Acute and recent air pollution exposure and cardiovascular events at labour and delivery

Sexual dimorphism association of combined exposure to volatile organic compounds (VOC) with kidney damage

BACKGROUND

Epidemiological evidence emphasizes air pollutants' role in chronic kidney disease (CKD). Volatile organic compounds (VOCs) contribute to air pollution, yet research on VOCs and kidney damage, especially gender disparities, is limited.

METHODS

This study analyzed NHANES data to explore associations between urinary VOC metabolite mixtures (VOCMs) and key kidney-related parameters: estimated glomerular filtration rate (eGFR), albumin-to-creatinine ratio (ACR), chronic kidney disease (CKD), and albuminuria. Mediation analyses assessed the potential mediating roles of biological aging (BA) and serum albumin in VOCM mixtures' effects on kidney damage. Sensitivity analyses were also conducted.

RESULTS

The mixture analysis unveiled a noteworthy positive association between VOCM mixtures and the risk of developing CKD, coupled with a significant negative correlation with eGFR within the overall participant cohort. These findings remained consistent when examining the female subgroup. However, among male participants, no significant link emerged between VOCM mixtures and CKD or eGFR. Furthermore, in both the overall and female participant groups, there was an absence of a significant correlation between VOCM mixtures and either ACR or albuminuria. On the other hand, in male participants, while no significant correlation was detected with albuminuria, a significant positive correlation was observed with ACR. Pollutant analysis identified potential links between kidney damage and 1,3-butadiene, toluene, ethylbenzene, styrene, xylene, acrolein, crotonaldehyde and propylene oxide. Mediation analyses suggested that BA might partially mediate the relationship between VOCM mixtures and kidney damage.

CONCLUSION

The current findings highlight the widespread exposure to VOCs among the general U.S. adult population and indicate a potential correlation between exposure to VOC mixtures and compromised renal function parameters, with notable gender disparities. Females appear to exhibit greater sensitivity to impaired renal function resulting from VOCs exposure. Anti-aging treatments may offer some mitigation against kidney damage due to VOCs exposure.

Exposure to BTEX is associated with cardiovascular disease, dyslipidemia and leukocytosis in national US population

BACKGROUND

Comprehensive research on the effects of individual benzene, toluene, ethylbenzene, and xylenes (BTEX) and their mixture measured in blood samples, on cardiovascular diseases (CVD) and related risk factors among the general population is limited.

OBJECTIVES

To investigate the effects of blood individual and mixed BTEX on total CVD and its subtypes, lipid profiles, and white blood cell (WBC) count.

METHODS

Survey-weighted multivariate logistic regression was used to examine the associations between blood individual and mixed BTEX with CVD and its subtypes in 17,007 participants from NHANES 1999-2018. The combined effect of BTEX mixture on CVD was estimated using weighted quantile sum modeling and quantile g-computation. Weighted multivariate linear regression assessed the effects of BTEX on lipid profiles and WBC, including its five-part differential count.

RESULTS

In comparison to the reference quartile of BTEX mixture, individuals in the highest quartile had a significantly increased adjusted odds ratio of CVD risk (1.64, 95 % CI: 1.23 to 2.19, P for trend = 0.008). Positive associations were observed for benzene, toluene, ethylbenzene, and m-/p-xylene, demonstrating a monotonically increasing exposure-response relationship. Mixed BTEX was associated with congestive heart failure (CHF), angina pectoris, and heart attack. Individual benzene, toluene, and ethylbenzene were associated with CHF, while toluene, ethylbenzene, and all xylene isomers were linked to angina pectoris. Benzene, toluene, and o-xylene were associated with heart attack. Both mixed and individual BTEX showed positive associations with triglycerides, cholesterol, low-density lipoprotein, and WBC, including its five-part differential count, but a negative relationship with high-density lipoprotein. Subgroup analyses identified modifying effects of smoking, drinking, exercise, BMI, hypertension, and diabetes on the associations between specific toxicants and CVD risk.

CONCLUSIONS

Exposure to BTEX was associated with cardiovascular diseases and cardiovascular risk factors. These findings emphasize the importance of considering blood BTEX levels when assessing cardiovascular health risks.

Associations of urinary volatile organic compounds with cardiovascular disease among the general adult population

This study was to estimate the associations of volatile organic compounds (VOCs) exposure with the prevalence of total and specific cardiovascular disease (CVD) among the general adult population. This cross-sectional study analyzed 15 urinary VOC metabolites in the general population using the 2011-2016 National Health and Nutrition Examination Survey (n = 5,213). The weighted study population with 47.0 years median age, was primarily female (51.2%). The prevalence of total CVD in the overall population was 7.9%. The single-exposure analyzes of AAMA, ATCA, CEMA, CYMA, DHBMA, 3HPMA, and 3MHA +4MHA were significantly associated with increased prevalence of total CVD. Qgcomp regression consistently showed that urinary VOCs-mixed exposure was positively correlated with the prevalence of total and specific CVDs (chronic heart failure, angina, and stroke), and highlighted each VOCs metabolite weights and direction. The similar results were observed for the WQS regression using mixed analysis methods. In conclusion, exposure to VOCs increases CVD prevalence and advances the identification of risk factors for CVD for environmental study.

Ambient air pollution and maternal cardiovascular health in pregnancy

In this review, we summarise the current epidemiological and experimental evidence on the association of ambient (outdoor) air pollution exposure and maternal cardiovascular health during pregnancy. This topic is of utmost clinical and public health importance as pregnant women represent a potentially susceptible group due to the delicate balance of the feto-placental circulation, rapid fetal development and tremendous physiological adaptations to the maternal cardiorespiratory system during pregnancy.Several meta-analyses including up to 4 245 170 participants provide robust evidence that air pollutants, including particulate matter, nitrogen oxides and others, have adverse effects on the development of hypertensive disorders of pregnancy, gestational diabetes mellitus and cardiovascular events during labour. Potential underlying biological mechanisms include oxidative stress with subsequent endothelial dysfunction and vascular inflammation, β-cell dysfunction and epigenetic changes. Endothelial dysfunction can lead to hypertension by impairing vasodilatation and promoting vasoconstriction. Air pollution and the consequent oxidative stress can additionally accelerate β-cell dysfunction, which in turn triggers insulin resistance leading to gestational diabetes mellitus. Epigenetic changes in placental and mitochondrial DNA following air pollution exposures can lead to altered gene expression and contribute to placental dysfunction and induction of hypertensive disorders of pregnancy.The maternal and fetal consequences of such cardiovascular and cardiometabolic disease during pregnancy can be serious and long lasting, including preterm birth, increased risk of type 2 diabetes mellitus or cardiovascular disease later in life. Acceleration of efforts to reduce air pollution is therefore urgently needed to realise the full health benefits for pregnant mothers and their children.

Cross-sectional and longitudinal associations of styrene and ethylbenzene exposure with heart rate variability alternation among urban adult population in China

Styrene and ethylbenzene (S/EB) are the monomers of polystyrene (PS) and polyethylene (PE), respectively, and have been identified as significant hazardous air pollutants by the U.S. Environmental Protection Agency. However, the adverse effects of S/EB on human health, especially cardiovascular health, have not been well established. Urinary biomarker of S/EB exposure and heart rate variability (HRV) were measured in urban adults from the Wuhan-Zhuhai cohort and were repeated after 3-year and 6-year follow-ups. Linear mixed models were used to estimate associations of S/EB exposure biomarker with HRV and longitudinal additional annual change of HRV. The mediating role of transforming growth factor (TGF)-β1 was tested by using mediation analysis. A total of 2842 general adults were included at baseline analysis, and 4748 observations were included in the repeated measurement study. In the cross-sectional analysis, each 1% increment in urinary S/EB exposure biomarker was significantly associated with a 0.106 % (95 % CI: -0.160, -0.052), 0.109 % (-0.169, -0.049), 0.099 % (-0.145, -0.053), 0.040 % (-0.060, -0.020), and 0.031 % (-0.054, -0.007) decrement in low frequency (LF), high frequency (HF), total power (TP), standard deviation of all normal-to-normal intervals (SDNN), and square root of the mean squared difference between adjacent normal-to-normal interval, respectively. Smoking status modified the relationships of urinary S/EB exposure biomarker with TP and SDNN. TGF-β1 mediated 3.09-5.16 % of the association between urinary S/EB biomarker and lower HRV. The follow-up analyses detected a negative association between urinary S/EB exposure biomarker and the additional annual change of LF (β: -0.016; 95 % CI: -0.028, -0.004), HF (-0.014; -0.026, -0.001), and TP (-0.011; -0.021, -0.001). Our findings demonstrated that S/EB exposure was associated with HRV reduction among the general urban adults and the TGF-β pathway may play a part of the mediating role in this association.

Indoor exposure levels and risk assessment of volatile organic compounds in residences, schools, and offices in China from 2000 to 2021: A systematic review

The last two decades have witnessed rapid urbanization and economic growth accompanied by severe indoor air pollution of volatile organic compounds (VOCs) in China. However, indoor VOC pollution across China has not been well characterized and documented. This study is a systematic review of field measurements of eight target VOCs (benzene, toluene, xylenes, acetaldehyde, p-dichlorobenzene, butadiene, trichloroethylene, and tetrachloroethylene) in residences, offices, and schools in China from 2000 to 2021. The results show that indoor pollution of benzene, toluene, and xylenes has been more serious in China than in other countries. Spatiotemporal distribution shows lower indoor VOC levels in east and south-east regions and a declining trend from 2000 to 2021. Moving into a dwelling more than 1 year after decoration and improving ventilation could significantly reduce exposure to indoor VOCs. Reducing benzene exposure is urgently needed because it is associated with greater health risks (4.5 × 10^-4 for lifetime cancer risk and 8.3 for hazard quotient) than any other VOCs. The present study enriches the database of indoor VOC levels and provides scientific evidence for improving national indoor air quality standards as well as estimating the attributable disease burden caused by VOCs in China.

Acute ambient air pollution exposure and placental Doppler results in the NICHD fetal growth studies - Singleton cohort

BACKGROUND

Increased placental vascular resistance is a proposed mechanism by which air pollution exposure during pregnancy lowers birth weight and increases pregnancy-induced hypertensive disorders.

OBJECTIVE

To examine the impact of acute air pollution exposure during pregnancy on uterine and umbilical artery Doppler indicators of placental vascular resistance.

METHODS

After a first ultrasound to confirm gestational age, 2562 pregnant women recruited in 12 clinics throughout the United States underwent up to five standardized ultrasounds with Doppler measurements. Exposures to 11 air pollutants were estimated for the hour of ultrasound and each of the 2 h prior to ultrasound at the clinics using the National Air Quality Forecast Capability reanalysis products. We used mixed logistic regression to study the longitudinal odds ratio (OR) of any, uni- or bi-lateral systolic and diastolic uterine artery notching compared to no notching and the longitudinal OR of abnormal end diastolic flow of the umbilical artery compared to forward flow. Uterine and umbilical artery resistance indexes were studied using linear mixed models.

RESULTS

Each inter-quartile range (IQR) increase of particulate matter < 2.5 μm, nitrate, ammonium, primary organic matter (POM) and nitrogen dioxide during the hour of ultrasound was associated with a decreased risk of unilateral systolic notch and with increased resistance index of the left uterine artery. For the umbilical artery, each IQR increase in ozone was associated with decreased resistance index (b: -0.26, 95 % CI: -0.52, -0.01) and with a decreased risk of abnormal end diastolic flow (OR: 0.36, 95 % CI: 0.14, 0.94); while each IQR increase of elemental carbon and POM was associated with increased risk of abnormal end diastolic flow (OR: 1.47, 95 % CI: 1.02, 2.13 and OR: 1.67, 95 % CI: 1.17, 2.39, respectively).

DISCUSSION

Our results suggest acute air pollution exposure may influence placental vascular resistance.

A time series analysis of the ecologic relationship between acute and intermediate PM2.5 exposure duration on neonatal intensive care unit admissions in Florida

Admissions of newborn infants into Neonatal Intensive Care Units (NICU) has increased in the US over the last decade yet the role of environmental exposures as a risk factor for NICU admissions is under studied. Our study aims to determine the ecologic association between acute and intermediate ambient PM2.5 exposure durations and rates of NICU admissions, and to explore whether this association differs by area-level social stressors and meteorological factors. We conducted an ecologic time-series analysis of singleton neonates (N = 1,027,797) born in Florida hospitals between December 26, 2011 to April 30, 2019. We used electronic medical records (EMRs) in the OneFlorida Data Trust and included infants with a ZIP code in a Metropolitan Statistical Areas (MSA) and excluded extreme preterm births (<24wks gestation). The study outcome is the number of daily NICU admission at 28 days old or younger for each ZIP code in the study area. The exposures of interest are average same day, 1- and 2-day lags, and 1-3 weeks ambient PM2.5 concentration at the ZIP code-level estimated using inverse distance weighting (IDW) for each day of the study period. We used a zero-inflated Poisson regression mixed effects models to estimate adjusted associations between acute and intermediate PM2.5 exposure durations and NICU admissions rates. NICU admissions rates increased over time during the study period. Ambient 7-day average PM2.5 concentrations was significantly associated with incidence of NICU admissions, with an interquartile range (IQR = 2.37 μg/m³) increase associated with a 1.4% (95% CI: 0.4%, 2.4%) higher adjusted incidence of daily NICU admissions. No other exposure duration metrics showed a significant association with daily NICU admission rates. The magnitude of the association between PM2.5 7-day average concentrations with NICU admissions was significantly (p < 0.05) higher among ZIP codes with higher proportions of non-Hispanic Blacks, ZIP codes with household incomes in the lowest quartile, and on days with higher relative humidity. Our data shows a positive relationship between acute (7-day average) PM2.5 concentrations and daily NICU admissions in Metropolitan Statistical Areas of Florida. The observed associations were stronger in socioeconomically disadvantaged areas, areas with higher proportions with non-Hispanic Blacks, and on days with higher relative humidity. Further research is warranted to study other air pollutants and multipollutant effects and identify health conditions that are driving these associations with NICU admissions.

Exposure to volatile organic compounds - acrolein, 1,3-butadiene, and crotonaldehyde - is associated with vascular dysfunction

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of mortality worldwide. Exposure to air pollution, specifically particulate matter of diameter ≤2.5 μm (PM2.5), is a well-established risk factor for CVD. However, the contribution of gaseous pollutant exposure to CVD risk is less clear.

OBJECTIVE

To examine the vascular effects of exposure to individual volatile organic compounds (VOCs) and mixtures of VOCs.

METHODS

We measured urinary metabolites of acrolein (CEMA and 3HPMA), 1,3-butadiene (DHBMA and MHBMA3), and crotonaldehyde (HPMMA) in 346 nonsmokers with varying levels of CVD risk. On the day of enrollment, we measured blood pressure (BP), reactive hyperemia index (RHI - a measure of endothelial function), and urinary levels of catecholamines and their metabolites. We used generalized linear models for evaluating the association between individual VOC metabolites and BP, RHI, and catecholamines, and we used Bayesian Kernel Machine Regression (BKMR) to assess exposure to VOC metabolite mixtures and BP.

RESULTS

We found that the levels of 3HPMA were positively associated with systolic BP (0.98 mmHg per interquartile range (IQR) of 3HPMA; CI: 0.06, 1.91; P = 0.04). Stratified analysis revealed an increased association with systolic BP in Black participants despite lower levels of urinary 3HPMA. This association was independent of PM2.5 exposure and BP medications. BKMR analysis confirmed that 3HPMA was the major metabolite associated with higher BP in the presence of other metabolites. We also found that 3HPMA and DHBMA were associated with decreased endothelial function. For each IQR of 3HPMA or DHBMA, there was a -4.4% (CI: -7.2, -0.0; P = 0.03) and a -3.9% (CI: -9.4, -0.0; P = 0.04) difference in RHI, respectively. Although in the entire cohort the levels of several urinary VOC metabolites were weakly associated with urinary catecholamines and their metabolites, in Black participants, DHBMA levels showed strong associations with urinary norepinephrine and normetanephrine levels.

DISCUSSION

Exposure to acrolein and 1,3-butadiene is associated with endothelial dysfunction and may contribute to elevated risk of hypertension in participants with increased sympathetic tone, particularly in Black individuals.

Ambient air pollution and emergency department visits among children and adults in Casablanca, Morocco

This study presents the relationships between ambient air pollutants and morbidity and emergency department visits among children and adults performed in Great Casablanca, the most populated and economic region in Morocco. This research was analyzed using conditional Poisson model for the period 2011-2013. In the period of study, the daily average concentrations of SO2, NO2, O3 and PM10 in Casablanca were 209.4 µg/m3, 61 µg/m3, 113.2 µg/m3 and 75.1 µg/m3, respectively. In children less than 5 years old, risk of asthma could be increased until 12% per 10 µg/m3 increase in NO2, PM10, SO2 and O3. In children over 5 years and adults, an increase of 10 µg/m3 air pollutant can cause an increase until 3% and 4% in respiratory consultations and acute respiratory infection, respectively. Similarly, impact on emergency department visits due to respiratory and cardiac illness was established. Our results suggest a not negligible impact on morbidity of outdoor air pollution by NO2, SO2, O3, and PM10.

Using electronic health records for population health sciences: a case study to evaluate the associations between changes in left ventricular ejection fraction and the built environment

OBJECTIVE

Electronic health record (EHR) data linked with address-based metrics using geographic information systems (GIS) are emerging data sources in population health studies. This study examined this approach through a case study on the associations between changes in ejection fraction (EF) and the built environment among heart failure (HF) patients.

MATERIALS AND METHODS

We identified 1287 HF patients with at least 2 left ventricular EF measurements that are minimally 1 year apart. EHR data were obtained at an academic medical center in New York for patients who visited between 2012 and 2017. Longitudinal clinical information was linked with address-based built environment metrics related to transportation, air quality, land use, and accessibility by GIS. The primary outcome is the increase in the severity of EF categories. Statistical analyses were performed using mixed-effects models, including a subgroup analysis of patients who initially had normal EF measurements.

RESULTS

Previously reported effects from the built environment among HF patients were identified. Increased daily nitrogen dioxide concentration was associated with the outcome while controlling for known HF risk factors including sex, comorbidities, and medication usage. In the subgroup analysis, the outcome was significantly associated with decreased distance to subway stops and increased distance to parks.

CONCLUSIONS

Population health studies using EHR data may drive efficient hypothesis generation and enable novel information technology-based interventions. The availability of more precise outcome measurements and home locations, and frequent collection of individual-level social determinants of health may further drive the use of EHR data in population health studies.

Highly efficient decomposition of toluene using a high-temperature plasma-catalysis reactor

Plasma-catalysis technologies (PCTs) have the potential to control the emissions of volatile organic compounds, although their low-energy efficiency is a bottleneck for their practical applications. A plasma-catalyst reactor filled with a CeO₂/γ-Al₂O₃ catalyst was developed to decompose toluene with a high-energy efficiency enhanced by the elevating reaction temperature. When the reaction temperature was raised from 50 °C to 250 °C, toluene conversion dramatically increased from 45.3% to 95.5% and the energy efficiency increased from 53.5 g/kWh to 113.0 g/kWh. Conversely, the toluene conversion using a thermal catalysis technology (TCT) exhibited a maximum of 16.7%. The activation energy of toluene decomposition using PCTs is 14.0 kJ/mol, which is far lower than those of toluene decomposition using TCTs, which implies that toluene decomposition using PCT differs from that using TCT. The experimental results revealed that the Ce³⁺/Ce⁴⁺ ratio decreased and O_ads/O_latt ratio increased after the 40-h evaluation experiment, suggesting that CeO₂ promoted the formation of the reactive oxygen species that is beneficial for toluene decomposition.

Ambient Volatile Organic Compounds and Racial/Ethnic Disparities in Gestational Diabetes Mellitus: Are Asian/Pacific Islander Women at Greater Risk?

US Asian/Pacific Islander (API) communities experience high air pollution levels. APIs may be predisposed to pancreatic β-cell dysfunction and have the highest prevalence of gestational diabetes mellitus (GDM) compared with other racial/ethnic groups. Exposure to high levels of volatile organic compounds (VOCs) impairs pancreatic β-cell function, leading to insulin resistance, but racial/ethnic differences in this association are unexamined. We analyzed singleton deliveries (n = 220,065) from the Consortium on Safe Labor (2002-2008). Exposure to 14 VOCs in each hospital referral region was based on modified Community Multiscale Air Quality models. Logistic regression estimated odds ratios for GDM associated with high (≥75th percentile) versus low (<75th percentile) VOC exposure 3 months before conception and during the first trimester of pregnancy. Preconception and first-trimester exposure to high VOC levels was associated with increased odds of GDM among whites and APIs. GDM risk was significantly higher for APIs than whites for most VOCs. Preconception benzene exposure was associated with 29% (95% confidence interval: 12, 47) increased odds of GDM among whites compared with 45% (95% confidence interval: 16, 81) increased odds among APIs. These findings highlight environmental health disparities affecting pregnant women. Increased focus on GDM risk in US API communities is warranted.

Long-term ambient hydrocarbons exposure and incidence of ischemic stroke

Exposure to air pollutants is known to have adverse effects on human health; however, little is known about the association between hydrocarbons in air and an ischemic stroke (IS) event. We investigated whether long-term exposure to airborne hydrocarbons, including volatile organic compounds, increased IS risk. This retrospective cohort study included 283,666 people aged 40 years or older in Taiwan. Cox proportional hazards regression analysis was used to fit single- and multiple-pollutant models for two targeted pollutants, total hydrocarbons (THC) and nonmethane hydrocarbons (NMHC), and estimated the risk of IS. Before controlling for multiple pollutants, hazard ratios (HRs) of IS with 95% confidence intervals for the overall population were 2.69 (2.64-2.74) at 0.16-ppm increase in THC and 1.62 (1.59-1.66) at 0.11-ppm increase in NMHC. For the multiple-pollutant models controlling for PM2.5, the adjusted HR was 3.64 (3.56-3.72) for THC and 2.21 (2.16-2.26) for NMHC. Our findings suggest that long-term exposure to THC and NMHC may be a risk factor for IS development.

Using electronic health record data for environmental and place based population health research: a systematic review

PURPOSE

We conducted a systematic review of literature published on January 2000-May 2017 that spatially linked electronic health record (EHR) data with environmental information for population health research.

METHODS

We abstracted information on the environmental and health outcome variables and the methods and data sources used.

RESULTS

The automated search yielded 669 articles; 128 articles are included in the full review. The number of articles increased by publication year; the majority (80%) were from the United States, and the mean sample size was approximately 160,000. Most articles used cross-sectional (44%) or longitudinal (40%) designs. Common outcomes were health care utilization (32%), cardiometabolic conditions/obesity (23%), and asthma/respiratory conditions (10%). Common environmental variables were sociodemographic measures (42%), proximity to medical facilities (15%), and built environment and land use (13%). The most common spatial identifiers were administrative units (59%), such as census tracts. Residential addresses were also commonly used to assign point locations, or to calculate distances or buffer areas.

CONCLUSIONS

Future research should include more detailed descriptions of methods used to geocode addresses, focus on a broader array of health outcomes, and describe linkage methods. Studies should also explore using longitudinal residential address histories to evaluate associations between time-varying environmental variables and health outcomes.

Urinary trans-trans muconic acid (exposure biomarker to benzene) and hippuric acid (exposure biomarker to toluene) concentrations in Mexican women living in high-risk scenarios of air pollution

This study aimed to determine t,t-muconic acid (t,t-MA; exposure biomarker for benzene) and hippuric acid (HA; exposure biomarker for toluene) concentrations in the urine of women living in Mexico. In a cross-sectional study, apparently healthy women (n = 104) were voluntarily recruited from localities with a high risk of air pollution; t,t-MA and HA in urine were quantified using a high-performance liquid chromatography (HPLC) technique. Mean urinary levels of t,t-MA ranged from 680 to 1,310 μg/g creatinine. Mean values of HA ranged from 0.38 to 0.87 g/g creatinine. In conclusion, compared to data recently reported in literature, we found high urinary levels of t,t-MA and HA in assessed women participating in this study. We therefore deem the implementation of a strategy aimed at the reduction of exposure as a necessary measure for the evaluated communities.

Ambient temperature and risk of cardiovascular events at labor and delivery: A case-crossover study

BACKGROUND

Extreme ambient temperatures are linked to cardiac events in the general population, but this relationship is unclear among pregnant women. We estimated the associations and attributable risk between ambient temperature and the risk of cardiovascular event at labor/delivery, and investigated whether these associations vary by maternal race/ethnicity.

METHODS

We identified 680 women with singleton deliveries affected by cardiovascular events across 12 US sites (2002-2008). Average daily temperature during the week before, delivery day, and each of the seven days before delivery was estimated for each woman. In a case-crossover analysis, exposures during these hazard periods were compared to two control periods before and after delivery using conditional logistic regression adjusted for other environmental factors.

RESULTS

During the cold season (October-April), 1°C lower during the week prior to delivery was associated with a 4% (95% CI: 1-7%) increased risk of having a labor/delivery affected by cardiovascular events including cardiac arrest and stroke. During the warm season (May-September), 1°C higher during the week prior was associated with a 7% (95% CI: 3-12%) increased risk. These risks translated to 13.4 and 23.9 excess events per 100,000 singleton deliveries during the cold and warm season, respectively. During the warm season, the risks were more pronounced on days closer to delivery and Black women appeared to be more susceptible to the same temperature increase.

CONCLUSION

Small changes in temperature appear to affect the risk of having cardiovascular events at labor/delivery. Black women had a differentially higher warm season risk. These findings merit further investigation.

Air pollution and cardiovascular events at labor and delivery: a case-crossover analysis

PURPOSE

In this case-crossover study, we investigated the odds of having a labor/delivery with cardiovascular event (i.e., ischemic heart disease, stroke, heart failure, cardiac arrest/failure, and other or unspecified cardiovascular events) associated with acute exposure to common air pollutants.

METHODS

We selected 680 women with singleton pregnancy and cardiovascular events at labor/delivery from 12 U.S. clinical sites (2002-2008). Exposures to six criteria air pollutants, six particulate constituents, and 26 air toxics were obtained using modified Community Multiscale Air Quality models. Conditional logistic regression models calculated the odds ratio (OR) and 95% confidence intervals (CI) comparing exposures during the day of delivery, the week before delivery, and each of the days of the week before delivery to two control periods before and after.

RESULTS

An interquartile range increase in particulate matter (PM) ≤2.5 microns and nitric oxide exposures during the week before delivery was associated with an 11% (OR 1.11, 95% CI: 1.01-1.23) and 21% (OR 1.21, 95% CI: 1.04-1.42) increased cardiovascular events odds, respectively. These pollutants, sulfur dioxide, carbon monoxide, PM ≤ 10 microns, and some PM constituents showed associations with event odds for days 0, 1, 5, and 6 before delivery. Inverse associations were observed for O₃ and some PM constituents as well as air toxics.

CONCLUSIONS

Cardiovascular events at labor/delivery merit more attention in relation to air pollution.

Gaseous Air Pollution and the Risk for Stroke Admissions: A Case-Crossover Study in Beijing, China

Background: Though increasing evidence supports association between gaseous air pollution and stroke, it remains unclear whether the effects differ in season, sex and age. The aim of this study was to examine the associations of gaseous air pollution with stroke admissions in Beijing, 2013–2014 in different subgroups. Methods: Case-crossover design and conditional logistic regression were used to perform the analyses. We examined the exposure-response relationship between air pollution and stroke. Stratified analyses were performed in different seasons, sex, and age groups. Results: There were 147,624 stroke admissions during the study period. In the whole study period, percent changes of stroke admissions were 0.82% (95% CI: 0.52% to 1.13%) and 0.73% (95% CI: 0.44% to 1.03%) per 10 μg/m³ increase in the same day conentration of nitrogen dioxide (NO₂) and sulfur dioxide (SO₂). The positive associations were higher in warm seasons and with patients >65 years (p < 0.05). Contrary effects of carbon monoxide (CO) and ozone on stroke admissions were observed in different seasons. Conclusions: NO₂ and SO₂ were positively associated with stroke admissions, with stronger effects in warm seasons and with patients >65 years. The associations of CO and ozone with stroke admissions differed across seasons.