Prohypertensive effect of gestational personal exposure to fine particulate matter. Prospective cohort study in non-smoking and non-obese pregnant women

Impacts of changes in PM2.5 concentrations and their major components on blood pressure during pregnancy

Sulfate, nitrate, ammonium, organic matter, and black carbon account for more than two-thirds of the total mass of PM2.5 and have stronger cardiovascular toxicity than other components. However, evidence regarding the gestational cardiovascular toxicity of these PM2.5 components is lacking. A prospective cohort study was conducted among 1913 pregnant women in Guangzhou, Pearl River Delta, China, from 2017 to 2020. Each participant underwent two office blood pressure (BP) measurements: baseline BP was assessed during the first and second trimesters (mean gestational age: 13.77 ± 2.76 weeks) and follow-up BP was measured during the third trimester (mean gestational age: 39.00 ± 1.46 weeks). The level of the five main PM2.5 components were estimated using a tracking air pollution dataset. Changes in PM2.5 component concentrations and BP levels were determined by calculating the differences between follow-up and baseline values. We found that changes in PM2.5 mass and components significantly affected gestational BP variations (β = 1.88-3.42, P < 0.001). Most associations exhibited an inverted U-shaped non-linear relationship, initially increasing steeply before leveling off, without a clear threshold. Systolic blood pressure (SBP) was more sensitive to concentration changes in PM2.5 components, with nitrate showing a particularly pronounced effect. Our findings suggest that changes in PM2.5 mass and its specific components levels were associated with maternal BP, especially increased SBP, with nitrate being the major contributor. Stricter emission reduction measures are needed to mitigate urban pollution sources associated with particulate nitrate.

Climate change and its environmental and health effects from 2015 to 2022: A scoping review

Background

The rise in environmental pollutants has become a pressing global concern of international magnitude. Substantial evidence now demonstrates that escalating global temperatures and rising sea levels might exacerbate release of chemical pollutants into the environment which amplifies their toxicity. Existing research underscores the linkage between climate change and air pollution as driving forces, with increased mortality and morbidity.

Purpose of review

This review explores the reciprocal relationship between climate change and its impact on health, as well as the environment. We conducted an in-depth analysis of all relevant published studies, encompassing studies conducted across various regions worldwide, including the Eastern Mediterranean Regional Office (EMRO)1 region.

Summary

The environmental consequences of climate change have widespread impacts on various health systems and populations. Knowledge gaps remain in understanding the full scope of climate change effects, particularly through environmental pollution. The findings of this review highlight the need for global strategies to mitigate diverse health risks to protect from the growing threats of climate change.

Household Air Pollution Exposures Over Pregnancy and Maternal Blood Pressure Trajectories through 8 Years Postpartum: Evidence from the Ghana Randomized Air Pollution and Health Study (GRAPHS)

Background

Household air pollution is a major contributor to cardiovascular disease burden in women in Sub-Saharan Africa. However, little is known about exposures during pregnancy or the effect of clean cooking interventions on postpartum blood pressure trajectories.

Methods

The Ghana Randomized Air Pollution and Health Study (GRAPHS) randomized 1414 non-smoking women in the first and second trimesters to liquefied petroleum gas (LPG) or improved biomass stoves - vs control (traditional three-stone open fire). Personal exposure to carbon monoxide was measured at four prenatal timepoints and three times over the first postpartum year. Participants were prospectively followed with annual resting BP measurements at 2, 4, 5, 6, 7, and 8 years postpartum. We employed linear mixed effects models to determine effect of GRAPHS interventions on postpartum BP, and to examine associations between prenatal and postnatal CO and postpartum BP.

Results

LPG intervention was associated with 3.54mmHg (95% CI -5.55, -1.53) lower change in systolic BP from enrolment through 8 years postpartum, and 2.27mmHg (95% CI -3.61, -0.93) lower change in diastolic BP from enrolment through 8 years postpartum, as compared to control. In exposure-response analysis, average prenatal CO was positively associated with change in systolic BP from enrolment (β=0.71mmHg, 95% CI 0.08, 1.30, per doubling of CO).

Conclusions

LPG cookstove intervention initiated in early pregnancy and maintained through the first postpartum year was associated with lower systolic and diastolic BP trajectories through 8 years postpartum. These findings support the need to integrate clean cooking solutions into existing antenatal care packages.

Sources of personal PM2.5 exposure during pregnancy in the MADRES cohort

BACKGROUND

Personal exposure to fine particulate matter (PM2.5) is impacted by different sources each with different chemical composition. Determining these sources is important for reducing personal exposure and its health risks especially during pregnancy.

OBJECTIVE

Identify main sources and their contributions to the personal PM2.5 exposure in 213 women in the 3rd trimester of pregnancy in Los Angeles, CA.

METHODS

We measured 48-hr integrated personal PM2.5 exposure and analyzed filters for PM2.5 mass, elemental composition, and optical carbon fractions. We used the EPA Positive Matrix Factorization (PMF) model to resolve and quantify the major sources of personal PM2.5 exposure. We then investigated bivariate relationships between sources, time-activity patterns, and environmental exposures in activity spaces and residential neighborhoods to further understand sources.

RESULTS

Mean personal PM2.5 mass concentration was 22.3 (SD = 16.6) μg/m3. Twenty-five species and PM2.5 mass were used in PMF with a final R2 of 0.48. We identified six sources (with major species in profiles and % contribution to PM2.5 mass) as follows: secondhand smoking (SHS) (brown carbon, environmental tobacco smoke; 65.3%), fuel oil (nickel, vanadium; 11.7%), crustal (aluminum, calcium, silicon; 11.5%), fresh sea salt (sodium, chlorine; 4.7%), aged sea salt (sodium, magnesium, sulfur; 4.3%), and traffic (black carbon, zinc; 2.6%). SHS was significantly greater in apartments compared to houses. Crustal source was correlated with more occupants in the household. Aged sea salt increased with temperature and outdoor ozone, while fresh sea salt was highest on days with westerly winds from the Pacific Ocean. Traffic was positively correlated with ambient NO2 and traffic-related NOx at residence. Overall, 76.8% of personal PM2.5 mass came from indoor or personal compared to outdoor sources.

IMPACT

We conducted source apportionment of personal PM2.5 samples in pregnancy in Los Angeles, CA. Among identified sources, secondhand smoking contributed the most to the personal exposure. In addition, traffic, crustal, fuel oil, fresh and aged sea salt sources were also identified as main sources. Traffic sources contained markers of combustion and non-exhaust wear emissions. Crustal source was correlated with more occupants in the household. Aged sea salt source increased with temperature and outdoor ozone and fresh sea salt source was highest on days with westerly winds from the Pacific Ocean.

The impact of air quality on cardiovascular health: A state of the art review

Air pollution is a global health challenge, increasing the risk of cardiovascular diseases such as heart disease, stroke, and arrhythmias. Particulate matter (PM), particularly PM2.5 and ultrafine particles (UFP), is a key contributor to the adverse effects of air pollution on cardiovascular health. PM exposure can lead to oxidative stress, inflammation, atherosclerosis, vascular dysfunction, cardiac arrhythmias, and myocardial injury. Reactive oxygen species (ROS) play a key role in mediating these effects. PM exposure can also lead to hypertension, a significant risk factor for cardiovascular disease. The COVID-19 pandemic resulted in a significant reduction of air pollutants, leading to a decline in the incidence of heart attacks and premature deaths caused by cardiovascular diseases. This review highlights the relationship between environmental air quality and cardiovascular health, elucidating the pathways through which air pollutants affect the cardiovascular system. It also emphasizes the need for increased awareness, collective efforts to mitigate the adverse effects of air pollution, and strategic policies for long-term air quality improvement to prevent the devastating effects of air pollution on global cardiovascular health.

Association of ambient PM1 exposure with maternal blood pressure and hypertensive disorders of pregnancy in China

Evidence concerning PM1 exposure, maternal blood pressure (BP), and hypertensive disorders of pregnancy (HDP) is sparse. We evaluated the associations using 105,063 participants from a nationwide cohort. PM1 concentrations were evaluated using generalized additive model. BP was measured according to the American Heart Association recommendations. Generalized linear mixed models were used to assess the PM1-BP/HDP associations. Each 10 μg/m3 higher first-trimester PM1 was significantly associated with 1.696 mmHg and 1.056 mmHg higher first-trimester SBP and DBP, and with 11.4% higher odds for HDP, respectively. The above associations were stronger among older participants (> 35 years) or those educated longer than 17 years or those with higher household annual income (> 400,000 CNY). To conclude, first-trimester PM1 were positively associated with BP/HDP, which may be modified by maternal age, education level, and household annual income. Further research is warranted to provide more information for both health management of HDP and environmental policies enactment.

The pathophysiological and molecular mechanisms of atmospheric PM2.5 affecting cardiovascular health: A review

BACKGROUND

Exposure to ambient fine particulate matter (PM2.5, with aerodynamic diameter less than 2.5 µm) is a leading environmental risk factor for global cardiovascular health concern.

OBJECTIVE

To provide a roadmap for those new to this field, we reviewed the new insights into the pathophysiological and cellular/molecular mechanisms of PM2.5 responsible for cardiovascular health.

MAIN FINDINGS

PM2.5 is able to disrupt multiple physiological barriers integrity and translocate into the systemic circulation and get access to a range of secondary target organs. An ever-growing body of epidemiological and controlled exposure studies has evidenced a causal relationship between PM2.5 exposure and cardiovascular morbidity and mortality. A variety of cellular and molecular biology mechanisms responsible for the detrimental cardiovascular outcomes attributable to PM2.5 exposure have been described, including metabolic activation, oxidative stress, genotoxicity, inflammation, dysregulation of Ca2+ signaling, disturbance of autophagy, and induction of apoptosis, by which PM2.5 exposure impacts the functions and fates of multiple target cells in cardiovascular system or related organs and further alters a series of pathophysiological processes, such as cardiac autonomic nervous system imbalance, increasing blood pressure, metabolic disorder, accelerated atherosclerosis and plaque vulnerability, platelet aggregation and thrombosis, and disruption in cardiac structure and function, ultimately leading to cardiovascular events and death. Therein, oxidative stress and inflammation were suggested to play pivotal roles in those pathophysiological processes.

CONCLUSION

Those biology mechanisms have deepen insights into the etiology, course, prevention and treatment of this public health concern, although the underlying mechanisms have not yet been entirely clarified.

Impacts of Ambient Fine Particulate Matter on Blood Pressure Pattern and Hypertensive Disorders of Pregnancy: Evidence From the Wuhan Cohort Study

[Figure: see text].

Air pollution and pre-eclampsia; associations and potential mechanisms

INTRODUCTION

Air pollution has significant negative health impacts, particularly on the cardiovascular system. The aims of this narrative review were to identify whether there is an association between air pollution and the incidence of pre-eclampsia, and the potential mechanisms by which any effects may be mediated.

METHODS

We undertook a literature search using Google Scholar, PubMed, the Cochrane Library and NICE Evidence. The primary eligibility criterion was articles correlating exposure to air pollution with incidence of pre-eclampsia.

RESULTS

Meta-analyses currently show a positive association between pre-eclampsia and exposure to both particulate matter PM_2.5 and nitrogen dioxide, but no significant associations with ambient ozone or carbon monoxide exposure. No meta-analysis has been performed for exposure to sulfur dioxide. Variability in terms of quantification of exposure, the exposure period and co-founders among the studies makes comparisons complex. Adverse effects on trophoblast invasion and placental vascularisation, and increases in oxidative stress and anti-angiogenic factors, such as sFlt-1, in response to air pollution provide pathways by which exposure may contribute to the pathophysiology of pre-eclampsia. So far, studies have not discriminated between the early- and late-onset forms of the syndrome.

DISCUSSION

Future prospective studies using personal air pollution monitors and blood biomarkers of pre-eclampsia would strengthen the associations. Interactions between pollutants are poorly documented, and at present there is minimal informed advice available to women on the need to avoid exposure to air pollutants during pregnancy.

Placenta as a target of trichloroethylene toxicity

Trichloroethylene (TCE) is an industrial solvent and a common environmental contaminant detected in thousands of hazardous waste sites. Risk of exposure is a concern for workers in occupations that use TCE as well as for residents who live near industries that use TCE or who live near TCE-contaminated sites. Although renal, hepatic and carcinogenic effects of TCE have been documented, less is known about TCE impacts on reproductive functions despite epidemiology reports associating maternal TCE exposure with adverse pregnancy outcomes. Toxicological evidence suggests that the placenta mediates at least some of the adverse pregnancy outcomes associated with TCE exposure. Toxicology studies show that the TCE metabolite, S-(1,2-dichlorovinyl)-l-cysteine (DCVC) generates toxic effects such as mitochondrial dysfunction, apoptosis, oxidative stress, and release of prostaglandins and pro-inflammatory cytokines in placental cell lines. Each of these mechanisms of toxicity have significant implications for placental functions and, thus, ultimately the health of mother and developing child. Despite these findings there remain significant gaps in our knowledge about effects of TCE on the placenta, including effects on specific placental cell types and functions as well as sex differences in response to TCE exposure. Due to the critical role that the placenta plays in pregnancy, future research addressing some of these knowledge gaps could lead to significant gains in public health.

Personal exposure to PM2.5 constituents associated with gestational blood pressure and endothelial dysfunction

Ambient fine particulate matter (PM_2.5) pollution has been implicated in the development of hypertensive disorders of pregnancy. However, evidence on the effects of PM_2.5-derived chemical constituents on gestational blood pressure (BP) is limited, and the potential mechanisms underlying the association remain unclear. In this study, we repeated three consecutive 72-h personal air sampling and BP measurements in 215 pregnant women for 590 visits during pregnancy. Individual PM_2.5 exposure level was assessed by gravimetric method and 28 PM_2.5 chemical constituents were analyzed by ED-XRF method. Plasma biomarkers of endothelial function and inflammation were measured using multiplexed immunoassays. Robust multiple linear regression models were used to estimate the associations among personal PM_2.5 exposure and chemical constituents, BP changes (compared with pre-pregnancy BP) and plasma biomarkers. Mediation analyses were performed to evaluate underlying potential pathways. Result showed that exposure to PM_2.5 was significantly associated with increases in systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) in the early second trimester. Meanwhile, elevated concentration of lead (Pb) constituent in PM_2.5 was significant associated with increases in DBP and MAP after adjusting for PM_2.5 total mass. PM_2.5 and Pb constituent also presented positive associations with plasma biomarkers of endothelial function (ET-1, E-selectin, ICAM-1) and inflammation (IL-1β, IL-6, TNFα) significantly. After multiple adjustment, elevated ET-1 and IL-6 were significantly correlated with increased gestational BP, and respectively mediated 1.24%-25.06% and 7.01%-10.69% of the increased BP due to PM_2.5 and Pb constituent exposure. In conclusion, our results suggested that personal exposure to PM_2.5 and Pb constituent were significantly associated with increased BP during pregnancy, and the early second trimester might be the sensitive window of PM_2.5 exposure. The endothelial dysfunction and elevated inflammation partially mediated the effect of PM_2.5 and Pb constituent on BP during pregnancy.

Environmental Contaminants Exposure and Preterm Birth: A Systematic Review

Preterm birth is an obstetric condition associated with a high risk of infant mortality and morbidities in both the neonatal period and later in life, which has also a significant public health impact because it carries an important societal economic burden. As in many cases the etiology is unknown, it is important to identify environmental factors that may be involved in the occurrence of this condition. In this review, we report all the studies published in PubMed and Scopus databases from January 1992 to January 2019, accessible as full-text articles, written in English, including clinical studies, original studies, and reviews. We excluded articles not written in English, duplicates, considering inappropriate populations and/or exposures or irrelevant outcomes and patients with known risk factors for preterm birth (PTB). The aim of this article is to identify and summarize the studies that examine environmental toxicants exposure associated with preterm birth. This knowledge will strengthen the possibility to develop strategies to reduce the exposure to these toxicants and apply clinical measures for preterm birth prevention.

Biomarkers of Exposure to Secondhand and Thirdhand Tobacco Smoke: Recent Advances and Future Perspectives

Smoking is the leading preventable disease worldwide and passive smoking is estimated to be the cause of about 1.0% of worldwide mortality. The determination of tobacco smoke biomarkers in human biological matrices is key to assess the health effects related to the exposure to environmental tobacco smoke. The biomonitoring of cotinine, the main nicotine metabolite, in human biofluids-including urine, serum or saliva-has been extensively used to assess this exposure. However, the simultaneous determination of cotinine together with other tobacco biomarkers and the selection of alternative biological matrices, such as hair, skin or exhaled breath, would enable a better characterization of the kind and extent of tobacco exposure. This review aims to perform a critical analysis of the up-to-date literature focused on the simultaneous determination of multiple tobacco smoke biomarkers studied in different biological matrices, due to the exposure to secondhand smoke (SHS) and thirdhand smoke (THS). Target biomarkers included both tobacco-specific biomarkers-nicotine and tobacco specific nitrosamine biomarkers-and tobacco-related biomarkers, such as those from polycyclic aromatic hydrocarbons, volatile organic compounds, metals and carbon monoxide. To conclude, we discuss the suitability of determining multiple biomarkers through several relevant examples of SHS and THS exposure.

Impact of Maternal Air Pollution Exposure on Children's Lung Health: An Indian Perspective

Air pollution has become an emerging invisible killer in recent years and is a major cause of morbidity and mortality globally. More than 90% of the world’s children breathe toxic air every day. India is among the top ten most highly polluted countries with an average PM₁₀ level of 134 μg/m³ per year. It is reported that 99% of India’s population encounters air pollution levels that exceed the World Health Organization Air Quality Guideline, advising a PM_2.5 permissible level of 10 μg/m³. Maternal exposure to air pollution has serious health outcomes in offspring because it can affect embryonic phases of development during the gestation period. A fetus is more prone to effects from air pollution during embryonic developmental phases due to resulting oxidative stress as antioxidant mechanisms are lacking at that stage. Any injury during this vulnerable period (embryonic phase) will have a long-term impact on offspring health, both early and later in life. Epidemiological studies have revealed that maternal exposure to air pollution increases the risk of development of airway disease in the offspring due to impaired lung development in utero. In this review, we discuss cellular mechanisms involved in maternal exposure to air pollution and how it can impact airway disease development in offspring. A better understanding of these mechanisms in the context of maternal exposure to air pollution can offer a new avenue to prevent the development of airway disease in offspring.

Before the first breath: prenatal exposures to air pollution and lung development

Various environmental contaminants are known to impair the growth trajectories of major organs, indirectly (gestational exposure) or directly (postnatal exposure). Evidence associates pre-gestational and gestational exposure to air pollutants with adverse birth outcomes (e.g., low birth weight, prematurity) and with a wide range of diseases in childhood and later in life. In this review, we explore the way that pre-gestational and gestational exposure to air pollution affects lung development. We present results in topics underlining epidemiological and toxicological evidence. We also provide a summary of the biological mechanisms by which air pollution exposure possibly leads to adverse respiratory outcomes. We conclude that gestational and early life exposure to air pollutants are linked to alterations in lung development and function and to other negative respiratory conditions in childhood (wheezing, asthma) that may last into adulthood. Plausible mechanisms encompass changes in maternal physiology (e.g., hypoxia, oxidative stress and inflammation) and DNA alterations in the fetus. Evidence for pre-gestational and gestational effects on the lung is scarce compared with that on early life exposure and further studies are needed. However, the suggested mechanisms are credible and the evidence of pre-gestational and gestational air pollution exposure is robust for adverse birth outcomes. Air pollutants might change lung developmental trajectories of the unborn child predisposing it to diseases later in life highlighting the urgent need for controls on urban air pollution levels worldwide.

The health effects of ambient PM2.5 and potential mechanisms

The impacts of ambient PM2.5 on public health have become great concerns worldwide, especially in the developing countries. Epidemiological and toxicological studies have shown that PM2.5 does not only induce cardiopulmonary disorders and/or impairments, but also contributes to a variety of other adverse health effects, such as driving the initiation and progression of diabetes mellitus and eliciting adverse birth outcomes. Of note, recent findings have demonstrated that PM2.5 may still pose a hazard to public health even at very low levels (far below national standards) of exposure. The proposed underlying mechanisms whereby PM2.5 causes adverse effects to public health include inducing intracellular oxidative stress, mutagenicity/genotoxicity and inflammatory responses. The present review aims to provide an brief overview of new insights into the molecular mechanisms linking ambient PM2.5 exposure and health effects, which were explored with new technologies in recent years.

Ambient Fine Particulate Matter, Nitrogen Dioxide, and Hypertensive Disorders of Pregnancy in New York City

BACKGROUND

Previous studies suggested a possible association between fine particulate matter air pollution (PM2.5) and nitrogen dioxide (NO2) and the development of hypertensive disorders of pregnancy, but effect sizes have been small and methodologic weaknesses preclude firm conclusions.

METHODS

We linked birth certificates in New York City in 2008-2010 to hospital discharge diagnoses and estimated air pollution exposure based on maternal address. The New York City Community Air Survey provided refined estimates of PM2.5 and NO2 at the maternal residence. We estimated the association between exposures to PM2.5 and NO2 in the first and second trimester and risk of gestational hypertension, mild preeclampsia, and severe preeclampsia among 268,601 births.

RESULTS

In unadjusted analyses, we found evidence of a positive association between both pollutants and gestational hypertension. However, after adjustment for individual covariates, socioeconomic deprivation, and delivery hospital, we did not find evidence of an association between PM2.5 or NO2 in the first or second trimester and any of the outcomes.

CONCLUSIONS

Our data did not provide clear evidence of an effect of ambient air pollution on hypertensive disorders of pregnancy. Results need to be interpreted with caution considering the quality of the available exposure and health outcome measures and the uncertain impact of adjusting for hospital. Relative to previous studies, which have tended to identify positive associations with PM2.5 and NO2, our large study size, refined air pollution exposure estimates, hospital-based disease ascertainment, and little risk of confounding by socioeconomic deprivation, does not provide evidence for an association.

A register-based study of the association between air pollutants and hypertensive disorders in pregnancy among the Japanese population

BACKGROUND

Ambient air pollution is hypothesized to be a risk factor for hypertensive disorders in pregnancy, one of the major pregnancy complications. Past studies have reported the supporting evidence, however this mainly referred to the Western population, and results from trimester-specific analysis have been varied. In this study, we focused on exposure during the first trimester of pregnancy (placental development stage), and tested the hypothesis among the Japanese population.

METHODS

We drew on data from the Japan Perinatal Registry Network database, and studied 36,620 singleton pregnant women without medical complications, in western Japan (Kyushu and Okinawa districts) between 2005 and 2010. In addition, data on ozone, suspended particulate matter (SPM), nitrogen dioxide (NO2), and sulfur dioxide (SO2) concentrations were obtained. The nearest monitoring station to the respective birthing hospital was used as a reference point for assigning average concentrations of each pollutant during the first trimester of pregnancy for each woman. The logistic regression model was applied to assess the association between quintiles of each pollutant and hypertensive disorders in pregnancy.

RESULTS

Mean concentrations during the first trimester were 41.3 ppb for ozone, 27.4 μg/m(3) for SPM, 11.8 ppb for NO2, and 3.2 ppb for SO2. High exposure to ozone was associated with an increased risk of hypertensive disorders in pregnancy (for highest quintile vs. lowest: odds ratio=1.20, 95% confidence interval=1.01-1.42). With regard to SPM, NO2 and SO2, we did not obtain the results with constant directionality.

CONCLUSIONS

Ozone exposure during early pregnancy may be a risk factor for hypertensive disorders in pregnancy.

Blood Pressure Changes in Relation to Arsenic Exposure in a U.S. Pregnancy Cohort

BACKGROUND

Inorganic arsenic exposure has been related to the risk of increased blood pressure based largely on cross-sectional studies conducted in highly exposed populations. Pregnancy is a period of particular vulnerability to environmental insults. However, little is known about the cardiovascular impacts of arsenic exposure during pregnancy.

OBJECTIVES

We evaluated the association between prenatal arsenic exposure and maternal blood pressure over the course of pregnancy in a U.S.

METHODS

The New Hampshire Birth Cohort Study is an ongoing prospective cohort study in which > 10% of participant household wells exceed the arsenic maximum contaminant level of 10 μg/L established by the U.S. EPA. Total urinary arsenic measured at 24-28 weeks gestation was measured and used as a biomarker of exposure during pregnancy in 514 pregnant women, 18-45 years of age, who used a private well in their household. Outcomes were repeated blood pressure measurements (systolic, diastolic, and pulse pressure) recorded during pregnancy.

RESULTS

Using linear mixed effects models, we estimated that, on average, each 5-μg/L increase in urinary arsenic was associated with a 0.15-mmHg (95% CI: 0.02, 0.29; p = 0.022) increase in systolic blood pressure per month and a 0.14-mmHg (95% CI: 0.02, 0.25; p = 0.021) increase in pulse pressure per month over the course of pregnancy.

CONCLUSIONS

In our U.S. cohort of pregnant women, arsenic exposure was associated with greater increases in blood pressure over the course of pregnancy. These findings may have important implications because even modest increases in blood pressure impact cardiovascular disease risk.

Gestational Hypertension and Organophosphorus Pesticide Exposure: A Cross-Sectional Study

Hypertension is the most common medical problem encountered during pregnancy, complicating 2-3% of pregnancies. High blood pressure (BP) with diastolic BP ≥ 90 mm Hg and/or systolic BP ≥ 140 mm Hg arising after week 22 of pregnancy and resolving after delivery is defined as gestational hypertension (GHY). The aim of this cross-sectional study was to investigate whether occupational and/or environmental exposure to organophosphorus (OP) pesticide affects GHY. Women at approximately 22 weeks of gestation were recruited. OP pesticide exposure in the first trimester of pregnancy was classified into four categories: no exposure, indirect exposure, domestic exposure, and occupational exposure. Application of the exclusion criteria left 2203 participants (mean age 30.4 ± 11.6 years). Data analysis showed that in women with indirect OP pesticide exposure the incidence of GHY was slightly higher than that in the world population, whereas domestic exposure involved a 7% increase and occupational exposure a 12% increase. Analysis of the pesticides used by participants highlighted a possible role for malathion and diazinon (adjusted OR 1.09 and 1.14, resp.). Further investigation of exposed workers and the general population is clearly warranted given the broad diffusion of OP pesticides and their possible public health impact, maybe by including a wider range of health outcomes.

Framingham risk score modifies the effect of PM10 on heart rate variability

Health conditions may greatly modify the association between particulate matter (PM) and heart rate variability (HRV), but whether the modification of PM effect by coronary artery disease (CAD) risk status depends on the PM levels remains unknown. We investigated the associations between personal exposures to PM with aerodynamic diameter of ≤10μm (PM10) and ≤2.5μm (PM2.5) and concurrent HRV, and whether the effect of PM on HRV was modified by Framingham risk score (FRS) in healthy subjects with different PM exposure levels. Personal exposures to PM10 and PM2.5 were measured for 24h in 152 volunteers of community residents who were free of cardiovascular disease in two cities (Zhuhai and Wuhan) that differ in air quality. Simultaneously, 24h HRV indices were obtained from 3-channel Holter monitor. FRS was calculated based on age, sex, lipid profiles, blood pressure, diabetes, and smoking status. Linear regression models were constructed after adjusting for potential confounders. We found significant decrease in total power (TP) and low power (LF) with increased PM10 concentrations (P for trend<0.05) in the high PM levels city (Wuhan) and total population, but not in the low PM levels city (Zhuhai). We also observed significant modification of FRS on PM10 effect in Wuhan. Interestingly, elevated PM10 was associated in a greater decreased HRV in the low FRS subgroup, but not in the high FRS subgroup. However, we did not find any significant main effects of PM2.5 or PM2.5-FRS interactions on HRV in city-specified or city-combined analyses. Overall, the findings indicate that individual coronary risk profiles may modulate the association between particulate air pollution and HRV in high PM exposure levels.

Association between wood cooking fuel and maternal hypertension at delivery in central East India

OBJECTIVE

Smoke from burning of biomass fuels has been linked with adverse pregnancy outcomes and hypertension among nonpregnant subjects; association with hypertension during pregnancy has not been well studied. We evaluated whether the use of wood cooking fuel increases the risk of maternal hypertension at delivery compared to gas which burns with less smoke.

METHODS

Information on fuel use and blood pressure was available for analysis from a cross-sectional survey of 1369 pregnant women recruited at delivery in India.

RESULTS

Compared to gas users, women using wood as fuel had on average lower mean arterial pressure (adjusted effect size - 2.0 mmHg; 95% CI: -3.77, -0.31) and diastolic blood pressure (adjusted effect size -1.96 mmHg; 95% CI: -3.60, -0.30) at delivery. Risk of hypertension (systolic >139 mmHg or diastolic >89 mmHg) was 14.6% for wood users compared to 19.6% for gas users although this did not reach significance after adjustment, using propensity score techniques, for factors that make wood and gas users distinct (adjusted prevalence ratio 0.76; 95% CI: 0.49, 1.17).

CONCLUSIONS

Combustion products from the burning of biomass fuels are similar to those released with tobacco smoking, which has been linked with a reduced risk for preeclampsia. The direction of our findings suggests the possibility of a similar effect for biomass cook smoke. Whether clean cooking interventions being promoted by international advocacy organizations will impact hypertension in pregnancy warrants further analysis as hypertension remains a leading cause of maternal death worldwide and cooking with biomass fuels is widespread.

Acute air pollution exposure and blood pressure at delivery among women with and without hypertension

BACKGROUND

Chronic air pollution exposure increases risk for hypertensive disorders of pregnancy, but the effect of acute air pollution exposure on blood pressure during pregnancy is less well known.

METHODS

We studied 151,276 singleton term deliveries from the Consortium on Safe Labor (2002-2008) with clinical blood pressure measured at admission to labor/delivery and diagnoses of hypertensive disorders collected from electronic medical records and hospital discharge summaries. Air pollution exposures were estimated for the admission hour and the 4 hours preceding admission using a modified version of the Community Multiscale Air Quality models and observed air monitoring data. Blood pressure was categorized as normal; high normal; and mild, moderate, or severe hypertension based on pregnancy cut points. Adjusted ordinal logistic regression estimated the odds of women having a higher admission blood pressure category as a function of air pollutant, hypertensive disorders, and their interaction effect.

RESULTS

Odds of high blood pressure at admission to labor/delivery were increased in normotensive women after exposure to nitrogen oxides (by 0.2%/5 units), sulfur dioxide (by 0.3%/1 unit), carbon monoxide and several air toxics (by 3%-4%/high exposure). The effects were often similar or stronger among women with gestational hypertension and preeclampsia. Exposure to particulate matter <10 μm increased odds of high blood pressure in women with preeclampsia by 3%/5 units.

CONCLUSIONS

Air pollution can influence admission blood pressure in term deliveries and may increase likelihood of preeclampsia screening at delivery admission.

Ambient Air Pollution and Hypertensive Disorders of Pregnancy: A Systematic Review and Meta-analysis

Hypertensive disorders of pregnancy (HDP, including gestational hypertension, preeclampsia, and eclampsia) have a substantial public health impact. Maternal exposure to high levels of air pollution may trigger HDP, but this association remains unclear. The objective of our report is to assess and quantify the association between maternal exposures to criteria air pollutants (ozone, carbon monoxide, nitrogen dioxide, sulfur dioxide, and particulate matter ≤ 10, 2.5 μm) on HDP risk. PubMed, EMBASE, MEDLINE, Current Contents, Global Health, and Cochrane were searched (last search: September, 2013). After a detailed screening of 270 studies, 10 studies were extracted. We conducted meta-analyses if a pollutant in a specific exposure window was reported by at least four studies. Using fixed- and random-effects models, odds ratios (ORs) and 95% CIs were calculated for each pollutant with specific increment of concentration. Increases in risks of HDP (OR per 10 ppb = 1.16; 95% CI, 1.03-1.30) and preeclampsia (OR per 10 ppb = 1.10; 95% CI, 1.03-1.17) were observed to be associated with exposure to NO2 during the entire pregnancy, and significant associations between HDP and exposure to CO (OR per 1 ppm = 1.79; 95% CI, 1.31-2.45) and O3 (OR per 10 ppb = 1.09; 95% CI, 1.05-1.13) during the first trimester were also observed. Our review suggests an association between ambient air pollution and HDP risk. Although the ORs were relatively low, the population-attributable fractions were not negligible given the ubiquitous nature of air pollution.

Ambient Air Pollution and Pregnancy-Induced Hypertensive Disorders

Pregnancy-induced hypertensive disorders can lead to maternal and perinatal morbidity and mortality, but the cause of these conditions is not well understood. We have systematically reviewed and performed a meta-analysis of epidemiological studies investigating the association between exposure to ambient air pollution and pregnancy-induced hypertensive disorders including gestational hypertension and preeclampsia. We searched electronic databases for English language studies reporting associations between ambient air pollution and pregnancy-induced hypertensive disorders published between December 2009 and December 2013. Combined risk estimates were calculated using random-effect models for each exposure that had been examined in ≥4 studies. Heterogeneity and publication bias were evaluated. A total of 17 articles evaluating the impact of nitrogen oxides (NO 2 , NO X ), particulate matter (PM 10 , PM 2.5 ), carbon monoxide (CO), ozone (O 3 ), proximity to major roads, and traffic density met our inclusion criteria. Most studies reported that air pollution increased risk for pregnancy-induced hypertensive disorders. There was significant heterogeneity in meta-analysis, which included 16 studies reporting on gestational hypertension and preeclampsia as separate or combined outcomes; there was less heterogeneity in findings of the 10 studies reporting solely on preeclampsia. Meta-analyses showed increased risks of hypertensive disorders in pregnancy for all pollutants except CO. Random-effect meta-analysis combined odds ratio associated with a 5-µg/m 3 increase in PM 2.5 was 1.57 (95% confidence interval, 1.26–1.96) for combined pregnancy-induced hypertensive disorders and 1.31 (95% confidence interval, 1.14–1.50) for preeclampsia. Our results suggest that exposure to air pollution increases the risk of pregnancy-induced hypertensive disorders.

Indoor exposure and adverse birth outcomes related to fetal growth, miscarriage and prematurity-a systematic review

The purpose of this review was to summarize existing epidemiological evidence of the association between quantitative estimates of indoor air pollution and all-day personal exposure with adverse birth outcomes including fetal growth, prematurity and miscarriage. We carried out a systematic literature search of MEDLINE and EMBASE databases with the aim of summarizing and evaluating the results of peer-reviewed epidemiological studies undertaken in “westernized” countries that have assessed indoor air pollution and all-day personal exposure with specific quantitative methods. This comprehensive literature search identified 16 independent studies which were deemed relevant for further review and two additional studies were added through searching the reference lists of all included studies. Two reviewers independently and critically appraised all eligible articles using the Critical Appraisal Skills Programme (CASP) tool. Of the 18 selected studies, 14 adopted a prospective cohort design, three were case-controls and one was a retrospective cohort study. In terms of pollutants of interest, seven studies assessed exposure to electro-magnetic fields, four studies assessed exposure to polycyclic aromatic hydrocarbons, four studies assessed PM_2.5 exposure and three studies assessed benzene, phthalates and noise exposure respectively. Furthermore, 12 studies examined infant growth as the main birth outcome of interest, six examined spontaneous abortion and three studies assessed gestational age at birth and preterm delivery. This survey demonstrates that there is insufficient research on the possible association of indoor exposure and early life effects and that further research is needed.

Maternal engineered nanomaterial exposure and fetal microvascular function: does the Barker hypothesis apply?

OBJECTIVE

The continued development and use of engineered nanomaterials (ENM) has given rise to concerns over the potential for human health effects. Although the understanding of cardiovascular ENM toxicity is improving, one of the most complex and acutely demanding "special" circulations is the enhanced maternal system to support fetal development. The Barker hypothesis proposes that fetal development within a hostile gestational environment may predispose/program future sensitivity. Therefore, the objective of this study was 2-fold: (1) to determine whether maternal ENM exposure alters uterine and/or fetal microvascular function and (2) test the Barker hypothesis at the microvascular level.

STUDY DESIGN

Pregnant (gestation day 10) Sprague-Dawley rats were exposed to nano-titanium dioxide aerosols (11.3 ± 0.039 mg/m(3)/hr, 5 hr/d, 8.2 ± 0.85 days) to evaluate the maternal and fetal microvascular consequences of maternal exposure. Microvascular tissue isolation (gestation day 20) and arteriolar reactivity studies (<150 μm passive diameter) of the uterine premyometrial and fetal tail arteries were conducted.

RESULTS

ENM exposures led to significant maternal and fetal microvascular dysfunction, which was seen as robustly compromised endothelium-dependent and -independent reactivity to pharmacologic and mechanical stimuli. Isolated maternal uterine arteriolar reactivity was consistent with a metabolically impaired profile and hostile gestational environment that impacted fetal weight. The fetal microvessels that were isolated from exposed dams demonstrated significant impairments to signals of vasodilation specific to mechanistic signaling and shear stress.

CONCLUSION

To our knowledge, this is the first report to provide evidence that maternal ENM inhalation is capable of influencing fetal health and that the Barker hypothesis is applicable at the microvascular level.