Analyses of trends in prevalence of congenital heart defects and folic acid supplementation

Associations of congenital heart disease with deprivation index by rural-urban maternal residence: a population-based retrospective cohort study in Ontario, Canada

BACKGROUND

The risk of congenital heart disease (CHD) has been found to vary by maternal socioeconomic status (SES) and rural-urban residence. In this study, we examined associations of CHD with two maternal SES indicators and stratified the analysis by maternal rural-urban residence.

METHODS

This was a population-based retrospective cohort study. We included all singleton stillbirths and live hospital births from April 1, 2012 to March 31, 2018 in Ontario, Canada. We linked the BORN Information System and Canadian Institute for Health Information databases. Multivariable logistic regression models were used to examine associations of CHD with material deprivation index (MDI), social deprivation index (SDI), and maternal residence while adjusting for maternal age at birth, assisted reproductive technology, obesity, pre-pregnancy maternal health conditions, mental health illness before and during pregnancy, substance use during pregnancy, and infant's sex. MDI and SDI were estimated at a dissemination area level in Ontario and were categorized into quintiles (Q1-Q5).

RESULTS

This cohort study included 798,173 singletons. In maternal urban residence, the p trend (Cochran-Armitage test) was less than 0.0001 for both MDI and SDI; while for rural residence, it was 0.002 and 0.98, respectively. Infants living in the most materially deprived neighbourhoods (MDI Q5) had higher odds of CHD (aOR: 1.21, 95% CI: 1.12-1.29) compared to Q1. Similarly, infants living in the most socially deprived neighbourhoods (SDI Q5) had an 18% increase in the odds of CHD (aOR: 1.18, 95% CI: 1.1-1.26) compared to Q1. Rural infants had a 13% increase in the odds of CHD compared to their urban counterparts. After stratifying by maternal rural-urban residence, we still detected higher odds of CHD with two indices in urban residence but only MDI in rural residence.

CONCLUSION

Higher material and social deprivation and rural residence were associated with higher odds of CHD. Health interventions and policies should reinforce the need for optimal care for all families, particularly underprivileged families in both rural and urban regions. Future studies should further investigate the effect of social deprivation on the risk of CHD development.

[Association of maternal MTHFD1 and MTHFD2 gene polymorphisms with congenital heart disease in offspring]

OBJECTIVES

To study the association of maternal methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) and methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) gene polymorphisms with congenital heart disease (CHD) in offspring.

METHODS

A hospital-based case-control study was conducted. The mothers of 683 children with CHD alone who attended Hunan Children's Hospital, from November 2017 to March 2020 were enrolled as the case group, and the mothers of 740 healthy children who attended the same hospital during the same period and did not have any deformity were enrolled as the control group. A questionnaire survey was performed to collect related exposure data, and then venous blood samples (5 mL) were collected from the mothers to detect MTHFD1 and MTHFD2 gene polymorphisms. A multivariate logistic regression analysis was used to evaluate the association of MTHFD1 and MTHFD2 gene polymorphisms with CHD. The four-gamete test in Haploview 4.2 software was used to construct haplotypes and evaluate the association between haplotypes and CHD. The generalized multifactor dimensionality reduction method and logistic regression analysis were used to examine gene-gene interaction and its association with CHD.

RESULTS

The multivariate logistic regression analysis showed that maternal MTHFD1 gene polymorphisms at rs11849530 (GA vs AA: OR=1.49; GG vs AA: OR=2.04) andat rs1256142 (GA vs GG: OR=2.34; AA vs GG: OR=3.25) significantly increased the risk of CHD in offspring (P<0.05), while maternal MTHFD1 gene polymorphisms at rs1950902 (AA vs GG: OR=0.57) and MTHFD2 gene polymorphisms at rs1095966 (CA vs CC: OR=0.68) significantly reduced the risk of CHD in offspring (P<0.05). The haplotypes of G-G-G (OR=1.86) and G-A-G (OR=1.35) in mothers significantly increased the risk of CHD in offspring (P<0.05). The gene-gene interaction analyses showed that the first-order interaction between MTHFD1 rs1950902 and MTHFD1 rs2236222 and the second-order interaction involving MTHFD1 rs1950902, MTHFD1 rs1256142, and MTHFD2 rs1095966 might be associated with risk of CHD (P<0.05).

CONCLUSIONS

Maternal MTHFD1 and MTHFD2 gene polymorphisms and their haplotypes, as well as the interaction between MTHFD1 rs1950902 and MTHFD1 rs2236222 and between MTHFD1 rs1950902, MTHFD1 rs1256142, and MTHFD2 rs1095966, are associated with the risk of CHD in offspring.

Gestational Leucylation Suppresses Embryonic T-Box Transcription Factor 5 Signal and Causes Congenital Heart Disease

Dysregulated maternal nutrition, such as vitamin deficiencies and excessive levels of glucose and fatty acids, increases the risk for congenital heart disease (CHD) in the offspring. However, the association between maternal amino-acid levels and CHD is unclear. Here, it is shown that increased leucine levels in maternal plasma during the first trimester are associated with elevated CHD risk in the offspring. High levels of maternal leucine increase embryonic lysine-leucylation (K-Leu), which is catalyzed by leucyl-tRNA synthetase (LARS). LARS preferentially binds to and catalyzes K-Leu modification of lysine 339 within T-box transcription factor TBX5, whereas SIRT3 removes K-Leu from TBX5. Reversible leucylation retains TBX5 in the cytoplasm and inhibits its transcriptional activity. Increasing embryonic K-Leu levels in high-leucine-diet fed or Sirt3 knockout mice causes CHD in the offspring. Targeting K-Leu using the leucine analogue leucinol can inhibit LARS activity, reverse TBX5 K-Leu modification, and decrease the occurrence of CHD in high-leucine-diet fed mice. This study reveals that increased maternal leucine levels increases CHD risk in the offspring through inhibition of embryonic TBX5 signaling, indicating that leucylation exerts teratogenic effects during heart development and may be an intervening target of CHD.

Neighbourhood maternal socioeconomic status indicators and risk of congenital heart disease

BACKGROUND

This study aimed to examine the relationships between various maternal socioeconomic status (SES) indicators and the risk of congenital heart disease (CHD).

METHODS

This was a population-based retrospective cohort study, including all singleton stillbirths and live births in Ontario hospitals from April 1, 2012 to March 31, 2018. Multivariable logistic regression models were performed to examine the relationships between maternal neighbourhood household income, poverty, education level, employment and unemployment status, immigration and minority status, and population density and the risk of CHD. All SES variables were estimated at a dissemination area level and categorized into quintiles. Adjustments were made for maternal age at birth, assisted reproductive technology, obesity, pre-existing maternal health conditions, substance use during pregnancy, rural or urban residence, and infant's sex.

RESULTS

Of 804,292 singletons, 9731 (1.21%) infants with CHD were identified. Compared to infants whose mothers lived in the highest income neighbourhoods, infants whose mothers lived in the lowest income neighbourhoods had higher likelihood of developing CHD (adjusted OR: 1.29, 95% CI: 1.20-1.38). Compared to infants whose mothers lived in the neighbourhoods with the highest percentage of people with a university or higher degree, infants whose mothers lived in the neighbourhoods with the lowest percentage of people with university or higher degree had higher chance of CHD (adjusted OR: 1.34, 95% CI: 1.24-1.44). Compared to infants whose mothers lived in the neighbourhoods with the highest employment rate, the odds of infants whose mothers resided in areas with the lowest employment having CHD was 18% higher (adjusted OR: 1.18, 95% CI: 1.10-1.26). Compared to infants whose mothers lived in the neighbourhoods with the lowest proportion of immigrants or minorities, infants whose mothers resided in areas with the highest proportions of immigrants or minorities had 18% lower odds (adjusted OR: 0.82, 95% CI: 0.77-0.88) and 16% lower odds (adjusted OR: 0.84, 95% CI: 0.78-0.91) of CHD, respectively.

CONCLUSION

Lower maternal neighbourhood household income, poverty, lower educational level and unemployment status had positive associations with CHD, highlighting a significant social inequity in Ontario. The findings of lower CHD risk in immigrant and minority neighbourhoods require further investigation.

Environmental Risk Factors for Congenital Heart Disease

Congenital heart disease (CHD) has many forms and a wide range of causes. Clinically, it is important to understand the causes. This allows estimation of recurrence rate, guides treatment options, and may also be used to formulate public health advice to reduce the population prevalence of CHD. The recent advent of sophisticated genetic and genomic methods has led to the identification of more than 100 genes associated with CHD. However, despite these great strides, to date only one-third of CHD cases have been shown to have a simple genetic cause. This is because CHD can also be caused by oligogenic factors, environmental factors, and/or gene-environment interaction. Although solid evidence for environmental causes of CHD have been available for almost 80 years, it is only very recently that the molecular mechanisms for these risk factors have begun to be investigated. In this review, we describe the most important environmental CHD risk factors, and what is known about how they cause CHD.

Folate supplementation for prevention of congenital heart defects and low birth weight: an update

Women planning a pregnancy and pregnant women in the first trimester are recommended to use folate-containing supplements in order to prevent neural tube defects. The prevention of many cases of neural tube defects with folic acid is evident from meta-analysis, randomized controlled trials (RCTs), observational studies in humans and experimental evidence in animals. However, folate supplementation in pregnant women or a higher maternal folate status has been shown to be protective against other adverse birth outcomes such as congenital heart defects, low birth weight, and preterm birth. Additionally, infants and children with congenital heart defects often show disorders in folate metabolism (low folate, higher homocysteine, or low vitamin B12). Maternal genotype for several folate metabolizing genes has shown associations with the risk of having a child with congenital heart defect. There is some evidence that folate supplementation could have differential effects on sub-types of congenital heart defects, but it is not clear whether the prevention time window is the same as for neural tube defects. Some studies proposed a high dose of folic acid (in mg/d) to prevent congenital heart defects in women with a high global risk (such as those with diabetes or obesity). There are currently no RCTs to support that doses of folic acid in mg range are more effective than the currently recommended 400-800 µg/d taken at least 2-3 months before conception until the end of the first trimester.