Associations between congenital heart disease and air pollutants at different gestational weeks: a time-series analysis

Maternal Exposure to Ozone and the Risk of Birth Defects: A Time-Stratified Case-Crossover Study in Southwestern China

A few studies have explored the relationship between air pollution exposure and the risk of birth defects; however, the ozone-related (O3) effects on preconception and first-trimester exposures are still unknown. In this time-stratified case-crossover study, conditional logistic regressions were applied to explore the associations between O3 exposure and the risk of birth defects in Chongqing, China, and stratified analyses were constructed to evaluate the modifiable factors. A total of 6601 cases of birth defects were diagnosed, of which 56.16% were male. O3 exposure was associated with an increased risk of birth defects, and the most significant estimates were observed in the first month before pregnancy: a 10 ug/m3 increase of O3 was related to an elevation of 4.2% [95% confidence interval (CI), 3.4-5.1%]. The associations between O3 exposure and congenital malformations and deformations of the musculoskeletal system were statistically significant during almost all exposure periods. Pregnant women with lower education and income, and from rural areas, were more susceptible to O3 exposure, with the strongest odds ratios (ORs) of 1.066 (95%CI, 1.046-1.087), 1.086 (95%CI, 1.034-1.140), and 1.053 (95%CI, 1.034-1.072), respectively. Our findings highlight the health risks of air pollution exposure and raise awareness of pregnant women's vulnerability and the susceptibility window period.

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.

Global air pollution exposure and congenital anomalies: an updated systematic review and meta-analysis of epidemiological studies

A systematic review and meta-analysis was conducted to evaluate recent epidemiological evidence on the association of air pollution with congenital anomalies (CAs). Of 11,014 records, 49 were finally included in this meta-analysis. Per 10 μg/m3 increase in air pollutant, PM10 exposure during the 1st month of pregnancy and at the first trimester (T1) was associated with increased overall CAs. Further, exposure to PM10 was associated with congenital heart disease (OR = 1.055, 95% CI: 1.035, 1.074) and patent ductus arteriosus (OR = 1.094, 95% CI: 1.020, 1.168) at T1, with chromosomal anomalies during the entire pregnancy and with nervous system anomalies when exposure occurred 3 months prior to pregnancy, during the 1st, 2nd months of pregnancy and at T1. Besides, a significant association with overall CAs was observed for a combined exposure of PM10 and SO2 during the 1st month of gestation (OR: 1.101, 95% CI: 1.023, 1.180). A combined exposure of PM10 and CO was also associated with tetralogy of Fallot during 3-8 weeks of gestation (OR: 1.016, 95% CI: 1.005, 1.027). No significant associations were observed between PM2.5, NO2, and O3 exposure and CAs.

Maternal exposure to ambient ozone and fetal conotruncal heart defects in China: A multicenter cohort study

BACKGROUND

The relationships between maternal genetic and environmental exposure and conotruncal heart defects (CTDs) have been extensively investigated. Nevertheless, there is limited knowledge regarding the impact of ozone (O3) on the risk of CTDs.

OBJECTIVE

To explore the correlation between maternal exposure to O3 and CTDs in China.

METHODS

Pregnant women who underwent fetal echocardiography at Beijing Anzhen Hospital between January 2013 and December 2021 were enrolled. Their sociodemographic characteristics and lifestyle information, along with fetal data, were systematically collected. Fetal echocardiography was used to detect CTDs. Maternal exposure to ambient O3 during the embryonic period, the first trimester, the three months preceding the last menstrual period, and the perinatal period was estimated using residential addresses or hospital addresses associated with prenatal visits. The concentration of O3 was divided by quartiles, with the first quartile serving as a reference. Adjusted logistic regression models were employed to examine the associations between every 10 μg/m3 increase or quartile increase in ambient O3 exposure and CTDs.

RESULTS

Among 24,278 subjects, 1069 exhibited fetuses with CTDs. Maternal exposure to ambient O3 during three pregnancy periods was associated with increased CTD risk. The adjusted odds ratio (OR) and 95% confidence interval (CI) were 1.271 (1.189-1.360) per 10 μg/m3 increase in O3 during the perinatal period. For each quartile of O3, the risk increased with increasing exposure concentration, particularly during the perinatal period (OR = 2.206 for quartile 2, 2.367 for quartile 3, and 3.378 for quartile 4, all P<0.05).

CONCLUSIONS

Elevated maternal exposure to O3 during pregnancy, particularly in the perinatal period, is linked to an increased risk of fetal CTDs. Further longitudinal analyses are needed to validate these results.

Integrated single-cell RNA-seq and DNA methylation reveal the effects of air pollution in patients with recurrent spontaneous abortion

Background

Maternal air pollutants exposure is associated with a number of adverse pregnancy outcomes, including recurrent spontaneous abortion (RSA). However, the underlying mechanisms are still unknown. The present study aimed to understand the mechanism of RSA and its relationship with air pollution exposure. We compared data of decidual tissue from individuals with induced abortions and those with RSA by bulk RNA sequencing (RNA-seq), reduced representation bisulfite sequencing (RRBS), and single-cell RNA sequencing (scRNA-seq). Differentially expressed genes (DEGs) were verified using RT-qPCR and pyrosequencing. A logistic regression model was used to investigate the association between air pollutants exposure and RSA.

Results

We identified 98 DEGs with aberrant methylation by overlapping the RRBS and RNA-seq data. Nineteen immune cell subsets were identified. Compared with normal controls, NK cells and macrophages accounted for different proportions in the decidua of patients with RSA. We observed that the methylation and expression of IGF2BP1 were different between patients with RSA and controls. Furthermore, we observed significant positive associations between maternal air pollutants exposure during the year prior to pregnancy and in early pregnancy and the risk of RSA. Mediation analyses suggested that 24.5% of the effects of air pollution on the risk of RSA were mediated through IGF2BP1 methylation.

Conclusion

These findings reveal a comprehensive cellular and molecular mechanism of RSA and suggest that air pollution might cause pregnancy loss by affecting the methylation level of the IGF2BP1 promoter.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-022-01327-2.