Spatial variations in ambient ultrafine particle concentrations and risk of congenital heart defects

Effects of particulate air pollution exposure on lung-brain axis and related miRNAs modulation in mouse models

Particulate matter exposure is linked to numerous health issues, including respiratory, cardiovascular, and neurodegenerative diseases. This review focuses on the biological mechanisms through which air pollution influences the lung-brain axis, highlighting the role of miRNAs in regulating gene pathways affected by PM. Some microRNAs (miRNAs) are identified as key modulators of cellular processes, including inflammation, epithelial-to-mesenchymal transition (EMT), and blood-brain barrier integrity. Using mice models to study these effects allows for controlled experimentation on the systemic distribution of PM across biological barriers. Among the imaging technologies, Positron Emission Tomography is the best approach to monitor the distribution and effects of PM in vivo. The research underscores the importance of miRNA profiles as potential markers for the health effects of PM exposure, suggesting that specific miRNAs could serve as early indicators of damage to the lung-brain axis.

Maternal exposure to fine particulate matter in the air and risk for fetal congenital heart defects: A case-control study

Prior research into the association between fine particulate matter (PM2.5) exposure and the risk for fetal congenital heart defect (CHD) has yielded inconclusive and conflicting results. More epidemiologic evidence from different regions is necessary. A case-control study was conducted with 360 CHD cases and 3600 healthy newborns. Both the cases and the controls were registered by the mothers in the Prenatal Health Care System during the first trimester and gave birth at hospitals in the Tongzhou District of Beijing between 2013 and 2018. Information on PM2.5 was obtained from satellite remote sensing monitoring data. We estimated average monthly PM2.5 exposure for participants from 3 months before the last menstrual period through 6 months of gestational period. A logistic regression model was used to estimate odd ratio (OR) (95 % confidence interval, CI) for PM2.5 exposure level and fetal risk for CHD. In our study, PM2.5 concentrations before pregnancy and in the first trimester were not associated with CHD risk. In the second trimester, 2nd high quartile PM2.5 group during the second month were associated with a lower CHD risk (adjusted OR(aOR)= 1.42, 95 % CI: 1.04-1.94) and highest quartile level group of PM2.5 exposure in the third month were associated with a reduced risk for fetal CHD (aOR=0.70, 95 % CI: 0.51-0.97). After Bonferroni's α correction, no comparisons were statistically significant. In conclusion, no associations were found between PM2.5 exposure level and fetal risk for CHD in our study.

Birth Outcomes among Infants Born between 2006 and 2018 after Maternal Exposure during Pregnancy to Ultrafine Particles from Aviation around a Large International Airport in the Netherlands

BACKGROUND

People who live near airports are exposed to higher concentrations of ultrafine particles (UFPs) from aviation. Pregnant women and their fetuses, in particular, are considered to be highly susceptible to environmental exposures.

OBJECTIVE

Using existing national databases, we investigated associations between adverse birth outcomes and exposure to UFPs from aviation (UFP-aviation) at the residential address during pregnancy.

METHODS

We identified ∼ 286,000 singleton birth records (from between 2006 and 2018) from mothers who, for at least 6 months during pregnancy, lived in a 50 × 56 km area around Schiphol Airport. This information was linked to modeled monthly averaged UFP-aviation concentrations at the residential address during pregnancy. We modeled the association between exposure to UFP-aviation during pregnancy and pregnancy outcomes through logistic regression, adjusting for individual and neighborhood level covariates. We performed a number of sensitivity analyses to investigate the robustness of the results, including adjustment for other air pollutants and noise.

RESULTS

Effect estimates, expressed per 3,500 particles/cm3 (approximately the 5th-9th percentile difference) increase, were generally positive in the main model for preterm birth (PTB) and small for gestational age (SGA) [PTB OR = 1.02 (95% CI: 0.96, 1.07) and SGA OR = 1.02 (95% CI: 0.98, 1.07)] and congenital anomalies (CAs) at birth [any CA OR = 1.05 (95% CI: 0.98, 1.07)]. Associations with UFP-aviation became stronger in some of the sensitivity analyses, such as when the four municipalities with the lowest exposure were excluded (for PTB, SGA, and CA), when the population was restricted to mothers with a Dutch background (PTB), after nonlinear adjustment for nitrogen dioxide (NO 2 ) and elemental carbon (EC) (PTB), after including municipality as a random effect (CA), and in some specific strata of the population. No associations were found with infant mortality, low Apgar score, and low birth weight.

CONCLUSIONS

We found suggestive evidence for associations between exposure to UFP-aviation during pregnancy and pregnancy outcomes. https://doi.org/10.1289/EHP14398.

Fine particulate matter‑induced cardiac developmental toxicity (Review)

Fine particulate matter (PM2.5) has become an important risk factor threatening human health. Epidemiological and toxicological investigations have revealed that PM2.5 not only leads to cardiovascular dysfunction, but it also gives rise to various adverse health effects on the human body, such as cardiovascular and cerebrovascular diseases, cancers, neurodevelopmental disorders, depression and autism. PM2.5 is able to penetrate both respiratory and placental barriers, thereby resulting in negative effects on fetal development. A large body of epidemiological evidences has suggested that gestational exposure to PM2.5 increases the incidence of congenital diseases in offspring, including congenital heart defects. In addition, animal model studies have revealed that gestational exposure to PM2.5 can disrupt normal heart development in offspring, although the potential molecular mechanisms have yet to be fully elucidated. The aim of the present review was to provide a brief overview of what is currently known regarding the molecular mechanisms underlying cardiac developmental toxicity in offspring induced by gestational exposure to PM2.5.

Identifying the critical windows of temperature extremes exposure and congenital heart diseases

The associations between atmospheric temperature and congenital heart disease (CHD) and its subtypes are still inconclusive. In this population-based retrospective case-control study, 643 CHD cases and 3,215 non-CHD controls were analyzed through distributed lag nonlinear model to estimate the effect of weekly temperature exposure on CHD risk and to identify potentially vulnerable windows. Through the binary logistic regression model, we found that elevated temperature in the first trimester was associated with an increased risk of overall CHD and ventricular septal defect (VSD) (OR: 1.059, 95% CI: 1.002-1.119; OR: 1.094, 95% CI: 1.005-1.190, respectively), while increased temperature in the second trimester was significantly positively correlated with atrial septal defect (ASD) risk. However, the results of the DLNM showed a nonlinear relationship between the weekly average temperature and the risk of total CHDs and the subtypes. Exposure to extremely, moderately, and mildly high temperatures significantly increased the risk of overall CHD, ASD and VSD, and the critical windows were mainly concentrated at the 5th-11th and 23rd-27th weeks of gestation. Low-temperature extreme exposure resulted in vulnerable windows for ASD only: 13th-14th gestational weeks. No significant positive associations were found between extreme temperature and patent ductus arteriosus or tetralogy of Fallot. In the current context of climate change, our results add new evidence to the present understanding of the effects of high- and low-temperature extreme exposure on CHD and its main subtypes.

Maternal exposure to ambient ozone and fetal congenital heart defects: a national multicenter study in China

BACKGROUND

Ambient O3 has demonstrated an aggravated increasing trend in the context of global warming. The available evidence of maternal exposure to ambient O3 on fetal congenital heart defects (CHD) is still limited, especially in high polluted areas.

OBJECTIVE

To examine associations of maternal exposure to ambient O3 during early pregnancy with fetal CHDs.

METHODS

We conducted a national multicenter study in 1313 hospitals from 26 provinces in China and collected a total of 27,817 participants at high risk of CHD from 2013 to 2021. Exposure to ambient O3 during the embryonic period, preconception, the first trimester and periconception was assessed by extracting daily concentrations from a validated grid dataset at each subject's residential district. CHDs were diagnosed based on fetal echocardiography.

RESULTS

Each 10 µg/m3 increase of exposure to ambient O3 during the embryonic period was approximately linearly associated with a 12.7% (odds ratio [OR]: 1.127, 95% confidence interval [CI]: 1.098, 1.155) increase in odds of pooled CHD (p < 0.001). The associations remain robust after adjusting for ambient PM2.5 and NO2 exposure. The odds of different types of CHD in association with ambient O3 exposure varied greatly. We observed significant association of ambient O3 exposure with ventricular septal defect (VSD), tetralogy of Fallot (TOF); pulmonary stenosis (PS), pulmonary atresia (PA), transposition of great arteries (TGA) and persistent left superior vena cava (PLSVC), with TOF demonstrating the strongest estimates (OR: 1.194, 95% CI:1.107, 1.288). The estimates for preconception, the first trimester and periconception demonstrate consistent findings with the main analyses, indicating stronger associations of ambient O3 exposure during the periconception period.

IMPACT

Our study provides evidence that higher ambient O3 during early pregnancy was significantly associated with increased odds of fetal CHD. Our findings suggest that pregnant women, clinical practitioners, and policy makers need to pay more attention to the exposure to higher ambient O3 during early pregnancy to reduce the risk of developing CHD and to improve outcomes across the life span.

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.

Maternal exposure to fine particulate matter and congenital heart defects during preconception and pregnancy period: A cohort-based case-control study in the Taiwan maternal and child health database

BACKGROUND

Few studies have explored the association between maternal exposure to particulate matter with an aerodynamic diameter of ≤2.5 μm (PM2.5) and congenital heart defects occurring before and during pregnancy. We aimed to investigate the association and the critical time windows between the maternal exposure to PM2.5 and congenital heart defects.

METHOD

We conducted a cohort-based case-control study of 507,960 participants obtained from the Taiwan Maternal and Child Health Database between 2004 and 2015. We applied satellite-based spatiotemporal models with 1-km resolution to calculate the average PM2.5 concentration during preconception and the specific periods of pregnancy. We also performed conditional logistic regression with distributed lag non-linear models (DLNMs) to assess the effects of weekly average PM2.5 on both congenital heart defects and their isolated subtypes, as well as the concentration-response relationships.

RESULTS

In DLNMs, exposure to PM2.5 (per 10 μg/m3) during weeks 7-12 before conception and weeks 3-9 after conception was associated with congenital heart defects. The strongest association at 12 weeks before conception (odds ratio [OR] = 1.026, 95% confidence intervals [CI]: 1.012-1.040) and 7 weeks after conception (OR = 1.024, 95% CI: 1.012-1.036) for every 10 μg/m3 increase in PM2.5 concentration. In modification analysis, strongest associations were observed for low SES.

CONCLUSIONS

Our study revealed that exposure to ambient PM2.5 raises the risk of congenital heart defects, particularly among individuals with lower socioeconomic status. Moreover, our findings suggest that preconception exposure to PM2.5 may be a crucial period for the development of congenital heart defects.

Prenatal exposure to ambient air pollutants and congenital heart defects: An umbrella review

BACKGROUND

Prenatal exposure to ambient air pollutants has been linked to congenital heart defects (CHD), but findings of existing systematic reviews have been mixed.

OBJECTIVE

To assess the epidemiological evidence on associations between prenatal exposure to ambient air pollutants and CHD subtypes, based on a systematic overview of reviews ("umbrella review").

METHODS

We conducted a systematic search for reviews assessing associations between prenatal exposure to criteria air pollutants and CHD. The risk of bias was evaluated using the Risk of Bias in Systematic Reviews (ROBIS) tool. The certainty of the systematic review findings was graded using the Navigation Guide methodology.

RESULTS

We identified eleven systematic reviews, including eight with meta-analyses, assessing in total 35 primary studies of prenatal exposure to criteria air pollutants and various CHD subtypes. The certainty of the findings of four meta-analyses indicating an increased risk for coarctation of the aorta associated with nitrogen dioxide exposure was rated as moderate. The certainty of findings indicating positive, inverse, or null associations for other pollutant-subtype combinations was rated as very low to low, based on low precision and high statistical heterogeneity of summary odds ratios (SOR), substantial inconsistencies between review findings, and methodological limitations of the systematic reviews.

DISCUSSION

The inconsistent findings and high statistical heterogeneity of many SOR of the included systematic reviews may partly be traced to differences in methodological approaches, and the risk of bias across included reviews (e.g., inclusion criteria, systematic search strategies, synthesis methods) and primary studies (e.g., exposure assessment, diagnostic criteria). Adherence to appropriate systematic review guidelines for environmental health research, as well as rigorous evaluation of risk of bias in primary studies, are essential for future risk assessments and policy-making. Still, our findings suggest that prenatal exposure to ambient air pollutants may increase risks for at least some CHD subtypes.

Association between First Trimester Exposure to Ambient PM2.5 and NO2 and Congenital Heart Defects: A Population-Based Cohort Study of 1,342,198 Live Births in Canada

BACKGROUND

The extent to which ambient air pollution contributes to the pathogenesis of congenital heart defects remains uncertain.

OBJECTIVE

We investigated whether first trimester exposure to ambient fine particulate matter (PM2.5) and nitrogen dioxide (NO2) was associated with the risk of critical and noncritical heart defects in a large population-based cohort of births.

METHODS

We carried out a retrospective cohort study of children conceived between 2000 and 2016 in Quebec, Canada. Heart defects were identified via data from the Maintenance and Use of Data for the Study of Hospital Clientele registry. The main exposures were average concentration of PM2.5 and NO2 in a) the first trimester and b) the month of conception. Exposures were estimated at the residential postal code. Associations with critical and noncritical heart defects were assessed using logistic regression models, adjusted for maternal and infant characteristics. We considered single- and two-pollutant models and assessed modifying effects of maternal comorbidity, including preexisting hypertension, preeclampsia, anemia, and diabetes.

RESULTS

The cohort comprised 1,342,198 newborns, including 12,715 with heart defects. Exposure in the first trimester and month of conception yielded similar results; both were associated with a greater risk of heart defects. Adjusted odds ratios (OR) for any heart defect per interquartile range increase were 1.02 (95% CI: 1.00, 1.05) for PM2.5 and 1.10 (95% CI: 1.07, 1.13) for NO2. Associations with atrial septal defects were 1.08 (95% CI: 1.03, 1.14) for PM2.5 and 1.19 (95% CI: 1.12, 1.25) for NO2. Corresponding ORs for ventricular septal defects and individual critical heart defects were not significant. PM2.5 (OR=1.11; 95% CI: 1.06, 1.17) and NO2 (OR=1.23; 95% CI: 1.17, 1.31) exposure were associated with a greater risk of heart defects in mothers with comorbidity.

DISCUSSION

In this population-based cohort, prenatal exposure to ambient air pollution during the first trimester was associated with an increased risk of heart defects, particularly atrial septal defects. The association with heart defects was greater in mothers with comorbidity. https://doi.org/10.1289/EHP11120.

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

Exposure to air pollution during pregnancy has been linked to birth defects. But the directions of studies on the associations between air pollutants exposure and effect on the incidence of congenital heart disease (CHDs) were inconsistent. To date, few studies were concentrated on the effects of both particulate matter and gaseous air pollutant exposure on CHDs across the full gestational week simultaneously. Our study aimed to investigate the critical exposure windows for each air pollutant throughout 40 gestational weeks. Data on CHDs, air pollution, and meteorological factors from 2013 to 2019 were collected in Lanzhou, China. A distributed lag nonlinear model combined with a quasi-Poisson regression model was applied to evaluate the weekly exposure-lag-response association between air pollutants levels and CHDs, and the subgroup analyses were conducted by gender (baby boy and baby girl). The study included 1607 mother-infant pairs. The results demonstrated that exposure of pregnant women to particulate matter ≤ 5 μm (PM_2.5) at lag 1-4 weeks was significantly associated with the risk of CHDs, and the strongest effects were observed in the lag 1 week (1.150, 95%CI 1.059-1.248). For exposure to particulate matter ≤ 10 μm (PM₁₀) at lag 1-3 weeks, the strongest effects were observed in the lag 1 week (1.075, 95% CI 1.026-1.128). For exposure to sulfur dioxide (SO₂) at lag 1-4 weeks, the strongest effects were observed in the lag 1 week (1.154, 95% CI 1.025-1.299). For exposure to carbon monoxide (CO) at lag 1-3 weeks, the strongest effects were observed in the lag 1 week (1.089, 95% CI 1.002-1.183). For exposure to ozone (O₃) concentration at lag 9-15 weeks, the strongest effects were observed in the lag 15 weeks (1.628, 95% CI 1.001-2.649). The cumulative effects of PM_2.5, PM₁₀, SO₂, and CO along weeks with a maximum of 1.609 (95%CI 1.000-2.589), 1.286 (95%CI 1.007-1.641), 1.648 (95%CI 1.018-2.668), and 1.368 (95%CI 1.003, 1.865), respectively. The effects were obvious in the initial gestational weeks too. Through the gender stratification analysis, the air pollutants with significant effects were PM_2.5 for baby boys and PM_2.5, PM₁₀, SO₂, CO, NO₂, and O₃ for baby girl. For the relationship between CHDs and air pollution in Lanzhou, PM_2.5, PM₁₀, SO₂, CO, and O₃ played an important role in the initial gestational weeks, especially for baby girl.

Experimental human placental models for studying uptake, transport and toxicity of micro- and nanoplastics

Micro- and nanoplastics (MNPs) are ubiquitous in the environment and have recently been found in human lungs, blood and placenta. However, data on the possible effects of MNPs on human health is extremely scarce. The potential toxicity of MNPs during pregnancy, a period of increased susceptibility to environmental insults, is of particular concern. The placenta provides a unique interface between maternal and fetal circulation which is essential for in utero survival and healthy pregnancy. Placental toxicokinetics and toxicity of MNPs are still largely unexplored and the limited studies performed up to now focus mainly on polystyrene particles. Practical and ethical considerations limit research options in humans, and extrapolation from animal studies is challenging due to marked differences between species. Nevertheless, diverse in vitro and ex vivo human placental models exist e.g., plasma membrane vesicles, mono-culture and co-culture of placental cells, placenta-on-a-chip, villous tissue explants, and placental perfusion that can be used to advance this research area. The objective of this concise review is to recapitulate different human placental models, summarize the current understanding of placental uptake, transport and toxicity of MNPs and define knowledge gaps. Moreover, we provide perspectives for future research urgently needed to assess the potential hazards and risks of MNP exposure to maternal and fetal health.

Assessing the effect of fine particulate matter on adverse birth outcomes in Huai River Basin, Henan, China, 2013-2018

Previous studies have indicated that maternal exposure to particles with aerodynamic diameter <2.5 μm (PM_2.5) is associated with adverse birth outcomes. However, the critical exposure windows remain inconsistent. A retrospective cohort study was conducted in Huai River Basin, Henan, China during 2013-2018. Daily PM_2.5 concentration was collected using Chinese Air Quality Reanalysis datasets. We calculated exposures for each participant based on the residential address during pregnancy. Binary logistic regression was used to examine the trimester-specific association of PM_2.5 exposure with preterm birth (PTB), low birth weight (LBW) and term LBW (tLBW), and we further estimated monthly and weekly association using distributed lag models. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for each 10 μg/m³ increase in PM_2.5 exposure. Stratified analyses were performed by maternal age, infant gender, parity, and socioeconomic status (SES). In total, 196,780 eligible births were identified, including 4257 (2.2%) PTBs, 3483 (1.8%) LBWs and 1770 (0.9%) tLBWs. Maternal PM_2.5 exposure during the second trimester were associated with the risk of PTB and LBW. At the monthly level, the PTB and LBW risks were associated with PM_2.5 exposure mainly in the 4th -6th month. By estimating the weekly-specific association, we observed that critical exposure windows of PM_2.5 exposure and PTB were in the 18th- 27th gestational weeks. Stronger associations were found in younger, multiparous mothers and those with a female baby and in low SES. In conclusion, the results indicate that maternal PM_2.5 exposure during the second trimester was associated with PTB and LBW. Younger, multiparous mothers and those with female babies and in low SES were susceptible.

Modeling complex effects of exposure to particulate matter and extreme heat during pregnancy on congenital heart defects: A U.S. population-based case-control study in the National Birth Defects Prevention Study

BACKGROUND/OBJECTIVE

Research suggests gestational exposure to particulate matter ≤2.5 μm (PM2.5) and extreme heat may independently increase risk of birth defects. We investigated whether duration of gestational extreme heat exposure modifies associations between PM2.5 exposure and specific congenital heart defects (CHDs). We also explored nonlinear exposure-outcome relationships.

METHODS

We identified CHD case children (n = 2824) and non-malformed live-birth control children (n = 4033) from pregnancies ending between 1999 and 2007 in the National Birth Defects Prevention Study, a U.S. population-based multicenter case-control study. We assigned mothers 6-week averages of PM2.5 exposure during the cardiac critical period (postconceptional weeks 3-8) using the closest monitor within 50 km of maternal residence. We assigned a count of extreme heat days (EHDs, days above the 90th percentile of daily maximum temperature for year, season, and weather station) during this period using the closest weather station. Using generalized additive models, we explored logit-nonlinear exposure-outcome relationships, concluding logistic models were reasonable. We estimated joint effects of PM2.5 and EHDs on six CHDs using logistic regression models adjusted for mean dewpoint and maternal age, education, and race/ethnicity. We assessed multiplicative and additive effect modification.

RESULTS

Conditional on the highest observed EHD count (15) and at least one critical period day during spring/summer, each 5 μg/m3 increase in average PM2.5 exposure was significantly associated with perimembranous ventricular septal defects (VSDpm; OR: 1.54 [95% CI: 1.01, 2.41]). High EHD counts (8+) in the same population were positively, but non-significantly, associated with both overall septal defects and VSDpm. Null or inverse associations were observed for lower EHD counts. Multiplicative and additive effect modification estimates were consistently positive in all septal models.

CONCLUSIONS

Results provide limited evidence that duration of extreme heat exposure modifies the PM2.5-septal defects relationship. Future research with enhanced exposure assessment and modeling techniques could clarify these relationships.

Maternal exposure to air pollution and congenital heart diseases in Henan, China: A register-based case-control study

BACKGROUND

Association between ambient air pollution and congenital heart diseases (CHDs) remains inconclusive, and the critical exposure windows has not been well studied.

OBJECTIVES

This case-control study aimed to assess the effect of ambient air pollution exposure on the risk of CHDs and the subtypes in Henan, China, and further to explore potential susceptible windows.

METHODS

Daily average particulate matter with an aerodynamic diameter of ≤2.5 µm (PM_2.5) and ≤10 µm (PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), carbon monoxide (CO) and ozone (O₃) were collected by Chinese Air Quality Reanalysis datasets. Binary logistic regression was used to examine trimester-specific associations between per 10 μg/m³ increase in air pollutants and CHDs as well as the major subtypes. Distributed lag models incorporating logistic regression were applied to explore weekly-specific associations.

RESULTS

A total of 196,069 singleton live births were included during 2013-2018, 643 CHDs were identified (3.3‰). We found that first and second trimester CO exposure increased overall CHDs risk, the adjusted odds ratio (aOR) and 95% confidence interval (CI) were 1.066 (1.010-1.125) and 1.065 (1.012-1.122). For CHDs subtypes, we observed that NO₂ and CO in first trimester, PM_2.5 and PM₁₀ in the second trimester exposure were associated with the risk of atrial septal defect (ASD), the susceptible windows of air pollutants and ASD mainly occurred in the 1st- 6th gestational weeks. No positive association was observed for air pollution and tetralogy of Fallot.

CONCLUSION

Our findings suggest that ambient air pollution exposure is associated with the risk of CHDs especially for ASD, and the susceptible windows generally occurred in first trimester. Further well-designed longitudinal studies are warranted to confirm our findings.

Congenital anomalies associated with ambient temperature variability during fetal organogenesis period of pregnancy: Evidence from 4.78 million births

BACKGROUNDS

Evidence for the effects of temperature variability on risk of congenital anomalies is lacking. We aimed to examine the association of temperature variability during fetal organogenesis period (weeks 3-8 post-conception) with major congenital anomalies.

METHODS

A retrospective cohort study comprising 4,787,356 singleton live-births and stillbirths in China was performed. We defined two temperature variability indices within gestational week i: the standard deviation (SD) of daily temperature (TVSD_i) and the maximum day-to-day temperature difference (TVD_i). At 6-week long timescales, we computed the SD of daily temperature (TVSD_3-8) and the average value of TVD_i (TVD_3-8). We matched two temperature variability indices, pollutant exposure levels over entire exposure window and data of each mother-infant pairs. An extended generalized estimating equation log-binomial regression model was constructed to explore their associations after adjusting for individual characters, temperature extremes and air pollutants. Stratified and sensitivity analyses were also performed.

RESULTS

59,571 neonates were registered as major congenital anomalies besides genetic and chromosomal anomalies. At weekly levels, the highest risk estimates of two temperature variability indices occurred at the 5th week for most anomaly groups. All TVSD₅, TVD₅, and maximum weekly TVSD and TVD were significantly associated with all anomaly groups; with the increment of 1 °C, the estimated risk ratio (RR) and corresponding 95% confidence interval (CI) ranges from 1.03 (1.01-1.05) to 1.19 (1.08-1.31). At 6-week scales, TVSD_3-8 and TVD_3-8 were associated with most anomaly subgroups. Overall, the strongest associations were estimated for isolated defects among morphology subgroups and cardiac defects among type subgroups.

CONCLUSIONS

Exposure to temperature variability during fetal organogenesis period of pregnancy is associated with increased risk of major congenital defects. Our findings provide a research foundation for public health policies, and further mechanism investigation.

Associations between air pollution exposure and birth defects: a time series analysis

Air pollution is a serious environmental problem in China. Birth defects are particularly vulnerable to outdoor air pollution. Our study was to evaluate the association between short-term exposure to air pollutants and the risk of birth defects. Daily data including the air pollutants, meteorological characteristics, and birth records were obtained in Hefei, China, during January 2013 to December 2016. The findings showed that PM_2.5, PM₁₀, SO₂, NO₂, and O₃ exposures were positively correlated with the risk of birth defects. Maternal exposure to PM_2.5 and SO₂ during the 4th to 13th gestational weeks was observed to have a significant association with the risk of birth defects, with the maximum effect in the 7th or 8th week for PM_2.5 and the maximum effect in the 7th week for SO₂. The positively significant exposure windows were the 4th to 14th weeks for PM₁₀, the 4th to 12th weeks for NO₂, and the 26th to 35th weeks for O₃, respectively. The strongest associations were observed in the 8th week for PM₁₀, the 7th week for NO₂, and in the 31st or 32nd week for O_3. The findings of this study demonstrate that air pollutants increase the risk of birth defects among women during pregnancy in Hefei, China, which provide evidence for improving the health of pregnant women and neonates in developing countries, and uncovered potential opportunities to reduce or prevent birth defects by proactive measures during pregnancy.

Meta-analyses of maternal exposure to atmospheric particulate matter and risk of congenital anomalies in offspring

Congenital anomalies are the main causes of infant death and disability. Previous studies have suggested that maternal exposure to particulate matter is related to congenital malformation. However, the conclusions of this study remain controversial. Hence, meta-analyses were performed to assess the relationship between maternal exposure to particulate matter and the risk of congenital anomalies. The Medline, Embase, and Web of Science databases were systemically searched from inception until August 2020 to find articles related to birth defects and particulate matter. The pooled risk estimated for the combination of pollution outcomes was calculated for each study by performing fixed effects or random effects models. The existence of heterogeneity and publication bias in relevant studies was also examined. Thirty studies were included in the analysis. A statistically increased summary risk valuation was found. PM₁₀ exposure was associated with an increased risk of congenital heart disease, neural tube defects, and cleft lip with or without cleft palate (OR per 10 μg/m³ = 1.05, 95% CI, 1.03-1.07; OR per 10 μg/m³ = 1.04, 95% CI, 1.01-1.06; OR per 10 μg/m³ = 1.03, 95% CI, 1.01-1.06). Maternal exposure to particulate matter might be associated with an increased risk of congenital anomalies. Our results indicate the dangers of particulate matter exposure on fetal development and the importance of protection against exposure to such particles during pregnancy. The schematic representation of the association between maternal exposure to PM_2.5/PM₁₀ and congenital anomalies in offspring, and geographic distribution of the included reports in the meta-analyses.

Association between maternal exposure to gaseous pollutants and atrial septal defect in China: A nationwide population-based study

BACKGROUND

The association between maternal exposure to gaseous air pollutants and congenital heart defects (CHD) remains unclear. The concentration-response relationship and the time windows of susceptibility to gaseous pollutants may vary by pollutant species and CHD subtypes.

OBJECTIVE

We aimed to examine the relationship between maternal exposures to four species of gaseous pollutants (NO₂, O₃, SO₂, and CO) and atrial septal defect (ASD), which is a common subtype of CHD, and to determine the critical time windows of susceptibility for each gaseous pollutant.

METHODS

Among 1,253,633 infants born between October 1, 2013 and December 31, 2016 in China, 1937 newborns were diagnosed with isolated ASD, a prevalence of 1.55‰. Maternal exposures to the gaseous pollutants were estimated by matching the geocoded maternal addresses with the gridded ambient concentrations. The adjusted odds ratios (aOR) between exposures and ASD were quantified by using mixed-effects logistic regression models.

RESULTS

We found significantly positive associations between ASD and maternal exposures to NO₂, O₃, SO₂, and CO during entire pregnancy, first-, second-, and third-trimester. However, no statistically significant association was found between maternal exposure to PM_2.5, PM_2.5-10 and ASD risk (P > 0.05). In the fully adjusted model with respect to average exposure over entire pregnancy, the adjusted odds ratios (aOR) for each 10 μg/m³ increment of NO₂, O₃, SO₂ were 1.33 (95% CI: 1.22-1.45), 1.13 (95% CI: 1.10-1.16), 1.28 (95% CI: 1.20-1.35), respectively; the aOR for each 100 μg/m³ increment of CO was 1.10 (95% CI: 1.06-1.15). The observed concentration-response relationships varied by exposure periods and pollutants, with the strongest association for NO₂ during the 1st-8th embryology weeks, for O₃ during the third trimester, for SO₂ during the second trimester, and for CO without obvious variation.

CONCLUSIONS

The findings suggest an increased risk of ASD in association with maternal exposures to four common gaseous pollutants. From the perspective of birth defects prevention and ASD risk mitigation, it is critical to reduce maternal exposure to gaseous pollutants especially during the most susceptible time windows.

Independent and interactive effects of air pollutants and ambient heat exposure on congenital heart defects

Accumulating studies have been focused on the independent effects of air pollutants and ambient heat exposure on congenital heart defects (CHDs) but with inconsistent results, and their interactive effect remains unclear. A case-control study including 921 cases and 9210 controls was conducted in Changsha, China in warm season in 2015-2018. The gravidas were assigned monthly averages of daily air pollutants and daily maximum temperature using the nearest monitoring station method and city-wide average method, respectively, during the first trimester of pregnancy. Multivariate logistic regression models were used to estimate the independent effects of each air pollutant and different ambient heat exposure indicators. Their additive joint effects were quantified using attribute proportions of interaction (API). Increasing SO₂ consistently increased the risk of CHDs in the first trimester of pregnancy, with aORs ranging from 1.78 to 2.04. CO, NO₂ and PM_2.5 exposure in the first month of pregnancy, and O₃ exposure in the second and third month of pregnancy were also associated with elevated risks of CHDs, with aORs ranging from 1.04 to 1.15. Depending on the ambient heat exposure indicator used, air pollutants showed more apparent synergistic effects (API > 0) with less and moderately intense heat exposure. Maternal exposure to CO, NO₂, SO₂, PM_2.5 and O₃ during early pregnancy increased risk of CHDs, and ambient heat exposure may enhance these effects. Our findings help to understand the interactive effect of air pollution with ambient heat exposure on CHDs, which is of vital public health significance.

A Satellite-Based Spatio-Temporal Machine Learning Model to Reconstruct Daily PM2.5 Concentrations across Great Britain

Epidemiological studies on the health effects of air pollution usually rely on measurements from fixed ground monitors, which provide limited spatio-temporal coverage. Data from satellites, reanalysis, and chemical transport models offer additional information used to reconstruct pollution concentrations at high spatio-temporal resolutions. This study aims to develop a multi-stage satellite-based machine learning model to estimate daily fine particulate matter (PM_2.5) levels across Great Britain between 2008–2018. This high-resolution model consists of random forest (RF) algorithms applied in four stages. Stage-1 augments monitor-PM_2.5 series using co-located PM₁₀ measures. Stage-2 imputes missing satellite aerosol optical depth observations using atmospheric reanalysis models. Stage-3 integrates the output from previous stages with spatial and spatio-temporal variables to build a prediction model for PM_2.5. Stage-4 applies Stage-3 models to estimate daily PM_2.5 concentrations over a 1 km grid. The RF architecture performed well in all stages, with results from Stage-3 showing an average cross-validated R² of 0.767 and minimal bias. The model performed better over the temporal scale when compared to the spatial component, but both presented good accuracy with an R² of 0.795 and 0.658, respectively. These findings indicate that direct satellite observations must be integrated with other satellite-based products and geospatial variables to derive reliable estimates of air pollution exposure. The high spatio-temporal resolution and the relatively high precision allow these estimates (approximately 950 million points) to be used in epidemiological analyses to assess health risks associated with both short- and long-term exposure to PM_2.5.

Prenatal exposure to traffic-related air pollution and risk of congenital diseases in South Korea

BACKGROUND

Previous studies have suggested links between exposure to ambient air pollutants and increased risk of congenital heart defects. However, few studies have investigated the association between other congenital diseases and traffic-related air pollution. In this study, we assessed the relationship between prenatal exposure to fine particulate matter (PM_2.5) and nitrogen dioxide (NO₂) with congenital diseases in South Korea.

METHODS

Patients with one or more congenital diseases and a control group of patients with non-infective gastroenteritis and colitis with a case:control ratio of 1:3 were obtained from the National Health Insurance Service data for 2008-2013 in South Korea. We estimated the associations of PM_2.5 and NO₂ exposures with congenital diseases using generalized estimation equations after controlling for covariates.

RESULTS

Maternal PM_2.5 exposure during the first and second trimester showed positive associations with overall congenital diseases, with changes of 14.7% (95% confidence intervals (CI), 9.3%, 20.3%) and 16.2% (95% CI, 11.0%, 21.7%), respectively, per 11.1 μg/m³ and 10.2 μg/m³ increase of PM_2.5 interquartile range (IQR). Similarly, NO₂ exposure during the first and second trimester was associated with increased numbers of overall congenital anomalies, with 8.2% (95% CI, 4.2%, 12.3%) and 15.6% (95% CI, 9.3%, 22.2%) more cases, respectively, per 10.6 ppb increase of NO₂. We found that maternal PM_2.5 exposure during the first and second trimesters of pregnancy was significantly associated with increased risk of specific congenital diseases, including subtypes affecting the circulatory, genitourinary, and musculoskeletal system. However, no significant associations were observed during the third trimester. Maternal NO₂ exposure across the entire pregnancy was associated with malformations of the musculoskeletal system.

CONCLUSIONS

Our study identified significant links between in utero exposure to PM_2.5 and NO₂ and certain congenital diseases, and suggests that stricter controls on PM_2.5 and NO₂ concentrations are required.

Translocation of (ultra)fine particles and nanoparticles across the placenta; a systematic review on the evidence of in vitro, ex vivo, and in vivo studies

Fetal development is a crucial window of susceptibility in which exposure may lead to detrimental health outcomes at birth and later in life. The placenta serves as a gatekeeper between mother and fetus. Knowledge regarding the barrier capacity of the placenta for nanoparticles is limited, mostly due to technical obstacles and ethical issues. We systematically summarize and discuss the current evidence and define knowledge gaps concerning the maternal-fetal transport and fetoplacental accumulation of (ultra)fine particles and nanoparticles. We included 73 studies on placental translocation of particles, of which 21 in vitro/ex vivo studies, 50 animal studies, and 2 human studies on transplacental particle transfer. This systematic review shows that (i) (ultra)fine particles and engineered nanoparticles can bypass the placenta and reach fetal units as observed for all the applied models irrespective of the species origin (i.e., rodent, rabbit, or human) or the complexity (i.e., in vitro, ex vivo, or in vivo), (ii) particle size, particle material, dose, particle dissolution, gestational stage of the model, and surface composition influence maternal-fetal translocation, and (iii) no simple, standardized method for nanoparticle detection and/or quantification in biological matrices is available to date. Existing evidence, research gaps, and perspectives of maternal-fetal particle transfer are highlighted.

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.

Maternal air pollution exposure and congenital heart defects in offspring: A systematic review and meta-analysis

BACKGROUND

Congenital heart defects (CHDs) has a multifactorial causation with a strong genetic component and many environmental triggers. Emerging body of empirical studies suggest that air pollution is an important contributor to the development of CHDs, however, there still remains some controversy over the current evidence, and to the authors' knowledge, no studies have reviewed the most recent evidence.

OBJECTIVES

We performed a systematic review and meta-analysis of epidemiological literature to investigate the relationship between maternal air pollution exposure and CHDs risk in offspring. The presence of heterogeneity and publication bias across available studies were also examined.

METHODS

An extensive literature search of epidemiological studies pertaining to air pollution and CHDs, published in English language, until August 1, 2019 was conducted. Summary risk estimates of pollution-outcome combinations were calculated for i) risk per specific increment of concentration and ii) risk at high versus low exposure level in each study using fixed-effect model or random-effects model.

RESULTS

A total of 26 studies were finally included. In the meta-analyses, high versus low carbon monoxide (CO) exposure was associated with an increased risk of tetralogy of Fallot [odds ratio (OR) = 1.21, 95% confidence interval (CI): 1.04-1.41], yet particulate matter ≤ 5 μm (PM_2.5) exposure was marginally associated with it. Increased risk of atrial septal defects (ASDs) was found for each 10 μg/m³ and 10 ppb increment in particulate matter ≤ 10 μm (PM₁₀) and ozone (O₃) exposure, respectively (OR = 1.04, 95% CI: 1.00-1.09; OR = 1.09, 95% CI: 1.02-1.17). Categorical nitrogen dioxide (NO₂) exposure was associated with an increased risk of coarctation of the aorta (OR for high versus low = 1.14, 95% CI: 1.02-1.26). Analyses for other combinations yielded none statistically significant associations. Sensitive analyses showed similar findings.

CONCLUSIONS

The summary effect estimates from this study suggest statistically significant associations between increased risk of specific CHDs subtypes and PM_2.5, PM₁₀, NO₂, CO, and O₃ exposures. Further studies, especially conducted in developing countries, with improvements in exposure assessing, outcome harmonizing, and mechanistic understanding are needed to elaborate the suggestive associations.