Maternal exposure to fine particulate matter and the risk of fetal distress

The role of maternal age on adverse pregnancy outcomes among primiparous women with singleton birth: a retrospective cohort study in urban areas of China

BACKGROUND

Both young and advanced maternal age pregnancies have strong associations with adverse pregnancy outcomes; however, there is limited understanding of how these associations present in an urban environment in China. This study aimed to analyze the associations between maternal age and pregnancy outcomes among Chinese urban women.

METHODS

We performed a population-based study consisting of 60,209 singleton pregnancies of primiparous women whose newborns were delivered after 20 weeks' gestation between January 2012 and December 2015 in urban areas of China. Participants were divided into six groups (19 or younger, 20-24, 25-29, 30-34, 35-39, 40 or older). Pregnancy outcomes include gestational diabetes mellitus (GDM), preeclampsia, placental abruption, placenta previa, premature rupture of membrane (PROM), postpartum hemorrhage, preterm birth, low birthweight, small for gestational age (SGA), large for gestational age (LGA), fetal distress, congenital microtia, and fetal death. Logistic regression models were used to assess the role of maternal age on the risk of adverse pregnancy outcomes with women aged 25-29 years as the reference group.

RESULTS

The risks of GDM, preeclampsia, placenta previa, and postpartum hemorrhage were decreased for women at a young maternal age and increased for women with advanced maternal age. Both young and advanced maternal age increased the risk of preterm birth and low birthweight. Young maternal age was also associated with increased risk of SGA (aOR 1.64, 95% CI 1.46-1.83) and fetal death (aOR 2.08, 95% CI 1.35-3.20). Maternal age over 40 years elevated the odds of placental abruption (aOR 3.44, 95% CI 1.47-8.03), LGA (aOR 1.47, 95% CI 1.09-1.98), fetal death (aOR 2.67, 95% CI 1.16-6.14), and congenital microtia (aOR 13.92, 95% CI 3.91-49.57). There were positive linear associations between maternal age and GDM, preeclampsia, placental abruption, placenta previa, PROM, postpartum hemorrhage, preterm birth, LGA and fetal distress (all P for linear trend < .05), and a negative linear association between maternal age and SGA (P for linear trend < .001). The analysis of the associations between maternal age and adverse fetal outcomes showed U-shape for preterm birth, low birth weight, SGA, fetal death and congenital microtia (all P for quadratic trend < .001).

CONCLUSIONS

Advanced maternal age predisposes women to adverse obstetric outcomes. Young maternal age manifests a bidirectional effect on adverse pregnancy outcomes. The findings may contribute to improving women's antenatal care and management.

The adverse effect of gestational diabetes mellitus and hypertensive disorders of pregnancy on maternal-perinatal outcomes among singleton and twin pregnancies: a retrospective cohort study (2011-2019)

Background

Gestational diabetes mellitus (GDM) and hypertensive disorders of pregnancy (HDP) are the predominant pregnancy complications among singleton and twin pregnancies worldwide. Our primary objective was to explore the adverse effect of GDM and HDP on maternal-perinatal outcomes compared with non-GDM and non-HDP in singleton and twin pregnancies. The secondary objective was to find the risk of adverse maternal-perinatal outcomes in twin pregnancies compared with singleton pregnancies complicated with GDM and HDP in Hubei, China.

Methods

A tertiary hospital-based retrospective study was conducted at Wuhan University Renmin Hospital, Hubei Province, China, from 2011 to 2019. A chi-square test was used to determine the difference in adverse maternal-perinatal outcomes between singleton and twin pregnancies. A multiple binary logistic regression model and a joinpoint regression model were used to determine the association of GDM and HDP with adverse maternal-perinatal outcomes and GDM and HDP temporal trend among singleton and twin pregnancies.

Results

The trend of HDP [average annual percentage change (AAPC) 15.1% (95% confidence interval (95%CI): 5.3, 25.7)] among singleton pregnancies and GDM [AAPC 50.4% (95%CI: 19.9, 88.7)] among twin pregnancies significantly increased from 2011 to 2019. After adjusting for confounding factors, GDM is associated with an increased risk of C-section (adjusted odds ratio (aOR), 1.5; 95%CI: 1.3, 1.6) and macrosomia (aOR, 1.3; 95%CI: 1.1, 1.6) in singleton and preterm birth (PTB) (aOR, 2.1; 95%CI: 1.2, 3.3) in twin pregnancies compared with non-GDM. HDP was associated with a higher risk of C-section, PTB, perinatal mortality, and low birth weight (LBW) in both singleton and twin pregnancies compared with the non-HDP. Compared with singleton pregnancies complicated with GDM and HDP, twin pregnancies showed higher odds of C-section [(aOR, 1.7; 95%CI: 1.1, 2.7), (aOR, 4.6; 95%CI: 2.5, 8.7), respectively], PTB [(aOR, 22.9; 95%CI: 14.1, 37.3), (aOR, 8.1; 95%CI: 5.3, 12.3), respectively], LBW [(aOR, 12.1; 95%CI: 8.2, 18.1), (aOR, 5.1; 95%CI: 3.6, 7.4), respectively], and low Apgar score [(aOR, 8.2; 95%CI: 4.4, 15.1), (aOR, 3.8; 95%CI: 2.4, 5.8), respectively] complicated with GDM and HDP.

Conclusion

In conclusion, GDM showed an increased risk of a few adverse maternal-perinatal outcomes and HDP is associated with a higher risk of several adverse maternal-perinatal outcomes in singleton and twin pregnancies compared to non-GDM and non-HDP. Moreover, twin pregnancies complicated with GDM and HDP showed higher odds of adverse maternal-neonatal outcomes compared with singleton pregnancies complicated with GDM and HDP.

Effect of gestational diabetes mellitus on pregnancy outcomes among younger and older women and its additive interaction with advanced maternal age

Background

The prevalence of gestational diabetes mellitus (GDM) and advanced maternal age (AMA, ≥ 35 years) has shown an increasing trend worldwide. This study aimed to evaluate the risk of pregnancy outcomes among younger (20-34 years) and older (≥ 35 years) women with GDM and further analyze the epidemiologic interaction of GDM and AMA on these outcomes.

Methods

This historical cohort study included 105 683 singleton pregnant women aged 20 years or older between January 2012 and December 2015 in China. Stratified by maternal age, the associations between GDM and pregnancy outcomes were analyzed by performing logistic regression. Epidemiologic interactions were assessed by using relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and synergy index (SI) with their 95% confidence intervals (95%CIs).

Results

Among younger women, individuals with GDM had a higher risk of all maternal outcomes, preterm birth (relative risk [RR] 1.67, 95%CI 1.50-1.85), low birthweight (RR 1.24, 95%CI 1.09-1.41), large for gestational age (RR 1.51, 95%CI 1.40-1.63), macrosomia (RR 1.54, 95%CI 1.31-1.79), and fetal distress (RR 1.56, 95%CI 1.37-1.77) than those without GDM. Among older women, GDM increased the risk of gestational hypertension (RR 2.17, 95%CI 1.65-2.83), preeclampsia (RR 2.30, 95%CI 1.81-2.93), polyhydramnios (RR 3.46, 95%CI 2.01-5.96), cesarean delivery (RR 1.18, 95%CI 1.10-1.25), preterm birth (RR 1.35, 95%CI 1.14-1.60), large for gestational age (RR 1.40, 95%CI 1.23-1.60), macrosomia (RR 1.65, 95%CI 1.28-2.14) and fetal distress (RR 1.46, 95%CI 1.12-1.90). Additive interactions of GDM and AMA on polyhydramnios and preeclampsia were found, with RERI of 3.11 (95%CI 0.05-6.16) and 1.43 (95%CI 0.09-2.77), AP of 0.51 (95%CI 0.22-0.80) and 0.27 (95%CI 0.07-0.46), and SI of 2.59 (95%CI 1.17-5.77) and 1.49 (95%CI 1.07-2.07), respectively.

Conclusion

GDM is an independent risk factor for multiple adverse pregnancy outcomes, and may exert additive interactions with AMA on the risk of polyhydramnios and preeclampsia.

Association between maternal short-term exposure to ambient air pollution and the risk of fetal distress: A matched case-control study

BACKGROUND

Ambient air pollution has been linked to gestational complications. However, the evidence on the relationship between air pollution and fetal distress is limited.

OBJECTIVES

To investigate the relationship between maternal short-term air pollution exposure and fetal distress, and to identify a potential susceptible population.

METHODS

This matched case-control study, involving 313 pregnancy women with fetal distress was conducted in Xi'an, the largest city in Northwest China from 2013 to 2016. Each woman with fetal distress was randomly matched with four women without fetal distress of the same age, same gestational week, and registration in the same period (n = 1252). Inverse distance-weighted (IDW) interpolation was applied to estimate maternal air pollution exposure based on the residential addresses. We employed conditional logistic regression model to evaluate the relationship between air pollutants and fetal distress. Distributed lag nonlinear model (DLNM) was performed to examine the exposure-response relationship between air pollutants and fetal distress.

RESULTS

Maternal short-term exposure to PM₁₀, PM_2.5-10 (PMc), SO₂, NO₂, and CO was associated with increased risk of fetal distress. Each 10 μg/m³ increment in PM₁₀, PMc, SO₂ at lag 014, and NO₂ at lag 010, the odds ratio (ORs) of fetal distress were 1.027 (95 % confidence interval (CI): 1.004, 1.050), 1.058 (95 % CI: 1.014, 1.105), 1.140 (95 % CI: 1.029, 1.264), and 1.158 (95 % CI: 1.046, 1.283), respectively. Similarly, with a 0.1 mg/m³ increment in CO at lag 014, the OR of fetal distress was 1.029 (95 % CI: 1.002, 1.058). Stratified analyses showed that the estimate associations of PM₁₀, PM_2.5 and CO appeared to be stronger, although not statistically significantly, among women with gestational complications.

CONCLUSION

Maternal short-term exposure to ambient air pollution may increase the risk of fetal distress. Understanding the detrimental role of air pollution in fetal distress can help us better develop preventative methods in reducing its' impact on maternal and fetal health.

Secular trends and age-period-cohort effect on adverse perinatal outcomes in Hubei, China (2011-2019)

The increasing trend in the incidence of adverse perinatal outcomes is a public health concern globally as well as in China. However, the causes of the increasing trend are not well understood. The present tertiary-hospital-based retrospective study (2011-2019) aims to determine the secular trends and age-period-cohort effect on adverse perinatal outcomes in Hubei, China. The age-standardized incidence rates of adverse perinatal outcomes significantly decreased such as preterm births by 22% [AAPC - 3.4% (95% CI - 7.8, - 1.2)], low birth weight (LBW) by 28.5% [AAPC - 4.7% (95% CI - 6.0, - 3.3)], and fetal distress by 64.2% [AAPC - 14.0% (95% CI - 17.8, - 10.0)] during 2011-2019. Both extremes of maternal age groups (18-20 years and 42-44 years) had a higher risk ratio for adverse perinatal outcomes including preterm birth, perinatal mortality, LBW, low ponderal index (LPI), low Apgar score, and congenital defect compared to the reference age group (30-32 years). A higher risk ratio for perinatal mortality, intrauterine growth restriction (IUGR), and fetal distress and a lower risk ratio for preterm births and LBW were observed in the period 2017-2019. Both the young cohort (1997-1999) and the old cohort (1976-1969) had a higher risk ratio for preterm birth, perinatal mortality, macrosomia, and congenital defect compared to the reference cohort (1982-1984). In conclusion, some of the adverse perinatal outcomes incidence significantly decreased in the last 9 years in Hubei. However, extremes of maternal age groups and both young and old cohorts were associated with a higher risk of preterm birth, perinatal mortality, and congenital defect.

Time-varying association between fetal death and gestational exposure to ambient fine particles: a nationwide epidemiological study of 49 million fetuses in the contiguous US from 1989 to 2004

BACKGROUND

Gestational exposure to fine particulate matter (PM2.5) has been reported to be associated with an increased risk of fetal death in recent studies, but earlier studies in the past century have usually reported a non-significant association. As such, it remains unknown whether this adverse effect of PM2.5 exposure varies with time.

METHODS

Nearly 49.2 million eligible birth and fetal death records from 1989 to 2004 were selected from the United States (US) birth and fetal death certificate datasets. For each record, the level of prenatal exposure to PM2.5 was taken as the average concentration in the mother's residential county during the entire gestational period, according to well-established estimates of monthly levels across the contiguous US. We first stratified the dataset by the month of the last menstrual period (LMP) and then independently evaluated the nationwide association between PM2.5 exposure and fetal death within each stratum using five typical logit models: unadjusted, covariate-adjusted, propensity-score, double robust, and diagnostic-score models. Finally, we conducted a meta-analysis to pool estimated LMP-specific associations and explored how the overall association varied by LMP month.

RESULTS

Different models showed temporal heterogeneity in the estimated association between PM2.5 exposure and fetal death. According to the meta-analysis, double robust model estimates were more homogeneous than the rest, and thus the model outcome was recognized as the main result. For each 1-µg/m3 increase in prenatal exposure to PM2.5, the pooled odds ratio (OR) of fetal death was estimated to be 1.08 [95% confidence interval (CI): 1.05, 1.10]. The LMP-specific ORs exhibited a slightly increasing trend and a significant seasonal pattern. Compared with the pooled OR among samples with the LMP in spring, the estimates for summer, fall and winter were higher by 11.1% (95% CI: 6.2%, 16.3%), 27.8% (95% CI: 22.1%, 33.8%) and 28.8% (95% CI: 23.7%, 34.1%), respectively. We also found that temporal patterns in the association between PM2.5 exposure and fetal death could be explained by several population-level indicators or modifiers (i.e. ethnicity, maternal age, gestational weight gain, previous pregnancy of abnormal termination and diabetes).

CONCLUSIONS

Prenatal exposure to PM2.5 can increase the risk of fetal death. The effects of PM2.5 exposure may be modified by complex factors, which leads to a time-varying association.

Association of exposure to ambient particulate matter with maternal thyroid function in early pregnancy

BACKGROUND

It is known that maternal thyroid dysfunction during early pregnancy can cause adverse pregnancy complications and birth outcomes. This study was designed to examine the association between ambient particulate matter with aerodynamic diameters ≤2.5 μm (PM2.5) and particulate matter with aerodynamic diameters ≤10 μm (PM10) exposure and maternal thyroid function during early pregnancy.

METHODS

This study was based on data from a birth cohort study of 921 pregnant women in China. We estimated associations between ambient PM2.5 and PM10 exposure during the first trimester of pregnancy (estimated with land-use regression models) and maternal thyroid hormone concentrations (free thyroxine (FT4), free tri-iodothyronine (FT3), and thyroid-stimulating hormone (TSH)) collected between weeks 10 and 17 of gestation using linear regression models adjusting for potential confounders. Ambient PM2.5 and PM10 concentrations were modeled per interquartile range (IQR) increment and as tertiles based on the distribution of the exposure levels.

RESULTS

An IQR increment (68 μg/m3) in PM2.5 exposure was associated with a significant decrease in maternal FT4 levels (β = -0.60, 95% CI: -1.07, -0.12); and a significant decrease in FT4/FT3 ratio (β = -0.13, 95% CI: -0.25, -0.02). Further analyses showed that, relative to the lowest tertile, women in both the middle and highest tertiles of PM2.5 had significantly lower concentrations of maternal FT4 and FT4/FT3 ratio. No significant associations were found between PM2.5 and FT3 or TSH levels. PM10 exposure was not significantly associated with maternal thyroid function.

CONCLUSIONS

Our study suggested that higher ambient PM2.5, not PM10, exposed during the first trimester of pregnancy were associated with a significant decrease in maternal serum FT4 concentrations and FT4/FT3 ratio. Studies in populations with different exposure levels are needed to replicate our study results.

The trend in delayed childbearing and its potential consequences on pregnancy outcomes: a single center 9-years retrospective cohort study in Hubei, China

BACKGROUND

Due to the advancement of modern societies, the proportion of women who delay childbearing until or beyond 30 years has dramatically increased in the last three decades and has been linked with adverse maternal-neonatal outcomes.

OBJECTIVE

To determine the trend in delayed childbearing and its negative impact on pregnancy outcomes.

MATERIAL AND METHODS

A tertiary hospital-based retrospective study was conducted in Wuhan University Renmin Hospital, Hubei Province, China, during the years 2011-2019. The joinpoint regression analysis was used to find a trend in the delayed childbearing and the multiple binary logistic regression model was used to estimate the association between maternal age and pregnancy outcomes.

RESULTS

Between 2011 and 2019, the trend in advanced maternal age (AMA ≥35 years) increased by 75% [AAPC 7.5% (95% CI: - 10.3, 28.9)]. Based on maternal education and occupation, trend in AMA increased by 130% [AAPC 11.8% (95% CI: 1.1, 23.7)] in women of higher education level, and 112.5% [AAPC 10.1% (95% CI: 9.4, 10.9)] in women of professional services. After adjusting for confounding factors, AMA was significantly associated with increased risk of gestational hypertension (aOR 1.5; 95% CI: 1.2, 2.1), preeclampsia (aOR 1.6; 95% CI: 1.4, 1.9), sever preeclampsia (aOR 1.7; 95% CI: 1.1, 2.6), placenta previa (aOR 1.8; 95% CI: 1.5, 2.2), gestational diabetes mellitus (aOR 2.5; 95% CI: 2.3, 2.9), preterm births (aOR 1.6; 95% CI: 1.4, 1.7), perinatal mortality (aOR 1.8; 95% CI: 1.3, 2.3), and low birth weight (aOR 1.3; 95% CI: 1.2, 1.4) compared with women aged < 30 years.

CONCLUSION

Our findings show a marked increase in delayed childbearing and its negative association with pregnancy outcomes.

Review of Particle Filters for Internal Combustion Engines

Diesel engines have gradually become one of the main forces in the human transportation industry because of their high efficiency, good durability, and stable operation. However, compared with gasoline vehicles, the high emission of diesel vehicles forces manufacturers to introduce new pollutant control technologies. Although the particulate matter emissions of gasoline vehicles are lower than that of diesel vehicles, with the popularity of gasoline vehicles and the continuous rise of power, the impact of these particles on the environment cannot be ignored. Therefore, diesel particulate filters and gasoline particulate filters have been invented to collect the fine particles in the exhaust gas to protect the environment and meet increasingly stringent emission regulations. This paper summarizes the research progress on diesel particulate filters and gasoline particulate filters at present and comprehensively introduces the diesel particulate filter and gasoline particulate filter from the mechanism, composition, and operation processes. Additionally, the laws and regulations of various countries and the impact of gas waste particulates on the human body are described. In addition, the mechanisms of the diesel particulate filter, gasoline particulate filter, and regeneration were studied. Finally, the prospects and future directions for the development of particle filters for internal combustion engines are presented.

Changes in adverse pregnancy outcomes in women with advanced maternal age (AMA) after the enactment of China's universal two-child policy

The universal two-child policy (TCP; 2016) in China has affected many aspects of maternal-neonatal health. A tertiary hospital-based retrospective study (2011–2019) was used to find the association of these policy changes with maternal age and pregnancy outcomes in women with AMA (≥ 35 years) in the Hubei Province, China. The proportion of neonatal births to women with AMA increased by 68.8% from 12.5% in the one-child policy (OCP) period to 21.1% in the universal TCP period [aOR 1.76 (95% CI: 1.60, 1.93)]. In the univariate analysis, the proportion of preterm births (29.4% to 24.1%), low birth weight (LBW) (20.9% to 15.9%), and hypertensive disorders of pregnancy (HDP) (11.5% to 9.2%) significantly (p < 0.05) decreased in women with AMA from the OCP period to universal TCP period. However, the proportion of intrauterine growth restriction (IUGR) (0.2% to 0.7%) and gestational diabetes mellitus (GDM) (1.7% to 15.6%) was significantly (p < 0.05) increased over the policy changes. After adjusting for confounding factors, only the risk of GDM increased [aOR 10.91 (95% CI: 6.05, 19.67)] in women with AMA from the OCP period to the universal TCP period. In conclusion, the risk of GDM increased in women with AMA from the OCP period to the universal TCP period.

Characterization of ambient carbon monoxide and PM 2.5 effects on fetus development, liver enzymes and TSH in Isfahan City, central Iran

Ambient carbon monoxide (CO) and particulate matters (PMs) are two important air pollutants in urban areas with known impacts on fetuses. Hence, this study measured some biochemistry factors of 200 neonates with birth dates from January 19 to October 12, 2020, including the birth weight and height and the serum levels of ALT, AST, ALP, GGT, and TSH. The Support Vector Machine-fitted land-use regression approach was used to predict the spatio-temporal variability of intra-urban PM 2.5 and CO concentrations by month during the pregnancy period of the cases employing 5 variables of Digital Elevation Model (DEM), slope, and distance from Compressed Natural Gas (CNG) stations, Bus Rapid Transit (BRT) stations, and mines and industries. Spearman correlation analysis (p < 0.05) was performed between the neonate indices and mean monthly PM 2.5 and CO concentrations at the exact residential address of maternal cases and their nearby areas in 250, 500, 1000, 1500, and 2000 m-radius buffer rings. All modeling efforts succeeded in predicting CO and PM 2.5 levels with acceptable adjusted r² values. Northern Isfahan had relatively higher CO and PM 2.5 concentrations due to its adjacency to low-vegetated open lands and its high traffic load as compared to southern areas. The correlation results between the neonate biochemistry indices and mean PM 2.5 and CO concentrations were mostly positive in most buffer rings, especially in the >500 m-radius buffer rings for PM 2.5 and in the 2000 m-radius rings for CO. Although the correlation results of PM 2.5 followed a detectable trend in the buffer rings, the associations between CO and the neonate biochemistry indices differed significantly between the buffer rings. Results showed that increasing mean monthly concentration of CO and PM 2.5 may stimulate further production of liver enzymes while decreasing the birth weight and height.

Prenatal low-dose antibiotic exposure and children allergic diseases at 4 years of age: A prospective birth cohort study

BACKGROUND

Based on a medical record or questionnaire survey approach, previous epidemiological studies have investigated associations between maternal antibiotic exposure during pregnancy and childhood allergic diseases. However, biomonitoring studies on the prenatal low-dose antibiotic exposure, mainly from the environment and contaminated food, and in relation to children allergic diseases, are missing.

OBJECTIVES

This research aimed to examine the associations between prenatal low-dose antibiotic exposure measured at multiple time points and children current allergic diseases at 4 years of age.

METHODS

The current study including 2453 mother-child pairs was based on the Ma'anshan Birth Cohort study. Selected 41 antibiotics and their two metabolites, which including human antibiotics (HAs), preferred as human antibiotics (PHAs), veterinary antibiotics (VAs) and preferred as veterinary antibiotics (PVAs), in urine samples from 2453 pregnant women were biomonitored through liquid chromatography-triple quadrupole tandem mass spectrometry. Information on children current allergic diseases were collected via validated questionnaires. Generalized estimating equation were used to explore the associations between the repeated measurements of maternal urinary antibiotic over three trimesters and current allergic diseases in children.

RESULTS

The detection rates of nine individual antibiotics in the three trimester during pregnancy are greater than 10%, and the 90th percentile concentration of the detected antibiotics ranges from 0.07 to 22.34 µg/g, and the 95th percentile concentration ranges from 0.17 to 59.57 µg/g. Among the participants, each one-unit concentration increment of sulfamethazine (adjusted OR=1.28, 95% CI: 1.10, 1.49, P-_FDR=0.014) in the first trimester and ciprofloxacin (adjusted OR=1.17, 95% CI: 1.07, 1.28, P-_FDR=0.008) in the second trimester were associated with an increased risk of current eczema in children. In the third trimester, each one-unit concentration increment of oxytetracycline (adjusted OR=1.90, 95% CI: 1.30, 2.78, P-_FDR=0.014) was associated with an increased risk of current asthma in children. Gender-stratified analyses demonstrated that no gender differences were observed in the associations between prenatal antibiotic exposure and current allergic diseases in children.

CONCLUSIONS

Maternal exposure to certain specific VAs or PVAs (sulfamethazine, ciprofloxacin and oxytetracycline) in different trimesters was associated with an increased risk of current asthma and current eczema in 4-year-old children. No gender differences were found in these associations. Further studies are warranted to confirm our findings and explore the potential mechanisms.

Ambient particulate matter triggers defective autophagy and hijacks endothelial cell renewal through oxidative stress-independent lysosomal impairment

Ambient particulate matter (APM) has been authenticated to exert hazards on human vascular endothelial cells, including abnormal autophagy. However, the potential reasons for autophagosome accumulation are still obscure. Since autophagy is a dynamic process, it is imperative to systemically consider the autophagic induction combined with its degradation to reflect realistic scenarios. Therefore, in the current study, different exposure durations were initially employed for the detection of autophagic marker proteins to assess the dynamic autophagic state preliminarily. Additionally, LC3 turn-over and autophagic flux assays were used to determine the specific cause of LC3II upregulation in EA.hy926 human vascular endothelial cells by a type of standard urban particulate matter, PM SRM1648a. As a result, PM SRM1648a stimulates excess autophagic vacuoles in EA. hy926 cells, in which the underlying causes are probably different at varying incubation endpoints. Intriguingly, LC3II upregulation was due to the intensifying autophagic initiation after 6 h of exposure, whereas as exposure period was extended to 24 h, overloaded autophagic vacuoles were attributed to the defective autophagy. Mechanistically, PM SRM1648a damages EA. hy926 cells by inducing lysosomal disequilibrium and resultant autophagic malfunction which are not directly mediated by oxidative stress. These data indicate that appropriate maintenance of lysosomal function and autophagic flux is probably a protective measure against APM-induced endothelial cell damage.

Ambient particulate matter triggers dysfunction of subcellular structures and endothelial cell apoptosis through disruption of redox equilibrium and calcium homeostasis

Ambient particulate matter (APM) is becoming a global environmental problem that seriously jeopardizes public health. Previous evidence hinted that APM correlates to cardiovascular diseases. As a potential target, equilibrium of endothelial cell is a prerequisite for vascular health which could be vulnerably attacked by particles, but the specific mechanisms whereby APM damages endothelial cells have not been fully elucidated. In the current study, based on two classical mechanisms of oxidative stress and intracellular calcium overload, we aimed to explore their roles in APM-induced endothelial cell apoptosis from the perspective of subcellular levels, including endoplasmic reticulum (ER) stress and mitochondrial dysfunction. As a result, PM SRM1648a results in oxidative stress and calcium overload in EA.hy926 cells. Additionally, ERs and mitochondria could be severely disturbed by particles in morphology and function, characterized by swelling ERs, mitochondrial fission and disappearance of cristae, coupled with ER damage, mtROS overproduction and significant reduction in mitochondrial membrane potential (MMP). Adverse effects on these organelles are the prime culprits of following apoptosis in endothelial cells. Fortunately, additional antioxidants and calcium inhibitors could mitigate cellular lesion through improvement of subcellular function. Intriguingly, antioxidants relieve cell stress via both mitochondrial and ER stress-mediated pathways, whereas the role of calcium modulators in cell apoptosis is independent of the mitochondrial pathway but could be explained by amelioration of ER stress. In conclusion, our data basically revealed that internalized PM SRM1648a triggers oxidative stress and calcium influx in EA.hy926 endothelial cells, followed by multiple subcellular damage and eventually contributes to cell death, during which antioxidants and calcium inhibitors confer protective effects.

Associations of exposure to fine particulate matter during pregnancy with maternal blood glucose levels and gestational diabetes mellitus: Potential effect modification by ABO blood group

BACKGROUND

Previous studies have examined the relationships between prenatal fine particulate matter (PM_2.5) exposure and gestational diabetes mellitus (GDM), but the results were inconsistent. Furthermore, the possible effect modification by ABO blood group has not been explored.

OBJECTIVES

To assess the associations of PM_2.5 exposures during pregnancy with maternal glucose levels as well as GDM, and further to evaluate the potential effect modification by ABO blood group.

METHODS

Between January 2013 and January 2015, 4783 pregnant women were enrolled in our study based on a birth cohort in Wuhan. Daily PM_2.5 exposure levels for each woman during pregnancy were estimated using a spatial-temporal land-use regression model. Linear regressions with general estimating equations (GEE) were performed to assess the associations between trimester-specific PM_2.5 exposures and maternal glucose levels. Modified Poisson regressions with GEE analyses were used to evaluate the impacts of PM_2.5 exposures during each trimester on the risk of GDM. The associations of PM_2.5 exposure during the whole study period with glucose levels and GDM were estimated using multiple linear regression model and modified Poisson regression model, respectively. We conducted a stratified analysis to explore the potential effect modification by ABO blood group.

RESULTS

Among all the 4783 participants, 394 (8.24%) had GDM. Exposure to PM_2.5 was found to be positively associated with elevated fasting glucose level during the whole study period [0.382 mg/dL, 95% confidence interval (CI): 0.179-0.586, per 10 μg/m³ increase in PM_2.5], the first trimester (0.154 mg/dL ,95% CI: 0.017-0.291) and the second trimester (0.541 mg/dL, 95% CI: 0.390-0.692). No statistically significant results were observed between PM_2.5 and 1-h and 2-h glucose levels during any study period. Increased risks of GDM for each 10 μg/m³ increase in PM_2.5 levels were observed during the whole study period [relative risk (RR): 1.120, 95% CI: 1.021-1.228] and the first trimester (RR: 1.074, 95% CI: 1.012-1.141), but not the second trimester (RR: 1.035, 95% CI: 0.969-1.106). Stratified analysis indicated that the associations of PM_2.5 exposures with GDM were more pronounced among pregnant women with blood group A, but no significant effect modifications were observed.

CONCLUSION

Our study enriched epidemiological evidence linking PM_2.5 exposures during pregnancy to elevated maternal glucose levels and increased risk of GDM. More importantly, we first highlighted that the impact of PM_2.5 on GDM might be greater among pregnant women with blood group A.

Environmental Particulate Matter Levels during 2017 Large Forest Fires and Megafires in the Center Region of Portugal: A Public Health Concern?

This work characterizes the dimension and the exceptionality of 2017 large- and mega-fires that occurred in the center region of Portugal through the assessment of their impact on the ambient levels of particulate matter (PM10 and PM2.5), retrieved from local monitoring stations, and the associated public health risks. PM10 and PM2.5 concentrations were increased during the occurrence of large fires and megafires, with daily concentrations exceeding the European/national guidelines in 7-14 and 1-12 days of 2017 (up to 704 µg/m3 for PM10 and 46 µg/m3 for PM2.5), respectively. PM10 concentrations were correlated with total burned area (0.500 < r < 0.949; p > 0.05) and with monthly total burned area/distance2 (0.500 < r < 0.667; p > 0.05). The forest fires of 2017 took the life of 112 citizens. A total of 474 cases of hospital admissions due to cardiovascular diseases and 3524 cases of asthma incidence symptoms per 100,000 individuals at risk were assessed due to exposure to 2017 forest fires. Real-time and in situ PM methodologies should be combined with protection action plans to reduce public health risks. Portuguese rural stations should monitor other health-relevant pollutants (e.g., carbon monoxide and volatile organic compounds) released from wildfires to allow performing more robust and comprehensive measurements that will allow a better assessment of the potential health risks for the exposed populations.

Spatiotemporal variations and characterization of the chronic cancer risk associated with benzene exposure

A spatiotemporal analysis of benzene was performed in east of the USA and in a representative station in Baltimore County, in order to assess its trend over a 25-year time span between 1993 and 2018. A novel time series analysis technique known as TBATS (an ensemble of Trigonometric seasonal models, Box-Cox transformation, ARMA error plus Trend and Seasonal components) was applied for the first time on an air contaminant. The results demonstrated an annual seasonality and a continuously declining trend in this respect. The success of Reformulated Gasoline Program (RFG), initiated in 1995, was obviously detected in time series data since the daily benzene concentrations reduced to one-sixth of its original level in 1995. In this regard, the respective values of mean absolute scaled error (MASE) were 0.35 and 0.45 for training and test series. Given the observed concentrations of benzene, the hot spot areas in east of the US were identified by spatial analysis, as well. A chronic cancer risk was followed along the study area, by both a deterministic and probabilistic risk assessment (PRA) techniques. It was indicated that children are at higher risk than that of adults. The range of estimated risk values for PRA was higher and varied between 6.45 × 10^-6 and 1.68 × 10^-4 for adults and between 8.13 × 10^-6 and 8.29 × 10^-4 for children. According to the findings of PRA, and referring to the threshold level of 1 × 10^-4, only 1.2% of the adults and 28.77% of the children were categorized in an immediate risk group.