Maternal personal exposure to airborne benzene and intrauterine growth

The methodology of quantitative risk assessment studies

Once an external factor has been deemed likely to influence human health and a dose response function is available, an assessment of its health impact or that of policies aimed at influencing this and possibly other factors in a specific population can be obtained through a quantitative risk assessment, or health impact assessment (HIA) study. The health impact is usually expressed as a number of disease cases or disability-adjusted life-years (DALYs) attributable to or expected from the exposure or policy. We review the methodology of quantitative risk assessment studies based on human data. The main steps of such studies include definition of counterfactual scenarios related to the exposure or policy, exposure(s) assessment, quantification of risks (usually relying on literature-based dose response functions), possibly economic assessment, followed by uncertainty analyses. We discuss issues and make recommendations relative to the accuracy and geographic scale at which factors are assessed, which can strongly influence the study results. If several factors are considered simultaneously, then correlation, mutual influences and possibly synergy between them should be taken into account. Gaps or issues in the methodology of quantitative risk assessment studies include 1) proposing a formal approach to the quantitative handling of the level of evidence regarding each exposure-health pair (essential to consider emerging factors); 2) contrasting risk assessment based on human dose-response functions with that relying on toxicological data; 3) clarification of terminology of health impact assessment and human-based risk assessment studies, which are actually very similar, and 4) other technical issues related to the simultaneous consideration of several factors, in particular when they are causally linked.

Exposure to volatile organic compounds induces cardiovascular toxicity that may involve DNA methylation

Volatile organic compounds (VOCs) are common air pollutants and water contaminants. We previously found maternal exposure to VOCs was associated with offspring congenital heart disease (CHD). However, little information is available about the effects of VOCs on cardiovascular development at embryonic stage and the underlying mechanism remains unclear. In this study, we aimed to investigate the effects of a mixture of six VOCs on cardiovascular development in zebrafish embryos. Embryos were exposed to different concentrations of VOCs mixture (32 mg/L, 64 mg/L and 128 mg/L) for 96 h, cardiovascular abnormalities including elongated heart shape, increased distance between sinus venosus and bulbus arteriosus, slowed circulation and altered heart rate were observed in a dose- and time-dependent manner. Meanwhile, VOCs exposure increased global DNA methylation levels in embryos. Analysis identified hundreds of differentially methylated sites and the enrichment of differentially methylated sites on cardiovascular development. Two differentially methylated-associated genes involved in MAPK pathway, hgfa and ntrk1, were identified to be the potential genes mediating the effects of VOCs. By enzyme-linked immunosorbent assay, altered human serum hgf and ntrk1 levels were detected in abnormal pregnancies exposed to higher VOCs levels with fetal CHD. For the first time, our study revealed exposure to VOCs induced severe cardiovascular abnormalities in zebrafish embryos. The toxicity might result from alterations in DNA methylation and corresponding expression levels of genes involved in MAPK pathway. Our study provides important information for the risk of VOCs exposure on embryonic cardiovascular development.

Adult-Onset Transcriptomic Effects of Developmental Exposure to Benzene in Zebrafish (Danio rerio): Evaluating a Volatile Organic Compound of Concern

Urban environments are afflicted by mixtures of anthropogenic volatile organic compounds (VOCs). VOC sources that drive human exposure include vehicle exhaust, industrial emissions, and oil spillage. The highly volatile VOC benzene has been linked to adverse health outcomes. However, few studies have focused on the later-in-life effects of low-level benzene exposure during the susceptible window of early development. Transcriptomic responses during embryogenesis have potential long-term consequences at levels equal to or lower than 1 ppm, therefore justifying the analysis of adult zebrafish that were exposed during early development. Previously, we identified transcriptomic alteration following controlled VOC exposures to 0.1 or 1 ppm benzene during the first five days of embryogenesis using a zebrafish model. In this study, we evaluated the adult-onset transcriptomic responses to this low-level benzene embryogenesis exposure (n = 20/treatment). We identified key genes, including col1a2 and evi5b, that were differentially expressed in adult zebrafish in both concentrations. Some DEGs overlapped at the larval and adult stages, specifically nfkbiaa, mecr, and reep1. The observed transcriptomic results suggest dose- and sex-dependent changes, with the highest impact of benzene exposure to be on cancer outcomes, endocrine system disorders, reproductive success, neurodevelopment, neurological disease, and associated pathways. Due to molecular pathways being highly conserved between zebrafish and mammals, developmentally exposed adult zebrafish transcriptomics is an important endpoint for providing insight into the long term-effects of VOCs on human health and disease.

Association between ambient air pollution exposure in pregnant women with antiphospholipid syndrome in Nanjing, China

Antenatal exposure to air pollutants is thought to be associated with a variety of maternal blood markers as well as adverse birth outcomes. However, the dysgenic influence of air pollutants on the antiphospholipid syndrome (APS) in mothers and their pregnancy outcomes remains unclear. In the current study, 371 mother-infant pairs (189 healthy: 182 APS) from Nanjing Maternal and Child Health Hospital as well as air pollutants concentration from their living environment were used to investigate correlations between air pollution with maternal blood indicators and fetal birth weight in the groups of APS and healthy mothers. Generalized linear model was used to evaluate the contributions of air pollutant exposure during pregnancy to the blood indicators variation. The relationships between birth weight with specific air pollutant and blood index were analyzed using ridge regression. Results showed that APS fetal birth weight was significantly impacted by air pollutant exposure during pregnancy, in particular, the birth weight decreased significantly along with increasing fine particulate matter 2.5 (PM2.5) and fine particulate matter 10 (PM10) exposure concentrations throughout pregnancy. In contrast, birth weight increased significantly with sulfur dioxide (SO2) exposure. In addition, APS-related blood indicators comprised of platelet distribution width (PDW), total bilirubin (TBIL), mean platelet volume (MPV), platelet-larger cell ratio (P_LCR), homocysteine (HCY), alkaline phosphatase (ALP), direct bilirubin (DBIL), basophilic granulocyte (BAS), platelet thrombocytocrit (PCT), preprandial glucose levels (OGTT0), monocytes (MON), and monocytes ratio (MON_ratio) were also strongly related with prenatal exposure to PM2.5 and PM10, in which PDW levels showed most strongly negative impaction on fetal birth weight. Together, we showed that prenatal exposure to air pollutant (PM2.5 and PM10) may exacerbate the poor birth outcomes of low birth weight by impacting APS maternal blood indicators especially for PDW.

Urinary metabolites of multiple volatile organic compounds among pregnant women across pregnancy: Variability, exposure characteristics, and associations with selected oxidative stress biomarkers

Volatile organic compounds (VOCs) are a group of pollutants pervasive in daily life with identified adverse health effects. However, no study has investigated the variability in VOC metabolites during pregnancy and their relationships with oxidative stress biomarkers in pregnant women. In the present study, the variability of 21 selected VOC metabolites was examined and their relationships with three selected oxidative stress biomarkers measured in spot urine samples at three trimesters of 1094 pregnant women were analyzed. Nineteen VOC metabolites were ubiquitous in the urine samples with detection rates ranging from 75.9% to 100%. Monohydroxybutenyl mercapturic acid (MHBMA) and s-phenyl mercapturic acid (PMA) had detection rates lower than 1.00%. Intraclass correlation coefficients (ICCs) of the detected analytes at three trimesters ranged 0.07-0.24, and the concentrations were highest in the first trimester. Higher concentrations of some VOC metabolites were related with participant characteristics including higher pre-pregnancy body mass index (BMI), lower education level, unemployment during pregnancy, multiparity, and sampling season of summer or winter. In repeated cross-sectional analyses, interquartile range (IQR) increases in the 19 detected VOC metabolites were positively related with 8-hydroxy-2'-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), and 4-hydroxy nonenal mercapturic acid (HNEMA) with the estimates ranging from 9.00% to 204%. The mixture effect of the VOC metabolites on the oxidative stress biomarkers was further assessed using weighted quantile sum regression (WQS) models and the results showed that the WQS index of VOC metabolite mixture was significantly associated with 8-OHdG (β: 0.37, 0,32, and 0.39 at the 1st, 2nd, and 3rd trimester, respectively), 8-OHG (0.38, 0.32, and 0.39) and HNEMA (1.21, 1.08, and 1.10). Glycidamide mercapturic acid (GAMA), and trans,trans-muconic acid (MU) were the strongest contributors of the mixture effect on 8-OHdG, 8-OHG, and HNEMA, respectively. Overall, urinary concentrations of the VOC metabolites during pregnancy were strongly associated with the oxidative stress biomarkers.

Prenatal Pollutant Exposures and Hypothalamic Development: Early Life Disruption of Metabolic Programming

Environmental contaminants in ambient air pollution pose a serious risk to long-term metabolic health. Strong evidence shows that prenatal exposure to pollutants can significantly increase the risk of Type II Diabetes (T2DM) in children and all ethnicities, even without the prevalence of obesity. The central nervous system (CNS) is critical in regulating whole-body metabolism. Within the CNS, the hypothalamus lies at the intersection of the neuroendocrine and autonomic systems and is primarily responsible for the regulation of energy homeostasis and satiety signals. The hypothalamus is particularly sensitive to insults during early neurodevelopmental periods and may be susceptible to alterations in the formation of neural metabolic circuitry. Although the precise molecular mechanism is not yet defined, alterations in hypothalamic developmental circuits may represent a leading cause of impaired metabolic programming. In this review, we present the current knowledge on the links between prenatal pollutant exposure and the hypothalamic programming of metabolism.

Evaluating Phenotypic and Transcriptomic Responses Induced by Low-Level VOCs in Zebrafish: Benzene as an Example

Urban environments are plagued by complex mixtures of anthropogenic volatile organic compounds (VOCs), such as mixtures of benzene, toluene, ethylene, and xylene (BTEX). Sources of BTEX that drive human exposure include vehicle exhaust, industrial emissions, off-gassing of building material, as well as oil spillage and leakage. Among the BTEX mixture, benzene is the most volatile compound and has been linked to numerous adverse health outcomes. However, few studies have focused on the effects of low-level benzene on exposure during early development, which is a susceptible window when hematological, immune, metabolic, and detoxification systems are immature. In this study, we used zebrafish to conduct a VOC exposure model and evaluated phenotypic and transcriptomic responses following 0.1 and 1 ppm benzene exposure during the first five days of embryogenesis (n = 740 per treatment). The benzene body burden was 2 mg/kg in 1 ppm-exposed larval zebrafish pools and under the detection limit in 0.1 ppm-exposed fish. No observable phenotypic changes were found in both larvae except for significant skeletal deformities in 0.1 ppm-exposed fish (p = 0.01) compared with unexposed fish. Based on transcriptomic responses, 1 ppm benzene dysregulated genes that were implicated with the development of hematological system, and the regulation of oxidative stress response, fatty acid metabolism, immune system, and inflammatory response, including apob, nfkbiaa, serpinf1, foxa1, cyp2k6, and cyp2n13 from the cytochrome P450 gene family. Key genes including pik3c2b, pltp, and chia.2 were differentially expressed in both 1 and 0.1 ppm exposures. However, fewer transcriptomic changes were induced by 0.1 ppm compared with 1 ppm. Future studies are needed to determine if these transcriptomic responses during embryogenesis have long-term consequences at levels equal to or lower than 1 ppm.

Association between maternal exposure to indoor air pollution and offspring congenital heart disease: a case–control study in East China

Background

Previous research suggested an association between maternal exposure to ambient air pollutants and the risk of congenital heart disease (CHD). However, the effect of individual prenatal exposure to indoor air pollutants on CHD occurrence was not reported.

Methods

We performed a hospital-based case–control study to investigate the association between personal air pollution exposure during pregnancy and the risk of CHD in offspring. A total of 44 cases and 75 controls were included from two hospitals in East China. We investigated maternal and residential environmental characteristics using a questionnaire and obtained personal indoor air samples to assess particulate matter (PM) and volatile organic compounds (VOCs) from 22–30 gestational weeks. Formaldehyde, benzene, toluene, xylene, total volatile organic compounds (TVOCs), PM_2.5, and PM₁₀ were assessed. Logistic regression was performed to assess associations and interactions between individual indoor air pollutants and CHD after adjusting for confounders. The potential residential environmental factors affecting the risks of indoor air pollutants on CHD were also assessed.

Results

Median TVOC (0.400 vs. 0.005 mg/m³, P < 0.001) exposure levels in cases were significantly higher than controls. A logistic regression model adjusted for confounders revealed that exposure to high levels of indoor TVOCs (AOR 7.09, 95% CI 2.10–23.88) during pregnancy was associated with risks for CHD and the occurrence of some major CHD subtype in offspring. These risk effects were enhanced in pregnant women living in a newly renovated house but were mitigated by household use of smoke ventilators when cooking. We observed a positive interaction of maternal exposure to TVOCs and PM_2.5 and the risk for CHD.

Conclusions

Maternal exposure to indoor VOCs and PMs may increase the risk of giving birth to foetuses with CHD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13174-0.

Density and proximity to hydraulic fracturing wells and birth outcomes in Northeastern British Columbia, Canada

BACKGROUND

Hydraulic fracturing, a method used in Northeastern British Columbia (Canada) to extract natural gas, can release contaminants with potential deleterious health effects on fetal development. To date, the association between hydraulic fracturing activity and birth outcomes has not been evaluated in this region.

OBJECTIVE

To evaluate the association between the hydraulic fracturing well density/proximity and birth outcomes (birthweight, head circumference, preterm birth and small for gestational age (SGA)).

METHODS

We used birth records from the Fort St John hospital between December 30, 2006 and December 29, 2016 (n = 6333 births). To estimate gestational exposure, we used inverse distance weighting (IDW) to calculate the density/proximity of hydraulic fracturing wells to pregnant women's postal code centroid. For each birth, we calculated three IDWs using 2.5, 5, and 10 km buffer zones around women's postal code centroid. We used linear and logistic regressions to evaluate associations between quartiles of postal code well density/proximity and birth outcomes, controlling for relevant covariates.

RESULTS

No associations were found between postal code well density/proximity and head circumference or SGA. A negative association was found between postal code well density/proximity and birthweight for infants born to women in the 2nd quartile of the 10 km buffer (β [95% confidence interval (CI)]: -47.28 g [-84.30; -10.25]), and in the 2nd (β [95% CI]: -40.87 g [-78.01; -3.73]) and 3rd (β [95% CI]: -42.01 g [-79.15; -4.87]) quartiles of the 5 km buffer. Increased odds of preterm birth were observed among women in the 2nd quartile of the 2.5 km buffer (odds ratio (OR) [95% CI]: 1.60 [1.30; 2.43]).

CONCLUSIONS

This is the first epidemiological study in Northeastern British Columbia evaluating associations between hydraulic fracturing and health outcomes. Our results show inconsistent patterns of association between hydraulic fracturing, preterm birth and reduced birthweight, and effect estimates did not match expected dose-response relationships.

Association between exposure to air pollution during intrauterine life and cephalic circumference of the newborn

It has been observed that air pollution can affect newborn health due to the negative effects of pollutants on pregnancy development. However, few studies have evaluated the impact of maternal exposure to urban air pollution on head circumference (HC) at birth. Reduced head growth during pregnancy may be associated with neurocognitive deficits in childhood. The objectives of this study were to evaluate the association between maternal exposure to air pollution and HC at birth and to provide context with a systematic review to investigate this association. This was a prospective study of low-risk pregnant women living in São Paulo, Brazil. Exposure to pollutants, namely, nitrogen dioxide (NO₂) and ozone (O₃), was measured during each trimester using passive personal samplers. We measured newborn HC until 24 h after birth. We used multiple linear regression models to evaluate the association between pollutants and HC while controlling for known determinants of pregnancy. To perform the systematic review, four different electronic databases were searched through November 2018: CENTRAL, EMBASE, LILACS, and MEDLINE. We selected longitudinal or transversal designs associating air pollution and HC at birth. Two reviewers evaluated the inclusion criteria and risk of bias and extracted data from the included papers. Thirteen studies were selected for the systematic review. We evaluated 391 patients, and we did not observe a significant association between air pollution and HC. Regarding the systematic review, 13 studies were selected for the systematic review, 8 studies showed an inverse association between maternal exposure to pollutants and HC, 4 showed no association, and one observed a direct association. In the city of São Paulo, maternal exposure to pollutants was not significantly associated with HC at birth. The systematic review suggested an inverse association between air pollution and HC at birth.

Associations of birth outcomes with air pollution and land use characteristics in the Greater Taipei Area

BACKGROUND

Understanding the effects of environmental factors on birth outcomes is crucial for public health because newborns' birth size affects their likelihood of childhood survival, risk of perinatal morbidity, and subsequent health and growth. Therefore, we investigated the associations of birth outcomes with prenatal air pollutant exposure and residential land use characteristics in the Greater Taipei Area.

METHODS

Participants were selected from the Longitudinal Examination across Prenatal and Postpartum Health in Taiwan study, which is an ongoing prospective study launched in July 2011. Parental sociodemographic data and medical histories were collected using standardized questionnaires. Mean air pollutant levels during each trimester were estimated using the spatial interpolation technique (Ordinary Kriging). Land use types surrounding participants' homes were evaluated within a designated radius of their residential addresses. We used multiple regressions to examine relationships between birth outcomes (i.e., birth weight, height, and head circumference) and environmental factors after adjustment for parental characteristics.

RESULTS

A total of 436 pregnant women-infant pairs were included. Birth weight was negatively associated with commercial land and greenhouse areas near the residence. Living near greenhouse areas negatively affected birth height, but higher greenness level within 100 m of the residence had a positive effect. Birth head circumference was only associated with sociodemographic factors in the multivariate model.

CONCLUSION

Land use types near the homes of pregnant women, but not exposure to air pollutants, were significantly associated with birth weight and height in the Greater Taipei Area. Increased greenness level was positively associated with birth height, and living near commercial or greenhouse areas had adverse effects on birth outcomes. Living in a healthy neighborhood is critical for the birth outcomes of infants and presumably their health in early childhood.

A Review of Volatile Organic Compound Contamination in Post-Industrial Urban Centers: Reproductive Health Implications Using a Detroit Lens

Volatile organic compounds (VOCs) are a group of aromatic or chlorinated organic chemicals commonly found in manufactured products that have high vapor pressure, and thus vaporize readily at room temperature. While airshed VOCs are well studied and have provided insights into public health issues, we suggest that belowground VOCs and the related vapor intrusion process could be equally or even more relevant to public health. The persistence, movement, remediation, and human health implications of subsurface VOCs in urban landscapes remain relatively understudied despite evidence of widespread contamination. This review explores the state of the science of subsurface movement and remediation of VOCs through groundwater and soils, the linkages between these poorly understood contaminant exposure pathways and health outcomes based on research in various animal models, and describes the role of these contaminants in human health, focusing on birth outcomes, notably low birth weight and preterm birth. Finally, this review provides recommendations for future research to address knowledge gaps that are essential for not only tackling health disparities and environmental injustice in post-industrial cities, but also protecting and preserving critical freshwater resources.

Immediate and durable effects of maternal tobacco consumption alter placental DNA methylation in enhancer and imprinted gene-containing regions

BACKGROUND

Although exposure to cigarette smoking during pregnancy has been associated with alterations of DNA methylation in the cord blood or placental cells, whether such exposure before pregnancy could induce epigenetic alterations in the placenta of former smokers has never been investigated.

METHODS

Our approach combined the analysis of placenta epigenomic (ENCODE) data with newly generated DNA methylation data obtained from 568 pregnant women, the largest cohort to date, either actively smoking during their pregnancy or formerly exposed to tobacco smoking.

RESULTS

This strategy resulted in several major findings. First, among the 203 differentially methylated regions (DMRs) identified by the epigenome-wide association study, 152 showed "reversible" alterations of DNA methylation, only present in the placenta of current smokers, whereas 26 were also found altered in former smokers, whose placenta had not been exposed directly to cigarette smoking. Although the absolute methylation changes were smaller than those observed in other contexts, such as in some congenital diseases, the observed alterations were consistent within each DMR. This observation was further supported by a demethylation of LINE-1 sequences in the placentas of both current (beta-coefficient (β) (95% confidence interval (CI)), - 0.004 (- 0.008; 0.001)) and former smokers (β (95% CI), - 0.006 (- 0.011; - 0.001)) compared to nonsmokers. Second, the 203 DMRs were enriched in epigenetic marks corresponding to enhancer regions, including monomethylation of lysine 4 and acetylation of lysine 27 of histone H3 (respectively H3K4me1 and H3K27ac). Third, smoking-associated DMRs were also found near and/or overlapping 10 imprinted genes containing regions (corresponding to 16 genes), notably including the NNAT, SGCE/PEG10, and H19/MIR675 loci.

CONCLUSIONS

Our results pointing towards genomic regions containing the imprinted genes as well as enhancers as preferential targets suggest mechanisms by which tobacco could directly impact the fetus and future child. The persistence of significant DNA methylation changes in the placenta of former smokers supports the hypothesis of an "epigenetic memory" of exposure to cigarette smoking before pregnancy. This observation not only is conceptually revolutionary, but these results also bring crucial information in terms of public health concerning potential long-term detrimental effects of smoking in women.

Prenatal airshed pollutants and preterm birth in an observational birth cohort study in Detroit, Michigan, USA

Detroit, Michigan, currently has the highest preterm birth (PTB) rate of large cities in the United States. Disproportionate exposure to ambient air pollutants, including particulate matter ≤2.5 μm (PM_2.5), PM ≤ 10 μm (PM₁₀), nitrogen dioxide (NO₂) and benzene, toluene, ethylbenzene, and xylenes (BTEX) may contribute to PTB. Our objective was to examine the association of airshed pollutants with PTB in Detroit, MI. The Geospatial Determinants of Health Outcomes Consortium (GeoDHOC) study collected air pollution measurements at 68 sites in Detroit in September 2008 and June 2009. GeoDHOC data were coupled with 2008-2010 Michigan Air Sampling Network measurements in Detroit to develop monthly ambient air pollution estimates at a spatial density of 300 m². Using delivery records from two urban hospitals, we established a retrospective birth cohort of births by Detroit women occurring from June 2008 to May 2010. Estimates of air pollutant exposure throughout pregnancy were assigned to maternal address at delivery. Our analytic sample size included 7961 births; 891 (11.2%) were PTB. After covariate adjustment, PM₁₀ (P = 0.003) and BTEX (P < 0.001), but not PM_2.5 (P = 0.376) or NO₂ (P = 0.582), were statistically significantly associated with PTB. In adjusted models, for every 5-unit increase in PM₁₀ there was a 1.21 times higher odds of PTB (95% CI 1.07, 1.38) and for every 5-unit increase in BTEX there was a 1.54 times higher odds of PTB (95% CI 1.25, 1.89). Consistent with previous studies, higher PM₁₀ was associated with PTB. We also found novel evidence that higher airshed BTEX is associated with PTB. Future studies confirming these associations and examining direct measures of exposure are needed.

Maternal exposure to air pollutants and birth weight in Tehran, Iran

BACKGROUND

Air pollution can cause various health outcomes, especially in susceptible groups including pregnant women. Low birth weight (LBW) is among the adverse birth outcomes and is one of the main causes of infant mortality. The aim of this study was to assess the association between air pollutants and LBW in Tehran, Iran.

METHODS

In this case-control study, 2144 babies born in three hospitals of Tehran (Iran) during 2011 to 2012 whose mothers were the residents of this city in last 5 years were considered. Of these, 468 infants with birth weight < 2500 g and 1676 with birth weight ≥ 2500 g were regarded as case and control groups, respectively. Gestational age was also considered for definition of cases (small for gestational age (SGA)) and controls (appropriate for gestational age). Land use regression models were used to assess exposure to particulate matter ≤10 μm in aerodynamic diameter (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂) and volatile organic compounds (benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene (BTEX), and total BTEX) during pregnancy. Logistic regression model was applied to assess the association between air pollutants and LBW.

RESULTS

The concentrations of air pollutants were very high but similar in cases and controls. After adjustment for potential confounding variables, no statistically significant association was observed between air pollutants and LBW. The adjusted odds ratios (95% confidence interval) for PM₁₀, SO₂, and benzene were 0.999 (0.994-1.005), 0.998 (0.993-1.003), and 0.980 (0.901-1.067), respectively.

CONCLUSIONS

No association was found between LBW and air pollutants. Further studies with more rigorous designs and access to more comprehensive information are suggested to assess the effect of other air pollutants, such as CO, O₃, PM_2.5, ultrafine particles, and oxidative potential of particles on birth outcomes.

Deciphering the Impact of Early-Life Exposures to Highly Variable Environmental Factors on Foetal and Child Health: Design of SEPAGES Couple-Child Cohort

In humans, studies based on Developmental Origins of Health and Disease (DOHaD) concept and targeting short half-lived chemicals, including many endocrine disruptors, generally assessed exposures from spot biospecimens. Effects of early-life exposure to atmospheric pollutants were reported, based on outdoor air pollution levels. For both exposure families, exposure misclassification is expected from these designs: for non-persistent chemicals, because a spot biospecimen is unlikely to capture exposure over windows longer than a few days; for air pollutants, because indoor levels are ignored. We developed a couple-child cohort relying on deep phenotyping and extended personal exposure assessment aiming to better characterize the effects of components of the exposome, including air pollutants and non-persistent endocrine disruptors, on child health and development. Pregnant women were included in SEPAGES couple-child cohort (Grenoble area) from 2014 to 2017. Maternal and children exposure to air pollutants was repeatedly assessed by personal monitors. DNA, RNA, serum, plasma, placenta, cord blood, meconium, child and mother stools, living cells, milk, hair and repeated urine samples were collected. A total of 484 pregnant women were recruited, with excellent compliance to the repeated urine sampling protocol (median, 43 urine samples per woman during pregnancy). The main health outcomes are child respiratory health using early objective measures, growth and neurodevelopment. Compared to former studies, the accuracy of assessment of non-persistent exposures is expected to be strongly improved in this new type of birth cohort tailored for the exposome concept, with deep phenotyping and extended exposure characterization. By targeting weaknesses in exposure assessment of the current approaches of cohorts on effects of early life environmental exposures with strong temporal variations, and relying on a rich biobank to provide insight on the underlying biological pathways whereby exposures affect health, this design is expected to provide deeper understanding of the interplay between the Exposome and child development and health.

A systematic review of associations between maternal exposures during pregnancy other than smoking and antenatal fetal measurements

BACKGROUND

Reduced birth weight is associated with many maternal environmental exposures during pregnancy, but the gestational age at onset of this association is unknown. We have previously reported associations between maternal smoking and fetal size.

OBJECTIVE

To report on our systematic review of the literature describing associations between antenatal size and growth and maternal exposures during pregnancy.

DATA SOURCES

Electronic databases (OVID and EMBASE) and web sites for cohort studies were searched. Studies were eligible if they examined associations between maternal environmental exposures (including ambient air exposure, diet and alcohol) and antenatal fetal ultrasound measurements. The Navigation Guide was used to assess the strength of evidence.

RESULTS

There were 451 abstracts identified and 36 papers were included of which maternal diet was the exposure of interest in 15, maternal ambient air exposure in 10, maternal alcohol in 3 and other exposures in 8. The first paper was published in 2006. Associations were present between exposures and fetal measurements in 18% of comparisons with second trimester measurements and in 46% of comparisons with third trimester measurements. In the third trimester, when an association was present, reduced head size was most commonly (58%) associated with current or previous maternal exposure, with reduced length being least commonly (32%) associated and reduced weight being intermediate (52%). In the third trimester, increased maternal nitrogen dioxide exposure was associated with reduced head size was associated with in all seven studies identified and reduced fetal weight in five out of six studies.

CONCLUSION

There is sufficient evidence of toxicity in the context of maternal exposure to nitrogen dioxide and reduced third trimester fetal head size. There is currently insufficient evidence of toxicity with regard to maternal exposures to dietary factors, alcohol and environmental chemicals and reduced fetal size.

Maternal exposure to ambient fine particulate matter and fetal growth in Shanghai, China

BACKGROUND

Fetal growth restriction (FGR) is not only a major determinant of perinatal morbidity and mortality but also leads to adverse health effects in later life. Over the past decade, numerous studies have indicated that maternal exposure to ambient air pollution has been a risk factor for abnormal fetal growth in developed countries where PM2.5 levels are relatively low. However, studies in highly polluted regions, such as China, and studies that rely on assessments in utero are scarce.

METHODS

A total of 7965 women were selected from 11,441 women from the Shanghai Maternity and Infant Living Environment (SMILE) cohort who were pregnant between January 1, 2014, and April 30, 2015. From January 1, 2014, to April 30, 2015, weekly average PM2.5 values from 53 monitors were calculated and the inverse distance weighted (IDW) method was used to create a Shanghai pollution surface map according to the participants residential addresses. Individual exposure was the average PM2.5 value of every gestational week between the first gestational week and one week before the ultrasound measurement date (the range of measurements per participant was 1 to 10). Repeated fetal ultrasound measurements during gestational weeks 14~40 were selected. The estimated fetal weight (EFW) was calculated by biparietal diameter (BPD), abdominal circumference (AC), and femur length (FL) formulas. In total, 29,926 ultrasound measurements were analysed. Demographic variables, other pollutants (SO2, NO2, PM10 and O3) and relative humidity and temperature were controlled for potential confounding through generalized estimating equations (GEE).

RESULTS

The full model showed that with each 10 μg/m3 increase in PM2.5 exposure, the means (mm) of AC, BPD, FL decreased by 5.48 (- 9.06, - 1.91), 5.57 (- 6.66, - 4.47), and 5.47 (- 6.39, - 4.55), respectively; the mean EFW decreased by 14.49 (- 16.05, - 13.49) grams by Hadlock's third formula and 13.56 (- 14.71, - 12.50) grams by Shepard's formula with each 10 μg/m3 increase in PM2.5 exposure.

CONCLUSIONS

A negative correlation existed between maternal PM2.5 exposure during pregnancy and fetal growth indicators, which may increase the risk of fetal growth restriction.

Maternal Exposure to Indoor Air Pollution and Birth Outcomes

There is a growing body of research on the association between ambient air pollution and adverse birth outcomes. However, people in high income countries spend most of their time indoors. Pregnant women spend much of that time at home. The aim of this study was to investigate if indoor air pollutants were associated with poor birth outcomes. Pregnant women were recruited prior to 18 weeks gestation. They completed a housing questionnaire and household chemical use survey. Indoor pollutants, formaldehyde (HCHO), nitrogen dioxide (NO2) and volatile organic compounds (VOCs), were monitored in the women's homes at 34 weeks gestation. Gestational age (GA), birth weight (BW) and length (BL) and head circumference (HC) were collected from birth records. The associations between measured pollutants, and pollution surrogates, were analysed using general linear models, controlling for maternal age, parity, maternal health, and season of birth. Only HCHO was associated with any of the birth outcomes. There was a 0.044 decrease in BW z-score (p = 0.033) and 0.05 decrease in HC z-score (p = 0.06) for each unit increase in HCHO. Although HCHO concentrations were very low, this finding is consistent with other studies of formaldehyde and poor birth outcomes.

Ambient air pollution, H19/DMR methylation in cord blood and newborn size: A pilot study in Zhengzhou City, China

Prenatal exposure to air pollutants is believed to be associated with adverse birth outcomes. However, the potential mechanisms, especially the epigenetic modified effects, still remain unclear. This study was designed to explore the association of air pollution, H19/DMR methylation levels, and birth weight and length. A total of 527 mother-infant pairs were recruited from Houzhai Center Hospital, Zhengzhou. Air pollution data during the study period was collected. The methylation at H19 promoter region and H19 DMR in maternal and cord bloods were determined using real-time PCR analysis. Ridge regression was used to analyze the association of air pollutants exposure during gestation with H19/DMR methylation and birth weight and length respectively. Results showed that prenatal exposure to NO₂ was associated with higher H19 methylation in cord blood. Whereas SO₂ and PM₁₀ exposure were associated with lower H19 and H19 DMR methylation respectively. After stratification by pregnancy trimesters, the association of H19 methylation in cord blood with PM₁₀ exposure also was found. Furthermore, prenatal exposures to air pollutants also were associated with birth weight and length. Specifically, with the increase of maternal SO₂ exposure during the entire pregnancy, birth weight and length significantly decreased. While birth weight and birth length were significantly increased with NO₂ exposure. The stratified analysis also found the associations between PM₁₀ exposure and birth sizes in different trimesters. In conclusion, the gene methylation level in cord blood might be associated with prenatal environmental exposures. Birth weight and length were associated with both prenatal environmental exposures and genetic factors.

Associations between maternal residential proximity to air emissions from industrial facilities and low birth weight in Texas, USA

BACKGROUND

Most previous studies examining associations between maternal exposures to air pollutants during pregnancy and low birth weight (LBW) in offspring focused on criteria air pollutants (PM_2.5, PM₁₀, O₃, NO₂, SO₂, CO, and Pb). The relationship between non-criteria air pollutants and LBW is understudied and requires greater coverage.

OBJECTIVES

This study investigated associations between maternal residential exposure to industrial air pollutants during pregnancy and LBW in offspring.

METHODS

This study used a case-control study design that included 94,106 term LBW cases and 376,424 controls. It covered 78 air pollutants common to both the Toxics Release Inventory (TRI) and ground air quality monitoring databases in Texas during 1996-2008. A modified version of the Emission Weighted Proximity Model (EWPM), calibrated with ground monitoring data, was used to estimate maternal residential exposure to industrial air pollutants during pregnancy. Binary logistic regression analyses were performed to calculate odds ratios (ORs) reflecting the associations of maternal exposure to industrial air pollutants and LBW in offspring, adjusted for child's sex, gestational weeks, maternal age, education, race/ethnicity, marital status, prenatal care, tobacco use during pregnancy, public health region of maternal residence, and year of birth. In addition, the Bonferroni correction for multiple comparisons was applied to the results of logistic regression analysis.

RESULTS

Relative to the non-exposed reference group, maternal residential exposure to benzene (adjusted odds ratio (aOR) 1.06, 95% confidence interval (CI) 1.04, 1.08), benzo(g,h,i)perylene (aOR 1.04, 95% CI 1.02, 1.07), cumene (aOR 1.05, 95% CI 1.03, 1.07), cyclohexane (aOR 1.04, 95% CI 1.02, 1.07), dichloromethane (aOR 1.04, 95% CI 1.03, 1.07), ethylbenzene (aOR 1.05, 95% CI 1.03, 1.06), ethylene (aOR 1.06, 95% CI 1.03, 1.09), mercury (aOR 1.04, 95% CI 1.02, 1.07), naphthalene (aOR 1.03, 95% CI 1.01, 1.05), n-hexane (aOR 1.06, 95% CI 1.04, 1.08), propylene (aOR 1.06, 95% CI 1.03, 1.10), styrene (aOR 1.06, 95% CI 1.04, 1.08), toluene (aOR 1.05, 95% CI 1.03, 1.07), and zinc (fume or dust) (aOR 1.10, 95% CI 1.06, 1.13) was found to have significantly higher odds of LBW in offspring. When the estimated exposures were categorized into four different groups (zero, low, medium, and high) in the analysis, eleven of the fourteen air pollutants, with the exception of benzo(g,h,i)perylene, ethylene, and propylene, remained as significant risk factors.

CONCLUSIONS

Results indicate that maternal residential proximity to industrial facilities emitting any of the fourteen pollutants identified by this study during pregnancy may be associated with LBW in offspring. With the exception of benzene, ethylbenzene, toluene, and zinc, the rest of the fourteen air pollutants are identified as LBW risk factors for the first time by this study. Further epidemiological, biological, and toxicological studies are suggested to verify the findings from this study.

Industrial air pollution and low birth weight: a case-control study in Texas, USA

Many studies have investigated associations between maternal residential exposures to air pollutants and low birth weight (LBW) in offspring. However, most studies focused on the criteria air pollutants (PM_2.5, PM₁₀, O₃, NO₂, SO₂, CO, and Pb), and only a few studies examined the potential impact of other air pollutants on LBW. This study investigated associations between maternal residential exposure to industrial air emissions of 449 toxics release inventory (TRI) chemicals and LBW in offspring using a case-control study design based on a large dataset consisting of 94,106 LBW cases and 376,424 controls in Texas from 1996 to 2008. Maternal residential exposure to chemicals was estimated using a modified version of the emission-weighted proximity model (EWPM). The model takes into account reported quantities of annual air emission from industrial facilities and the distances between the locations of industrial facilities and maternal residence locations. Binary logistic regression was used to compute odds ratios measuring the association between maternal exposure to different TRI chemicals and LBW in offspring. Odds ratios were adjusted for child's sex, birth year, gestational length, maternal age, education, race/ethnicity, and public health region of maternal residence. Among the ten chemicals selected for a complete analysis, maternal residential exposures to five TRI chemicals were positively associated with LBW in offspring. These five chemicals include acetamide (adjusted odds ratio [aOR] 2.29, 95% confidence interval [CI] 1.24, 4.20), p-phenylenediamine (aOR 1.63, 95% CI 1.18, 2.25), 2,2-dichloro-1,1,1-trifluoroethane (aOR 1.41, 95% CI 1.20, 1.66), tributyltin methacrylate (aOR 1.20, 95% CI 1.06, 1.36), and 1,1,1-trichloroethane (aOR 1.11, 95% CI 1.03, 1.20). These findings suggest that maternal residential proximity to industrial air emissions of some chemicals during pregnancy may be associated with LBW in offspring.

Effects of prenatal exposure to ambient air pollutant PM10 on ultrasound-measured fetal growth

Background

Limited epidemiological studies have investigated the relationship between prenatal exposure to ambient particulate matter and risk of abnormal fetal growth, and have reached inconclusive results. No study has been conducted in areas with very high air pollution levels. We investigated the hypothesis that exposure to high levels of particulate matter with aerodynamic diameter no larger than 10 µm (PM10) during pregnancy increases the risk of abnormal fetal growth.

Methods

A birth cohort study was performed in Lanzhou, China, 2010-12, including 8877 pregnant women with 18 583 ultrasound measurements of four fetal growth parameters during pregnancy, including biparietal diameter (BPD), femur length (FL), head circumference (HC) and abdominal circumference (AC). Mixed-effects modelling was used to examine the associations between PM10 exposure and risk of abnormal fetal growth.

Results

When average PM10 exposure from conception until the ultrasound examination exceeded 150 µg/m3, there were significant increases in standardized FL (β = 0.095, P = 0.0012) and HC (β = 0.090, P = 0.0078) measures. When average PM10 exposure was treated as continuous variable, we found a significant decrease in standardized BPD (β = -0.018, P = 0.0016) as per 10 µg/m3 increase in PM10. After examining the associations by various exposure windows, positive associations between higher levels of PM10 and fetal overgrowth were consistently seen for HC measures.

Conclusions

Our study suggested that prenatal exposure to high levels of ambient PM10 increased the risk of abnormal fetal growth. The findings from our study have important public health implications and also call for future studies to explore the underlying mechanisms and post-natal consequences of these findings.

Impact of a gestational exposure to diesel exhaust on offspring gonadal development: experimental study in the rabbit

The aim of the present work was to address experimentally the possible impact of exposure to air pollution during gestation on the differentiation and function of the gonads of the offspring using a rabbit model. Rabbits were exposed daily to diluted diesel exhaust gas or filtered air from the 3rd until the 27th day of gestation, during which time germ cells migrate in genital ridges and divide, and fetal sex is determined. Offspring gonads were collected shortly before birth (28th day of gestation) or after puberty (7.5 months after birth). The structure of the gonads was analyzed by histological and immunohistological methods. Serum concentrations of testosterone and anti-Müllerian hormone were determined using ELISA. The morphology and the endocrine function of the gonads collected just at the arrest of the exposure were similar in polluted and control animals in both sexes. No differences were observed as well in gonads collected after puberty. Sperm was collected at the head of the epididymis in adults. Sperm motility and DNA fragmentation were measured. Among all parameters analyzed, only the sperm DNA fragmentation rate was increased three-fold in exposed males. Mechanisms responsible for these modifications and their physiological consequences are to be further clarified.

Air pollution exposure during pregnancy and ultrasound and birth measures of fetal growth: A prospective cohort study in Korea

Few studies have examined the effects of air pollution on fetal growth based on ultrasound measures during pregnancy. More data is needed to evaluate the windows of special vulnerability. Our aim was to investigate the association of ambient air pollution during pregnancy with fetal and neonatal characteristics in a cohort of Korean women. Maternal exposure to particulate matter with an aerodynamic diameter<10μm (PM₁₀) and nitrogen dioxide (NO₂) was estimated using land-use regression models based on residential address. The biparietal diameter (BPD), abdominal circumference (AC), femur length (FL), and estimated fetal weight (EFW) were evaluated via ultrasonography, and birth weight (BW), birth length (BL), and head circumference at birth (BHC) were obtained from medical records. The multiple linear regression model was used to adjust for confounders, and the mixed-effect model was used to evaluate longitudinal effect. The negative effects for NO₂ and PM₁₀ were estimated; in the adjusted analyses the decreases of BPD were -0.26mm (95% confidence interval [CI]=-0.41 to -0.11, with a 10μg/m³ increase) in the second trimester for NO₂, and -0.30mm (95% CI=-0.59 to -0.03, with a 10μg/m³ increase) in the third trimester for PM₁₀. Both NO₂ and PM₁₀ levels (10μg/m³) during third trimester were inversely associated with BHC, and NO₂ level was inversely associated with BL in all exposure windows. No significant associations for AC, FL, and EFW were observed. The longitudinal analyses showed inverse association of NO₂ exposure with head and length growth (P<0.001). Our findings suggest that ambient air pollution is associated with impaired fetal head size from mid-gestation onwards.

Prenatal TVOCs exposure negatively influences postnatal neurobehavioral development

Prenatal exposure to volatile organic compounds may restrict fetal development and adversely influence infants' life. Therefore, we investigated the relationship between prenatal exposure to total volatile organic compounds (TVOC) and postnatal neurobehavioral development. A subsample of 383 pregnant participants was chosen from the prospective birth cohort study of Mother and Children's Environmental Health Study; MOCEH (N=1,751) from three regions of the Republic of Korea (Seoul, Cheon-an, and Ulsan). Participants were enrolled during their first trimester with informed consent. We investigated maternal characteristics including socio-economic and obstetrical history using questionnaires. An environmental hygienist measured participating mothers' personal TVOC exposure using passive samplers during pregnancy. Participants visited the research center at 6, 12, 24 and 36 months. At each visit, questionnaires about infantile environment and health conditions were answered and a neurobehavioral test (BSID-II) was conducted by certified investigators. We conducted multiple general linear and mixed model analyses to investigate the relationship between TVOC and infantile neurobehavioral development (SAS 9.3). Mean prenatal TVOC exposure was 284.2μg/m³. In longitudinal analyses on infantile neurobehavioral development, adjusted mean psychomotor development index and mental developmental index scores in high TVOC exposure group (cut off at Q3: 374.0 ug/m3) were 3 points lower than the low exposure group. Results suggested exposure to higher TVOC during the fetal period may adversely influence neurobehavioral development in the early life stage.

Gestational exposure to volatile organic compounds (VOCs) in Northeastern British Columbia, Canada: A pilot study

BACKGROUND

Northeastern British Columbia (Canada) is an area of intense hydraulic fracturing for unconventional natural gas exploitation. There have been multiple reports of air and water contamination by volatile organic compounds in the vicinity of gas wells. Although these chemicals are known developmental toxicants, no biomonitoring effort has been carried out in the region.

OBJECTIVE

To evaluate gestational exposure to benzene and toluene in the Peace River Valley, Northeastern British Columbia (Canada).

METHODS

Urine samples were collected over five consecutive days from 29 pregnant women. Metabolites of benzene (s-phenylmercapturic acid (S-PMA) and trans, trans-muconic acid (t,t-MA)) and toluene (s-benzylmercapturic acid (S-BMA)) were measured in pooled urine samples from each participant. Levels of benzene metabolites were compared to those from the general Canadian population and from a biomonitoring study of residents from an area of active gas exploitation in Pavillion, Wyoming (USA). Levels measured in participants from the two recruitment sites, and self-identifying as Indigenous or non-Indigenous, were also compared.

RESULTS

Whereas the median S-PMA level (0.18μg/g creatinine) in our study was similar to that in the general Canadian population, the median t,t-MA level (180μg/g creatinine) was approximately 3.5 times higher. Five women had t,t-MA levels above the biological exposure index® proposed by the American Conference of Governmental Industrial Hygienists. The median urinary S-BMA level in our pilot study was 7.00μg/g creatinine. Urinary metabolite levels were slightly higher in self-identifying Indigenous women, but this difference was only statistically significant for S-PMA.

DISCUSSION

Urinary t,t-MA levels, but not S-PMA levels, measured in our study are suggestive of a higher benzene exposure in participating pregnant women from the Peace River Valley than in the general Canadian population. Given the small sample size and limitations of t,t-MA measurements (e.g., non-specificity), more extensive monitoring is warranted.

Maternal exposure to ambient air pollution and fetal growth in North-East Scotland: A population-based study using routine ultrasound scans

BACKGROUND

Maternal ambient air pollution exposure is associated with reduced birthweight. Few studies have examined the effect on growth in utero and none have examined the effect of exposure to particulates less than 2.5µm (PM_2.5) and possible effect modification by smoking status.

OBJECTIVES

Examine the effect of maternal exposure to ambient concentrations of PM₁₀, PM_2.5 and nitrogen dioxide (NO₂) for in utero fetal growth, size at birth and effect modification by smoking status.

METHODS

Administratively acquired second and third trimester fetal measurements (bi-parietal diameter, femur length and abdominal circumference), birth outcomes (weight, crown heel length and occipito-frontal circumference) and maternal details were obtained from routine fetal ultrasound scans and maternity records (period 1994-2009). These were modelled against residential annual pollution concentrations (calendar year mean) adjusting for covariates and stratifying by smoking status.

RESULTS

In the whole sample (n=13,775 pregnancies), exposure to PM₁₀, PM_2.5 and NO₂ was associated with reductions in measurements at birth and biparietal diameter from late second trimester onwards. Among mothers who did not smoke at all during pregnancy (n=11,075), associations between biparietal diameter and pollution exposure remained significant but were insignificant among those who did smoke (n=2700). Femur length and abdominal circumference were not significantly associated with pollution exposure.

CONCLUSIONS

Fetal growth is strongly associated with particulates exposure from later in second trimester onwards but the effect appears to be subsumed by smoking. Typical ambient exposures in this study were relatively low compared to other studies and given these results, it may be necessary to consider reducing recommended "safe" ambient air exposures.

The effect of prenatal TVOC exposure on birth and infantile weight: the Mothers and Children's Environmental Health study

BACKGROUNDVolatile organic compounds (VOCs) might restrict prenatal and postnatal growth. However, the effect of the exposure of prenatal VOCs on postnatal growth has not been studied sufficiently. Thus, we investigated the relationship between the exposure of total volatile organic compounds (TVOCs) during pregnancy and its effects on postnatal growth.METHODSA total of 383 pregnant participants were enrolled from 2006 to 2008. We investigated maternal characteristics using a questionnaire. Personal air samples of TVOCs were obtained in mid or late pregnancy. After these mothers had given birth, 360 singleton newborns were selected and postnatal follow-up data were collected at 6, 12, 24, and 36 months, as well as anthropometric factors including body weight. Multiple general linear and mixed models were applied for statistical analyses.RESULTSThe mean concentration of prenatal exposure to TVOCs was 284.2 μg/m³ and that of formaldehyde was 81.6 μg/m³. The birth weight of newborns decreased significantly with prenatal TVOC exposure (β=-45.89, P=0.04). The adjusted mean body weight was 300 g lower in the high-TVOC group (⩾75th) compared with that in the low-exposure group (<75th).CONCLUSIONThese results indicate that elevated exposure to TVOCs during the prenatal period may adversely influence early postnatal growth.

Ambient air pollution and low birth weight - are some women more vulnerable than others?

BACKGROUND AND OBJECTIVES

Ambient air pollution is controllable, and it is one of the greatest environmental threats to human health. Studies conducted worldwide have provided evidence that maternal exposure to ambient air pollution during pregnancy enhances the risk of low birth weight at term (TLBW, <2500g among infants born ≥37 completed weeks of gestation), a maker of intrauterine growth restriction (IUGR), and suggest that some subgroups of pregnant women who are smoking, of low or high body-mass index (BMI), low socioeconomic status (SES) or asthma are more vulnerable towards the effect of ambient air pollution. The aim of this commentary is to review the published literature on the association between ambient air pollution and TLBW regarding increased vulnerability for the above-mentioned subgroups.

RESULTS

Although more than fifty epidemiological studies have examined the associations between ambient air pollution and TLBW to date, we only identified six studies that examined the potential effect modification of the association between ambient air pollution and TLBW by the above listed maternal risk factors. Two studies assessed effect modification caused by smoking on the association between ambient air pollution and TLBW. The adjusted odds ratio (OR) for TLBW associated with exposure to ambient air pollution were in one study higher among women who smoked during pregnancy, as compared to the OR of non-smoking women, while in the other study the association was in the opposite direction. The association of ambient air pollution and TLBW were higher among women characterized by extreme BMI (two studies) and low SES compared to non-obese women or women of higher SES (four studies), respectively. Only one study reported the estimated effects among asthmatic and non-asthmatic women and no statistically significant effect modification was evident for the risk of TLBW associated with ambient air pollution.

CONCLUSION AND RECOMMENDATIONS

The current epidemiologic evidence is scarce, but suggests that pregnant women who are smoking, being underweight, overweight/obese or having lower SES are a vulnerable subpopulation when exposed to ambient air pollution, with and increased risk of having a child with TLBW. The limited evidence precludes for definitive conclusions and further studies are recommended.

Influence of oil-related environmental pollutants on female reproduction

The petroleum low-weight aromatic hydrocarbons benzene, toluene, ethylbenzene, m/p-xylene, and o-xylene, also known as BTEX, are among the most common hazardous sources of environmental contamination. This paper reviews the available data concerning the effects of BTEX on different aspects of female reproduction, including the fecundity, ovaries, central nervous system (CNS), oocytes, embryos, oviducts, cytogenetics of somatic and generative cells, intracellular signaling systems, and hypothalamic, pituitary and peripheral reproductive hormones. Analysis of the available literature demonstrates that BTEX can exert negative effects on various female reproductive sites, including the CNS-pituitary-ovarian axis, their signaling molecules and receptors, ovarian follicles, corpora lutea, oocytes, embryos, oviducts, ovarian cycles, fertility, and the viability of offspring. These effects could be due to the ability of BTEX to destroy chromosomes, to affect cell metabolism, including the accumulation of free radicals, and to affect the release of hormonal regulators of reproductive processes and intracellular protein kinases.

Fetal growth and air pollution - A study on ultrasound and birth measures

Air pollution has been suggested to affect fetal growth, but more data is needed to assess the timing of exposure effects by using ultrasound measures. It is also important to study effects in low exposure areas to assess eventual thresholds of effects. The MAPSS (Maternal Air Pollution in Southern Sweden) cohort consists of linked registry data for around 48,000 pregnancies from an ultrasound database, birth registry and exposure data based on residential addresses. Measures of air pollution exposure were obtained through dispersion modelling with input data from an emissions database (NO_x) with high resolution (100-500m grids). Air pollution effects were assessed with linear regressions for the following endpoints; biparietal diameter, femur length, abdominal diameter and estimated fetal weight measured in late pregnancy and birth weight and head circumference measured at birth. We estimated negative effects for NO_x; in the adjusted analyses the decrease of abdominal diameter and femur length were -0.10 (-0.17, -0.03) and -0.13 (-0.17, -0.01)mm, respectively, per 10µg/m³ increment of NO_x. We also estimated an effect of NO_x-exposures on birth weight by reducing birth weight by 9g per 10µg/m³ increment of NO_x. We estimated small but statistically significant effects of air pollution on late fetal and birth size and reduced fetal growth late in pregnancy in a geographic area with levels below current WHO air quality guidelines.

Paving the way of systems biology and precision medicine in allergic diseases: the MeDALL success story: Mechanisms of the Development of ALLergy; EU FP7-CP-IP; Project No: 261357; 2010-2015

MeDALL (Mechanisms of the Development of ALLergy; EU FP7-CP-IP; Project No: 261357; 2010-2015) has proposed an innovative approach to develop early indicators for the prediction, diagnosis, prevention and targets for therapy. MeDALL has linked epidemiological, clinical and basic research using a stepwise, large-scale and integrative approach: MeDALL data of precisely phenotyped children followed in 14 birth cohorts spread across Europe were combined with systems biology (omics, IgE measurement using microarrays) and environmental data. Multimorbidity in the same child is more common than expected by chance alone, suggesting that these diseases share causal mechanisms irrespective of IgE sensitization. IgE sensitization should be considered differently in monosensitized and polysensitized individuals. Allergic multimorbidities and IgE polysensitization are often associated with the persistence or severity of allergic diseases. Environmental exposures are relevant for the development of allergy-related diseases. To complement the population-based studies in children, MeDALL included mechanistic experimental animal studies and in vitro studies in humans. The integration of multimorbidities and polysensitization has resulted in a new classification framework of allergic diseases that could help to improve the understanding of genetic and epigenetic mechanisms of allergy as well as to better manage allergic diseases. Ethics and gender were considered. MeDALL has deployed translational activities within the EU agenda.

Associations between maternal exposure to air pollution and traffic noise and newborn's size at birth: A cohort study

BACKGROUND

Maternal exposure to air pollution and traffic noise has been suggested to impair fetal growth, but studies have reported inconsistent findings. Objective To investigate associations between residential air pollution and traffic noise during pregnancy and newborn's size at birth.

METHODS

From a national birth cohort we identified 75,166 live-born singletons born at term with information on the children's size at birth. Residential address history from conception until birth was collected and air pollution (NO2 and NOx) and road traffic noise was modeled at all addresses. Associations between exposures and indicators of newborn's size at birth: birth weight, placental weight and head and abdominal circumference were analyzed by linear and logistic regression, and adjusted for potential confounders.

RESULTS

In mutually adjusted models we found a 10μg/m(3) higher time-weighted mean exposure to NO2 during pregnancy to be associated with a 0.35mm smaller head circumference (95% confidence interval (CI): 95% CI: -0.57; -0.12); a 0.50mm smaller abdominal circumference (95% CI: -0.80; -0.20) and a 5.02g higher placental weight (95% CI: 2.93; 7.11). No associations were found between air pollution and birth weight. Exposure to residential road traffic noise was weakly associated with reduced head circumference, whereas none of the other newborn's size indicators were associated with noise, neither before nor after adjustment for air pollution.

CONCLUSIONS

This study indicates that air pollution may result in a small reduction in offspring's birth head and abdominal circumference, but not birth weight, whereas traffic noise seems not to affect newborn's size at birth.

Sampling of BTX in Hat Yai city using cost effective laboratory-built PCB passive sampler

A laboratory-built printed circuit board (PCB) passive sampler used for the monitoring of xylene and styrene in copy print shops was re-validated for detecting benzene, toluene and xylene (BTX) and applied for the sampling of ambient air from Hat Yai city, Songkhla, Thailand, in the month of November 2014. For monitoring, the PCB passive samplers were exposed to target analytes in 16 locations covering high to low exposure areas. After sampling, the samplers were thermally desorbed and the analytes were trapped by multi-walled carbon nanotubes packed into a micro-preconcentrator coupled to a gas chromatograph (GC) equipped with a flame ionization detector. At the optimum GC operating conditions, the linear dynamic ranges for BTX were 0.06-5.6 µg for benzene, 0.07-2.2 µg for toluene and 0.23-2.5 µg for xylene with R(2) > 0.99 with the limits of detection being 6.6, 6.8 and 19 ng for benzene, toluene and xylene, respectively. The concentrations of BTX in the 16 sampling sites were in the range of N.D.-1.3 ± 1.6, 4.50 ± 0.76-49.6 ± 3.7 and 1.00 ± 0.21-39.6 ± 3.1 µg m(-3), respectively. When compared to past studies, there had been an increase in the benzene concentration.

Maternal exposure to diluted diesel engine exhaust alters placental function and induces intergenerational effects in rabbits

BACKGROUND

Airborne pollution is a rising concern in urban areas. Epidemiological studies in humans and animal experiments using rodent models indicate that gestational exposure to airborne pollution, in particular diesel engine exhaust (DE), reduces birth weight, but effects depend on exposure duration, gestational window and nanoparticle (NP) concentration. Our aim was to evaluate the effects of gestational exposure to diluted DE on feto-placental development in a rabbit model. Pregnant females were exposed to diluted (1 mg/m(3)), filtered DE (NP diameter ≈ 69 nm) or clean air (controls) for 2 h/day, 5 days/week by nose-only exposure (total exposure: 20 days in a 31-day gestation).

RESULTS

DE exposure induced early signs of growth retardation at mid gestation with decreased head length (p = 0.04) and umbilical pulse (p = 0.018). Near term, fetal head length (p = 0.029) and plasma insulin and IGF1 concentrations (p = 0.05 and p = 0.019) were reduced. Placental function was also affected, with reduced placental efficiency (fetal/placental weight) (p = 0.049), decreased placental blood flow (p = 0.009) and fetal vessel volume (p = 0.002). Non-aggregated and "fingerprint" NP were observed at various locations, in maternal blood space, in trophoblastic cells and in the fetal blood, demonstrating transplacental transfer. Adult female offspring were bred with control males. Although fetoplacental biometry was not affected near term, second generation fetal metabolism was modified by grand-dam exposure with decreased plasma cholesterol (p = 0.008) and increased triglyceride concentrations (p = 0.015).

CONCLUSIONS

Repeated daily gestational exposure to DE at levels close to urban pollution can affect feto-placental development in the first and second generation.

Use of geographic indicators of healthcare, environment and socioeconomic factors to characterize environmental health disparities

BACKGROUND

An environmental health inequality is a major public health concern in Europe. However just few studies take into account a large set of characteristics to analyze this problematic. The aim of this study was to identify and describe how socioeconomic, health accessibility and exposure factors accumulate and interact in small areas in a French urban context, to assess environmental health inequalities related to infant and neonatal mortality.

METHODS

Environmental indicators on deprivation index, proximity to high-traffic roads, green space, and healthcare accessibility were created using the Geographical Information System. Cases were collected from death certificates in the city hall of each municipality in the Nice metropolitan area. Using the parental addresses, cases were geocoded to their census block of residence. A classification using a Multiple Component Analysis following by a Hierarchical Clustering allow us to characterize the census blocks in terms of level of socioeconomic, environmental and accessibility to healthcare, which are very diverse definition by nature. Relation between infant and neonatal mortality rate and the three environmental patterns which categorize the census blocks after the classification was performed using a standard Poisson regression model for count data after checking the assumption of dispersion.

RESULTS

Based on geographic indicators, three environmental patterns were identified. We found environmental inequalities and social health inequalities in Nice metropolitan area. Moreover these inequalities are counterbalance by the close proximity of deprived census blocks to healthcare facilities related to mother and newborn. So therefore we demonstrate no environmental health inequalities related to infant and neonatal mortality.

CONCLUSION

Examination of patterns of social, environmental and in relation with healthcare access is useful to identify census blocks with needs and their effects on health. Similar analyzes could be implemented and considered in other cities or related to other birth outcomes.

City-Specific Spatiotemporal Infant and Neonatal Mortality Clusters: Links with Socioeconomic and Air Pollution Spatial Patterns in France

Infant and neonatal mortality indicators are known to vary geographically, possibly as a result of socioeconomic and environmental inequalities. To better understand how these factors contribute to spatial and temporal patterns, we conducted a French ecological study comparing two time periods between 2002 and 2009 for three (purposefully distinct) Metropolitan Areas (MAs) and the city of Paris, using the French census block of parental residence as the geographic unit of analysis. We identified areas of excess risk and assessed the role of neighborhood deprivation and average nitrogen dioxide concentrations using generalized additive models to generate maps smoothed on longitude and latitude. Comparison of the two time periods indicated that statistically significant areas of elevated infant and neonatal mortality shifted northwards for the city of Paris, are present only in the earlier time period for Lille MA, only in the later time period for Lyon MA, and decrease over time for Marseille MA. These city-specific geographic patterns in neonatal and infant mortality are largely explained by socioeconomic and environmental inequalities. Spatial analysis can be a useful tool for understanding how risk factors contribute to disparities in health outcomes ranging from infant mortality to infectious disease-a leading cause of infant mortality.

Associations of maternal personal exposure to air pollution on fetal weight and fetoplacental Doppler: A prospective cohort study

We determined the influence of maternal air pollution exposure during each trimester of pregnancy on fetal and birth weight and fetoplacental hemodynamics. In total, 366 women with singleton pregnancies were prospectively followed in the city of São Paulo, Brazil. Nitrogen dioxide (NO2) and ozone (O3) were measured during each trimester using passive personal samplers. We evaluated fetal weight and Doppler velocimetry data from the umbilical, middle cerebral, and uterine arteries in the 3rd trimester, and birth weight. Multivariate analysis was performed, controlling for known determinants of fetal weight. Exposure to higher levels of O3 during the 2nd trimester was associated with higher umbilical artery pulsatility indices (PIs) [p=0.013; beta=0.017: standard error (SE)=0.007]. Exposure to higher levels of O3 during the 3rd trimester was associated with lower umbilical artery PIs (p=0.011; beta=-0.021; SE=0.008). Our results suggest that in the environment of São Paulo, O3 may affects placental vascular resistance.

Adverse Health Effects of Benzene Exposure Among Children Following a Flaring Incident at the British Petroleum Refinery in Texas City

This study examined the health effects of benzene exposure among children from a flaring incident at the British Petroleum (BP) refinery in Texas City, Texas. A total of 899 children (benzene exposed, n = 641 and unexposed, n = 258), aged <17 years, were included. Hematological analysis showed that white blood cell (×10(3)/µL) counts were significantly decreased in the exposed children compared with the unexposed children (7.1 ± 2.2 versus 7.6 ± 2.1, P = .001). Similarly, the hemoglobin (g/dL) levels were decreased significantly in the exposed group compared with the unexposed group (12.7 ± 1.3 vs 13.1 ± 1.5, P = .001). Conversely, platelet (×10(3)/µL) counts were increased significantly in the exposed group compared with the unexposed group (318.6 ± 79.8 versus 266.9 ± 58.8, P = .001). Hepatic enzymes were also significantly elevated among exposed children compared with the unexposed children. These findings suggest that children exposed to benzene are at a higher risk of developing both hepatic and bone marrow-related disorders.

Prenatal Exposure to NO2 and Ultrasound Measures of Fetal Growth in the Spanish INMA Cohort

BACKGROUND

Air pollution exposure during pregnancy has been associated with impaired fetal growth. However, few studies have measured fetal biometry longitudinally, remaining unclear as to whether there are windows of special vulnerability.

OBJECTIVE

The aim was to investigate the impact of nitrogen dioxide (NO2) exposure on fetal and neonatal biometry in the Spanish INMA study.

METHODS

Biparietal diameter (BPD), femur length (FL), abdominal circumference (AC), and estimated fetal weight (EFW) were evaluated for up to 2,478 fetuses in each trimester of pregnancy. Size at 12, 20, and 34 weeks of gestation and growth between these points, as well as anthropometry at birth, were assessed by SD scores derived using cohort-specific growth curves. Temporally adjusted land-use regression was used to estimate exposure to NO2 at home addresses for up to 2,415 fetuses. Associations were investigated by linear regression in each cohort and subsequent meta-analysis.

RESULTS

A 10-μg/m(3) increase in average exposure to NO2 during weeks 0-12 was associated with reduced growth at weeks 0-12 in AC (-2.1%; 95% CI: -3.7, -0.6) and EFW (-1.6%; 95% CI: -3.0, -0.3). The same exposure was inversely associated with reduced growth at weeks 20-34 in BPD (-2.6%; 95% CI: -3.9, -1.2), AC (-1.8%; 95% CI: -3.3, -0.2), and EFW (-2.1%; 95% CI: -3.7, -0.2). A less consistent pattern of association was observed for FL. The negative association of this exposure with BPD and EFW was significantly stronger in smoking versus nonsmoking mothers.

CONCLUSIONS

Maternal exposure to NO2 in early pregnancy was associated with reduced fetal growth based on ultrasound measures of growth during pregnancy and measures of size at birth.

Effects of Environmental Exposures on Fetal and Childhood Growth Trajectories

Delayed fetal growth and adverse birth outcomes are some of the greatest public health threats to this generation of children worldwide because these conditions are major determinants of mortality, morbidity, and disability in infancy and childhood and are also associated with diseases in adult life. A number of studies have investigated the impacts of a range of environmental conditions during pregnancy (including air pollution, endocrine disruptors, persistent organic pollutants, heavy metals) on fetal and child development. The results, while provocative, have been largely inconsistent. This review summarizes up to date epidemiologic studies linking major environmental pollutants to fetal and child development and suggested future directions for further investigation.

Sex-specific differences in fetal growth in newborns exposed prenatally to traffic-related air pollution in the PELAGIE mother-child cohort (Brittany, France)

BACKGROUND

Numerous studies have linked prenatal traffic-related air pollution exposure to fetal growth. Recently, several studies have suggested exploring this association independently among boys and girls because of potential sex-specific biological vulnerability to air pollution. Residence-based factors can also influence fetal growth by enhancing susceptibility to the toxic effects of air pollution and must also be considered in these relations.

OBJECTIVE

We examined sex-specific associations between prenatal air pollution exposure and fetal growth and explored whether they differed by the urban-rural status of maternal residence.

METHODS

This study relied on the PELAGIE mother-child cohort (2521 women, Brittany, France, 2002-2006). Fetal growth was assessed through birth weight, head circumference and small weight (SGA) and small head circumference (SHC) for gestational age. Nitrogen dioxide (NO2) concentrations at mothers' homes were estimated by using a land use regression model taking into account temporal variation during pregnancy. Associations between estimated NO2 concentrations and fetal growth were assessed with linear regression or logistic regression models, depending on the outcome investigated.

RESULTS

An interquartile range (8.8 µg m(-3)) increase in NO2 exposure estimates was associated with a 27.4 g (95% CI 0.8 to 55.6) increase in birth weight and a 0.09 cm (95% CI 0.00-0.17) significant increase in head circumference, among newborn boys only. Their risks of SGA and SHC were reduced (OR 0.70, 95% CI 0.53-0.92, OR 0.76, 95% CI 0.56-1.03, respectively, for an increase of 8.8 µg m(-3)). No statistically significant trends were observed among girls. Urban-rural status modified the effect of air pollution only for SHC and again only for newborn boys.

CONCLUSION

Findings from this study confirm the need to consider sex-specific associations between air pollution and fetal growth and to investigate possible mechanisms by which traffic-related air pollution may increase anthropometric parameters at birth.

The health burden of pollution: the impact of prenatal exposure to air pollutants

Exposure to atmospheric pollutants in both open and closed environments is a major cause of morbidity and mortality that may be both controlled and minimized. Despite growing evidence, several controversies and disagreements exist among the studies that have analyzed the effects of prenatal pollutant exposure. This review article aims to analyze primary scientific evidence of the effects of air pollution during pregnancy and the impact of these effects on the fetus, infant health, and in particular, the respiratory system. We performed a review of articles from the PubMed and Web of Science databases that were published in English within the past 5 years, particularly those related to birth cohorts that began in pregnancy with follow-up until the first years of life. The largest reported effects are associated with prenatal exposure to particulate matter, nitrogen dioxide, and tobacco smoke. The primary effects affect birth weight and other parameters of fetal biometry. There is strong evidence regarding the impact of pollutants on morbidity secondary to respiratory problems. Growing evidence links maternal smoking to childhood asthma and wheezing. The role of passive maternal smoking is less clear. Great heterogeneity exists among studies. There is a need for additional studies on birth cohorts to monitor the relationship between the exposure of pregnant women to pollutants and their children’s progress during the first years of life.

Effect of indoor air pollution from biomass and solid fuel combustion on symptoms of preeclampsia/eclampsia in Indian women

Available evidence concerning the association between indoor air pollution (IAP) from biomass and solid fuel combustion and preeclampsia/eclampsia is not available in developing countries. We investigated the association between exposure to IAP from biomass and solid fuel combustion and symptoms of preeclampsia/eclampsia in Indian women by analyzing cross-sectional data from India's third National Family Health Survey (NFHS-3, 2005-2006). Self-reported symptoms of preeclampsia/eclampsia during pregnancy such as convulsions (not from fever), swelling of legs, body or face, excessive fatigue or vision difficulty during daylight, were obtained from 39,657 women aged 15-49 years who had a live birth in the previous 5 years. Effects of exposure to cooking smoke, ascertained by type of fuel used for cooking on preeclampsia/eclampsia risk, were estimated using logistic regression after adjusting for various confounders. Results indicate that women living in households using biomass and solid fuels have two times higher likelihood of reporting preeclampsia/eclampsia symptoms than do those living in households using cleaner fuels (OR = 2.21; 95%: 1.26-3.87; P = 0.006), even after controlling for the effects of a number of potentially confounding factors. This study is the first to empirically estimate the associations of IAP from biomass and solid fuel combustion and reported symptoms suggestive of preeclampsia/eclampsia in a large nationally representative sample of Indian women and we observed increased risk. These findings have important program and policy implications for countries such as India, where large proportions of the population rely on polluting biomass fuels for cooking and space heating. More epidemiological research with detailed exposure assessments and clinical measures of preeclampsia/eclampsia is needed in a developing country setting to validate these findings.

Effect of indoor air pollution from biomass and solid fuel combustion on symptoms of preeclampsia/eclampsia in Indian women

Available evidence concerning the association between indoor air pollution (IAP) from biomass and solid fuel combustion and preeclampsia/eclampsia is not available in developing countries. We investigated the association between exposure to IAP from biomass and solid fuel combustion and symptoms of preeclampsia/eclampsia in Indian women by analyzing cross-sectional data from India's third National Family Health Survey (NFHS-3, 2005-2006). Self-reported symptoms of preeclampsia/eclampsia during pregnancy such as convulsions (not from fever), swelling of legs, body or face, excessive fatigue or vision difficulty during daylight, were obtained from 39,657 women aged 15-49 years who had a live birth in the previous 5 years. Effects of exposure to cooking smoke, ascertained by type of fuel used for cooking on preeclampsia/eclampsia risk, were estimated using logistic regression after adjusting for various confounders. Results indicate that women living in households using biomass and solid fuels have two times higher likelihood of reporting preeclampsia/eclampsia symptoms than do those living in households using cleaner fuels (OR = 2.21; 95%: 1.26-3.87; P = 0.006), even after controlling for the effects of a number of potentially confounding factors. This study is the first to empirically estimate the associations of IAP from biomass and solid fuel combustion and reported symptoms suggestive of preeclampsia/eclampsia in a large nationally representative sample of Indian women and we observed increased risk. These findings have important program and policy implications for countries such as India, where large proportions of the population rely on polluting biomass fuels for cooking and space heating. More epidemiological research with detailed exposure assessments and clinical measures of preeclampsia/eclampsia is needed in a developing country setting to validate these findings.