Association Between Ambient Air Pollution and Birth Weight by Maternal Individual- and Neighborhood-Level Stressors

Climate change and air pollution can amplify vulnerability of glucose metabolism: The mediating effects of biological aging

Climate change and air pollution pose significant global health threats, including impacts on diabetes risk; however, their long-term effects on insulin resistance (IR), a key determinant in diabetes pathophysiology, remain unclear. This study investigated whether exposure to heatwaves, temperature fluctuations, and warm-season ozone (O3) contributes to or exacerbates IR and explored the potential mediating role of biological aging. The study enrolled 6901 participants and assessed both traditional and novel IR indicators: estimated glucose disposal rate (eGDR), triglyceride-glucose (TyG) index, triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-c), metabolic score for IR (METS-IR), TyG-body mass index (TyG-BMI), TyG-waist circumference (TyG-WC), waist-to-height ratio (WHtR), TyG-WHtR, and lipid accumulation product (LAP). Ordinary least squares regression models were applied to evaluate the long-lasting effects of heatwaves, temperature fluctuation, and warm-season O3 on IR, incorporating Huber-White robust standard errors for model stability. Causal mediation analysis was utilized to investigate the mediating effects of biological aging. We found that exposure to heatwaves and higher concentrations of warm-season O3 was associated with elevated IR levels, with males, smokers, drinkers, and low-income individuals being more vulnerable. Accelerated biological aging (including body age, metabolomic aging rate, etc.) could significant mediate the long-lasting effects of heatwaves and warm-season O3. Our findings suggest that climate change and air pollution could amplify the vulnerability of glucose metabolism, particularly in males, smokers, drinkers, and individuals with low-income. More importantly, our findings reveal the importance of mitigating biological aging to prevent IR in the future, as global diabetes prevalence escalates rapidly.

Dynamic Single-Index Scalar-On-Function Model

Environmental exposures often exhibit temporal variability, prompting extensive research to understand their dynamic impacts on human health. There has been a growing interest in studying time-dependent exposure mixtures beyond a single exposure. However, current analytic methods typically assess each exposure individually or assume an additive relationship. This paper aims to fill the gap in method development for evaluating the joint effects of multiple time-dependent exposures on a scalar outcome. We introduce a dynamic single-index scalar-on-function model to characterize the exposure mixture's time-varying effect through a non-parametric bivariate exposure-time-outcome surface function. Utilizing B-spline tensor product bases to approximate the surface function, we propose a profiling algorithm for model estimation and establish large-sample properties for the resulting single-index estimators. In addition, we introduce a non-parametric hypothesis testing procedure to determine whether the surface function varies over time at each fixed mixture level and a model averaging solution to circumvent the issue of knot selection for spline approximations. The performance of our proposed methods is examined through extensive simulations and further illustrated using real-world applications.

Ambient ozone exposure and pregnancy complications and adverse birth outcomes: A systematic review and meta-analysis

BACKGROUND

Ambient ozone pollution is becoming a global health threat under global warming. Evidence on the association between ambient ozone and pregnancy complications and adverse birth outcomes has grown enormously. To provide a comprehensive assessment of the evidence, we performed a systematic review and meta-analysis to outline current epidemiological evidence.

METHODS

A systematic literature search up to January 2024 was conducted in PubMed, Web of Science, Cochrane Library and Embase. We included studies that examined the association of ambient ozone exposure with pregnancy complications and birth outcomes. Data extraction was performed independently. All eligible studies were synthesized qualitatively. A random-effects meta-analysis was used to summarize the available effect estimates that calculated with a 10 μg/m3 exposure. We further evaluated whether geographic location, study design, study quality, and exposure assessments explain the heterogeneity. This study protocol was registered with PROSPERO (CRD42024499445).

RESULTS

A total of 10,940 records were originally searched, 65 articles were finally included. Our results showed that first trimester ozone exposure significantly increased the risk of preeclampsia (pooled odds ratio (OR) = 1.018, 95%CI: 1.006-1.030). For birth outcomes, short-term ozone exposure was associated with the risk of preterm birth, with the pooled OR of 1.005 (95%CI: 1.002-1.008) and 1.003(95%CI:1.000-1.005). First trimester and whole pregnancy ozone exposure were associated with the risk of small for gestational age, with the pooled OR of 1.007 (95%CI: 1.002-1.012) and 1.030 (95%CI: 1.010-1.050), respectively.

CONCLUSION

First trimester ozone exposure was associated with adverse pregnancy complications and adverse birth outcomes. Future investigations that considering local climates and population characteristics are warranted to explore the vulnerability at local and regional levels for tailored preventions.

Maternal metabolomics linking prenatal exposure to fine particulate matter and birth weight: a cross-sectional analysis of the MADRES cohort

BACKGROUND

Prenatal exposure to air pollution has been associated with an increased risk of low birth weight. Disrupted metabolism may serve as an underlying mechanism, but the specific metabolic pathways involved remain unclear.

METHODS

In the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) study, 382 third-trimester maternal serum samples were analyzed for untargeted metabolomics using liquid chromatography with Fourier transform high-resolution mass spectrometry. Ambient concentrations of fine particulate matter (PM2.5), particulate matter ≤ 10 μm in diameter (PM10), nitrogen dioxide (NO2), and ozone (O3) were estimated using inverse-distance-squared weighted spatial interpolation based on daily residential histories. Birth weight was retrieved from medical records. Linear regression identified metabolomic features associated with air pollution exposure or birth weight, followed by Mummichog pathway enrichment and mediation analyses for the selected features.

RESULTS

Second-trimester PM2.5 exposure was associated with lower birth weight. Fourteen metabolic pathways were significantly associated with second-trimester PM2.5 exposure, with C21-steroid hormone biosynthesis and metabolism showing the most significant association. Sixteen metabolic pathways were significantly associated with birth weight, with vitamin A (retinol) metabolism being the most significantly enriched pathway. Seven pathways were associated with both PM2.5 exposure and birth weight, including C21-steroid hormone biosynthesis and metabolism, bile acid biosynthesis, tyrosine metabolism, ascorbate (vitamin C) and aldarate metabolism, vitamin D3 (cholecalciferol) metabolism, vitamin A (retinol) metabolism, and pyrimidine metabolism. Overweight or obese women exhibited more metabolomic features and metabolic pathways associated with PM2.5 exposure compared to underweight or normal-weight women. No associations were observed between PM10, NO2, or O3 and birth weight.

CONCLUSIONS

Maternal metabolic pathways involving steroid metabolism, oxidative stress and inflammation, vitamin metabolism, and DNA damage may link prenatal PM2.5 exposure to lower birth weight, with overweight or obese women potentially more susceptible to these metabolic disruptions.

The effect of PM2.5 exposure on placenta and its associated metabolites: A birth cohort study

The placenta is an important organ for fetal growth. Air pollution during pregnancy may cause adverse effects on offsprings via placental dysfunction. However, the metabolites underlie the effects of PM2.5 on placenta have not been well studied. 329 pregnant women were randomly selected from the Shanghai Maternal-Child Pairs Cohort. Gestational PM2.5 exposure levels were assessed using individual air sampling method and satellite-based exposure assessment mode, respectively. Placental weight, length, width and thickness were measured by obstetrician-gynecologist at the time of delivery. Ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to quantify metabolites in serum from the first and third trimester. Associations between PM2.5 and placental characteristics were analyzed by generalized estimating equation and multiple linear regression. The exposure-response relationship was plotted using restricted cubic splines (RCS). Based on the meet-in-the-middle approach, the metabolites underlying the effects of PM2.5 on placenta were explored. The associations between placental width (βTrimester2=-0.497, 95 %CI: -0.801, -0.193), (βTrimester3=-0.279, 95 % CI: -0.543, -0.016) and chorionic disk area (βTrimester2=-12.634,95 %CI: -21.698, -3.570), (βTrimester3=-9.113, 95 %CI: -17.113, -1.112) with PM2.5 exposure at the second and third trimester were found. The associations between placental characteristics with PM2.5 exposure assessed by individual air sampling and satellite-based methods were consistent. L-arginine (L-Arg), caprylic acid (CA), tauroursodeoxycholic acid (TUDCA), glycylproline (Gly-Pro), maltotriose (MT) and N-acetylneuramic acid (NANA) intermediate the effect of PM2.5 exposure on placental chorionic disk area in the third trimester. CONCLUSION: The second and third trimesters may be the sensitive windows of placental abnormalities to PM2.5 exposure. Caprylic acid (CA), glycylproline (Gly-Pro), and N-acetylneuramic acid (NANA) play a key role on the effects of PM2.5 exposure on placenta. This study provides potential biomarkers of placental exposure to PM2.5, providing an opportunity for future research as well as detection.

Sensitive months for green spaces' impact on macrosomia and interaction with air pollutants: A birth cohort study

Macrosomia poses significant health risks to mother and fetuses, yet the protective sensitive window for the effects of green space resources on the risk of macrosomia remains unexplored. This study identified sensitive windows of green space exposure and examined the interactions with air pollutants. In a study of 221,380 full-term newborns delivered at the Hospital, from 2017 to 2021, Normalized Difference Vegetation Index (NDVI) and atmospheric pollutant concentrations were matched to participants based on their residences in the Ningxia region. A Cox proportional hazards model was utilized to estimate the association between green space exposure and macrosomia and analyze the differences between the macrosomia (<4500 g) and macrosomia (≥4500 g) groups. Green space exposure for each month of pregnancy was employed to identify possible sensitive windows. Possible interactions between green spaces and air pollutants were tested on additive and multiplicative scales. Across 250, 500, 1000, and 2000-m buffers, increased NDVI exposure and range throughout the pregnancy were linked to a lower macrosomia risk, with the strongest association in the macrosomia (≥4500 g) group. The key window for the protective effect of green spaces was in late pregnancy, with the most pronounced protective effect noted in the 9th month of pregnancy. We also found a consistent combined effect between low green space and the air pollutants (NO2 and SO2). The research highlights the beneficial impact of increased green space during late pregnancy and the combined effect of low green space and elevated air pollutant levels on macrosomia risk, which can support government initiatives in urban green space development and public health protection.

Associations of preconception air pollution exposure with growth trajectory in young children: A prospective cohort study

Gestational air pollution exposure was associated with childhood obesity. However, little is known about the effect of air pollution exposure during the preconception period, a critical window when environmental exposures may affect body growth trajectory and increase obesity risk. We conducted a population-based prospective cohort study of preconception women and their newborn children followed until 2 years old from metropolitan Shanghai, China to investigate the impact of preconception air pollution on childhood weight and body mass index (BMI) growth trajectories. Exposures to PM2.5, PM10, and NO2 during 3 months before conception and each trimester of pregnancy were estimated using high-resolution spatiotemporal models matched at residential addresses. Children's weight and BMI were assessed postnatally every three months. Multivariate and longitudinal models with piecewise linear mixed effects were used to examine the relationship between preconception air pollution and child growth trajectories of weight, BMI, and standardized BMI (BMIZ). The study population comprised 26,714 women in the baseline enrolled in preconception clinics and 5,834 children reached 2 years included in the analysis with 34,398 longitudinal weight and height measurements. One interquartile range (IQR) increase in preconception PM2.5 (16.2 μg/m3) was associated with a 0.078 (95% confidence interval (CI): 0.002-0.154, p = 0.04) increase in attained BMIZ and 1 IQR increase of PM10 (21.1 μg/m3) were associated with an 0.093 (95% CI: 0.002-0.184, p = 0.04) kg/m2 increase in attained BMI, respectively, at the age of two years, after controlling for individual covariates and gestational air pollution exposure. Higher weight, BMI, and BMIZ growth rates during 6-24 months of life were also associated with higher preconception NO2 and PM exposure. Males and children born to mothers less than 35 years old or with overweight/obesity status were more affected by preconception air pollution exposure on weight growth. The 3-month preconception period was a critical time window for air pollution exposure.

Life-course exposure to air pollution and the risk of dementia in the Lothian Birth Cohort 1936

Background

Air pollution in later life has been associated with dementia; however, limited research has investigated the association between air pollution across the life course, either at specific life periods or cumulatively. The project investigates the association of air pollution with dementia via a life-course epidemiological approach.

Methods

Participants of the Lothian Birth Cohort, born in 1936, provided lifetime residential history in 2014. Participant's air pollution exposure for time periods 1935, 1950, 1970, 1980, 1990, 2001, and 2007 was modeled using an atmospheric chemistry transport model. Lifetime cumulative exposures were calculated as time-weighted mean exposure. Of 572 participants, 67 developed all-cause dementia [35 with Alzheimer's dementia (AD)] by wave 5 (~82 years). Cox proportional hazards and competing risk models assessed the association between all-cause dementia and AD with particulate matter (diameter of ≤2.5 µm) PM2.5 and nitrogen dioxide (NO2) exposure at specific life periods and cumulatively. False discovery rate (FDR) correction was applied for multiple testing.

Results

The mean follow-up was 11.26 years. One standard deviation (SD) higher exposure to air pollution in 1935 (PM2.5 = 14.03 μg/m3, NO2 = 5.35 μg/m3) was positively linked but not statistically significant to all-cause dementia [PM2.5 hazard ratio (HR) = 1.16, 95% confidence interval (CI) = 0.90, 1.49; NO2 HR = 1.13, 95% CI = 0.88, 1.47] and AD (PM2.5 HR = 1.38, 95% CI = 1.00, 1.91; NO2 HR = 1.35, 95% CI = 0.92, 1.99). In the competing risk model, one SD elevated PM2.5 exposure (1.12 μg/m3) in 1990 was inversely associated with dementia (subdistribution HR = 0.82, 95% CI = 0.67, 0.99) at P = 0.034 but not after FDR correction (P FDR = 0.442). Higher cumulative PM2.5 per one SD was associated with an increased risk of all-cause dementia and AD for all accumulation models except for the early-life model.

Conclusion

The in-utero and early-life exposure to PM2.5 and NO2 was associated with higher AD and all-cause dementia risk, suggesting a sensitive/critical period. Cumulative exposure to PM2.5 across the life course was associated with higher dementia risk. Midlife PM2.5 exposure's negative association with all-cause dementia risk may stem from unaddressed confounders or bias.

Beyond a simple cause and effect relationship: Exploring the long-term outcomes of children prenatally exposed to opioids and other substances

The long-term outcomes of children exposed to opioids and other substances in utero, specifically those diagnosed with Neonatal Abstinence Syndrome (NAS), present a complex interaction of different factors. First, NAS and its clinical presentation will be defined, then summarized will be an overview of NAS prevalence, recent trends, and significance of NAS in the context of the rising synthetic opioid and polysubstance use. Highlighted will also be the identified risk factors for NAS, especially regarding the role of environmental and psychosocial stressors during pregnancy. Finally, reviewed will be the existing NAS literature, including its gaps and limitations, and suggested recommendations for future research and policy considerations for improving care for children and families impacted by NAS.

Prenatal exposure to ambient air pollution and persistent postpartum depression

BACKGROUND

Ambient air pollution during pregnancy has been linked with postpartum depression up to 12 months, but few studies have investigated its impact on persistent depression beyond 12 months postpartum. This study aimed to evaluate prenatal ambient air pollution exposure and the risk of persistent depression over 3 years after childbirth and to identify windows of susceptibility.

METHODS

This study included 361 predominantly low-income Hispanic/Latina participants with full-term pregnancies in the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) cohort. We estimated daily residential PM2.5, PM10, NO2, and O3 concentrations throughout 37 gestational weeks using inverse-distance squared spatial interpolation from monitoring data and calculated weekly averaged levels. Depression was assessed by the 20-item Center for Epidemiologic Studies-Depression (CES-D) scale at 12, 24, and 36 months postpartum, with persistent postpartum depression defined as a CES-D score ≥16 at any of these timepoints. We performed robust Poisson log-linear distributed lag models (DLM) via generalized estimating equations (GEE) to estimate the adjusted risk ratio (RR).

RESULTS

Depression was observed in 17.8 %, 17.5 %, and 13.4 % of participants at 12, 24, and 36 months, respectively. We found one IQR increase (3.9 ppb) in prenatal exposure to NO2 during the identified sensitive window of gestational weeks 13-29 was associated with a cumulative risk ratio of 3.86 (95 % CI: 3.24, 4.59) for persistent depression 1-3 years postpartum. We also found one IQR increase (7.4 μg/m3) in prenatal exposure to PM10 during gestation weeks 12-28 was associated a cumulative risk ratio of 3.88 (95 % CI: 3.04, 4.96) for persistent depression. No clear sensitive windows were identified for PM2.5 or O3.

CONCLUSIONS

Mid-pregnancy PM10 and NO2 exposures were associated with nearly 4-fold increased risks of persistent depression after pregnancy, which has critical implications for prevention of perinatal mental health outcomes.

Interpregnancy interval, air pollution, and the risk of low birth weight: a retrospective study in China

BACKGROUND

Both interpregnancy intervals (IPI) and environmental factors might contribute to low birth weight (LBW). However, the extent to which air pollution influences the effect of IPIs on LBW remains unclear. We aimed to investigate whether IPI and air pollution jointly affect LBW.

METHODS

A retrospective cohort study was designed in this study. The data of birth records was collected from the Jiangsu Maternal Child Information System, covering January 2020 to June 2021 in Nantong city, China. IPI was defined as the duration between the delivery date for last live birth and date of LMP for the subsequent birth. The maternal exposure to ambient air pollutants during pregnancy-including particulate matter (PM) with an aerodynamic diameter of ≤ 2.5 μm (PM2.5), PM10, ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2) and carbon monoxide (CO)-was estimated using a hybrid kriging-LUR-RF model. A novel air pollution score was proposed, assessing combined exposure to five pollutants (excluding CO) by summing their concentrations, weighted by LBW regression coefficients. Multivariate logistic regression models were used to estimate the effects of IPI, air pollution and their interactions on LBW. Relative excess risk due to interaction (RERI), attributable proportion of interaction (AP) and synergy index (S) were utilized to assess the additive interaction.

RESULTS

Among 10, 512 singleton live births, the LBW rate was 3.7%. The IPI-LBW risk curve exhibited an L-shaped pattern. The odds ratios (ORs) for LBW for each interquartile range increase in PM2.5, PM10, O3 and the air pollution score were 1.16 (95% CI: 1.01-1.32), 1.30 (1.06-1.59), 1.22 (1.06-1.41), and 1.32 (1.10-1.60) during the entire pregnancy, respectively. An additive interaction between IPI and PM2.5 was noted during the first trimester. Compared to records with normal IPI and low PM2.5 exposure, those with short IPI and high PM2.5 exposure had the highest risk of LBW (relative risk = 3.53, 95% CI: 1.85-6.49, first trimester).

CONCLUSION

The study demonstrates a synergistic effect of interpregnancy interval and air pollution on LBW, indicating that rational birth spacing and air pollution control can jointly improve LBW outcomes.

Maternal ozone exposure lowers infant's birthweight: A nationwide cohort of over 4 million livebirths in Iran

BACKGROUND

Nationwide evidence linking maternal ozone exposure with fetal growth restriction (FGR) was extensively scarce, especially in the Middle East with dry climate and distinct religious culture.

METHODS

We carried out a national retrospective birth cohort study using registry-based records from 749 hospitals across 31 provinces in Iran from 2013 to 2018. Monthly concentrations of maximum daily average 8-hour (MDA8) ozone at 0.125° × 0.125° resolution were extracted from well-validated spatiotemporal grid dataset. Linear and logistic regression models were employed to evaluate associations of maternal MDA8 ozone exposure with birthweight outcomes. Assuming causality, the comparative risk assessment framework was utilized to estimate the burden of low birthweight (LBW), small for gestational age (SGA), and birthweight loss per livebirth (BLL) attributable to ambient ozone pollution.

RESULTS

Of 4030383 livebirths included in the study, 264304 (6.6%) were LBW and 484405 (12.0%) were SGA. Each 10-ppb increase in MDA8 ozone exposure was associated with an odds ratio of 1.123 (95% confidence interval [CI]: 1.104 to 1.142) for LBW and 1.210 (95% CI: 1.197 to 1.223) for SGA, and a 30.5-g (95% CI: 29.0 to 32.0) reduction in birthweight. We observed approximately linear exposure-response relationships of maternal MDA8 ozone exposure with LBW (Pnonlinear= 0.786), SGA (Pnonlinear= 0.156), and birthweight reduction (Pnonlinear= 0.104). Under the premise of causal association, we estimated 6.6% (95% CI: 5.7 to 7.5) of LBW, 10.1% (95% CI: 9.6 to 10.6) of SGA, and 18.8 g (95% CI: 17.9 to 19.7) of BLL could be attributable to maternal ozone exposure in Iran. Considerably greater risk and burden of ozone-related FGR were observed among younger, less-educated, and rural-dwelling mothers.

CONCLUSIONS

Our study provided compelling evidence that maternal ozone exposure was associated with heightened FGR risk and burden, particularly among socioeconomically disadvantaged mothers. These findings underscored the urgent need for government to incorporate socioeconomic factors into future ozone-related health policies, not only to mitigate pollution, but also minimize inequality.

Increased Risk of Gestational Hypertension by Periconceptional Exposure to Ambient Air Pollution and Effect Modification by Prenatal Depression

BACKGROUND

Air pollution has been associated with gestational hypertension (GH) and preeclampsia, but susceptible windows of exposure and potential vulnerability by comorbidities, such as prenatal depression, remain unclear.

METHODS

We ascertained GH and preeclampsia cases in a prospective pregnancy cohort in Los Angeles, CA. Daily levels of ambient particulate matters (with a diameter of ≤10 μm [PM10] or ≤2.5 μm [PM2.5]), nitrogen dioxide, and ozone were averaged for each week from 12 weeks preconception to 20 gestational weeks. We used distributed lag models to identify susceptible exposure windows, adjusting for potential confounders. Analyses were additionally stratified by probable prenatal depression to explore population vulnerability.

RESULTS

Among 619 participants, 60 developed preeclampsia and 42 developed GH. We identified a susceptible window for exposure to PM2.5 from 1 week preconception to 11 weeks postconception: higher exposure (5 µg/m3) within this window was associated with an average of 8% (95% CI, 1%-15%) higher risk of GH. Among participants with probable prenatal depression (n=179; 32%), overlapping sensitive windows were observed for all pollutants from 8 weeks before to 10 weeks postconception with increased risk of GH (PM2.5, 16% [95% CI, 3%-31%]; PM10, 39% [95% CI, 13%-72%]; nitrogen dioxide, 65% [95% CI, 17%-134%]; and ozone, 45% [95% CI, 9%-93%]), while the associations were close to null among those without prenatal depression. Air pollutants were not associated with preeclampsia in any analyses.

CONCLUSIONS

We identified periconception through early pregnancy as a susceptible window of air pollution exposure with an increased risk of GH. Prenatal depression increases vulnerability to air pollution exposure and GH.

Impact of ambient air pollution on lung function in preterm-born school-aged children

RATIONALE

Increased outdoor air pollution worsens lung function in children. However, these associations are less well studied in preterm-born individuals.

OBJECTIVES

We assessed associations between ambient air pollutants and spirometry measures in preterm-born children.

METHODS

The Respiratory Health Outcomes in Neonates study recruited preterm-born children aged 7-12 years who were born at ≤34 week's gestation. We associated four ambient air pollutants (particulate matter with aerodynamic diameter ≤2.5 µm (PM2.5), PM10, nitrogen dioxide (NO2) and sulfur dioxide) at time of birth and spirometry assessment and averaged exposure between these two time points with spirometry measures, using linear regression analyses. Gestational age was banded into 23-28, 29-31 and 32-34 week's. Regression models estimated spirometry values against pollutant levels at birth and at the time of spirometry.

MEASUREMENTS AND MAIN RESULTS

From 565 preterm-born children, 542 (96%) had satisfactory data. After adjustments for early and current life factors, significant detrimental associations were noted between PM10 at birth and per cent predicted forced vital capacity (%FVC) for the 23-28 and 29-31 week's gestation groups and between current PM2.5 and NO2 exposure and %FVC for the 23-28 week's gestation group. No associations with spirometry were noted for the averaged pollution exposure between birth and spirometry. Predictive models showed 5.9% and 7.4% differences in %FVC between the highest and lowest current pollution exposures for PM2.5 and NO2, respectively, in the 23-28 week group.

CONCLUSIONS

Birth and current exposures to road-traffic-associated pollutants detrimentally affected %FVC in preterm-born school-aged children, who already have compromised lung function.

Intrauterine and early postnatal exposures to submicron particulate matter and childhood allergic rhinitis: A multicity cross-sectional study in China

BACKGROUND

Airborne particulate matter pollution has been linked to occurrence of childhood allergic rhinitis (AR). However, the relationships between exposure to particulate matter with an aerodynamic diameter ≤1 μm (PM1) during early life (in utero and first year of life) and the onset of childhood AR remain largely unknown. This study aims to investigate potential associations of in utero and first-year exposures to size-segregated PMs, including PM1, PM1-2.5, PM2.5, PM2.5-10, and PM10, with childhood AR.

METHODS

We investigated 29286 preschool children aged 3-6 years in 7 Chinese major cities during 2019-2020 as the Phase II of the China Children, Families, Health Study. Machine learning-based space-time models were utilized to estimate early-life residential exposure to PM1, PM2.5, and PM10 at 1 × 1-km resolutions. The concentrations of PM1-2.5 and PM2.5-10 were calculated by subtracting PM1 from PM2.5 and PM2.5 from PM10, respectively. Multiple mixed-effects logistic models were used to assess the odds ratios (ORs) and 95% confidence intervals (CIs) of childhood AR associated with per 10-μg/m3 increase in exposure to particulate air pollution during in utero period and the first year of life.

RESULTS

Among the 29286 children surveyed (mean ± standard deviation, 4.9 ± 0.9 years), 3652 (12.5%) were reported to be diagnosed with AR. Average PM1 concentrations during in utero period and the first year since birth were 36.3 ± 8.6 μg/m3 and 33.1 ± 6.9 μg/m3, respectively. Exposure to PM1 and PM2.5 during pregnancy and the first year of life was associated with an increased risk of AR in children, and the OR estimates were higher for each 10-μg/m3 increase in PM1 than for PM2.5 (e.g., 1.132 [95% CI: 1.022-1.254] vs. 1.079 [95% CI: 1.014-1.149] in pregnancy; 1.151 [95% CI: 1.014-1.306] vs. 1.095 [95% CI: 1.008-1.189] in the first year of life). No associations were observed between AR and both pre- and post-natal exposure to PM1-2.5, indicating that PM1 rather than PM1-2.5 contributed to the association between PM2.5 and childhood AR. In trimester-stratified analysis, childhood AR was only found to be associated with exposure to PM1 (OR = 1.077, 95% CI: 1.027-1.128), PM2.5 (OR = 1.048, 95% CI: 1.018-1.078), and PM10 (OR = 1.032, 95% CI: 1.007-1.058) during the third trimester of pregnancy. Subgroup analysis suggested stronger PM-AR associations among younger (<5 years old) and winter-born children.

CONCLUSIONS

Prenatal and postnatal exposures to ambient PM1 and PM2.5 were associated with an increased risk of childhood AR, and PM2.5-related hazards could be predominantly attributed to PM1. These findings highlighted public health significance of formulating air quality guideline for ambient PM1 in mitigating children's AR burden caused by particulate air pollution.

Assessment of the association between ambient air pollution and stillbirth in the UK: Results from a secondary analysis of the MiNESS case-control study

OBJECTIVE

We examined whether the risk of stillbirth was related to ambient air pollution in a UK population.

DESIGN

Prospective case-control study.

SETTING

Forty-one maternity units in the UK.

POPULATION

Women who had a stillbirth ≥28 weeks' gestation (n = 238) and women with an ongoing pregnancy at the time of interview (n = 597).

METHODS

Secondary analysis of data from the Midlands and North of England Stillbirth case-control study only including participants domiciled within 20 km of fixed air pollution monitoring stations. Pollution exposure was calculated using pollution climate modelling data for NO2 , NOx and PM2.5 . The association between air pollution exposure and stillbirth risk was assessed using multivariable logistic regression adjusting for household income, maternal body mass index (BMI), maternal smoking, Index of Multiple Deprivation quintile and household smoking and parity.

MAIN OUTCOME MEASURE

Stillbirth.

RESULTS

There was no association with whole pregnancy ambient air pollution exposure and stillbirth risk, but there was an association with preconceptual NO2 exposure (adjusted odds ratio [aOR] 1.06, 95% CI 1.01-1.08 per microg/m3 ). Risk of stillbirth was associated with maternal smoking (aOR 2.54, 95% CI 1.38-4.71), nulliparity (aOR 2.16, 95% CI 1.55-3.00), maternal BMI (aOR 1.05, 95% CI 1.01-1.08) and placental abnormalities (aOR 4.07, 95% CI 2.57-6.43).

CONCLUSIONS

Levels of ambient air pollution exposure during pregnancy in the UK, all of were beneath recommended thresholds, are not associated with an increased risk of stillbirth. Periconceptual exposure to NO2 may be associated with increased risk but further work is required to investigate this association.

Prenatal exposure to air pollution and BWGA Z-score: Modifying effects of placenta leukocyte telomere length and infant sex

BACKGROUND

Air pollutants, such as fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3), have been associated with adverse birth outcomes, including low birth weight, often exhibiting sex-specific effects. However, the modifying effect of placental telomere length (TL), reflecting cumulative lifetime oxidative stress in mothers, remains unexplored.

METHOD

Using data from a Northeastern U.S. birth cohort (n = 306), we employed linear regression and weighted quantile sum models to assess trimester-average air pollution exposures and birth weight for gestational age (BWGA) z-scores. Placental TL, categorized by median split, was considered as an effect modifier. Interactions among air pollutants, placental TL, infant sex, and BWGA z-score were evaluated.

RESULTS

Without placental TL as a modifier, only 1st trimester O3 was significantly associated with BWGA z-scores (coefficient: 0.33, 95% CI: 0.03, 0.63). In models considering TL interactions, a significant modifying effect was observed between 3rd trimester NO2 and BWGA z-scores (interaction p-value = 0.02). Specifically, a one interquartile range (1-IQR) increase in 3rd trimester NO2 was linked to a 0.28 (95% CI: 0.06, 0.52) change in BWGA z-score among shorter placental TL group, with no significant association among longer TL group. Among male infants, there were significant associations between 3rd trimester PM2.5 exposure and BWGA z-scores in the longer TL group (coefficient: -0.34, 95% CI: -0.61, -0.02), and between 1st trimester O3 exposure and BWGA z-scores among males in the shorter TL group (coefficient: 0.59, 95% CI: 0.06, 1.08). For females, only a negative association in 2nd trimester mixture model was observed within the longer TL group (coefficient: -0.10, 95% CI: -0.21, -0.01).

CONCLUSION

These findings highlight the need to consider the complex interactions among prenatal air pollutant exposures, placental TL, and fetal sex to better elucidate those at greatest risk for adverse birth outcomes.

Individual ambient ozone exposure during pregnancy and adverse birth outcomes: Exploration of the potentially vulnerable windows

BACKGROUND

Ambient ozone (O3) exposure during pregnancy might be associated with preterm birth (PTB) and low birth weight (LBW); however, existing evidence remains inconclusive. It is necessary to explore the relationships and potential susceptible periods further.

METHODS

To explore the relationship between O3 exposure and adverse birth outcomes, a study using records of 34,122 singleton live births in Beijing between 2016 and 2019 was conducted. The O3 exposure in each gestational week of pregnant women was estimated, and Cox proportional hazard models were used to estimate the hazard ratios (HRs) and corresponding 95% confidence intervals (CIs). Distributed lag nonlinear model (DLNM) incorporated in Cox proportional hazard models were used to explore potential critical windows.

RESULTS

An increase of 10 μg/m3 in O3 exposure was associated with a 3.9% (95%CI: 0.6-7.3%) higher risk of PTB. Additionally, this increase in O3 exposure was positively linked to PTB during the 2nd - 7th, 22nd - 29th, and 37th gestational weeks, and LBW during the 2nd - 7th, 24th - 29th, and 37th gestational weeks.

CONCLUSIONS

This study demonstrates a positive correlation between O3 exposure and PTB, and identified specific sensitive periods during pregnancy when the risk was higher.

Weekly prenatal PM2.5 and NO2 exposures in preterm, early term, and full term infants: Decrements in birth weight and critical windows of susceptibility

BACKGROUND

Previous studies have observed associations between birth weight and prenatal air pollution exposure, but there is not consensus on timing of critical windows of susceptibility.

OBJECTIVE

We estimated the difference in birth weight among preterm, early term and full term births associated with weekly exposure to PM2.5 and NO2 throughout gestation.

METHODS

We included all singleton live births in the Lower Peninsula of Michigan (United States) between 2007 and 2012 occurring at or after 32 weeks gestational age (n = 497,897). Weekly ambient PM2.5 and NO2 concentrations were estimated at maternal residences using 1-km gridded data from ensemble-based models. We utilized a distributed lag nonlinear model to estimate the difference in birth weight associated with weekly exposures from the last menstrual period (week 0) through 31 weeks gestation for preterm births; through 36 weeks gestation for early term births; and through 38 weeks gestation for full term births.

RESULTS

In single-pollutant models, a 5 μg/m3 increase in PM2.5 exposure was associated with a reduction in birth weight among preterm births (-37.1 g [95% confidence interval [CI]: 60.8 g, -13.5 g]); early term births (-13.5 g [95% CI: 26.2 g, -0.67 g]); and full term births (-8.23 g [95% CI: 15.8 g, -0.68 g])]. In single-pollutant models, a 10 ppb increase in NO2 exposure was associated with a -11.7 g (95% CI: 14.46 g, -8.92 g) decrement in birth weight among full term births only. In models co-adjusted for PM2.5 and NO2, PM2.5 exposure was associated with reduced birth weight among preterm births (-36.9 g [95% CI: 61.9 g, -11.8 g]) and NO2 exposure was associated with reduced birth weight among full term births (-11.8 g [95% CI: 14.7 g, -8.94 g]). The largest decrements in birth weight were associated with PM2.5 exposure between approximately 10 and 26 weeks of pregnancy; for NO2 exposure, the largest decrements in birth weight in full term births were associated with exposure between weeks 6-18.

CONCLUSION

We observed the largest and most persistent adverse associations between PM2.5 exposure and birth weight in preterm infants, and between NO2 exposure and birth weight in full term infants. Exposure during the first half of pregnancy had a greater impact on birthweight.

Role of antenatal anxiety in the relationship between maternal exposure to nitrogen dioxide and small for gestational age: A birth cohort study

BACKGROUND

Both Nitrogen dioxide (NO2) exposure and antenatal anxiety have individually been associated with small for gestational age (SGA). Little is known, however, about whether there is effect modification of antenatal anxiety on NO2-related SGA.

METHODS

The prospective birth cohort study included 1823 mother-newborn pairs in Guangzhou, China, from January 2017 to April 2020. Exposure to NO2 during the pre-conceptional and prenatal periods was estimated using an inverse distance weighted method. Antenatal anxiety was assessed by Trait Anxiety Inventory. SGA was determined by the Chinese gestational age- and sex-specific birthweight standards. Cox proportional hazards regression models was used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for SGA as per 10 μg/m3 increase in NO2. Modifying effects of trait anxiety on NO2-related SGA were identified by stratified analyses, and three-dimensional response surface plots and two-dimensional heat maps.

RESULTS

Each 10 μg/m3 increase in NO2 exposure during the third trimester was significantly associated with SGA risk among overall participants (HR = 1.221, 95 % CI: 1.014-1.471) and primipara (HR = 1.271, 95 % CI: 1.023-1.579). We found significant effect modification of anxiety level for NO2-related SGA in the third trimester (Pinteraction < 0.05). Pregnant women with higher levels of trait anxiety were more likely to deliver SGA newborns, particularly for those with high trait anxiety (HR = 1.781, 95 % CI: 1.007-2.945). Primiparous women were more susceptible.

CONCLUSIONS

This study provides evidence that antenatal trait anxiety may modify the effects of maternal NO2 exposure on SGA risk. The third trimester could be a critical window of susceptibility.

Identifying critical windows of air pollution exposure during preconception and gestational period on birthweight: a prospective cohort study

BACKGROUND

Few studies have assessed air pollution exposure association with birthweight during both preconception and gestational periods.

METHODS

Leveraging a preconception cohort consisting of 14220 pregnant women and newborn children in Shanghai, China during 2016-2018, we aim to assess associations of NO2 and PM2.5 exposure, derived from high-resolution spatial-temporal models, during preconception and gestational periods with outcomes including term birthweight, birthweight Z-score, small-for-gestational age (SGA) and large-for-gestational age (LGA). Linear and logistic regressions were used to estimate 3-month preconception and trimester-averaged air pollution exposure associations; and distributed lag models (DLM) were used to identify critical exposure windows at the weekly resolution from preconception to delivery. Two-pollutant models and children's sex-specific associations were explored.

RESULTS

After controlling for covariates, one standard deviation (SD) (11.5 μg/m3, equivalent to 6.1 ppb) increase in NO2 exposure during the second and the third trimester was associated with 13% (95% confidence interval: 2 - 26%) and 14% (95% CI: 1 - 29%) increase in SGA, respectively; and one SD (9.6 μg/m3) increase in PM2.5 exposure during the third trimester was associated with 15% (95% CI: 1 - 31%) increase in SGA. No association have been found for outcomes of birthweight, birthweight Z-score and LGA. DLM found that gestational weeks 22-32 were a critical window, when NO2 exposure had strongest associations with SGA. The associations of air pollution exposure tended to be stronger in female newborns than in male newborns. However, no significant associations of air pollution exposure during preconception period on birthweight outcomes were found.

CONCLUSION

Consistent with previous studies, we found that air pollution exposure during mid-to-late pregnancy was associated with adverse birthweight outcomes.

Prenatal PM2.5 exposure increases the risk of adverse pregnancy outcomes: evidence from meta-analysis of cohort studies

Adverse pregnancy outcomes (APOs) are a significant cause of fetal death. A wide range of maternal psychological, social, and environmental factors may contribute to these outcomes. Mounting epidemiological studies have indicated that PM2.5 may result in these unfavorable consequences. Previously published meta-analyses have been updated and extended. Cohort studies were searched from three databases (up to July 24, 2023), and their quality was assessed by Newcastle-Ottawa Scale (NOS). Publication bias was examined by Egger's test and funnel plot. Despite a large number of studies showing similar results, the inconsistencies between these findings require careful generalization before concluding. This meta-analysis included 67 cohort studies from 20 countries, and the findings revealed that maternal PM2.5 exposure and five APOs were correlated significantly throughout pregnancy: preterm birth (PTB) (RR = 1.05; 95% CI: 1.03, 1.07); low birth weight (LBW) (RR = 1.02; 95% CI: 1.01, 1.04); small for gestational age (SGA) (RR = 1.03; 95% CI: 1.01, 1.04); stillbirth (RR = 1.24; 95% CI: 1.06, 1.45); and change in birthweight (weight change = -6.82 g; 95% CI: -11.39, -2.25). A positive association was found between APOs and PM2.5 exposure in this meta-analysis, and the degree of increased risk of APOs varied due to different gestation periods. Therefore, it is necessary to protect pregnant women at specific times.

Preconceptional and prenatal exposure to air pollutants and risk of gestational diabetes in the MADRES prospective pregnancy cohort study

Background

Air pollution has been associated with gestational diabetes mellitus (GDM). We aim to investigate susceptible windows of air pollution exposure and factors determining population vulnerability.

Methods

We ascertained GDM status in the prospective Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) pregnancy cohort from Los Angeles, California, USA. We calculated the relative risk of GDM by exposure to ambient particulate matter (PM10; PM2.5), nitrogen dioxide (NO2), and ozone (O3) in each week from 12 weeks before to 24 weeks after conception, adjusting for potential confounders, with distributed lag models to identify susceptible exposure windows. We examined effect modification by prenatal depression, median-split pre-pregnancy BMI (ppBMI) and age.

Findings

Sixty (9.7%) participants were diagnosed with GDM among 617 participants (mean age: 28.2 years, SD: 5.9; 78.6% Hispanic, 11.8% non-Hispanic Black). GDM risk increased with exposure to PM2.5, PM10, and NO2 in a periconceptional window ranging from 5 weeks before to 5 weeks after conception: interquartile-range increases in PM2.5, PM10, and NO2 during this window were associated with increased GDM risk by 5.7% (95% CI: 4.6-6.8), 8.9% (8.1-9.6), and 15.0% (13.9-16.2), respectively. These sensitive windows generally widened, with greater effects, among those with prenatal depression, with age ≥28 years, or with ppBMI ≥27.5 kg/m2, than their counterparts.

Interpretation

Preconception and early-pregnancy are susceptible windows of air pollutants exposure that increased GDM risk. Prenatal depression, higher age, or higher ppBMI may increase one's vulnerability to air pollution-associated GDM risk.

Funding

National Institutes of Health, Environmental Protection Agency.

Environmentally Mediated Health Disparities

We describe important settings where environmental exposure leads to disease disparities. Lead exposure in urban settings disproportionately impacts the urban Black poor. Native Americans have been forcibly relocated to areas of the West that have arsenic-contaminated groundwater or exposure to radionuclides near mines and nuclear development. Latino farm workers are disproportionately exposed to pesticides and herbicides. These chemicals are associated with cancer, neuropsychiatric disorders, renal failure, and respiratory disorders. The rural poor, both white and of color, are disproportionately impacted by hydraulic fracturing, exposing residents to volatile organic compounds such as toluene and benzene and heavy metals such as lead and arsenic. The urban and rural poor are both exposed to air pollution that significantly impact health. Short- and long-term ambient air pollution exposure has been associated with all-cause cardiovascular disease, stroke, blood pressure, and ischemic heart disease. Cancer due to air pollution has disproportionately impacted poor communities like "Cancer Alley" where numerous industrial sources are geographically clustered. Understanding local environmental hazards and available resources to address them can enhance the quality of medical care.

Cellular mechanisms linking to outdoor and indoor air pollution damage during pregnancy

Pregnancies are a critical window period for environmental influences over the mother and the offspring. There is a growing body of evidence associating indoor and outdoor air pollution exposure to adverse pregnancy outcomes such as preterm birth and hypertensive disorders of pregnancy. Particulate matter (PM) could trigger oxi-inflammation and could also reach the placenta leading to placental damage with fetal consequences. The combination of strategies such as risk assessment, advise about risks of environmental exposures to pregnant women, together with nutritional strategies and digital solutions to monitor air quality can be effective in mitigating the effects of air pollution during pregnancy.

Associations between maternal exposure to ambient air pollution and very low birth weight: A birth cohort study in Chongqing, China

Introduction

There have been many researches done on the association between maternal exposure to ambient air pollution and adverse pregnancy outcomes, but few studies related to very low birth weight (VLBW). This study thus explores the association between maternal exposure to ambient air pollutants and the risk of VLBW, and estimates the sensitive exposure time window.

Methods

A retrospective cohort study analyzed in Chongqing, China, during 2015-2020. The Generalized Additive Model were applied to estimate exposures for each participant during each trimester and the entire pregnancy period.

Results

For each 10 μg/m³ increase in PM_2.5 during pregnancy, the relative risk of VLBW increased on the first trimester, with RR = 1.100 (95% CI: 1.012, 1.195) in the single-pollutant model. Similarly, for each 10 μg/m³ increase in PM₁₀, there was a 12.9% (RR = 1.129, 95% CI: 1.055, 1.209) increase for VLBW on the first trimester in the single-pollutant model, and an 11.5% (RR = 1.115, 95% CI: 1.024, 1.213) increase in the multi-pollutant model, respectively. The first and second trimester exposures of NO₂ were found to have statistically significant RR values for VLBW. The RR values on the first trimester were 1.131 (95% CI: 1.037, 1.233) and 1.112 (95% CI: 1.015, 1.218) in the single-pollutant model and multi-pollutant model, respectively; The RR values on the second trimester were 1.129 (95% CI: 1.027, 1.241) and 1.146 (95% CI: 1.038, 1.265) in the single-pollutant model and multi-pollutant model, respectively. The RR of O3 exposure for VLBW on the entire trimester was 1.076 (95% CI: 1.010-1.146), and on the second trimester was 1.078 (95% CI: 1:016, 1.144) in the single-pollutant model.

Conclusion

This study indicates that maternal exposure to high levels of PM_2.5, PM₁₀, NO₂, and O₃ during pregnancy may increase the risk of very low birth weight, especially for exposure on the first and second trimester. Reducing the risk of early maternal exposure to ambient air pollution is thus necessary for pregnant women.