Self-reported maternal cigarette smoke exposure during the periconceptional period and the risk for omphalocoele

Frequency of gastroschisis and omphalocele and possible influence of maternal folic acid supplementation. A narrative review

There is an increase in the worldwide prevalence of congenital abdominal wall defects (CAWD), with gastroschisis (GS) and omphalocele (OC) being the most common. It is widely accepted that folic acid supplementation (FAS) in the maternal diet decreases the incidence of anomalies such as neural tube defects, but there is controversy regarding the possible beneficial role for other congenital malformations. Several epidemiological studies raise controversy regarding a possible relationship between vitamin supplementation with the occurrence of abdominal wall malformations. The aim of the present study is to obtain an updated review of the global frequency of CAWD in neonates and the relationship with FAS in the mothers. For this we have carried out a systematic search of epidemiological studies in different article databases between 2011 and 2022. The analysis of 25 studies conducted in different countries where cases of OC and/or GS are registered directly or together with other congenital defects shows that 60% inquire into the relationship of FAS with the incidence of CAWD. Half of them proposes a beneficial effect of FAS and the other half find no association, concluding that there is no unanimous evidence that FAS in the maternal diet decreases the incidence of CAWD. However, it seems that an influential factor to take into account is the nutritional habits of the mothers.

Associations between maternal periconceptional alcohol consumption and risk of omphalocele among offspring, National Birth Defects Prevention Study, 1997-2011

OBJECTIVE

Previous studies of alcohol consumption during pregnancy and omphalocele have produced mixed results. We updated an earlier analysis of National Birth Defects Prevention Study (NBDPS) data, adding six years of participants, to examine associations between maternal alcohol consumption and omphalocele.

METHODS

NBDPS was a multi-site, population-based case-control study in the United States. Cases were identified from birth defect surveillance programs in 10 states; controls were liveborn infants without a birth defect randomly selected from the same catchment areas. Mothers self-reported alcohol consumption during the periconceptional period (one month before through the third gestational month) via telephone interview. Our study included mothers of 410 omphalocele cases and 11,219 controls with estimated dates of delivery (EDDs) during 1997-2011. We used logistic regression to estimate adjusted odds ratios (AORs) and 95% confidence intervals (CIs) for periconceptional alcohol consumption and omphalocele. We performed a probabilistic bias analysis to evaluate the impact of alcohol exposure misclassification on our results.

RESULTS

Overall, 44% of case and 38% of control mothers reported periconceptional alcohol consumption; 22% and 17%, respectively, reported binge drinking. Any maternal periconceptional alcohol consumption was associated with modestly increased odds of omphalocele (AOR 1.35, 95% CI 1.09, 1.68), as was binge drinking (AOR 1.47, 95% CI 1.08, 2.01). Our bias analysis yielded estimates further from the null.

CONCLUSIONS

We observed modest associations between maternal periconceptional alcohol consumption and omphalocele. Based on our bias analysis, studies of alcohol and birth defects not accounting for exposure misclassification may underestimate associations.

Extended spectrum penicillins reduce the risk of omphalocele: A population-based case-control study

BACKGROUND

Omphalocele is a major congenital anomaly associated with significant morbidity and mortality. Regardless, the influence of maternal use of prescription drugs on the risk of omphalocele has only been addressed in a handful of studies. The aim of this study was to assess the influence of maternal risk factors and prescription drugs in early pregnancy on the risk of omphalocele.

METHODS

We performed a nationwide register-based case-control study in Finland. The analysis is based on the Finnish Register of Congenital Malformations and Drugs and Pregnancy databases, both upheld by the Finnish Institute for Health and Welfare. All omphalocele cases were identified between Jan 1, 2004, and Dec 31, 2014. Five age-matched controls from the same geographical region were randomly selected for each case. The main outcome measures were maternal risk factors for omphalocele. Our analysis compared the maternal characteristics and the use of prescription drugs during the first trimester of pregnancy between case and control mothers.

RESULTS

Mothers of 359 omphalocele cases were compared with 1738 randomly selected age and area-matched mothers of healthy infants between 1 January 2014 and 31 December 2014. Both maternal obesity (BMI ≥30) and diabetes increased the risk for omphalocele, and their co-occurrence accumulated this risk (aOR 5.06, 95% Cl 1.19-21.4). Similarly, history of multiple miscarriages was an independent risk factor (2.51, 1.16-5.43). The oral use of extended spectrum penicillins during the first trimester of pregnancy had a significant, protective influence (0.17, 0.04-0.71). These analyses were adjusted for sex, parity, and risk factors reported above. No significant changes in risk were observed with any other medication used during the first trimester.

CONCLUSION

In conclusion, these findings may suggest that extended spectrum penicillins in the first trimester reduces the risk of omphalocle formation. Additionally, consistent with earlier studies, previous repeated miscarriages, maternal obesity, and diabetes were significant risk factors for omphalocele.

Quantification of selection bias in studies of risk factors for birth defects among livebirths

BACKGROUND

Risk factors for birth defects are frequently investigated using data limited to liveborn infants. By conditioning on survival, results of such studies may be distorted by selection bias, also described as "livebirth bias." However, the implications of livebirth bias on risk estimation remain poorly understood.

OBJECTIVES

We sought to quantify livebirth bias and to investigate the conditions under which it arose.

METHODS

We used data on 3994 birth defects cases and 11 829 controls enrolled in the National Birth Defects Prevention Study to compare odds ratio (OR) estimates of the relationship between three established risk factors (antiepileptic drug use, smoking, and multifetal pregnancy) and four birth defects (anencephaly, spina bifida, omphalocele, and cleft palate) when restricted to livebirths as compared to among livebirths, stillbirths, and elective terminations. Exposures and birth defects represented varying strengths of association with livebirth; all controls were liveborn. We performed a quantitative bias analysis to evaluate the sensitivity of our results to excluding terminated and stillborn controls.

RESULTS

Cases ranged from 33% liveborn (anencephaly) to 99% (cleft palate). Smoking and multifetal pregnancy were associated with livebirth among anencephaly (crude OR [cOR] 0.61 and cOR 3.15, respectively) and omphalocele cases (cOR 2.22 and cOR 5.22, respectively). For analyses of the association between exposures and birth defects, restricting to livebirths produced negligible differences in estimates except for anencephaly and multifetal pregnancy, which was twofold higher among livebirths (adjusted OR [aOR] 4.93) as among all pregnancy outcomes (aOR 2.44). Within tested scenarios, bias analyses suggested that results were not sensitive to the restriction to liveborn controls.

CONCLUSIONS

Selection bias was generally limited except for high mortality defects in the context of exposures strongly associated with livebirth. Findings indicate that substantial livebirth bias is unlikely to affect studies of risk factors for most birth defects.

A multi-country study of prevalence and early childhood mortality among children with omphalocele

BACKGROUND

Omphalocele is the second most common abdominal birth defect and often occurs with other structural and genetic defects. The objective of this study was to determine omphalocele prevalence, time trends, and mortality during early childhood, by geographical region, and the presence of associated anomalies.

METHODS

We conducted a retrospective study with 23 birth defect surveillance systems in 18 countries who are members of the International Clearinghouse for Birth Defects Surveillance and Research that submitted data on cases ascertained from 2000 through 2012, approximately 16 million pregnancies were surveyed that resulted in live births, stillbirths, or elective terminations of pregnancy for fetal anomalies (ETOPFA) and cases with omphalocele were included. Overall prevalence and mortality rates for specific ages were calculated (day of birth, neonatal, infant, and early childhood). We used Kaplan-Meier estimates with 95% confidence intervals (CI) to calculate cumulative mortality and joinpoint regression for time trend analyses.

RESULTS

The prevalence of omphalocele was 2.6 per 10,000 births (95% CI: 2.5, 2.7) and showed no temporal change from 2000-2012 (average annual percent change = -0.19%, p = .52). The overall mortality rate was 32.1% (95% CI: 30.2, 34.0). Most deaths occurred during the neonatal period and among children with multiple anomalies or syndromic omphalocele. Prevalence and mortality varied by registry type (e.g., hospital- vs. population-based) and inclusion or exclusion of ETOPFA.

CONCLUSIONS

The prevalence of omphalocele showed no temporal change from 2000-2012. Approximately one-third of children with omphalocele did not survive early childhood with most deaths occurring in the neonatal period.

Prevalence rates study of selected isolated non-Mendelian congenital anomalies in the Hutterite population of Alberta, 1980-2016

A study of the prevalence rates for selected isolated non-Mendelian congenital anomalies in the Hutterite Brethren of Alberta, Canada was undertaken to further examine longitudinal data in this isolated community that was last reported in 1985 (Lowry et al., 1985), although there are numerous publications on recessive disorders (Boycott et al., 2008; Triggs-Raine et al., 2016). Cases were ascertained from the Alberta Congenital Anomaly Surveillance System for the years 1997-2016. Since our initial results showed some surprising findings in the Hutterite Brethren, such as zero cases of spina bifida, cleft lip and palate, gastroschisis, and omphalocele, and a significant excess of cases with hypospadias, we extended the study to prior years (1980-1996) for selected anomalies. For the extended study period (1980-2016), there was a significant increased prevalence of hypospadias, tetralogy of Fallot and tricuspid atresia in the Hutterite population, and although not statistically significant, zero cases of cleft lip with cleft palate, gastroschisis and omphalocele were confirmed. Further research is needed to determine the precise effects of rural environmental exposures, lifestyle factors, and genetic associations for selected multifactorial congenital anomalies.

Potential risk factors for Ebstein anomaly, National Birth Defects Prevention Study, 1997-2011

BACKGROUND

Ebstein anomaly is a rare congenital heart defect (CHD) that, when severe, requires corrective surgery or other catheter-based intervention in the first year of life. Due to its rarity, risk factors for Ebstein anomaly remain largely unknown. Using national data, we examined 18 potential risk factors for Ebstein anomaly.

METHODS

Using 1997-2011 data from the National Birth Defects Prevention Study, a population-based case-control study, we calculated crude and adjusted odds ratios and 95% confidence intervals for paternal age, maternal socio-demographics, reproductive history, and modifiable risk factors, and infant characteristics reported by mothers of 135 Ebstein anomaly cases and 11,829 controls.

RESULTS

Mothers of Ebstein anomaly cases had 4.1 (95% confidence interval: 1.8, 9.5) times the odds of reporting a family history of CHD compared with mothers of controls. Ebstein anomaly was associated with maternal second-hand cigarette smoke exposure at home (odds ratio = 2.2 [95% confidence interval: 1.1, 4.4]), but not maternal cigarette smoking (odds ratio = 1.3 [95% confidence interval: 0.8, 2.1]). Odds were elevated, but the 95% confidence interval included 1.0, for maternal marijuana use (odds ratio = 1.8 [95% confidence interval: 0.9, 3.8]) and paternal age ≥40 years at delivery (odds ratio = 1.9 [95% confidence interval: 1.0, 3.5]).

CONCLUSIONS

Maternal exposure to second-hand cigarette smoke at home and a family history of CHD were associated with elevated odds of Ebstein anomaly. Genetic analyses could clarify the potential heritability of Ebstein anomaly.

Sequence variants identification at the KCNQ1OT1:TSS differentially Methylated region in isolated omphalocele cases

Background

Omphalocele is a congenital midline ventral body wall defect that can exist as isolated malformation or as part of a syndrome. It can be considered one of the major and most frequent clinical manifestation of Beckwith-Wiedemann Syndrome (BWS) in case of loss of methylation at KCNQ1OT1: Transcription Star Site-Differentially Methylated Region (TSS-DMR) or in presence of CDKN1C mutations. The isolated form of the omphalocele accounts approximately for about the 14% of the total cases and its molecular etiology has never been fully elucidated.

Methods

Given the tight relationship with BWS, we hypothesized that the isolated form of the omphalocele could belong to the heterogeneous spectrum of the BWS associated features, representing an endophenotype with a clear genetic connection. We therefore investigated genetic and epigenetic changes affecting BWS imprinted locus at 11p15.5 imprinted region, focusing in particular on the KCNQ1OT1:TSS DMR.

Results

We studied 21 cases of isolated omphalocele detected during pregnancy or at birth and identified the following rare maternally inherited variants: i) the non-coding variant G > A at nucleotide 687 (NR_002728.3) at KCNQ1OT1:TSS-DMR, which alters the methylation pattern of the imprinted allele, in one patient; ii) the deletion c.624-629delGGCCCC at exon 1 of CDKN1C, with unknown clinical significance, in two unrelated cases.

Conclusions

Taken together, these findings suggest that KCNQ1OT1:TSS-DMR could be a susceptibility locus for the isolated omphalocele.

Electronic supplementary material

The online version of this article (10.1186/s12881-017-0470-z) contains supplementary material, which is available to authorized users.

The role of micronutrients in the response to ambient air pollutants: Potential mechanisms and suggestions for research design

People living in regions of low socioeconomic status are thought to be prone to higher exposures to environmental pollutants, poor nutrition, and numerous preventable diseases and infections. Poverty correlates with pollution and malnutrition; however, limited studies examined their interrelationship. The well-studied, deleterious health effects attributed to environmental pollutants and poor nutrition may act in combination with produce more severe adverse health outcomes than any one factor alone. Deficiencies in specific nutrients render the body more susceptible to injury which may influence the pathways that serve as the mechanistic responses to ambient air pollutants. This review (1) explores specific micronutrients that are of global concern, (2) explains how these nutrients may impact the body's response to ambient air pollution, and (3) provides guidance on designing animal models of nutritional deficiency. It is likely that those individuals who reside in regions of high ambient air pollution are similarly malnourished. Therefore, it is important that research identifies specific nutrients of concern and their impact in identified regions of high ambient air pollution.

Associations between maternal periconceptional exposure to secondhand tobacco smoke and major birth defects

BACKGROUND

While associations between secondhand smoke and a few birth defects (namely, oral clefts and neural tube defects) have been noted in the scientific literature, to our knowledge, there is no single or comprehensive source of population-based information on its associations with a range of birth defects among nonsmoking mothers.

OBJECTIVE

We utilized data from the National Birth Defects Prevention Study, a large population-based multisite case-control study, to examine associations between maternal reports of periconceptional exposure to secondhand smoke in the household or workplace/school and major birth defects.

STUDY DESIGN

The multisite National Birth Defects Prevention Study is the largest case-control study of birth defects to date in the United States. We selected cases from birth defect groups having >100 total cases, as well as all nonmalformed controls (10,200), from delivery years 1997 through 2009; 44 birth defects were examined. After excluding cases and controls from multiple births and whose mothers reported active smoking or pregestational diabetes, we analyzed data on periconceptional secondhand smoke exposure-encompassing the period 1 month prior to conception through the first trimester. For the birth defect craniosynostosis, we additionally examined the effect of exposure in the second and third trimesters as well due to the potential sensitivity to teratogens for this defect throughout pregnancy. Covariates included in all final models of birth defects with ≥5 exposed mothers were study site, previous live births, time between estimated date of delivery and interview date, maternal age at estimated date of delivery, race/ethnicity, education, body mass index, nativity, household income divided by number of people supported by this income, periconceptional alcohol consumption, and folic acid supplementation. For each birth defect examined, we used logistic regression analyses to estimate both crude and adjusted odds ratios and 95% confidence intervals for both isolated and total case groups for various sources of exposure (household only; workplace/school only; household and workplace/school; household or workplace/school).

RESULTS

The prevalence of secondhand smoke exposure only across all sources ranged from 12.9-27.8% for cases and 14.5-15.8% for controls. The adjusted odds ratios for any vs no secondhand smoke exposure in the household or workplace/school and isolated birth defects were significantly elevated for neural tube defects (anencephaly: adjusted odds ratio, 1.66; 95% confidence interval, 1.22-2.25; and spina bifida: adjusted odds ratio, 1.49; 95% confidence interval, 1.20-1.86); orofacial clefts (cleft lip without cleft palate: adjusted odds ratio, 1.41; 95% confidence interval, 1.10-1.81; cleft lip with or without cleft palate: adjusted odds ratio, 1.24; 95% confidence interval, 1.05-1.46; cleft palate alone: adjusted odds ratio, 1.31; 95% confidence interval, 1.06-1.63); bilateral renal agenesis (adjusted odds ratio, 1.99; 95% confidence interval, 1.05-3.75); amniotic band syndrome-limb body wall complex (adjusted odds ratio, 1.66; 95% confidence interval, 1.10-2.51); and atrial septal defects, secundum (adjusted odds ratio, 1.37; 95% confidence interval, 1.09-1.72). There were no significant inverse associations observed.

CONCLUSION

Additional studies replicating the findings are needed to better understand the moderate positive associations observed between periconceptional secondhand smoke and several birth defects in this analysis. Increased odds ratios resulting from chance (eg, multiple comparisons) or recall bias cannot be ruled out.

A review of toxicity and mechanisms of individual and mixtures of heavy metals in the environment

The rational for the study was to review the literature on the toxicity and corresponding mechanisms associated with lead (Pb), mercury (Hg), cadmium (Cd), and arsenic (As), individually and as mixtures, in the environment. Heavy metals are ubiquitous and generally persist in the environment, enabling them to biomagnify in the food chain. Living systems most often interact with a cocktail of heavy metals in the environment. Heavy metal exposure to biological systems may lead to oxidation stress which may induce DNA damage, protein modification, lipid peroxidation, and others. In this review, the major mechanism associated with toxicities of individual metals was the generation of reactive oxygen species (ROS). Additionally, toxicities were expressed through depletion of glutathione and bonding to sulfhydryl groups of proteins. Interestingly, a metal like Pb becomes toxic to organisms through the depletion of antioxidants while Cd indirectly generates ROS by its ability to replace iron and copper. ROS generated through exposure to arsenic were associated with many modes of action, and heavy metal mixtures were found to have varied effects on organisms. Many models based on concentration addition (CA) and independent action (IA) have been introduced to help predict toxicities and mechanisms associated with metal mixtures. An integrated model which combines CA and IA was further proposed for evaluating toxicities of non-interactive mixtures. In cases where there are molecular interactions, the toxicogenomic approach was used to predict toxicities. The high-throughput toxicogenomics combines studies in genetics, genome-scale expression, cell and tissue expression, metabolite profiling, and bioinformatics.