospadias (aRR 0.55, 95% CI 0.40, 0.76).

CONCLUSIONS

FA or MMFA supplementation during the maternal periconceptional period could reduce the risk for genitourinary system birth defects in offspring. More mechanisms should be explored for the protective effect.

IMPACT

Folic acid (FA) or multiple micronutrients containing folic acid (MMFA) supplementation during the maternal periconceptional period could reduce the risk for genitourinary system birth defects in offspring. Maternal FA/MMFA supplementation during the periconceptional period may reduce the risk for hypospadias.

Arsenic disturbs neural tube closure involving AMPK/PKB-mTORC1-mediated autophagy in mice

Arsenic exposure is a significant risk factor for folate-resistant neural tube defects (NTDs), but the potential mechanism is unclear. In this study, a mouse model of arsenic-induced NTDs was established to investigate how arsenic affects early neurogenesis leading to malformations. The results showed that in utero exposure to arsenic caused a decline in the normal embryos, an elevated embryo resorption, and a higher incidence of malformed embryos. Cranial and spinal deformities were the main malformation phenotypes observed. Meanwhile, arsenic-induced NTDs were accompanied by an oxidant/antioxidant imbalance manifested by elevated levels of reactive oxygen species (ROS) and decreased antioxidant activities. In addition, changes in the expression of autophagy-related genes and proteins (ULK1, Atg5, LC3B, p62) as well as an increase in autophagosomes were observed in arsenic-induced aberrant brain vesicles. Also, the components of the upstream pathway regulating autophagy (AMPK, PKB, mTOR, Raptor) were altered accordingly after arsenic exposure. Collectively, our findings propose a mechanism for arsenic-induced NTDs involving AMPK/PKB-mTORC1-mediated autophagy. Blocking autophagic cell death due to excessive autophagy provides a novel strategy for the prevention of folate-resistant NTDs, especially for arsenic-exposed populations.

Effect of folic acid supplementation in the association between short sleep duration and gestational diabetes mellitus

PURPOSE

To examine whether or not folic acid (FA) supplementation may modify the relationships between duration or quality of sleep and gestational diabetes mellitus (GDM) risk.

METHODS

In a case-control study of patients with GDM and controls, mothers were interviewed face-to-face at enrollment. The Pittsburgh Sleep Quality Scale was used to assess duration and quality of sleep during early pregnancy, and information on FA supplementation and covariates was obtained using a semiquantitative questionnaire.

RESULTS

Among 396 patients with GDM and 904 controls, GDM risk increased by 328% and 148% among women with short (< 7 h) and long (≥ 9 h) sleep durations, respectively, compared to those averaging 7-8.9 h sleep. Mothers with poor sleep quality increased their GDM risk by an average of 75% (all p < 0.05). The effect of short sleep duration on GDM risk was much weaker among women with adequate FA supplementation (taking supplements containing ≥ 0.4 mg FA daily for each day of the first three months of pregnancy) than that among women with inadequate FA supplementation, with a p-value for interaction = 0.003. There were no significant effects of FA on links among long duration and poor quality of sleep with GDM risk.

CONCLUSIONS

Sleep duration and quality in early gestation were related to increased GDM risks. FA supplementation may reduce GDM risk associated with short sleep duration.

Update from a cohort study for birth defects in Hunan Province, China, 2010-2020

To define the relationship between sex, residence, maternal age, and a broad range of birth defects by conducting a comprehensive cross-analysis based on up-to-date data. Data were obtained from the Birth Defects Surveillance System in Hunan Province, China, 2010-2020. Prevalences of birth defects (number of cases per 10,000 fetuses (births and deaths at 28 weeks of gestation and beyond)) with 95% confidence intervals (CI) were calculated by sex, residence, maternal age, year, and 23 specific defects. Cross-analysis of sex, residence, and maternal age was conducted, and crude odds ratios (ORs) were calculated to examine the association of each maternal characteristic with birth defects. A total of 1,619,376 fetuses and 30,596 birth defects were identified. The prevalence of birth defects was 188.94/10,000 (95% CI 186.82-191.05). Birth defects were more frequent in males than females (210.46 vs. 163.03/10,000, OR = 1.30, 95% CI 1.27-1.33), in urban areas than in rural areas (223.61 vs. 162.90/10,000, OR = 1.38, 95% CI 1.35-1.41), and in mothers ≥ 35 than mothers 25-29 (206.35 vs. 187.79/10,000, OR = 1.10, 95% CI 1.06-1.14). Cross-analysis showed that the prevalence of birth defects was higher in urban females than in rural males (194.53 vs. 182.25/10,000), the difference in prevalence between males and females was more significant for maternal age < 20 compared to other age groups (OR = 1.64, 95% CI 1.37-1.95), and the prevalence difference between urban and rural areas is more significant for maternal age 25-34 compared to other age groups (OR = 1.49, 95% CI 1.43-1.57). Cleft palates were more frequent in males, and nine specific defects were more frequent in females. Five specific defects were more frequent in rural areas, and eight were more frequent in urban areas. Compared to mothers 25-29, five specific defects were more frequent in mothers < 20, seven specific defects were more frequent in mothers 20-24, two specific defects were more frequent in mothers 30-34, and ten specific defects were more frequent in mothers ≥ 35. Our data indicate that sex, residence, and maternal age differences in the prevalences of birth defects and most specific defects are common. We have found some new epidemiological characteristics of birth defects using cross-analysis, such as residence is the determining factor for the prevalence of birth defects, the difference in prevalence between males and females was more significant for maternal age < 20 compared to other age groups, the prevalence difference between urban and rural areas is more significant for maternal age 25-34 compared to other age groups. And differences in the epidemiological characteristics of some specific defects from previous studies. Future studies should examine mechanisms. Our findings contributed to clinical counseling and advancing research on the risk factors for birth defects.

Periconceptional Folic Acid Use and Its Effects on Neural Tube Defects - Five Counties, Shanxi Province, China, 2010-2016

What is already known about this topic?

Robust evidence indicates that supplementing with folic acid periconceptionally may decrease the risk of neural tube defects (NTDs) in fetuses.

What is added by this report?

Over half of the mothers in both the NTD case group and the control group utilized folic acid supplements during the periconceptional period, showing no notable variations between the two groups. However, there was a significantly higher percentage of mothers with NTD cases who exhibited poor compliance in folic acid use compared to control mothers. A significantly lowered compliance with folic acid intake was observed among women facing unintended pregnancies and those with lower education levels.

What are the implications for public health practice?

Universal education regarding folic acid action for women of childbearing age should be strengthened to improve compliance with folic acid supplementation in the periconceptional period and further reduce the prevalence of NTDs.

The association between serum folate and gestational diabetes mellitus: a large retrospective cohort study in Chinese population

OBJECTIVE

To investigate the association between folate levels and the risk of gestational diabetes mellitus (GDM) risk during the whole pregnancy.

DESIGN

In this retrospective cohort study of pregnant women, serum folate levels were measured before 24 gestational weeks (GW). GDM was diagnosed between 24th and 28th GW based on the criteria of the International Association of Diabetes and Pregnancy Study Groups. General linear models were performed to examine the association of serum folate with plasma glucose (i.e. linear regressions) and risk of GDM (i.e. log-binomial regressions) after controlling for confounders. Restricted cubic spline regression was conducted to test the dosage-response relationship between serum folate and the risk of GDM.

SETTING

A sigle, urban hospital in Shanghai, China.

PARTICIPANTS

A total of 42 478 women who received antenatal care from April 2013 to March 2017 were included.

RESULTS

Consistent positive associations were observed between serum folate and plasma glucose levels (fasting, 1-h, 2-h). The adjusted relative risks (RR) and 95 % CI of GDM across serum folate quartiles were 1·00 (reference), 1·15 (95 % CI (1·04, 1·26)), 1·40 (95 % CI (1·27, 1·54)) and 1·54 (95 % CI (1·40, 1·69)), respectively (P-for-trend < 0·001). The positive association between serum folate and GDM remained when stratified by vitamin B12 (adequate v. deficient groups) and the GW of serum folate measurement (≤13 GW v. >13 GWs).

CONCLUSIONS

The findings of this study may provide important evidence for the public health and clinical guidelines of pregnancy folate supplementation in terms of GDM prevention.

The prevalence of trimester-specific dietary supplements and associated factors during pregnancy: An observational study

Objectives: This study aimed to assess the prevalence of trimester-specific dietary supplements (DS)s use and their possible correlates during pregnancy.

Method: Pregnant women were convenience sampled and recruited from a comprehensive obstetric care center in Shanghai, China. Data relating to the use of DS during pregnancy, social support and other social-demographic and obstetric data were collected. Trimester-specific DS use and factors related DS were explored.

Results: Of the 2803 women participating in this study, 94.8%, 96.2%, 93.8%, and 94.4% reported the use of at least one DS during pregnancy (all trimesters) and in the first, second, and third trimesters of pregnancy, respectively. Significant differences were noted in the use of DS containing folic acid, calcium, iron, vitamins, and docosahexaenoic acid (DHA), during the three trimesters of pregnancy. A higher proportion of DS use was negatively associated with certain categories of pregnant woman, including unemployed/housewife, low education level, obese, and low social support. A positive association was identified with gestational age.

Conclusion for practice: Considering the high prevalence of DS use during pregnancy, future studies are needed to evaluate the accuracy and suitability of DS usage during pregnancy.

Prenatal exposure to silver is associated with an elevated risk for neural tube defects: a case-control study

Exposure to copper, silver, and titanium has been reported to be associated with a variety of adverse effects on humans, but it is little focused on the fetus. We investigated the associations between prenatal exposure to the three metals (copper, silver, and titanium) and risk for fetal neural tube defects (NTDs). Placental samples from 408 women with pregnancies affected by NTDs and 593 women with normal pregnancies were collected from 2003 to 2016 in Pingding, Xiyang, Shouyang, Taigu, and Zezhou counties of China. Multilevel mixed-effects logistic regression and Bayesian kernel machine regression (BKMR) were used to evaluate the single and joint effects of the metals on NTDs. Silver was associated with an increased risk for NTDs in a dose-response fashion in single-metal logistic regression, with adjusted odds ratios (95% confidence intervals) of 1.78 (1.04-3.06) and 1.92 (1.11-3.32) in the second and third tertiles, respectively, compared to the lowest tertile. BKMR revealed toxic effects of silver on NTDs and the association appeared to be linear. No interaction of silver with any of the other two metals was observed. Besides, silver concentration was positively correlated with maternal certain dietary intakes. Placental high silver concentrations are associated with an elevated risk for NTDs. Maternal diet may be a source of silver exposure.

Proteome changes in autosomal recessive primary microcephaly

BACKGROUND/AIM

Autosomal recessive primary microcephaly (MCPH) is a rare and genetically heterogeneous group of disorders characterized by intellectual disability and microcephaly at birth, classically without further organ involvement. MCPH3 is caused by biallelic variants in the cyclin-dependent kinase 5 regulatory subunit-associated protein 2 gene CDK5RAP2. In the corresponding Cdk5rap2 mutant or Hertwig's anemia mouse model, congenital microcephaly as well as defects in the hematopoietic system, germ cells and eyes have been reported. The reduction in brain volume, particularly affecting gray matter, has been attributed mainly to disturbances in the proliferation and survival of early neuronal progenitors. In addition, defects in dendritic development and synaptogenesis exist that affect the excitation-inhibition balance. Here, we studied proteomic changes in cerebral cortices of Cdk5rap2 mutant mice.

MATERIAL AND METHODS

We used large-gel two-dimensional gel (2-DE) electrophoresis to separate cortical proteins. 2-DE gels were visualized by a trained observer on a light box. Spot changes were considered with respect to presence/absence, quantitative variation and altered mobility.

RESULT

We identified a reduction in more than 30 proteins that play a role in processes such as cell cytoskeleton dynamics, cell cycle progression, ciliary functions and apoptosis. These proteome changes in the MCPH3 model can be associated with various functional and morphological alterations of the developing brain.

CONCLUSION

Our results shed light on potential protein candidates for the disease-associated phenotype reported in MCPH3.

U-shaped Association Between Folic Acid Supplementation and the Risk of Gestational Diabetes Mellitus in Chinese Women

OBJECTIVE

Our aim in this study was to assess the association between folic acid (FA) supplementation before and during pregnancy and risk of gestational diabetes mellitus (GDM) in Chinese women.

METHODS

This case-control study was conducted at 2 hospitals in central China. A total of 1,300 pregnant women, including 396 GDM patients and 904 controls, participated in the study. Information on the dose and duration of FA supplementation was collected using a self-report questionnaire at enrolment (24 to 28 weeks of gestation).

RESULTS

We observed a U-shaped association between FA supplementation and GDM risk that demonstrated a 228% increased risk of GDM among women who never took FA supplements, a 28% increased risk among women who took supplements containing <400 μg/day FA or took FA supplements for <1 month and a 188% increased risk among women who took supplements containing ≥800 μg/day FA for an adequate duration (>1 month before pregnancy and >3 months during pregnancy) compared with women who took supplements containing 400 to 799 μg/day FA for an adequate duration (all p<0.05). For women who took supplements containing ≥800 μg/day FA for an adequate duration, the association between FA supplementation and GDM risk appeared to be stronger among those women with a prepregnancy body mass index (BMI) of ≥25 kg/m² than among those with a prepregnancy BMI of <25 kg/m² (p=0.006 for interaction).

CONCLUSIONS

There was a U-shaped association of FA supplementation with GDM risk; that is, FA supplementation both below and above the recommended levels may increase the risk of GDM.

The compliance of free folic acid supplements among pregnant women in rural areas of Northwestern China: The role of related knowledge

Background

High prevalence of neural tube defects remains one of the major threats to newborns in rural China. Folic acid supplementation before and during early pregnancy can effectively reduce the risk of neural tube defects. Despite the efforts of the free folic acid mass distribution, the actual usage of folic acid supplements was still suboptimal among rural pregnant women in China. The objective of this study is to investigate if and how knowledge can influence the picking up and intake of the free folic acid supplements distributed by the government.

Methods

We collected survey data from 821 pregnant women in rural areas of Shaanxi, China, in March and December of 2021. Face-to-face interviews and questionnaire surveys were conducted with every participant. Univariate and multivariate logistic regression analyses were performed to test the relationship between knowledge and dependent variables.

Results

Our study found that there were 76.4% of pregnant women would pick up folic acid supplements distributed by the government and only 44.5% of women would use folic acid before current pregnancy. Awareness of folic acid policy both affects the picking up (OR: 6.708, 95% CI: 4.672-9.632) and periconceptional intake (OR: 1.912, 95% CI:1.326-2.758) of folic acid supplements. Knowledge of health and nutrition in pregnancy showed no significant relationship with the picking up and periconceptional intake of folic acid supplements but was positively associated with the intake duration (Coefficient: 9.278, 95% CI: 2.966-15.591).

Conclusion

Despite the relatively high level of picking up, the actual folic acid usage was not ideal among pregnant women in rural areas of China. Folic acid policy awareness was positively associated with the picking up and intake of folic acid before and during conception. Knowledge of health and nutrition about pregnancy was related to a longer duration of folic acid intake but had no impact on the picking up rate and periconceptional intake of folic acid supplements.

Knowledge and intake of folic acid to prevent neural tube defects among pregnant women in urban China: a cross-sectional study

BACKGROUND

The prevalence of neural tube defects (NTDs) in China declined during 2000-2017 with periconceptional folic acid (FA) supplementation, which is effective in reducing the risk of birth defects. We aimed to assess the knowledge and actual use of FA among Chinese pregnant women and to explore factors associated with FA use before pregnancy.

METHODS

All data were collected in face-to-face interviews during health visits among pregnant women. We collected information about knowledge and use of FA supplements and demographic, socioeconomic, and health status. One maternity and childcare hospital was chosen in each of four cities: Beijing, Huaibei, Kunming, and Haikou. In total, 435 pregnant women were randomly recruited for interviews conducted from June to December 2016.

RESULTS

A total of 428 pregnant women were included in this survey. Of these, 82.0% (351/428) knew that FA can prevent NTDs, and 75.9% (325/428) knew the correct time to take FA. Overall, 65.9% (282/428) of women knew both that FA can prevent NTDs and the recommended time to take FA before pregnancy. Approximately 95.1% (407/428) of women reported having ever taken FA, only 46.3% (198/428) had begun to take FA supplementation before conception, and 64.5% (109/169) of women from rural areas failed to take FA before pregnancy. Women living in northern China (odds ratio [OR] = 1.81, 95% confidence interval [CI], 1.18-2.77), those with unplanned pregnancy (OR = 1.99, 95% CI 1.30-3.04), and highly educated women (OR = 2.37, 95% CI 1.45-3.88) were more likely to know about FA. Women who were homemakers (OR = 1.94, 95% CI 1.21-3.11) and had unplanned pregnancy (OR = 6.18, 95% CI 4.01-9.53) were less likely to begin taking FA before pregnancy.

CONCLUSIONS

Our survey showed that most pregnant women knew about FA. Although preconception intake of FA can help to reduce NTDs, improving the rate of FA intake before pregnancy is needed in urban areas of China, especially among homemakers and women from rural areas or with unplanned pregnancy. Campaigns are needed to increase awareness about FA and FA use before pregnancy among rural women, homemakers, and those with unplanned pregnancy and lower education levels.

Prenatal exposure to barium and the occurrence of neural tube defects in offspring

Neural tube defects (NTDs) have a complex etiology. Few studies have assessed alkaline earth metals exposures and occurrence of NTDs. We examined the association between prenatal exposure to magnesium (Mg), calcium (Ca), strontium (Sr) and barium (Ba) and risk for NTDs in a case-control study, and assessed the teratogenic effects of Ba on mice. Placentas were collected from 408 women with NTD-affected pregnancies and 593 women who delivered healthy infants, and concentrations of these metals were determined as prenatal exposure markers. The single effect of individual exposure and joint effect of coexposure to these metals were evaluated with logistic regression and Bayesian kernel machine regression (BKMR), respectively. Barium chloride (BaCl₂) was intragastrically administered to pregnant ICR mice and fetal mice were examined for NTDs. Median concentrations of Mg and Ba were higher in NTD cases than in controls (P_all < 0.001). In logistic regression, higher levels of Ba were associated with 1.6-fold increased risk for NTDs (95% confidence interval: 1.06-2.43). In BKMR, the joint effect of the four-metal mixture on NTD risk increased steadily with the levels of the mixture. A change in Ba concentration from the 25^th to 75^th percentile displayed a risk effect when the other three metals were fixed at the 25^th, 50^th or 75^th percentile, while such a change in Ca concentration showed a protective effect when the other metals were held at the 25^th or 50^th percentile. No interactions among metals were found. In the mouse experiment, dams treated with 200 mg/kg BaCl₂ showed 16.8% of NTDs in fetal mice, compared to 2.6% in the untreated control group (P < 0.01). Taken together, higher mixture levels of the four alkaline earth metals were associated with increased risk for NTDs, with Ba being the major contributor for the joint effect. Intragastric administration of Ba can induce NTDs in mice.

The association of maternal folic acid supplementation and prenatal folate and vitamin B12 concentrations with child dental development

OBJECTIVE

Low folic acid, folate and vitamin B12 might affect tooth formation and mineralization. The conversion of folic acid into folate is catalysed by the methylenetetrahydrofolate (MTHFR) enzyme which is encoded by the MTHFR gene. Among 3728 mothers and their 10-year-old children from the Generation R Study, we investigated associations of maternal folic acid supplementation and prenatal folate and vitamin B12 concentrations with child dental development. Secondly, we checked the modifying effect of MTHFR-C677T polymorphism.

METHODS

Information on folic acid supplementation was obtained by questionnaires. Concentrations of folate and vitamin B12 were measured from venous samples taken in early pregnancy. Developmental stages of teeth were defined by the Demirjian method at the age-10 assessment. In addition, dental age of the children was calculated using the Dutch standard. GLM and multivariate linear regression models were built to study the associations.

RESULTS

Folic acid supplementation started when pregnancy was known (β = -0.09; 95% CI: -0.17, -0.01) and folic acid supplementation started prior to known pregnancy (β = -0.12; 95% CI: -0.20, -0.04) were both associated with decelerated dental development by 1-2 months lower dental age of 10-year-old children. Folate (β = -0.02, 95% CI: -0.05, 0.02) and vitamin B12 (β = 0.03, 95% CI: -0.00, 0.06) were not associated with dental age. MTHFR-C677T did not modify the associations.

CONCLUSIONS

Maternal folic acid supplementation delays dental development of children by 1-2 months dental age, whereas maternal folate and vitamin B12 concentrations in early pregnancy do not affect the timing of child dental development.

Folic acid supplementation, dietary folate intake and risk of small for gestational age in China

OBJECTIVE

To investigate the hypothesis that folic acid supplementation and dietary folate intake before conception and during pregnancy reduce the risk of small for gestational age (SGA) and to examine the joint effect of folic acid supplementation and dietary folate intake on the risk of SGA.

DESIGN

Participants were interviewed by trained study interviewers using a standardized and structured questionnaire. Information on birth outcomes and maternal complications was abstracted from medical records and dietary information was collected via a semi-quantitative FFQ before conception and during pregnancy.

SETTING

A birth cohort data analysis using the 2010-2012 Gansu Provincial Maternity and Child Care Hospital.

PARTICIPANTS

Women (n 8758) and their children enrolled in the study.

RESULTS

Folic acid supplementation was associated with a reduced risk of SGA (OR = 0·72, 95 % CI 0·60, 0·86), with the reduced risk seen mainly for SGA at ≥37 weeks of gestational age (OR = 0·70, 95 % CI 0·58, 0·85) and nulliparous SGA (OR = 0·67, 95 % CI 0·54, 0·84). There was no significant association between dietary folate intake and SGA risk.

CONCLUSIONS

Our study suggested that folic acid supplementation was associated with a reduced risk of SGA and the risk varied by preterm status and parity.

Periconceptional folic acid supplementation and risk of parent-reported asthma in children at 4-6 years of age

BACKGROUND

Folic acid supplementation is universally recommended for women of child-bearing age to prevent fetal neural tube defects (NTDs). Concerns have arisen over the potential risk for childhood allergy and asthma due to folic acid supplementation. We examined whether periconceptional supplementation with low-dose folic acid only was associated with an increased risk for allergy symptoms or asthma in offspring at 4-6 years of age.

METHODS

Out of 247 831 participating women enrolled in 1993-1996, 9090 were randomly selected and their children were followed up in 2000-2001. Information on mothers' demographic characteristics, folic acid supplementation and allergic diseases among children was collected. We used logistic regression to evaluate the association between folic acid intake and risk for allergic disease while adjusting for potential confounding factors.

RESULTS

The rate of allergy symptoms was 1.54% among children whose mothers had taken folic acid compared with 2.04% among those whose mothers had not taken folic acid, and the rate of asthma was 0.92% and 0.88%, respectively. Maternal folic acid supplementation was not associated with risk for allergy symptoms or asthma, with odds ratios (95% CI) of 0.80 (0.58-1.11) and 1.04 (0.67-1.61), respectively. No differences in the occurrence of allergy symptoms or asthma were observed when data were analysed by timing of supplementation or compliance with folic acid supplementation.

CONCLUSIONS

Supplementation with low-dose folic acid only during the periconceptional period did not increase risk for allergy symptoms or asthma in children at 4-6 years of age in a population without staple fortification with folic acid.

Folate of pregnant women after a nationwide folic acid supplementation in China

Folate insufficiency during the periconceptional period increases the risk of neural tube defects (NTDs) in offspring, and folic acid supplementation substantially reduces the risk. Widespread large-scale folic acid supplementation (0.4-mg folic acid tablet) has been adopted as a main strategy to prevent NTDs in China since 2009. We examined folate concentrations in plasma and red blood cells (RBCs) of pregnant women and the factors associated with blood folate concentrations in a population with a high prevalence of NTDs in northern China. A cross-sectional survey was conducted in 2014, and 1,107 pregnant women were recruited from 11 county or city maternal and child health centres across Shanxi province. Microbiological assays were used to determine folate concentrations. Factors associated with blood folate insufficiency were identified. The median (25th and 75th percentiles) folate concentrations were 28.4 (17.6, 45.2) nmol L-1 and 1,001.2 (658.7, 1,402.5) nmol L-1 in plasma and RBCs, respectively. According to the proposed RBC (906 nmol L-1 ) concentrations for optimal NTD prevention, 42.4% participants had RBC folate insufficiency. Rural women had a higher proportion of folate insufficiency than urban women. Folic acid supplementation was the only factor associated with RBC folate insufficiency. A large proportion of women had RBC folate concentrations that are not optimal for the prevention of NTDs despite free access to folic acid supplements. Actions that aim to improve folic acid supplementation compliance are needed to reach the full potential of the nationwide folic acid supplementation programme in terms of NTD prevention.

Epidemiological characteristics of holoprosencephaly in China, 2007-2014: A retrospective study based on the national birth defects surveillance system

OBJECTIVE

To describe the epidemiology of holoprosencephaly (HPE) in China with special reference to prevalence and associated anomalies.

METHODS

Data were abstracted from the Chinese Birth Defects Monitoring Network for the period 2007-2014. Birth prevalence of HPE were assessed by birth year, fetal/infant sex, maternal age, and maternal residential area. Poisson regressions were used to calculate the crude and adjusted prevalence ratios (PR) and their 95% confidence intervals, and linear chi-square test was used to explore time trend for the prevalence of HPE.

RESULTS

A total of 1222 HPE cases were identified in 13,284,142 births, yielding an overall prevalence of 0.92 per 10,000 births. The annual prevalence of HPE presented an upward trend (P<0.001), from 0.54 per 10,000 births in 2007 to 1.21 per 10,000 births in 2014. Higher prevalence was found in older maternal-age groups (30-34 years, adjusted PR: 1.19, 95% CI: 1.02-1.40; ≥35 years, adjusted PR: 1.53, 95% CI: 1.26-1.86) in comparison with the maternal-age group of 25 to 29 years. Higher prevalence was also found in infants born to mothers resided in urban areas (adjusted PR: 1.23, 95% CI: 1.08-1.39) and female infants (adjusted PR: 1.30, 95% CI: 1.15-1.47).

CONCLUSIONS

HPE is an important perinatal health issue because of its poor prognosis. This is the first study depicting a picture of epidemiological characteristics of HPE in China, which can provide useful references for future studies.

Casp8 hypomethylation and neural tube defects in association with polycyclic aromatic hydrocarbon exposure

Background

Epidemiological studies have found that prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with increased risk for neural tube defects (NTDs). Aberrant DNA methylation, excessive apoptosis, and oxidative stress have been implied as the mechanism underlying the association between PAH exposure and NTDs, respectively. However, the role of DNA methylation aberration of apoptotic initiator CASP8 (caspase-8, apoptosis-related cysteine peptidase) in the formation of NTDs in association with PAH exposure is not known. By combining a case–control study and mouse model, we aimed to explore the full spectrum of the links from PAH exposure, oxidative stress, CASP8 methylation change, caspase-8 activation, apoptosis, to NTD formation.

Results

Hypomethylation of CASP8 promoter was noticed in the microarray profiled by Infinium HumanMethylation450 BeadChip using neural tissues from 10 terminated NTD fetuses and 8 terminated non-malformed fetuses (14 CpG sites, with β difference ranging between 8.8 and 26.3%), and was validated in a larger case–control sample performed with neural tissues from 80 NTD cases and 32 non-malformed fetuses, using the Sequenom MassARRAY system (7 CpG sites). Hypomethylation of CASP8 was a risk factor for NTDs (aOR = 1.11; 95% CI, 1.05–1.17) based on the logistic regression model. According to Pearson’s correlation, methylation levels of CASP8 were inversely correlated with PAH concentrations in maternal serum and with oxidative stress markers in fetal neural tissues (p < 0.05). In the animal study, increased NTD rates (13.5% frequency), Casp8 hypomethylation, caspase-8 upregulation, increased caspase-8 cleavage, and excessive apoptosis were found in mouse embryos cultured with benz(a)pyrene (BaP) in vitro. Antioxidant N-acetyl-L-cysteine (NAC) and BaP co-treatment attenuated the changes found in BaP treatment group.

Conclusions

Hypomethylation of Casp8 promoter is associated with the formation of NTDs, and Casp8 hypomethylation may be induced by oxidative stress that resulted from exposure to PAHs.

Electronic supplementary material

The online version of this article (10.1186/s13148-019-0673-6) contains supplementary material, which is available to authorized users.

Knowledge and intake of folic acid among teachers of childbearing age in the State of Qatar: a cross-sectional study

OBJECTIVES

To assess the knowledge and intake of folic acid among teachers of childbearing age and to identify barriers to folic acid intake.

SETTING

Governmental schools, which included 14 primary models, 29 primary, 14 preparatory and 16 secondary schools. The proportion of teachers in each stratum was then determined, and a stratified random sampling design had been used with proportional allocation.

STUDY DESIGN

Cross-sectional study PARTICIPANTS: A total of 406 non-pregnant teachers of childbearing age enrolled in the study. A validated questionnaire in the Arabic language was used.

RESULTS

The overall response rate was 98%. About 34.6% reported the optimal period in which they should take folic acid, 28.3% reported the correct intake duration and only 29.5% could name food rich in folic acid. Friends and healthcare providers were the main sources of information for the participants; however, 44% said that they did not receive enough information from their healthcare providers.

CONCLUSION

There is a lack of knowledge and poor intake of folic acid among the participants. In particular, they lacked information about the appropriate time to start folic acid supplementations, the duration of intake and the folic acid-rich food. The most common reason being the limited advice given by their healthcare providers.Awareness campaigns are recommended to emphasise the role of healthcare providers in counselling women about the proper use of folic acid before pregnancy.

Awareness and Attitudes Regarding Industrial Food Fortification in Mongolia and Harbin

This study assessed awareness and attitudes regarding industrial food fortification among adults in urban and rural Mongolia, and the city of Harbin, China. Between 2014 and 2017, surveys were collected from healthy men and women aged ≥18 years (182 Harbin residents and 129 urban and rural Mongolians participating in a nationwide nutrition survey in Mongolia). Survey reproducibility was assessed among 69 Mongolian participants to whom it was administered twice (summer and winter). Findings revealed that only 19% of rural and 30% of urban Mongolians, and 48% of Harbin residents were aware that industrial fortification is practiced in their countries. For most food groups evaluated, at least half of Mongolians and less than half of Harbin residents thought fortification was government-mandated (only the addition of iodine with salt is actually mandated in both countries). Fifty-five percent of rural and urban Mongolians favored mandatory fortification of foods, 14% disapproved of it, and 31% were uncertain (compared with 25%, 38%, and 37% respectively in Harbin). Upon learning that the primary purpose of adding vitamin D to milk is to prevent rickets, 75% of Mongolians but only 18% of Harbin residents favored mandatory fortification, while 42% of Harbin residents favored voluntary fortification (compared with <10% of Mongolians). In conclusion, in Mongolia and Harbin, awareness and understanding of food fortification is low, as is receptivity toward mandatory fortification. Health promotion and social marketing should be designed to create an enabling environment for increasing supply and demand of fortified foods, in support of upcoming program implementation in Mongolia and potential future legislation in northeern China.

Periconceptional folic acid supplementation and sex difference in prevention of neural tube defects and their subtypes in China: results from a large prospective cohort study

BACKGROUND

Folic acid (FA) supplementation is known to prevent neural tube defects (NTDs). We examined whether this preventive effect differs by the sex of the infant.

METHODS

Data were gathered from a large population-based cohort study in China that evaluated the effects of FA supplementation on NTDs. All births at 20 complete gestational weeks, including live births, stillbirths, and pregnancy terminations, and all NTDs, regardless of gestational age, were recorded. In a northern China province, a total of 30,801 singleton live births to women whose use of FA supplements during the first trimester was known at the time were included in the study. The birth prevalence of NTDs was classified by sex, subtype, and maternal FA supplementation. Male to female rate ratios [RR] and their 95% confidence intervals [CI] were calculated.

RESULTS

A total of 106 NTDs cases were recorded. The overall prevalence of NTDs was 2.5‰ among males and 4.4‰ among females; NTDs were less prevalent among males than among females (RR, 0.58; 95% CI, 0.54-0.63). There was a higher prevalence of anencephaly (RR, 0.34; 95% CI, 0.27-0.43) and spina bifida (RR, 0.73; 95% CI, 0.63-0.84) among females. However, FA supplementation led to significantly greater decreases in the rates of anencephaly (4.8‰) and total NTDs (7.6‰) in females than in males (1.6‰ and 2.8‰, respectively).

CONCLUSIONS

FA supplementation successfully reduces the prevalence of NTDs in both male and female infants, although we found a significantly greater decrease in anencephaly and total NTDs in females than in males. How the protective effects of FA supplementation affect the sexes differently needs to be studied further.

Sex differences in the prevalence of neural tube defects and preventive effects of folic acid (FA) supplementation among five counties in northern China: results from a population-based birth defect surveillance programme

OBJECTIVES

Sex differences in prevalence of neural tube defects (NTDs) have previously been recognised; however, the different susceptibility of men and women have not been examined in relation to the effects of folic acid (FA) supplementation. We hypothesised that FA may have a disproportionate effect that alters the sex-specific prevalence of NTDs.

SETTING

Data from two time points, before (2003-2004) and after (2011-2016) the start of the supplementation programme, were obtained from a population-based birth defect surveillance programme among five counties in northern China. All live births (28 or more complete gestational weeks), all stillbirths of at least 20 weeks' gestational age and pregnancy terminations at any gestational age following the prenatal diagnosis of NTDs were included.

PARTICIPANTS

A total of 25 249 and 83 996 births before and after the programme were included respectively.

PRIMARY AND SECONDARY OUTCOME MEASURES

The prevalence of NTDs by sex and subtype, Male:female rate ratios and their 95% CI were calculated.

RESULTS

Overall, NTDs were less prevalent among men than among women (rate ratio (RR) 0.92; 95% CI 0.90 to 0.94), so was anencephaly (RR 0.77; 95% CI 0.73 to 0.81) and encephalocele (RR 0.75; 95% CI 0.61 to 0.92), while spina bifida showed a male predominance (RR 1.10; 95% CI 1.05 to 1.15). The overall prevalence of NTDs decreased by 78/10 000 in men and 108.7/10 000 in women from 2003 to 2004 to 2011 to 2016. There was a significant sex difference in the magnitude of reduction, being greater in women than men, particularly for anencephaly.

CONCLUSIONS

The prevalence of NTDs decreased in both sexes after the implementation of a massive FA supplementation programme. While female predominance was observed in open NTDs and total NTDs, they also had a greater rate of decrease in NTDs after the supplementation programme.

High risk for neural tube defects; the role of arsenic in drinking water and rice in Asia

BACKGROUND

Neural tube defects (NTDs) affect >300,000 children annually worldwide. The incidence of NTDs in Northern India (7.7/1000), is tenfold higher than in the US (0.7/1000). Higher rates were previously reported in Northern China. The causes of these trends have not been elucidated. Arsenic is a teratogen shown in animals to induce NTDs. The main potential sources for environmental arsenic exposure, groundwater and rice as a staple food, are high in India and China.

OBJECTIVES

To discuss the possible association between high environmental arsenic exposure through drinking water and rice with the high NTDs rates in these regions.

DISCUSSION

Arsenic contamination of groundwater is the main source of environmental arsenic exposure. The locations of toxic arsenic regions in China and India correspond in most cases to the northern regions where the NTDs rates were high. Rice, the staple food in India and China, can absorb up to 10 times more arsenic than other crops, such as wheat and might further increase arsenic exposure.

CONCLUSIONS

We hypothesize that this NTD-arsenic in drinking water and rice association may explain why these areas in the northern regions of both countries have the highest incidence of NTDs. If proven true, this has major public health implications.

Prevalence and trend of isolated and complicated congenital hydrocephalus and preventive effect of folic acid in northern China, 2005-2015

Congenital hydrocephalus (CH) was a major birth defect of the central nervous system besides neural tube defects (NTDs). Few studies have focused on both the prevalence and trend of isolated and complicated CH in China. Data were drawn from a population-based birth defects surveillance program in five rural counties in northern China from 2005 to 2015. All livebirths and pregnancy terminations at any gestational age affected with CH were recorded. The prevalence and trend of isolated and complicated CH were examined. During the 11-year period, a total of 176,223 births and 357 CH cases were recorded, resulting in a prevalence rate of 20.3 CH cases per 10,000 births. Of the CH cases, 146 were isolated CH, resulting in a prevalence rate of 8.3 per 10,000 births. The pre-perinatal prevalence (<28 gestational weeks) was higher than the perinatal prevalence for both isolated and total CH. The prevalence rates of total and isolated CH showed a similar downward trend during the 11-year period. This downward trend was statistically significant after 2009 (p < 0.05), when a massive folic acid supplementation program was introduced. Although it decreased over time, the prevalence of CH remains high in this population which has a high prevalence of neural tube defects.

Trends in the prevalence of congenital hydrocephalus in 14 cities in Liaoning province, China from 2006 to 2015 in a population-based birth defect registry from the Liaoning Women and Children's Health Hospital

The aim of this study was to assess the prevalence and trends of congenital hydrocephalus (CH) using a large population-based sample with cases retrieved from the Liaoning Birth Defects Registry, which included 14 cities, over a 10-year period. CH prevalence, percent change, average change, and contribution rates of each city were calculated. Statistical analysis was performed using a Poisson regression model. There was a total of 3008 CH cases among 3,248,954 live births during the observational period (9.26 cases/10,000 live births). On average, the prevalence of CH had significantly decreased by 11.84% each year (P < 0.01). The three leading cities with the highest prevalence of CH were Chaoyang (13.73/10,000), Huludao (13.18/10,000), and Fuxin (12.71/10,000), while Yingkou (6.06/10,000), Dalian (6.27/10,000), and Anshan (6.56/10,000) had the lowest prevalence. Notably, significantly decreasing trends were observed in 10 (71.4%) of these 14 cities. In addition, the cities of Fushun, Shenyang, and Dalian had contributed to more than one-third of the decreasing trend in Liaoning province. In conclusion, this study provides evidence of the decreasing prevalence of CH over a 10-year period (2006–2015) in Liaoning province. Preventative efforts should be strengthened to further reduce the risk of CH in these high prevalence areas.

A unique methylation pattern co-segregates with neural tube defect statuses in Han Chinese pedigrees

Neural tube defects (NTDs) are a complex trait associated with gene-environment interactions. Folic acid deficiency and planar cell polarity gene mutations account for some NTD cases; however, the etiology of NTDs is still little understood. In this study, in three Han Chinese NTD pedigrees (two with multiple affected children), with no information on folic acid deficiency or supplement, we examined genome-wide methylation profiles of each individual in these families. We further compared methylation status among cases and normal individuals within the pedigrees. A unique methylation pattern co-segregated with affected status: NTD cases had more hypermethylated than hypomethylated CpG islands; genes with different methylations clustered in pathways associated with epithelial-to-mesenchymal transition (ZEB2, SMAD6, and CDH23), folic acid/homocysteine metabolism (MTHFD1L), transcription/nuclear factors (HDAC4, HOXB7, SOX18), cell migration/motility/adhesion, insulin and cell growth, and neuron/axon development. Although the genetics of NTD are likely complex, epigenetic changes may concentrate in certain key pathways.

A parental perspective concerning barriers to care for neural tube defects in China

Background:

The People's Republic of China (PRC) has the highest incidence of neural tube defects (NTDs) in the world. NTDs remain a significant contributor to the global burden of disease amendable to surgical care; however, no studies to date have evaluated the patients’ perspective regarding perceived barriers to care.

Methods:

The study was conducted at the Shanghai Children's Medical Center (SCMC) between 6/11/2014 and 7/17/2014. Surveys were administered to families presenting to the clinic of the SCMC director for Pediatric Neurosurgery. Additionally, orphaned patients under the care of the Baobei Foundation were surveyed for comparison. Participants were allowed to mark as many barriers on the survey as they deemed relevant to their experience.

Results:

A total of 69 patients were surveyed. The most frequently chosen barrier to care, with a P value < 10^-5, was that the referring physician did not know enough about the child's condition. As compared to the Baobei Foundation orphans, surveyed patients presented at an older age for initial treatment (7 months versus 1 month, P value = 0.001), and visited more hospitals before reaching SCMC (3.14 versus 1.0, P value < 10^-5).

Conclusions:

The results of this study highlight the referring physician as a primary barrier to care. The younger age at time of treatment for Baobei orphans born with NTDs supports this finding, as they essentially bypassed the referral process. An elaboration on reasons for this real or perceived barrier may provide insight into a means for expedited diagnosis and treatment of NTDs within the PRC.

The recurrence risk of neural tube defects (NTDs) in a population with high prevalence of NTDs in northern China

Background

Although a number of studies have reported the recurrence risk of NTDs in developed countries, there is little data on the rate of recurrence of NTDs in northern China, a region of high prevalence of NTDs.

Methods

Based on the population-based birth defects surveillance system of five counties, we identified women who had an NTD affected pregnancy from 2004-2015 and a retrospective survey was conducted. The rate of recurrence of NTDs was calculated by the number of recurrent NTDs divided by the first NTDs. Maternal age, body mass index (BMI), gestational weeks, education, and occupation were collected. Information on folic acid (FA) supplements, time and dosage were also recorded.

Results

Among 851 women who had a previous NTD-affected pregnancy, there were 578 subsequent pregnancies, with 10 recurrent NTDs, a 1.7% recurrence rate. The recurrence rate was 1.5% and 2.6% for those taking FA supplements and without FA supplementation respectively. Women with recurrent NTDs had higher BMI before pregnancy compared to those who had a second pregnancy without NTDs. Among the recurrent NTDs, the majority were spina bifida.

Conclusions

The recurrence rate of NTDs was approximately five times higher than the overall prevalence in the same region of northern China. Risk of recurrence appeared lower among women who took FA supplements. These findings are consistent with the reduction in NTD frequency in the population since introduction of the nationwide FA supplement program. Data on recurrence rates in northern China will inform power calculations for future intervention studies.

Time trends in the prevalence and epidemiological characteristics of neural tube defects in Liaoning Province, China, 2006-2015: A population-based study

To evaluate the time trends in the prevalence of neural tube defects and all their subtypes as well as to identify the epidemiological characteristics of these malformations documented in the Liaoning Province of northeast China from 2006 to 2015. This was a population-based observational study using data from 3,248,954 live births as well as from 6217 cases of neural tube defects, 1,600 cases of anencephaly, 2,029 cases of spina bifida, 404 cases of encephalocele, and 3,008 cases of congenital hydrocephalus from 14 cities in Liaoning Province from 2006 to 2015. All analyses were conducted using SPSS software. During the observational period, the prevalence of neural tube defects, anencephaly, spina bifida, encephalocele, and congenital hydrocephalus was 19.1, 4.9, 6.2, 1.2, and 9.3 per 10,000 live births, respectively. Significantly decreasing trends were observed in the prevalence of all these malformations except for encephalocele. Notably, relatively higher prevalence rates were found in isolated compared with non-isolated malformations, with significant differences in selected characteristics (e.g., prognosis status, gestational age, and birth weight) between isolated and non-isolated cases of these malformations. The prevalence of neural tube defects showed a downward trend in Liaoning Province from 2006 to 2015. However, more attention should be focused on non-isolated cases in the future because of the severe clinical manifestations. Future prevention efforts should be strengthened to reduce the risk of these malformations, especially the non-isolated subtype, in areas with high prevalence.

Prevalence of Neural Tube Defects and the Impact of Prenatal Diagnosis in Three Districts of Beijing, China

BACKGROUND

The objectives of this study were to explore the prevalence of neural tube defects (NTDs) in three districts of Beijing, and to evaluate the impact of prenatal diagnosis on the prevalence.

METHODS

Data were collected between 2006 and 2012 from the Beijing Birth Defects Surveillance System. P₁₃ and P₂₈ represent the prevalence of NTDs diagnosed from 13 weeks and 28 weeks of gestation, respectively, to 7 days after delivery. Populations were classified as household (permanent) and non-household (non-permanent) because differences exist in access to health care, education, and income, among others.

RESULTS

The P₁₃ of NTDs was 11.7 per 10 000 births in the three districts, which declined from 2006-12. In addition, the prevalence of NTDs in the non-household population was 1.7-fold higher than that among the household population. The P₁₃ of anencephaly, spina bifida, and encephalocele were 5.3, 4.9, 1.6, respectively, per 10 000 births. The P₂₈ of NTDs only represented 29.1% of P₁₃ , and this proportion decreased over the 7-year period.

CONCLUSIONS

The prevalence of NTDs remains high in the three districts of Beijing, and the rate was higher in the non-household than household population. The prevalence of birth defects would be under estimated by almost 70 per cent if the report time was set on 28 weeks' gestation or later compared with report time on 13 weeks of gestation. It is better to set the report time earlier in birth defect surveillance in contemporary China.

Changing trends in the prevalence of anencephaly in Liaoning province of Northeast China from 2006-2015: data from a population-based birth defects registry

The goal of this study was to assess the prevalence and trends of anencephaly on the basis of a large population-based cases identified by the Liaoning Birth Defects Registry, which included 14 cities over a 10-year period. Anencephaly prevalence, percent change, average changeand the contribution rates of each city were calculated. Statistical analysis was undertaken on the basis of a Poisson regression model. A total of 1600 anencephaly cases were collected during the observational period (4.92/10,000 live births). On average, the prevalence decreased 10.15% each year; this overall time trend was statistically significant (P<0.01). The top three leading cities were Huludao (10.33 per 10,000 live births), Chaoyang (8.56 per 10,000 live births) and Fuxin (6.36 per 10,000 live births). In contrast, Anshan (2.64 per 10,000 live births), Dalian (2.79 per 10,000 live births) and Yingkou (3.46 per 10,000 live births) were the cities with the lowest prevalence. Of note, significantly decreasing trends were observed in half of these cities (n=7). Additionally, Benxi, Yingkou and Dalian were the major cities contributing to over one third of the decreasing trend in Liaoning province. In conclusion, this study provided evidence of the decreasing prevalence of anencephaly from 2006 to 2015 in Liaoning province. In the future, prevention efforts should be strengthened to further reduce the risk of anencephaly in areas with high rates.

Prevalence and time trends of spina bifida in fourteen cities located in the Liaoning province of northeast China, 2006-2015

The present study sought to assess the time trends of spina bifida on the basis of cases identified by the Liaoning Birth Defects Registry in 14 cities from 2006 to 2015. We calculated the prevalence of spina bifida, percent and average change of time trends, and contribution rates of each city. Poisson regression model was used to find the line of best fit for spina bifida prevalence by year, with year as a continuous independent variable. From 2006 to 2015, a total of 2,029 spina bifida cases were identified from 3,248,954 live births (6.25/10,000 live births). We observed statistically significant decreasing trend of overall time trend (11.57% each year). Chaoyang, Fuxin, and Huludao were the top three leading cities, with 14.30/10,000 live births, 9.70/10,000 live births, and 9.20/10,000 live births, respectively. Inversely, the bottom three cities with lowest prevalence were Anshan (2.64/10,000 live births), Dandong (3.43/10,000 live births), and Dalian (3.45/10,000 live births). Of note, we observed significant decreasing trends in over half of these cities (n = 8). In addition, the decreasing trend of overall time trend could be mainly attributed to cities of Shenyang, Fushun, and Jinzhou which accounted for nearly one third. In summary, our study suggested a decreasing time trend of spina bifida during the past decade in the Liaoning province. The findings of this study provide evidence that the nationwide folic acid supplement program has been an effective strategy to prevent spina bifida.

Nutrition, One-Carbon Metabolism and Neural Tube Defects: A Review

Neural tube defects (NTDs) are a group of severe congenital malformations, induced by the combined effects of genes and the environment. The most valuable finding so far has been the protective effect of folic acid supplementation against NTDs. However, many women do not take folic acid supplements until they are pregnant, which is too late to prevent NTDs effectively. Long-term intake of folic acid–fortified food is a good choice to solve this problem, and mandatory folic acid fortification should be further promoted, especially in Europe, Asia and Africa. Vitamin B2, vitamin B-6, vitamin B-12, choline, betaine and n-3 polyunsaturated fatty acids (PUFAs) can also reduce the NTD risk by interacting with the one-carbon metabolism pathway. This suggest that multivitamin B combined with choline, betaine and n-3 PUFAs supplementation may have a better protective effect against NTDs than folic acid alone. Genetic polymorphisms involved in one-carbon metabolism are associated with NTD risk, and gene screening for women of childbearing age prior to pregnancy may help prevent NTDs induced by the risk allele. In addition, the consumption of alcohol, tea and coffee, and low intakes of fruit and vegetable are also associated with the increased risk of NTDs, and should be avoided by women of childbearing age.

Association between folate status and cervical intraepithelial neoplasia

Background/Objectives:

To investigate the effect of folate status on cervical intraepithelial neoplasia (CIN) progression and its relationship with high-risk human papillomavirus (hrHPV).

Subjects/Methods:

We evaluated 20 000 sexually active women aged <65 years in Yangqu County by using a questionnaire; the subjects were also screened using the ThinPrep cytologic test (TCT). Patients with abnormal TCT results (other than glandular cell abnormalities) who were willing to provide informed consent were further diagnosed using colposcopy and histopathological examination. We investigated 247 cases of low-grade cervical squamous intraepithelial lesions (LSIL), 125 cases of high-grade cervical squamous intraepithelial lesions (HSIL) and 877 controls. A 24-item food frequency questionnaire was filled out by the investigator to estimate the consumption of dietary folate. Positivity for hrHPV from residual exfoliated cervical cells was tested; serum folate was also measured.

Results:

The hrHPV infection rate in HSIL patients (77.6%) was higher than that in LSIL (33.2%) and control (32.0%) patients. Dietary folate intakes in controls, LSIL and HSIL were 306.9±176.6, 321.8±168.0 and 314.7±193.8 μg/kcal, respectively. The levels of serum folate in controls, LSIL and HSIL were 18.2±7.9, 15.9±7.1 and 14.3±7.5 nmol/l, respectively. Increased CIN correlated with higher rates of hrHPV infection and lower levels of serum folate.

Conclusions:

Low levels of serum folate may increase the risk of CIN progression. Furthermore, potential synergy may exist between low serum folate levels and hrHPV infection to promote CIN development.

Prevalence and trend of neural tube defects in five counties in Shanxi province of Northern China, 2000 to 2014

BACKGROUND

The prevalence of neural tube defects (NTDs) in northern China is among the highest in the world. A massive folic acid supplementation program as a specific countermeasure was introduced in 2009. Examining trends in NTD prevalence may provide evidence for future intervention.

METHODS

Data for 2000 to 2014 in five counties in northern China were obtained through a population-based birth defects surveillance system. All live births, stillbirths of over 20 gestational weeks, and pregnancy terminations because of NTDs at any gestational age were recorded. The prevalence of NTDs by gestational weeks (< 28 vs. ≥ 28), by calendar year, and by subtype was presented.

RESULTS

From 2000 to 2014, a total of 234,225 births and 2027 cases of NTDs were recorded. The prevalence of total NTDs was extremely high during 2000 to 2004, but it began to decrease continuously thereafter, from a peak of 120.0/10,000 in 2004 to a low of 31.5/10,000 in 2014. A significant decrease (60%) was observed from 78.8/10,000 in 2009 to 31.5/10,000 in 2014, 5 years after the folic acid supplementation program was introduced. All three major subtypes, namely anencephaly, spina bifida, and encephalocele, showed a decline over this period. Although the perinatal (≥ 28 gestational weeks) prevalence of NTDs decreased progressively, the pre-perinatal (< 28 gestational weeks) prevalence of NTDs remained high until 2011 and then decreased.

CONCLUSION

The prevalence of NTDs remains high despite a substantial and continuous decrease over the past 15 years. To further reduce NTD risk in the population, fortification staples with folic acid should be considered.