Health outcomes of smoking during pregnancy and the postpartum period: an umbrella review.

BACKGROUND: Smoking during pregnancy (SDP) and the postpartum period has serious health outcomes for the mother and infant. Although some systematic reviews have shown the impact of maternal SDP on particular conditions, a systematic review examining the overall health outcomes has not been published. Hence, this paper aimed to conduct an umbrella review on this issue. METHODS: A systematic review of systematic reviews (umbrella review) was conducted according to a protocol submitted to PROSPERO ( CRD42018086350 ). CINAHL, EMBASE, MEDLINE, PsycINFO, Web of Science, CRD Database and HMIC databases were searched to include all studies published in English by 31 December 2017, except those focusing exclusively on low-income countries. Two researchers conducted the study selection and quality assessment independently. RESULTS: The review included 64 studies analysing the relationship between maternal SDP and 46 health conditions. The highest increase in risks was found for sudden infant death syndrome, asthma, stillbirth, low birth weight and obesity amongst infants. The impact of SDP was associated with the number of cigarettes consumed. According to the causal link analysis, five mother-related and ten infant-related conditions had a causal link with SDP. In addition, some studies reported protective impacts of SDP on pre-eclampsia, hyperemesis gravidarum and skin defects on infants. The review identified important gaps in the literature regarding the dose-response association, exposure window, postnatal smoking. CONCLUSIONS: The review shows that maternal SDP is not only associated with short-term health conditions (e.g. preterm birth, oral clefts) but also some which can have life-long detrimental impacts (e.g. obesity, intellectual impairment). IMPLICATIONS: This umbrella review provides a comprehensive analysis of the overall health impacts of SDP. The study findings indicate that while estimating health and cost outcomes of SDP, long-term health impacts should be considered as well as short-term effects since studies not including the long-term outcomes would underestimate the magnitude of the issue. Also, interventions for pregnant women who smoke should consider the impact of reducing smoking due to health benefits on mothers and infants, and not solely cessation.

Effect of Sustained Interventions from Infancy to Toddlerhood in Children with Cleft Lip and Palate for Preventing Early Childhood Caries.

The study aimed to evaluate the effectiveness of sustained interventions in children with cleft lip and palate (CLP) for preventing early childhood caries (ECC). This prospective, nonrandomized interventional cohort study was conducted in infants aged 0-12 months with congenital CLP. Interventions were given to parents/primary caregivers in the form of combined oral health-care measures (sterile wet gauze piece, finger brush, toothbrush, and toothpaste) by a motivational interviewing approach. Education of primary caregivers on oral hygiene was provided by audiovisual aids and demonstration. Reinforcement of the prescribed regimen was done through daily short message services in caregivers' preferred language and bimonthly telephone calls. Participants were followed up for 9-32 months from the time of recruitment, with a mean period of 18.3 ± 5.1 months. Rates of dental caries were represented as prevalence rates, incidence density, and transitional probability. The distribution of the International Caries Detection and Assessment System (ICDAS) scores on different tooth surfaces affected in the intervention group was compared descriptively with that of the age- and sex-matched historical control groups. On analysis of surface-wise distribution of the ICDAS scores in the intervention group (n = 1,919), 1.2% (n = 24) had noncavitated lesions (ICDAS codes 1 and 2), 0.88% (n = 17) had cavitated lesions (ICDAS codes 3-6), and 0.26% (n = 5) had both cavitated and noncavitated lesions (ICDAS codes 1-6). The incidence density of caries-affected children observed at the first and last follow-ups was 1.2 persons/100 person-months and 1.3 persons/100 person-months of observation, respectively. The incidence density of new caries-affected tooth surfaces at the first and last follow-ups was 0.163 surfaces/100 surface-months and 0.062 surfaces/100 surface-months, respectively. Maxillary first molars had the maximum transition from sound to the cavitated lesion (11.5%), followed by maxillary incisors from sound to noncavitated (7.5%) at the last follow-up. Based on the newly developed assessment criteria in our study, sustained interventions proved to be significantly effective in preventing ECC in children with CLP.

SMAD2 overexpression rescues the TGF-ß3 null mutant mice cleft palate by increased apoptosis.

During palatal development, medial edge epithelium (MEE) disappearance is one of the crucial steps in the process of fusion. The fate of these cells is still debated, and controversies remain. During secondary palate fusion, TGF-ß3 signaling mediated in the cell through the SMAD2 protein plays an important role and leads to the disappearance of the midline epithelial seam (MES) and the confluence of the palatal mesenchyme. In mice, TGF-ß3 knock-out is lethal and mice are born with a cleft in the secondary palate. This phenotype has been rescued by targeted overexpression of SMAD2 in the medial edge epithelium (MEE). The goal of this research was to understand the mechanism of palatal fusion in the rescue mice. METHODS: The heads of embryos with four different genotypes (wild-type, K14-SMAD2/TGF-ß3(-/-), K14-SMAD2/TGF-ß3(±), and TGF-ß3 null) were collected at embryonic day E14.5, genotyped, fixed and embedded in paraffin. Serial sections were studied for detection of apoptosis and epithelial mesenchymal transition using immunofluorescence. RESULTS: TGF-ß3 null mice developed a cleft in the secondary palate while both mice with K14-SMAD2 overexpression had fusion of the secondary palate. The MEE of both the rescue mice and K14-SMAD2 overexpression had a much higher ratio of apoptotic cells than wild-type mice. The increase in apoptosis was correlated with increased phospho-SMAD2 in the MEE. CONCLUSION: SMAD2 overexpression rescued the cleft in the secondary palate by increasing apoptosis in the medial edge epithelium.

Maternal Folic Acid Intake and Risk of Nonsyndromic Orofacial Clefts: A Hospital-Based Case-Control Study in Bangalore, India.

BACKGROUND: Orofacial clefts are the most common congenital anomaly worldwide. Cleft etiology appears to be multifactorial, with genetic and environmental components. Although periconceptional folic acid supplementation has been shown to be protective for neural tube defects, current evidence for its role in cleft prevention is mixed with few studies from low- and middle-income countries. AIM: To investigate the association between periconceptional folic acid intake and incidence of nonsyndromic orofacial clefts among infants in Bangalore, India. METHODS: A hospital-based case-control study (106 cases, 212 controls) utilizing a questionnaire to collect data on prenatal supplements, dietary folate, and potentially confounding factors. Multivariate logistic regression analysis was used to assess relationships between folic acid supplementation and all nonsyndromic clefts, and in separate analyses for cleft lip and/or palate (CL/P) and cleft palate (CP), adjusting for statistically significant variables. RESULTS: A statistically significant protective association was found for separate folic acid supplements (not combined with iron or multivitamins) taken in the periconceptional period and all clefts combined (adjusted odds ratio [OR]: 0.62, 95% confidence interval [CI], 0.45-0.86) and CL/P (adjusted OR: 0.57; 95% CI, 0.38-0.86). Higher levels of dietary folate were found to be associated with a reduced risk for all clefts (adjusted OR: 0.98, 95% CI, 0.96-0.99), CL/P (adjusted OR: 0.98, 95% CI, 0.96-0.99), and CP (adjusted OR: 0.96, 95% CI, 0.93-0.99). CONCLUSION: This study provides limited evidence for a protective association of periconceptional folic acid supplementation with nonsyndromic orofacial clefts. The low proportion of mothers taking folic acid supplements in the periconceptional period highlights the need for increased education and awareness regarding prenatal nutrition.

An overview of cleft lip and palate.

Cleft lip and palate are types of craniofacial birth defects that affect thousands of children worldwide each year. These conditions are sensitive topics of conversations, often affected by the stigma of physical birth deformities and cultural myths. This article reviews the pathophysiology of cleft lip and palate, and describes the traditional management of patients with oral-facial clefts, including the extensive supportive care and an interprofessional team or cleft team approach that extends beyond the surgical correction.

Maternal folic acid supplementation reduces the severity of cleft palate in Tgf-ß3 null mutant mice.

BACKGROUND: Cleft palate (CP) constitutes the most frequently seen orofacial cleft and is often associated with low folate status. Folate plays an essential role in the human body as a major coenzyme in one-carbon metabolism, including DNA synthesis, repair, and methylation. Whether the administration of isolated folic acid (FA) supplements prevents the CP caused by genetic mutations is unknown, as is its effect on the mechanisms leading to palate fusion. METHODS: FA was administered to females from two different strains of transforming growth factor ß3 heterozygous mice. Null mutant progeny of these mice exhibit CP in 100% of cases of varying severity. We measured cleft length, height of palatal shelf adhesion, and the number of proliferating mesenchymal cells. Immunohistochemistry was also carried for collagen IV, laminin, fibronectin, cytokeratin-17, and EGF. RESULTS: FA supplementation significantly reduced CP severity and improved palatal shelf adhesion in both strains both in vivo and in vitro. Medial edge epithelium proliferation increased, and its differentiation was normalized as indicated by the presence and disposition of collagen IV, laminin, fibronectin, and cytokeratin-17. CONCLUSIONS: A maternal FA supplementation reduces the CP appearance by improving the mechanisms leading to palatal shelf adhesion.

Patterns of Orofacial Clefting in New York City From 1983 to 2010: Trends by Racial Background, Birthplace, and Public Health Strategies.

OBJECTIVE: To determine the role of racial background, public health initiatives, and residence on the prevalence of orofacial clefts (OFCs) in New York City (NYC). DESIGN/METHODS: Retrospective review of OFC cases from the New York State Congenital Malformations Registry. PATIENTS/PARTICIPANTS: Patients born with an OFC and all live births to mothers residing in NYC between 1983 and 2010. MAIN OUTCOME MEASURES: Orofacial cleft birth prevalence by cleft type, race, and borough of maternal residence for each year and by time period around the implementation of public health interventions including folate supplementation. RESULTS: A total of 3557 cases were reviewed. The prevalence remained stable for cleft palate and cleft lip with or without cleft palate (CL ± P) in sequential time periods of the study. Among CL ± P cases, cleft lip prevalence decreased early in the study compared to increases in cleft lip and palate prevalence. For most years, the prevalence of OFCs was lower among African Americans than whites. A total of 12% to 26% of mothers in 4 of the NYC boroughs deliver outside of their borough of residence, choosing to give birth in Manhattan most often. No difference in OFC prevalence was shown in any of the 5 NYC boroughs. CONCLUSIONS: The period prevalence remained relatively stable during the time periods before and after the implementation of folate supplementation for OFCs in NYC. Prevalence of OFC subtypes was lower for most time periods during this study among African Americans compared to whites. Several factors may explain the choice of birthplace outside of the mother's borough of residence.

Effects of folic acid fortification on orofacial clefts prevalence: a meta-analysis.

OBJECTIVE: Orofacial clefts (OFC) are the most prevalent craniofacial birth defect. Folic acid (FA) supplementation has been demonstrated as an effective intervention to reduce risk of OFC occurrence. However, the effect of mandatory FA fortification of wheat and/or maize flour on OFC prevalence has shown controversial results among countries adopting this policy. Thus, we performed a meta-analysis to synthesize the available evidence evaluating the global impact of this mandatory policy on OFC occurrence. DESIGN: Literature search in conventional and grey medical/scientific databases showed fifteen studies considering OFC prevalence in pre- and post-fortification periods with FA. The effect of this policy was evaluated by computing relative risk (RR) and separating samples into total OFC, non-syndromic forms, cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO). RESULTS: We found a significant effect of FA fortification only on non-syndromic CL/P (RR=0·88; 95 % CI 0·81, 0·96), whereas neutral effects were detected for total OFC (syndromic plus non-syndromic) and CPO. CONCLUSIONS: Our results may reflect the different aetiology of syndromic OFC with respect to non-syndromic forms and the CL/P related to CPO. Although the number of non-syndromic CL/P samples was lower than that for total OFC, the absence of both between-study heterogeneity and publication bias leads us to conclude that FA fortification may have beneficial effects on non-syndromic CL/P.

Comparative Study of Folic Acid and α-Naphthoflavone on Reducing TCDD-Induced Cleft Palate in Fetal Mice.

OBJECTIVE: Tocompare the effect of folic acid (FA) and α-naphthoflavone on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced cleft palate in fetal mice. DESIGN: Pregnant mice were randomly divided into seven groups. The mice treated with corn oil were used as a negative control. The mice in the other six groups were given a single dose of 28 µg/kg TCDD on GD 10 by gavage. For FA treatment, TCDD-treated mice were also dosed with 5, 10, and 15 mg/kg FA on GD 10, while for α-naphthoflavone treatment, the mice received a single dose of 50 µg/kg or 5 mg/kg α-naphthoflavone on GD 10. MAIN OUTCOME MEASURES: Fetal mice palates were imaged using light and scanning electron microscopy on GD 13.5, GD 14.5, and GD 15.5, and cleft palate were recorded on GD 17.5. The expression of guanosine diphosphate dissociation inhibitor (GDI) in fetal mice palate on GD 15.5 was examined by immunohistochemistry. RESULTS: TCDD successfully induced cleft palate. Ten mg/ml FA and 5 mg/ml α-naphthoflavone significantly reduced TCDD-induced cleft palate. FA and α-naphthoflavone partly reduced TCDD-induced cleft palate but did not affect the expression of Rho GDI. CONCLUSIONS: FA and α-naphthoflavone may reduce the generation of reactive oxygen species, inhibit MEE apoptosis through anti-oxidation, and increase filopodia and MEE movement. This may result in restoration of the ultrastructure of the palatal surface to a normal state, leading to the fusion and formation of complete palate in TCDD-treated fetal mice.

Dose-Dependent Antiteratogenic Effects of Folic Acid on All-Trans Retinoic Acid-Induced Cleft Palate in Fetal Mice.

OBJECTIVE: Although numerous studies have confirmed that consumption of folic acid (FA) during early pregnancy reduces the risk of oral facial clefts in newborn infants, the optimal dose of FA for reducing this risk remains unknown. We evaluated various doses of FA for their ability to reduce the incidence of all-trans retinoic acid (ATRA)-induced cleft palate in mice. METHODS: Pregnant C57BL/6J mice were randomly assigned to eight groups dosed with corn oil (control group), ATRA (80 mg/kg), FA (40 mg/kg), or ATRA (80 mg/kg) + FA (2.5 mg, 5 mg, 10 mg, 20 mg, or 40 mg/kg body weight) on gestation day 11 (GD11), after which samples of maternal blood obtained on GD 11 were analyzed for serum folate levels. After receiving the doses, randomly selected mice in each dose group were sacrificed on GDs 13.5, 14.5, and 15.5, and the fetuses were removed for examination by light microscopy and scanning electron microscopy to detect the incidence of cleft palate. RESULTS: Among the pregnant mice dosed with ATRA+FA, those dosed with 5 mg/kg FA had fetuses with the lowest incidence of cleft palate. In addition, the eight groups of pregnant mice had significantly different serum folate concentrations (P < .001). CONCLUSION: When administered to pregnant mice at a specific dose and on the proper gestation day, FA showed an antiteratogenic effect by reducing the incidence of ATRA-induced cleft palate in fetal mice.

[Cleft lip/palate and flour fortification with folic acid in Chile]. / Fisuras labio-palatinas y fortificación de la harina con ácido fólico en Chile: An exploratory study.

BACKGROUND: The effect of food fortification with folic acid on the incidence of lip-palate fissures (FLP) is under discussion. AIM: To calculate the rate of hospital discharges due to cleft lip and palate (CLP) and explore whether they decreased after the start of folic acid fortification in Chile. MATERIAL AND METHODS: The hospital discharge databases published by the Chilean Ministry of Health were analyzed. The trends of discharge rates due to CLP of children of less than one year of life (ICD-10 Q350-379 code) and live births (lb) were calculated from 1986 to 2012. Variables such as incidence of rubella, poverty rate, obesity in pregnant women, and percentage of women who smoked or drank alcohol in the last month were included. The relative risk (RR) of CLP pre-fortification (1986-1999) and post-fortification (2000-2010) was calculated. Mixed and Prais-Winsten models were used to adjust other variables. RESULTS: The hospital discharge rate due to CLP decreased from 1.88 x 1,000 lb during 1986-1996 to 1.68 x 1,000 lb (RR = 1.09 (95% CI 1.05-1.14, p < 0.001). Prais-Winsten and Mixed models, determined that folic acid fortification is the variable explaining this decrease. During 2004-2011, hospital discharge rates for cleft lip decreased but there was an increase in the figures for cleft lip and palate. CONCLUSIONS: The 9% decrease in hospital discharge rates for CLP is concomitant with wheat folic acid fortification.

Folic acid supplements and risk for oral clefts in the newborn: a population-based study.

Results from previous studies on maternal folic acid intake and infant oral clefts are inconclusive. The aim of the present study was to investigate the association between women's use of folic acid and/or multivitamin supplements and the risk for oral cleft in the newborn. We used data from the Medical Birth Registry of Norway based on all births in Norway from 1999 to 2013. A total of 528 220 women had 880 568 pregnancies, resulting in 896 674 live births and stillbirths, of which 1623 had oral clefts (isolated oral clefts, n 1311; non-isolated oral clefts, n 312). Altogether, 21·5% of women were vitamin supplement users before pregnancy. The birth prevalence of oral clefts was 1·81/1000 live births and stillbirths. Relative risks (RR) were estimated with log-binomial regression. For pregnancies with maternal use of vitamins, the adjusted RR for clefts overall was 0·90 (95% CI 0·79, 1·04). The adjusted RR for cleft palate only (n 586) was 0·84 (95% CI 0·66, 1·06) and that for cleft lip with or without cleft palate (n 1037) was 0·94 (95% CI 0·79, 1·13). Associations were stronger for cleft cases that occurred in combination with other malformations (adjusted RR 0·63; 95% CI 0·45, 0·88), although vitamin supplements provided no protection against isolated clefts (adjusted RR 0·98; 95% CI 0·84, 1·15). In conclusion, our study demonstrates no statistically significant association between vitamin use and isolated oral clefts. However, we found lower risk for oral clefts that occurred in combination with other malformations.

The role of the folic acid to the prevention of orofacial cleft: an epidemiological study.

BACKGROUND: Orofacial clefts (OFCs) have complex and multifactorial etiologies. Periconceptional folic acid supplementation can significantly reduce the risk of OFC. OBJECTIVE: To evaluate the role of folate and other factors in preventing OFC by analyzing the health and socio-demographic data collected from a population sample. METHODS: Retrospective case-control study in which mothers with children with or without OFC were evaluated for the following main parameters: nutritional factors, socio-demographic characteristics, pregnancy and family history, use of folate, and counseling by healthcare professionals. RESULTS: Socio-epidemiological analysis of the 80 participants, 40 in the case group and 40 in the control group, found a significant impact on the risk of OFC related to economic and educational status. The mothers who had a diet rich in vegetables and white meat had a lower risk of having children with OFC. A short interval between pregnancies, subsequent pregnancy while still breastfeeding, and family history also increased risk of OFC. CONCLUSIONS: Limited family planning, diet low in folate, and inadequate use of folate during the periconceptional period and during the first trimester of pregnancy were demonstrated a potential correlation with a high incidence of OFC in this study.

A Case-control Study of Environmental Risk Factors for Nonsyndromic Cleft of the Lip and/or Palate in Xuzhou, China.

In this study, we sought to determine the association between environmental factors and nonsyndromic cleft of the lip and/or palate (NSCLP) to understand the etiology of the disease. A total of 200 NSCLP cases and 327 controls were recruited at the Maternal and Child Health Hospital of Xuzhou City. We conducted face-to-face interviews with the mothers of both cases and controls. The factors increasing the risk of NSCLP were a positive family history [odds ratio (OR)=56.74], pesticide exposure (OR=8.90), and indoor decoration pollution (OR=4.32). On the other hand, the factors decreasing the risk of NSCLP were a high education level (OR=0.22) and supplementation of folic acid (OR=0.23) and multivitamins (OR=0.16). Positive family history, pesticide exposure, and indoor decoration pollution are associated with the risk of NSCLP. In contrast, high education level and folic acid and multivitamin supplementation are protective factors against NSCLP.

[Structure and dynamics of congenital maxillofacial malformation in Yakutiya region].

The aim of the study was to assess structure and dynamics of congenital facial clefts prevalence in Republic Sokha (Yakutiya) in the last 13 years. Both retrospective and prospective study included 423 children with congenital facial malformations. Dynamic analysis showed cyclical changes in the incidence of cleft lip and palate (CLP) and relatively high regional prevalence of CLIP with tendency to increase. The age of parents of children with congenital facial malformations tend to decrease with time. The received epidemiological data prove the need to improve treatment and rehabilitation protocols for CLP patients in Republic Sokha (Yakutiya).

Prevention of orofacial clefts caused by smoking: implications of the Surgeon General's report.

BACKGROUND: According to the 2014 Surgeon General's Report, smoking in early pregnancy can cause orofacial clefts. We sought to examine the implications of this causal link for the potential prevention of orofacial clefts in the United States. METHODS: Using published data on the strength of the association between orofacial clefts and smoking in early pregnancy and the prevalence of smoking at the start of pregnancy, we estimated the attributable fraction for smoking as a cause of orofacial clefts. We then used the prevalence of orofacial clefts in the United States to estimate the number of orofacial clefts that could be prevented in the United States each year by eliminating exposure to smoking during early pregnancy. We also estimated the financial impact of preventing orofacial clefts caused by maternal smoking based on a published estimate of attributable healthcare costs through age 10 for orofacial clefts. RESULTS: The estimated attributable fraction of orofacial clefts caused by smoking in early pregnancy was 6.1% (95% uncertainty interval 4.4%, 7.7%). Complete elimination of smoking in early pregnancy could prevent orofacial clefts in approximately 430 infants per year in the United States, and could save an estimated $40.4 million in discounted healthcare costs through age 10 for each birth cohort. CONCLUSION: Understanding the magnitude of the preventable burden of orofacial clefts related to maternal smoking could help focus smoking cessation efforts on women who might become pregnant.

Intra-amniotic transient transduction of the periderm with a viral vector encoding TGFß3 prevents cleft palate in Tgfß3(-/-) mouse embryos.

Cleft palate is a developmental defect resulting from the failure of embryonic palatal shelves to fuse with each other at a critical time. Immediately before and during palatal fusion (E13-E15 in mice), transforming growth factor ß3 (TGFß3) is expressed in the palatal shelf medial edge epithelium (MEE) and plays a pivotal role in palatal fusion. Using Tgfß3(-/-) mice, which display complete penetrance of the cleft palate phenotype, we tested the hypothesis that intra-amniotic gene transfer could be used to prevent cleft palate formation by restoring palatal midline epithelial function. An adenoviral vector encoding Tgfß3 was microinjected into the amniotic sacs of mouse embryos at successive developmental stages. Transduced Tgfß3(-/-) fetuses showed efficient recovery of palatal fusion with mesenchymal confluence following injection at E12.5 (100%), E13.5 (100%), E14.5 (82%), and E15.5 (75%). Viral vectors injected into the amniotic sac transduced the most superficial and transient peridermal cell layer but not underlying basal epithelial cells. TGFß3 transduction of the peridermdal cell layer was sufficient to induce adhesion, fusion, and disappearance of the palatal shelf MEE in a cell nonautonomous manner. We propose that intra-amniotic gene transfer approaches have therapeutic potential to prevent cleft palate in utero, especially those resulting from palatal midline epithelial dysfunction.

Periconceptional nutrient intakes and risks of orofacial clefts in California.

BACKGROUND: Evidence indicates that maternal nutrient intake may play a role in the development of birth defects. We investigated the association of maternal periconceptional intake of vitamin supplements and dietary nutrients with risk of developing cleft palate (CP) and cleft lip with or without cleft palate (CLP). METHODS: Data were from a population-based, case-control study of fetuses and liveborn infants delivered in California in 1999-2003. Analyses included 170 cases with CP, 425 with CLP, and 534 nonmalformed controls. Dietary intake was estimated from a food frequency questionnaire. RESULTS: Vitamin supplement intake was associated with a modestly decreased risk of clefts, but the confidence intervals (CIs) include 1.0. Among women who did not use vitamin supplements, dietary intake of several micronutrients was associated with risk of clefts. We found at least a twofold elevated risk of CP with low intake of riboflavin, magnesium, calcium, vitamin B12, and zinc; all CIs excluded 1.0. For CLP, we found at least a twofold elevated risk with low intake of niacin, riboflavin, vitamin B12, and calcium, and a decreased risk with high intake of folate and cryptoxanthin; all CIs excluded 1.0. CONCLUSION: The results suggest that periconceptional nutrient intake may be associated with risk of CP and CLP.

Periconceptional folic acid associated with an increased risk of oral clefts relative to non-folate related malformations in the Northern Netherlands: a population based case-control study.

Periconceptional folic acid has been associated with a reduced risk of neural tube defects, but findings on its effect in oral clefts are largely inconclusive. This case-control study assesses the effects of periconceptional folic acid on cleft risk, using complementary data from the Dutch Oral Cleft Registry and a population-based birth defects registry (Eurocat) of children and foetuses born in the Northern Netherlands between 1997 and 2009. Cases were live-born infants with non-syndromic clefts (n = 367) and controls were infants or foetuses with chromosomal/syndromal (n = 924) or non-folate related anomalies (n = 2,021). We analyzed type/timing/duration of supplement use related to traditional cleft categories as well as to their timing (early/late embryonic periods) and underlying embryological processes (fusion/differentiation defects). Consistent supplement use during the aetiologically relevant period (weeks 0-12 postconception) was associated with an increased risk of clefts (adjusted odds ratio 1.72, 95% confidence interval 1.19-2.49), especially of cleft lip/alveolus (3.16, 1.69-5.91). Further analysis systematically showed twofold to threefold increased risks for late differentiation defects-mainly clefts of the lip/alveolus-with no significant associations for early/late fusion defects. Effects were attributable to folic acid and not to other multivitamin components, and inclusion of partial use (not covering the complete aetiologically relevant period) generally weakened associations. In conclusion, this study presents several lines of evidence indicating that periconceptional folic acid in the Northern Netherlands is associated with an increased risk of clefts, in particular of cleft lip/alveolus. This association is strengthened by the specificity, consistency, systematic pattern, and duration of exposure-response relationship of our findings, underlining the need to evaluate public health strategies regarding folic acid and to further investigate potential adverse effects.

Maternal dietary intake of nitrates, nitrites and nitrosamines and selected birth defects in offspring: a case-control study.

BACKGROUND: Dietary intake of nitrates, nitrites, and nitrosamines can increase the endogenous formation of N-nitroso compounds in the stomach. Results from animal studies suggest that these compounds might be teratogenic. We examined the relationship between maternal dietary intake of nitrates, nitrites (including plant and animal sources as separate groups), and nitrosamines and several types of birth defects in offspring. METHODS: For this population-based case-control study, data from a 58-question food frequency questionnaire, adapted from the short Willett Food Frequency Questionnaire and administered as part of the National Birth Defects Prevention Study (NBDPS), were used to estimate daily intake of dietary nitrates, nitrites, and nitrosamines in a sample of 6544 mothers of infants with neural tube defects (NTD)s, oral clefts (OC)s, or limb deficiencies (LD)s and 6807 mothers of unaffected control infants. Total daily intake of these compounds was divided into quartiles based on the control mother distributions. Odds ratios (OR)s and 95% confidence intervals (CI)s were estimated using logistic regression; estimates were adjusted for maternal daily caloric intake, maternal race-ethnicity, education, dietary folate intake, high fat diet (>30% of calories from fat), and state of residence. RESULTS: While some unadjusted ORs for NTDS had 95% (CI)s that excluded the null value, none remained significant after adjustment for covariates, and the effect sizes were small (adjusted odds ratios [aOR]<1.12). Similar results were found for OCs and LDs with the exception of animal nitrites and cleft lip with/without cleft palate (aORs and CIs for quartile 4 compared to quartile 1 =1.24; CI=1.05-1.48), animal nitrites and cleft lip (4th quartile aOR=1.32; CI=1.01-1.72), and total nitrite and intercalary LD (4th quartile aOR=4.70; CI=1.23-17.93). CONCLUSIONS: Overall, odds of NTDs, OCs or LDs did not appear to be significantly associated with estimated dietary intake of nitrate, nitrite, and nitrosamines.