The non-genetic paternal factors for congenital heart defects: A systematic review and meta-analysis

Birth defects among offspring of California firefighters, 2007-2019

PURPOSE

Limited research examines birth defects from maternal or paternal firefighting exposure. This study aims to assess if maternal or paternal occupational exposure to firefighting during periconception is associated with offspring birth defects.

METHODS

Data from California birth certificates (2007-2019) were linked to maternal / offspring hospitalization records. Occupation during the periconceptional period was categorized from vital statistics as the following: paternal non-firefighting (n = 4,135,849), paternal firefighting (n = 22,732), maternal non-firefighting (n = 3,332,255) and maternal firefighting (n = 502). Birth defects were identified using ICD codes, grouped by anatomical regions. Adjusted odds ratios were estimated, and sensitivity analyses explored police officer reference groups and detailed birth defect categories.

RESULTS

Offspring of paternal firefighters had lower odds of circulatory defects (aOR = 0.9, 95% CI 0.8, 1.0), oral clefts (aOR = 0.6, 95% CI 0.4, 0.8) and respiratory defects (0.7, 95% CI 0.6, 0.9) compared to paternal non-firefighters. Associations between maternal firefighting and offspring birth defects were imprecise. Substituting police officers as the reference group attenuated findings.

CONCLUSIONS

Offspring of paternal firefighters may have similar or slightly lower birth defect odds compared to offspring of non-firefighters. Limited data was available for assessing maternal firefighting outcomes. Future studies should prioritize studies using occupational exposure matrices to limit misclassification of exposure.

Serum Raman spectroscopy: Unearthing the snapshot of distinct metabolic profile in patients with congenital heart defects (CHDs)

In the present study, efficacy of minimally-invasive serum Raman spectroscopy (SRS) in stratification of congenital heart diseases was explored. Blood was collected from 62 subjects [42 congenital heart defect (CHD) patients (19 with atrial septal defect, 13 with ventricular septal defect and 10 with tetralogy of fallot) and 20 controls], and serum separated. Raman spectra of sera were recorded, pre-processed and subjected to spectral and multivariate analyses. Multivariate curve resolution-alternating least squares (MCR-ALS) analyses indicated alterations in lipid and protein levels between the study groups. Principal Component Analysis (PCA) and Principal Component based Linear Discriminant Analysis (PC-LDA), cross-validated with Leave-one-out cross validation (LOOCV), were employed to study stratification between the different groups. CHD could be classified from controls with 76 % efficiency. The different CHD subtypes could be distinguished with efficiencies as high as ∼90 %. To the best of our knowledge, differentiation between controls and CHDs as well as the stratification between controls and CHDs subtypes was for the first time successfully accomplished by serum-based Raman spectroscopy.

Interaction between ozone and paternal smoking on fetal congenital heart defects among pregnant women at high risk: a multicenter maternal-fetal medicine study

BACKGROUND

Evidence remains limited on the association between maternal ozone (O3) exposure and congenital heart defects (CHDs) in offspring, and few studies have investigated the interaction and modification of paternal smoking on this association.

METHODS

Using a sample including pregnant women at high risk of fetal CHD (with metabolic disease, first-trimester viral infection, family history of CHD, etc.) from a maternal-fetal medicine study covering 1313 referral hospitals in China during 2013-2021, we examined the associations between maternal O3 exposure during 3-8 weeks of gestational age and fetal CHD in offspring and investigated the interaction and modification of paternal smoking on this association. CHD was diagnosed by fetal echocardiograms, maximum daily 8-hour average O3 exposure data at a 10 km × 10 km spatial resolution came from the Tracking Air Pollution in China dataset, and paternal smoking was collected using questionnaires. Logistic regression models were used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Among 27,834 pregnant women at high risk of fetal CHD, 17.4% of fetuses were diagnosed with CHD. Each 10 μg/m3 increase in maternal O3 exposure was associated with a 17% increased risk of CHD in offspring (OR = 1.17, 95% CI = 1.14-1.20). Compared with paternal nonsmoking and maternal low O3 exposure, the ORs (95% CI) of CHD for smoking and low O3 exposure, nonsmoking and high O3 exposure, and smoking and high O3 exposure were 1.25 (1.08-1.45), 1.81 (1.56-2.08), and 2.23 (1.84-2.71), respectively. Paternal smoking cessation seemingly mitigated the increased risk of CHD.

CONCLUSIONS

Maternal O3 exposure and paternal smoking were interactively associated with an increased risk of fetal CHD in offspring, which calls for effective measures to decrease maternal exposure to O3 pollution and secondhand smoke for CHD prevention.

Paternal peri-conceptional physical activity and the risk of congenital heart disease in offspring: A case-control study

BACKGROUND

Genetic and environmental factors have been shown to contribute to the development of congenital heart disease (CHD). To date, the focus of scientific articles has primarily centered on genetics and maternal environmental factors, with comparatively less attention given to paternal risk factors.

OBJECTIVES

This study aims to investigate the potential association between paternal pre-conceptional physical activity levels (PA), along with paternal peri-conceptional smoking and alcohol consumption, and the risk of CHD in offspring.

MATERIALS AND METHODS

An observational case-control study was conducted in Lebanon, with 279 participants, aiming to investigate potential risk factors for CHD. We included children with confirmed CHD, born between 2012 and 2022. Controls born in the same timeframe were selected randomly from the general population using online questionnaire forms. Mean age of children included was 6 years old (0-10). The pre-conceptional PA was assessed using the Global Physical Activity Questionnaire validated in Arabic. In addition, paternal smoking, alcohol consumption, and maternal risk factors were collected.

RESULTS

The study included 128 CHD cases (45.9%) and their parents, as well as 151 healthy infants (54.1%) and their parents. There were no statistically significant variations in the alcohol consumption noted between the fathers in the case and control groups (p = 0.18). The paternal involvement in recreational-related PA during the peri-conception period was associated with a reduced risk of the CHD development in offspring by 46.9% (OR = 0.531, 95% CI: 0.301-0.936, p = 0.029). Additionally, increasing paternal total sitting time by 1 h above the average, which was approximately 260 min (4 h), increased the risk of CHD in offspring by 0.4% (p = 0.001). Moreover, paternal smoking exhibited an apparent association with a 56% increased risk of offspring developing CHD, notwithstanding that the confidence intervals included the null (OR = 1.56, 95% CI: 0.86-2.8, p = 0.136).

DISCUSSION AND CONCLUSION

This observational study is the first to report a potential association between paternal PA, and CHD in offspring. This study aligns with previous reports, advocating for the paternal engagement in PA and the adoption of healthy lifestyle habits, especially during the critical stages of conception. Such practices are strongly recommended to enhance fertility and promote optimal health for offspring. However, due to the subjectivity in reporting PA and lack of molecular proof, additional prospective and molecular studies are required to validate these findings.

Understanding the Genetic and Non-genetic Interconnections in the Aetiology of Isolated Congenital Heart Disease: An Updated Review: Part 1

PURPOSE OF REVIEW

Congenital heart disease (CHD) is the most frequently occurring birth defect. Majority of the earlier reviews focussed on the association of genetic factors with CHD. A few epidemiological studies provide convincing evidence for environmental factors in the causation of CHD. Although the multifactorial theory of gene-environment interaction is the prevailing explanation, explicit understanding of the biological mechanism(s) involved, remains obscure. Nonetheless, integration of all the information into one platform would enable us to better understand the collective risk implicated in CHD development.

RECENT FINDINGS

Great strides in novel genomic technologies namely, massive parallel sequencing, whole exome sequencing, multiomics studies supported by system-biology have greatly improved our understanding of the aetiology of CHD. Molecular genetic studies reveal that cardiac specific gene variants in transcription factors or signalling molecules, or structural proteins could cause CHD. Additionally, non-hereditary contributors such as exposure to teratogens, maternal nutrition, parental age and lifestyle factors also contribute to induce CHD. Moreover, DNA methylation and non-coding RNA are also correlated with CHD. Here, we inform that a complex combination of genetic, environmental and epigenetic factors interact to interfere with morphogenetic processes of cardiac development leading to CHD. It is important, not only to identify individual genetic and non-inherited risk factors but also to recognize which factors interact mutually, causing cardiac defects.

Functions of cilia in cardiac development and disease

Errors in embryonic cardiac development are a leading cause of congenital heart defects (CHDs), including morphological abnormalities of the heart that are often detected after birth. In the past few decades, an emerging role for cilia in the pathogenesis of CHD has been identified, but this topic still largely remains an unexplored area. Mouse forward genetic screens and whole exome sequencing analysis of CHD patients have identified enrichment for de novo mutations in ciliary genes or non-ciliary genes, which regulate cilia-related pathways, linking cilia function to aberrant cardiac development. Key events in cardiac morphogenesis, including left-right asymmetric development of the heart, are dependent upon cilia function. Cilia dysfunction during left-right axis formation contributes to CHD as evidenced by the substantial proportion of heterotaxy patients displaying complex CHD. Cilia-transduced signaling also regulates later events during heart development such as cardiac valve formation, outflow tract septation, ventricle development, and atrioventricular septa formation. In this review, we summarize the role of motile and non-motile (primary cilia) in cardiac asymmetry establishment and later events during heart development.

Paternal age and risk for selected birth defects in a large South American sample

BACKGROUND

The relationship between maternal age (MA) and birth defects (BD) has been extensively studied while much less research, mostly with discordant results, has focused on the risk of paternal age (PA) for BD. Furthermore, no consensus has been reached on the best way to control the association of PA with MA.

OBJECTIVES

The aim of the study was to evaluate the risk of PA increase, at 1-year intervals, for selected BD, especially controlling for the confounding effect of MA.

METHODS

The sample comprised of 27,944 liveborns presenting 1 of 18 selected isolated BD. Conditional logistic regressions were applied to evaluate the risk of advanced PA and its yearly increase, adjusting by MA and other variables.

RESULTS

Of the 18 analyzed BD, only the risk for preaxial polydactyly (PreP) showed a significant association with increasing PA, while advanced MA was of low risk. For esophageal and anal atresia, associations with both PA and MA increases were observed.

CONCLUSIONS

Results support the hypothesis of advanced PA as a risk factor for PreP and helps clarify the so far unexplained nonrandom association between this defect and Down syndrome.

The association of preconception paternal metabolic syndrome on early childhood emergency department visits and hospitalizations

BACKGROUND

Increasing preconception paternal comorbidity has been associated with adverse pregnancy outcomes. However, whether the father's health impacts the child after birth is uncertain.

OBJECTIVES

In the present study, we examined the association of preconception paternal metabolic syndrome status with childhood emergency department visits and hospitalizations.

MATERIALS AND METHODS

This is a longitudinal cohort study of children (295,355 boys and 278,735 girls) born to linked pairs of fathers and mothers in the United States between 2009 and 2016 within the IBM MarketScan Research database. Associations between paternal and maternal metabolic syndrome component diagnoses and subsequent hospitalizations and emergency department visits for offspring within the first 2 years of life were determined.

RESULTS

Note that, 35.5% (203,617/574,090) of children had at least one emergency room visit and 6.1% (35,141/574,090) of children had an inpatient admission. After adjustment, the odds of inpatient admission and emergency department visits increased in a dose-dependent fashion among fathers with higher comorbidities. Similar trends were seen for emergency department visit utilization.

DISCUSSION AND CONCLUSION

Increasing paternal preconception comorbidity is associated with a higher risk that a child requires the emergency department and inpatient care in the first years of life. An opportunity exists to engage men in preconception counseling to optimize their and their offspring's health.

Paternal occupational exposures and infant congenital heart defects in the Japan Environment and Children's Study

BACKGROUND

Few prospective studies have investigated the association between paternal occupational exposures and risk of infant congenital heart defects (CHDs). We investigated the associations between paternal occupational exposures, frequency of use, and concurrent or sequential exposure to a mixture of compounds and the risk of infant CHDs.

METHODS

Our study examined 28,866 participants in the Japan Environment and Children's Study. Logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) associated with paternal occupational exposures during the 3 months until pregnancy was noticed after adjustment for potential confounding factors of the infant CHDs. CHD diagnosis was ascertained from medical record.

RESULTS

In total, 175 were diagnosed with infant CHDs. The number of fathers who were exposed to the following substances at least once a month were: 11,533 for photo copying machine/laser printer, 10,326 for permanent marker, 8,226 for soluble paint/inkjet printer, 6,188 for kerosene/petroleum/benzene/gasoline, 4,173 for organic solvents, 3,433 for chlorine bleach/germicide, 2,962 for engine oil, 2,931 for insecticide, 2,460 for medical sterilizing disinfectant, 1,786 for welding fumes, 1,614 for dyestuffs, 1,247 for any products containing lead-like solder, 986 for herbicide, 919 for radiation/radioactive substances/isotopes, 837 for lead-free solder, 341 for microbes, 319 for formalin/formaldehyde, 301 for agricultural chemical not listed above or unidentified, 196 for general anesthetic for surgery at hospital, 171 for anti-cancer drug, 147 for chromium/arsenic/cadmium, 88 for mercury and 833 for other chemical substances. Paternal occupational exposure regularly to photo copying machine or laser printer and soluble paint/inkjet printer were associated with higher risks of infant CHDs: the adjusted ORs (95%CIs) were 1.38 (1.00-1.91) and 1.60 (1.08-2.37), respectively. The higher risks were also observed for occasional exposure to engine oil, any products containing lead-like solder lead-free solder, and microbes; the adjusted ORs (95%CIs) were 1.68 (1.02-2.77), 2.03 (1.06-3.88), 3.45 (1.85-6.43), and 4.51, (1.63-12.49), respectively.

CONCLUSIONS

Periconceptional paternal occupational exposure was associated with a higher risk of infant CHDs. Further studies using biomarkers of the association between paternal occupational exposure and infant CHDs are warranted.

Assessment of evidence on reported non-genetic risk factors of congenital heart defects: the updated umbrella review

BACKGROUND

Congenital heart defect (CHD) is the leading cause of birth defects globally, which results in a great disease burden. It is still imperative to detect the risk factors of CHD. This umbrella review aimed to comprehensively summarize the evidence and grade the evidence of the associations between non-genetic risk factors and CHD.

METHODS

Databases including Medline, Embase, Web of Science, Cochrane Library, and four Chinese databases were searched from inception to 18 Jan 2022. The reference lists of systematic reviews (SR) and meta-analyses (MA) were screened, which aimed to explore the non-genetic risk factors of CHD. Subsequently, titles and abstracts of identified records and full texts of selected SR/MA were screened by two independent reviewers based on predefined eligibility criteria. A priori developed extraction form was used to abstract relative data following the PRISMA 2020 and MOOSE guidelines. The risk of bias was assessed with the AMSTAR2 instrument. Data were synthesized using fixed-effects and random-effects meta-analyses, respectively. Finally, the evidence on the association of non-genetic risk factors and CHD was graded using Ioannidis's five-class evidence grade.

RESULTS

A total of 56 SRs, encompassing 369 MAs, were identified. The risk factors included relative factors on air pollution, reproductive-related factors, parental age and BMI, parental life habits, working and dwelling environment, maternal drug exposure, and maternal disease. Based on AMSTAR2 criteria, only 16% (9/56) of SRs were classified as "Moderate". One hundred and two traceable positive association MAs involving 949 component individual studies were included in further analysis and grading of evidence. Family genetic history, number of abortions, maternal obesity, especially moderate or severe obesity, decoration materials, harmful chemicals, noise during pregnancy, folic acid supplementation, SSRIs, SNRIs, any antidepressants in the first trimester, maternal DM (including both PGDM and GDM), and gestational hypertension were convincing and highly suggestive factors for CHD. After sensitivity analyses based on cohort studies, some grades of evidence changed.

CONCLUSION

The present umbrella review will provide evidence-based information for women of childbearing age before or during pregnancy to prevent CHD. In addition, sensitivity analysis based on cohort studies showed the changed evidence levels. Therefore, future SR/MA should concern the sensitivity analysis based on prospective birth cohort studies and case-control studies.

SOX7 loss-of-function variation as a cause of familial congenital heart disease

INTRODUCTION

As the most frequent type of birth defect in humans, congenital heart disease (CHD) leads to a large amount of morbidity and mortality as well as a tremendous socioeconomic burden. Accumulating studies have convincingly substantiated the pivotal roles of genetic defects in the occurrence of familial CHD, and deleterious variations in a great number of genes have been reported to cause various types of CHD. However, owing to pronounced genetic heterogeneity, the hereditary components underpinning CHD remain obscure in most cases. This investigation aimed to identify novel genetic determinants underlying CHD.

METHODS AND RESULTS

A four-generation pedigree with high incidence of autosomal-dominant CHD was enrolled from the Chinese Han race population. Using whole-exome sequencing and Sanger sequencing assays of the family members available, a novel SOX7 variation in heterozygous status, NM_031439.4: c.310C>T; p.(Gln104*), was discovered to be in co-segregation with the CHD phenotype in the whole family. The truncating variant was absent in 500 unrelated healthy subjects utilized as control individuals. Functional measurements by dual-luciferase reporter analysis revealed that Gln104*-mutant SOX7 failed to transactivate its two important target genes, GATA4 and BMP2, which are both responsible for CHD. In addition, the nonsense variation invalidated the cooperative transactivation between SOX7 and NKX2.5, which is another recognized CHD-causative gene.

CONCLUSION

The present study demonstrates for the first time that genetically defective SOX7 predisposes to CHD, which sheds light on the novel molecular mechanism underpinning CHD, and implies significance for precise prevention and personalized treatment in a subset of CHD patients.

Environmental Exposures and Congenital Heart Disease

Congenital heart disease (CHD) is the most common congenital abnormality worldwide, affecting 8 to 12 infants per 1000 births globally and causing >40% of prenatal deaths. However, its causes remain mainly unknown, with only up to 15% of CHD cases having a determined genetic cause. Exploring the complex relationship between genetics and environmental exposures is key in understanding the multifactorial nature of the development of CHD. Multiple population-level association studies have been conducted on maternal environmental exposures and their association with CHD, including evaluating the effect of maternal disease, medication exposure, environmental pollution, and tobacco and alcohol use on the incidence of CHD. However, these studies have been done in a siloed manner, with few examining the interplay between multiple environmental exposures. Here, we broadly and qualitatively review the current literature on maternal and paternal prenatal exposures and their association with CHD. We propose using the framework of the emerging field of the exposome, the environmental complement to the genome, to review all internal and external prenatal environmental exposures and identify potentiating or alleviating synergy between exposures. Finally, we propose mechanistic pathways through which susceptibility to development of CHD may be induced via the totality of prenatal environmental exposures, including the interplay between placental and cardiac development and the internal vasculature and placental morphology in early stages of pregnancy.

Developmental toxicant exposures and sex-specific effects on epigenetic programming and cardiovascular health across generations

Despite substantial strides in diagnosis and treatment, cardiovascular diseases (CVDs) continue to represent the leading cause of death in the USA and around the world, resulting in significant morbidity and loss of productive years of life. It is increasingly evident that environmental exposures during early development can influence CVD risk across the life course. CVDs exhibit marked sexual dimorphism, but how sex interacts with environmental exposures to affect cardiovascular health is a critical and understudied area of environmental health. Emerging evidence suggests that developmental exposures may have multi- and transgenerational effects on cardiovascular health, with potential sex differences; however, further research in this important area is urgently needed. Lead (Pb), phthalate plasticizers, and perfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants with numerous adverse human health effects. Notably, recent evidence suggests that developmental exposure to each of these toxicants has sex-specific effects on cardiovascular outcomes, but the underlying mechanisms, and their effects on future generations, require further investigation. This review article will highlight the role for the developmental environment in influencing cardiovascular health across generations, with a particular emphasis on sex differences and epigenetic mechanisms. In particular, we will focus on the current evidence for adverse multi and transgenerational effects of developmental exposures to Pb, phthalates, and PFAS and highlight areas where further research is needed.

Gestational exposure to perfluoroalkyl substances and congenital heart defects: A nested case-control pilot study

BACKGROUND

Accumulating evidence suggests that environmental pollutants may contribute to the occurrence of congenital heart defects (CHDs). However, no previous studies have evaluated the impact of perfluoroalkyl substances (PFAS), persistent environmental pollutants, on CHDs. This exploratory study aimed to generate testable hypotheses of the association between gestational PFAS and the risk of CHDs.

METHODS

A nested case-control study was conducted in a cohort of 11,578 newborns. Exposure odds ratios were compared between 158 CHD cases and 158 non-malformed controls delivered at the same hospital, individually matched by maternal age (±5 years) and parity. Concentrations of 27 PFAS, including linear and branched isomers, were determined in maternal peripheral blood and cord blood plasma collected before and during delivery using a ultra-performance liquid chromatography coupled to mass spectrometry. Conditional logistic regression was utilized to evaluate associations between individual PFAS and the risk of CHDs, adjusted for confounding variables.

RESULTS

Maternal gestational exposure to the highly branched perfluorooctanesulfonate (PFOS) isomer potassium 6-trifluoromethyperfluoroheptanesulfonate [6 m-PFOS, adjusted odds ratio (aOR) (95% CI) = 2.47(1.05,5.83)] and perfluorodecanoic acid [PFDA, aOR (95% CI) = 2.33(1.00,5.45)] were associated with increased odds of septal defects with statistical significance, while linear PFOS [aOR (95% CI) = 3.65(1.09,12.16)] and perfluoro-n-dodecanoic acid [PFDoA, aOR (95% CI) = 6.82(1.75, 26.61)] were associated with conotruncal defects. Effect estimates also suggested associations for higher maternal 6 m-PFOS and PFDA concentrations with ventricular septal defect. However, we did not observe these associations in cord blood.

CONCLUSION

These exploratory findings suggested that gestational exposure to most PFAS, especially linear PFOS, 6 m-PFOS, PFDA, and PFDoA, was associated with greater risks for septal and conotruncal defects. However, a larger, adequately powered study is needed to confirm our findings, and to more comprehensively investigate the potential teratogenic effects of other more recently introduced PFAS, and on associations with individual CHD subtypes.

The role of NKX2-5 gene polymorphisms in congenital heart disease (CHD): a systematic review and meta-analysis

BACKGROUND

The gene NKX2-5 is a key transcription factor that plays an essential role in normal cardiac development. Although some recent studies have studied the role of polymorphisms in the NKX2-5 gene in congenital heart diseases (CHDs), the results were not consistent and remained uncertain. Therefore, we conduct a review of literature and investigate the association of genetic polymorphisms with CHDs.

RESULTS

We selected seventeen studies regarding the association of NKX2-5 gene rs2277923 polymorphism with CHDs. Overall, in all the tested genetic models, the 63A > G polymorphism was not significantly associated with increased congenital heart defects risk. We used pooled odds ratios (OR) to calculate the association of CHDs with rs2277923 including allelic model: OR 1.00, 95% CI 0.82-1.21; homozygote model: OR 0.95, 95%CI 0.68-1.33, recessive model: OR 0.89 CI 0.70-1.13, heterozygote model: OR: 1.09, 95%CI 0.87-1.37, dominant model: OR 1.08 CI 0.82-1.42 and overdominant model: OR 1.17 CI 1.01-1.35. In addition, our analysis suggests that no publication bias exists in this meta-analysis.

CONCLUSIONS

Our findings suggested that 63A > G polymorphism in the NKX2-5 gene was not significantly associated with congenital heart defects. However, in the future, more studies with increased sample size are required that may provide us more definite conclusions.

Environmental and Genetic Risk Factors of Congenital Anomalies: an Umbrella Review of Systematic Reviews and Meta-Analyses

BACKGROUND

The prevalence of congenital anomalies in newborns in South Korea was 272.9 per 100,000 in 2005, and 314.7 per 100,000 in 2006. In other studies, the prevalence of congenital anomalies in South Korea was equivalent to 286.9 per 10,000 livebirths in 2006, while it was estimated 446.3 per 10,000 births during the period from 2008 to 2014. Several systematic reviews and meta-analyses analyzing the factors contributing to congenital anomalies have been reported, but comprehensive umbrella reviews are lacking.

METHODS

We searched PubMed, Google Scholar, Cochrane, and EMBASE databases up to July 1, 2019, for systematic reviews and meta-analyses that investigated the effects of environmental and genetic factors on any type of congenital anomalies. We categorized 8 subgroups of congenital anomalies classified according to the 10th revision of the International Statistical Classification of Diseases (ICD-10). Two researchers independently searched the literature, retrieved the data, and evaluated the quality of each study.

RESULTS

We reviewed 66 systematic reviews and meta-analyses that investigated the association between non-genetic or genetic risk factors and congenital anomalies. Overall, 269 associations and 128 associations were considered for environmental and genetic risk factors, respectively. Congenital anomalies based on congenital heart diseases, cleft lip and palate, and others were associated with environmental risk factors based on maternal exposure to environmental exposures (air pollution, toxic chemicals), parental smoking, maternal history (infectious diseases during pregnancy, pregestational and gestational diabetes mellitus, and gestational diabetes mellitus), maternal obesity, maternal drug intake, pregnancy through artificial reproductive technologies, and socioeconomic factors. The association of maternal alcohol or coffee consumption with congenital anomalies was not significant, and maternal folic acid supplementation had a preventive effect on congenital heart defects. Genes or genetic loci associated with congenital anomalies included MTHFR, MTRR and MTR, GATA4, NKX2-5, SRD5A2, CFTR, and 1p22 and 20q12 anomalies.

CONCLUSION

This study provides a wide perspective on the distribution of environmental and genetic risk factors of congenital anomalies, thus suggesting future studies and providing health policy implications.

Association between advanced paternal age and congenital heart defects: a systematic review and meta-analysis

STUDY QUESTION

Is there an association between advanced paternal age and congenital heart defects (CHD)?

SUMMARY ANSWER

Advanced paternal age is associated with a 16% increase in the overall odds of CHD.

WHAT IS KNOWN ALREADY

CHD are the most common congenital malformations. Several risk factors for CHD have been identified in the literature, but the association between advanced paternal age and CHD remains unclear.

STUDY DESIGN, SIZE, DURATION

We conducted a systematic literature search on MEDLINE and EMBASE (1960-2019) to identify studies assessing the association between advanced paternal age (≥35 years) and the risk of CHD, unrestrictive of language or sample size. We used a combination of Medical Subject Headings (MeSH) terms and free text words such as 'paternal age', 'paternal factors', 'father's age', 'parental age', 'heart', 'cardiac', 'cardiovascular', 'abnormalities, congenital', 'birth defects', 'congenital malformations' and 'congenital abnormalities'.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We included observational studies aiming at assessing the association between paternal age and CHD. The included population could be live births, fetal deaths and terminations of pregnancy for fetal anomaly. To be included, studies had to provide either odds ratios (OR) with their 95% confidence interval (CI) or sufficient information to recalculate ORs with 95% CIs per paternal age category. We excluded studies if they had no comparative group and if they were reviews or case reports. Two independent reviewers selected the studies, extracted the data and assessed risk of bias using a modified Newcastle-Ottawa Scale. We used random-effects meta-analysis to produce summary estimates of crude OR. Associations were also tested in subgroups.

MAIN RESULTS AND THE ROLE OF CHANCE

Of 191 studies identified, we included nine studies in the meta-analysis (9 917 011 participants, including 34 447 CHD), including four population-based studies. Five studies were judged at low risk of bias. Only one population-based study specifically investigated isolated CHD. The risk of CHD was higher with advanced paternal age (summary OR 1.16, 95% CI, 1.07-1.25). Effect sizes were stable in population-based studies and in those with low risk of bias.

LIMITATIONS AND REASONS FOR CAUTION

The available evidence did not allow to assess (i) the risk of isolated CHD in population-based studies, (ii) the association between paternal age and the risk for specific CHD and (iii) the association between paternal age and CHD after adjustment for other risk factors, such as maternal age.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings suggest that advanced paternal age may be a risk factor for CHD. However, because the association is modest in magnitude, its usefulness as a criterion for targeted screening for CHD seems limited.

STUDY FUNDING/COMPETING INTEREST(S)

None.

PROSPERO REGISTRATION NUMBER

CRD42019135061.

Environmental Risk Factors and Congenital Heart Disease: An Umbrella Review of 165 Systematic Reviews and Meta-Analyses With More Than 120 Million Participants

Background: The etiology of congenital heart disease (CHD) has been extensively studied in the past decades. Therefore, it is critical to clarify clear hierarchies of evidence between types of environmental factors and CHD. Methods: Electronic searches in PubMed, Embase, Web of Science, Cochrane database were conducted from inception to April 20, 2020 for meta-analyses investigating the aforementioned topic. Results: Overall, 41 studies including a total of 165 meta-analyses of different environmental factors and CHD were examined, covering a wide range of risk factors. The summary random effects estimates were significant at P < 0.05 in 63 meta-analyses (38%), and 15 associations (9%) were significant at P < 10^-6. Of these meta-analyses, eventually one risk factor (severe obesity; relative risk: 1.38, 95% confidence interval: 1.30-1.47) had significant summary associations at P < 10^-6, included more than 1,000 cases, had 95% prediction intervals excluding the null value, and were not suggestive of large heterogeneity (I ² < 50%), small-study effects (P-value for Egger's test > 0.10), or excess significance (P > 0.10). Eight associations (5%) (including maternal lithium exposure, maternal obesity, maternal alcohol consumption, and maternal fever) had results that were significant at P < 10^-6, included more than 1,000 cases, and had 95% prediction intervals excluding the null value (highly suggestive). Conclusion: This umbrella review shows that many environmental factors have substantial evidence in relation to the risk of developing CHD. More and better-designed studies are needed to establish robust evidence between environmental factors and CHD. Systematic Review Registration: [PROSPERO], identifier [CRD42020193381].

Paternal genetic variants and risk of obstructive heart defects: A parent-of-origin approach

Previous research on risk factors for obstructive heart defects (OHDs) focused on maternal and infant genetic variants, prenatal environmental exposures, and their potential interaction effects. Less is known about the role of paternal genetic variants or environmental exposures and risk of OHDs. We examined parent-of-origin effects in transmission of alleles in the folate, homocysteine, or transsulfuration pathway genes on OHD occurrence in offspring. We used data on 569 families of liveborn infants with OHDs born between October 1997 and August 2008 from the National Birth Defects Prevention Study to conduct a family-based case-only study. Maternal, paternal, and infant DNA were genotyped using an Illumina Golden Gate custom single nucleotide polymorphism (SNP) panel. Relative risks (RR), 95% confidence interval (CI), and likelihood ratio tests from log-linear models were used to estimate the parent-of-origin effect of 877 SNPs in 60 candidate genes in the folate, homocysteine, and transsulfuration pathways on the risk of OHDs. Bonferroni correction was applied for multiple testing. We identified 3 SNPs in the transsulfuration pathway and 1 SNP in the folate pathway that were statistically significant after Bonferroni correction. Among infants who inherited paternally-derived copies of the G allele for rs6812588 in the RFC1 gene, the G allele for rs1762430 in the MGMT gene, and the A allele for rs9296695 and rs4712023 in the GSTA3 gene, RRs for OHD were 0.11 (95% CI: 0.04, 0.29, P = 9.16x10^-7), 0.30 (95% CI: 0.17, 0.53, P = 9.80x10^-6), 0.34 (95% CI: 0.20, 0.57, P = 2.28x10^-5), and 0.34 (95% CI: 0.20, 0.58, P = 3.77x10^-5), respectively, compared to infants who inherited maternally-derived copies of the same alleles. We observed statistically significant decreased risk of OHDs among infants who inherited paternal gene variants involved in folate and transsulfuration pathways.

Obstructive heart defects are birth defects that cause obstruction to the blood flow of the developing heart. Common OHDs include coarctation of the aorta, aortic stenosis and pulmonary stenosis. While there is a fair amount of literature indicating an association between maternal genetic variants and OHDs, less is known about the role of paternal genetic variants in the etiology of OHDs. We used a genotype clustering algorithm, SNPMClust, that was developed in-house at the Arkansas Center for Birth Defects Research and Prevention to study the role of paternal genetic variants in the folate, homocysteine and transsulfuration pathways. Maternal, paternal, and infant DNA specimens were collected from participants of the National Birth Defects Prevention Study, a large population-based case-control study in the United States, and were genotyped using an Illumina Golden Gate custom single nucleotide polymorphism (SNP) panel. We identified 4 SNPs in the folate and transsulfuration pathways, rs6812588, rs1762430, rs9296695, and rs4712023, that were associated with a statistically significant decreased risk of OHDs for infants who inherited a paternally-derived copy of the variant allele compared to infants who inherited a maternal copy of the variant allele. In conclusion, we observed a significantly decreased risk and less epigenetic influence of paternal genetic variants on OHDs compared to maternally-derived variants.

Element profiles in blood and teeth samples of children with congenital heart diseases in comparison with healthy ones

BACKGROUND

Some elements were claimed to play a role in the pathogenesis of congenital heart defects (CHD) and influence the general well-being and health of these children.

OBJECTIVES

We aimed to assess the levels of some elements simultaneously in the blood and teeth samples of children with cyanotic and acyanotic CHD compared with healthy children.

METHODS

A total of 39 children with CHD (11 with cyanotic and 28 with acyanotic CHD) and 42 age- and sex-adjusted controls were enrolled. Levels of 13 elements, including magnesium, phosphorus, calcium, chromium, manganese, iron, copper, zinc, strontium, cadmium, lead, mercury, and molybdenum, were assessed using inductively coupled plasma mass spectrometry.

RESULTS

Children with cyanotic and acyanotic CHD had significantly lower teeth calcium and calcium/phosphorus ratio as compared to the controls after adjusting for confounders. The mean blood iron level was found to be significantly higher in the cyanotic CHD group compared to the other groups. In addition, children with acyanotic CHD had significantly higher teeth copper levels, higher blood molybdenum and lower blood magnesium levels compared to the healthy control group. Blood cadmium and mercury levels were found to be significantly elevated in both the cyanotic and acyanotic CHD groups compared to the healthy control group. There were no differences in toxic metal levels of teeth in cases with CHD.

CONCLUSION

Monitoring adequate and balanced gestational micronutrient intake might support not only maternal health but also fetal cardiac development and infant well-being. Supplementation of magnesium should be evaluated in patients having CHD.

Effect of paternal age on offspring birth defects: a systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis was aimed at determining whether paternal age is a risk factor for offspring birth defects.

RESULTS

A total of 38 and 11 studies were included in the systematic review and meta-analysis, respectively. Compared with reference, fathers aged 25 to 29, young fathers (< 20 years) could increase the risk of urogenital abnormalities (OR: 1.50, 95 % CI: 1.03-2.19) and chromosome disorders (OR: 1.38, 95 % CI: 1.12-1.52) in their offsprings; old fathers (≥ 40 years) could increase the risk of cardiovascular abnormalities (OR: 1.10, 95 % CI: 1.01-1.20), facial deformities (OR: 1.08, 95 % CI: 1.00-1.17), urogenital abnormalities (OR: 1.28, 95 % CI: 1.07-1.52), and chromosome disorders (OR: 1.30, 95 % CI: 1.12-1.52).

CONCLUSIONS

Our study indicated that paternal age is associated with a moderate increase in the incidence of urogenital and cardiovascular abnormalities, facial deformities, and chromosome disorders.

METHODS

PubMed, Web of Science, the Cochrane Library, and Embase were searched for relevant literatures from 1960 to February 2020. The systematic review follows PRISMA guidelines. Relevant meta-analyses were performed.

Parental occupational exposure and congenital heart diseases in a Hungarian case-control study

Purpose

Our study aimed to explore the effect of parental occupational exposure to endocrine disrupting chemicals (EDCs) on the development of congenital heart diseases (CHDs) in the offspring, and to compare job-exposure matrix (JEM)-assessed and self-reported occupational exposures with each other.

Methods

Live-born infants born in 2007–2008 were selected from the population-based Hungarian Case–Control Surveillance of Congenital Abnormalities Study. 577 cases with any CHDs were compared to 1731 matched controls. Parental periconceptional occupational exposure to EDCs was assessed by a JEM and by questionnaire-based self-reporting of parents. Multivariate conditional logistic regression analyses were conducted to explore associations between parental occupational exposure to EDCs and the entire spectrum of CHDs and by CHD subtypes in the offspring. Kappa statistics were also performed to determine the consistency among JEM-assessed and self-reported occupational exposure of parents.

Results

JEM-assessed paternal exposure to polychlorinated organic substances, phthalates, biphenolic compounds, and solvents were significantly associated with the entire spectrum of CHDs. Ventricular septal defects were significantly associated with paternal self-reported exposure to pesticides, while atrial septal defects were significantly associated to paternal JEM-assessed phthalate exposure. Paternal solvent exposure was significantly associated with atrial septal defects and right ventricle outflow tract obstructions. JEM-assessed and self-reported exposures to pesticides, heavy metals, and solvents exhibited poor agreement for mothers and slight agreement for fathers.

Conclusion

Even though parental occupational exposure to EDCs seems to have a minor impact on the occurrence of CHDs, the results of biological and environmental monitoring should be taken into consideration as well.

Risk factor analysis for congenital heart defects in children

Congenital heart defects (CHDs) are the most common malformations, occurring in almost 1.0 in 100 births. We investigated an association between risk factors and CHDs, because epidemiological studies have reported conflicting results regarding risk factors and CHDs recently. The study of CHD frequency was conducted in Chernivtsi region (Northern Bukovina) on the basis of the medical genetic center. A retrospective method of research by studying registration genetic maps was used to analyze risk factors. 91 cards of infants suffering from CHD (47 boys and 44 girls) aged 0–1 living in the territory of Northern Bukovina were selected. In order to identify risk factors, 133 cards of healthy infants (77 boys and 56 girls) were used. The analysis of risk factors revealed that the female gender of a child is a risk factor for CHD development. The analysis of the ordinal number of pregnancy revealed that the second and the third pregnancies are probable risk factors for the development of this pathology. It was found in our study that folic acid intake during the first trimester prevented CHD development (OR 2.33). The study revealed that among stressful risk factors are: unplanned pregnancy (OR 3.13); out-of-wedlock pregnancy and stress during pregnancy. Maternal CHD increased the CHD development in offspring approximately by two times. Some factors, such as a woman doing hard physical work during pregnancy, having sedentary work during pregnancy, the mother being a housewife or having an incomplete secondary education (OR 3.61), the mother’s secondary education, the father’s incomplete secondary education (OR 18.62), the father serving in the army (OR 2.15) or being a student at the time of woman’s pregnancy (OR 2.97) were significant for CHD development in the fetal stage. A young age of the father (up to 43 years) was also considered as one of the risk factors. This article is expected to provide timely information on risk factors for CHD development to a wide range of medical staff, including pediatric and adult cardiologists, pediatricians, thoracic surgeons, obstetricians, gynecologists, medical geneticists, genetic counselors and other relevant clinicians.

Maternal residential greenness and congenital heart defects in infants: A large case-control study in Southern China

BACKGROUND

Proximity to greenness has shown protective effects on coronary heart diseases by limiting exposure to environmental hazards, encouraging physical activity, and reducing mental stress. However, no studies have previously evaluated the impacts of greenness on congenital heart defects (CHDs). We examined the association between maternal residential greenness and the risks of CHDs.

METHODS

We conducted a case-control study (8042 children with major CHDs and 6887 controls without malformations) in 21 cities in Southern China, 2004 - 2016. CHDs cases were diagnosed and verified by obstetrician, pediatrician, or pediatric cardiologists, within one year. We estimated maternal residential greenness using satellite-derived normalized difference vegetation index (NDVI) in zones of 500 meters (m) and 1000 m surrounding participants' residences. Logistic regression models were used to assess NDVI-CHD relationships adjusting for confounders.

RESULTS

Interquartile range NDVI increases within 500 m or 1000 m were associated with odds ratios (OR) of 0.95 (95% confidence interval (CI): 0.92, 0.98) and 0.94 (95%CI: 0.91, 0.97) for total CHDs respectively. Air pollutants mediated 52.1% of the association. We also identified a protective threshold at 0.21 NDVI on CHD. Similar protective effects from greenness were found in most CHDs subtypes. The protective associations were stronger for fall, urban or permanent residents, higher household income maternal age ≤35 years of age, and high maternal education (ORs: ranged from 0.85 to 0.96).

CONCLUSION

Our findings suggest a beneficial effect of maternal residential greenness on CHDs. Further studies are needed to confirm our findings, which will help to refine preventive health and urban design strategies.

A Chromosomal Inversion of 46XX, inv (6) (p21.3p23) Connects to Congenital Heart Defects

Congenital heart defects (CHDs) represent the most common human birth defects. Ventricular septal defect (VSD) is the most common subtype of CHDs. It has been shown that about 20–40% of VSDs are closely related to chromosomal aneuploidies or Mendelian diseases. In this study, we report a pedigree with VSD associated with a balanced paracentric inversion of chromosome 6, inv (6)(p21.3p23), a rarely reported CHD-associated chromosomal abnormality related to the fragile site at 6p23. We have found that the major clinical features of the proband include CHDs (ventricular septal defect, severe pulmonary hypertension, tricuspid regurgitation, and patent foramen ovale), severe pneumonia, and growth retardation. Our study reports a rare chromosomal abnormality connected to CHDs, which may represent a new genetic etiology for VSD.

The non-genetic paternal factors for congenital heart defects: A systematic review and meta-analysis

Background

Advances have been made in identifying genetic etiologies and maternal risk factors of congenital heart defects (CHDs), while few literatures are available regarding paternal risk factors for CHDs. Thus, we aim to conduct a meta‐analysis and systematic review about the non‐genetic paternal risk factors for CHDs.

Methods

We searched the PubMed, MEDLINE, and Cochrane Library online databases and identified 31 studies published between 1990 and 2018 according to the inclusion criteria. Paternal risk factors were divided into subgroups, and summarized odd ratios (OR) were calculated.

Results

Paternal age between 24 and 29 years decreased the risk of CHDs in the offspring (OR = 0.90 [0.82, 0.98]), while paternal age ≥ 35 years old increased the risk of CHDs (35‐39 years old: OR = 1.14 [1.09, 1.19], and ≥ 40 years: OR = 1.27 [1.14, 1.42]). Paternal cigarette smoking increased the risk of CHDs in a dose‐dependent way. Paternal wine drinking (OR = 1.47 [1.05, 2.07]) and exposure to chemical agents or drugs (OR = 2.15 [1.53, 3.02]) also increased the risk of CHDs. Some specific paternal occupations were also associated with increased risk for CHDs or CHD subtypes including factory workers, janitors, painters, and plywood mill workers.

Conclusions

This meta‐analysis and systematic review suggested that advanced paternal age, cigarette smoking, wine drinking, exposure to chemical agents or drugs and some specific occupations were associated with an increased risk of CHDs. More measures should be taken to reduce occupational and environment exposures. At the same time, fertility at certain age and establishment of healthy life habits are strongly recommended.