Ambient and household PM2.5 pollution and adverse perinatal outcomes: A meta-regression and analysis of attributable global burden for 204 countries and territories

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Adverse neurodevelopment in children associated with prenatal exposure to fine particulate matter (PM2.5) - Possible roles of polycyclic aromatic hydrocarbons (PAHs) and mechanisms involved

Prenatal exposure to ambient fine particles (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) has been associated with adverse birth outcomes including neurodevelopmental effects with cognitive and/or behavioral implications in early childhood. As a background we first briefly summarize human studies on PM2.5 and PAHs associated with adverse birth outcomes and modified neurodevelopment. Next, we add more specific information from animal studies and in vitro studies and elucidate possible biological mechanisms. More specifically we focus on the potential role of PAHs attached to PM2.5 and explore whether effects of these compounds may arise from disturbance of placental function or more directly by interfering with neurodevelopmental processes in the fetal brain. Possible molecular initiating events (MIEs) include interactions with cellular receptors such as the aryl hydrocarbon receptor (AhR), beta-adrenergic receptors (βAR) and transient receptor potential (TRP)-channels resulting in altered gene expression. MIE linked to the binding of PAHs to cytochrome P450 (CYP) enzymes and formation of reactive electrophilic metabolites are likely less important. The experimental animal and in vitro studies support the epidemiological findings and suggest steps involved in mechanistic pathways explaining the associations. An overall evaluation of the doses/concentrations used in experimental studies combined with the mechanistic understanding further supports the hypothesis that prenatal PAHs exposure may cause adverse outcomes (AOs) linked to human neurodevelopment. Several MIEs will likely occur simultaneously in various cells/tissues involving several key events (KEs) which relative importance will depend on dose, time, tissue, genetics, other environmental factors, and neurodevelopmental endpoint in study.

Polycyclic aromatic hydrocarbon exposure effects on trajectories of maternal and adolescent mental health

BACKGROUND

Parental psychological distress is a well-known risk factor for developmental psychopathology, with longer term parental distress associated with worse youth mental health. Neurotoxicant exposure during pregnancy is a risk factor for both poor maternal and youth mental health. The impact of one class of pollutant, polycyclic aromatic hydrocarbons (PAH), on long-term trajectories of maternal distress and youth self-reported mental health symptoms in adolescence has been understudied.

METHODS

PAH exposure was measured by DNA adducts in maternal blood sampled during the third trimester of pregnancy. Maternal distress, operationalized as maternal demoralization, was measured at 11 timepoints (prenatal to child age 16). Adolescent mental health symptoms were measured at age 13-15. Follow up analyses examined a subset of measures available at age 15-20 years. Structural equation modeling examined associations between PAH exposure during pregnancy and latent growth metrics of maternal distress, and between maternal distress (intercept and slope) and youth mental health symptoms in a prospective longitudinal birth cohort (N = 564 dyads).

RESULTS

Higher prenatal PAH exposure was associated with higher concurrent maternal distress. Prenatal maternal distress was associated with adolescent's self-reported anxiety, depression, and externalizing problems. On average, maternal distress declined over time; a slower decline in mother's distress across the course of the child's life was associated with greater self-reported anxiety and externalizing problems in youth.

CONCLUSIONS

Our findings are consistent with an intergenerational framework of environmental effects on mental health: PAH exposure during pregnancy affects maternal mental health, which in turn influences mental health outcomes for youth well into adolescence. Future research is necessary to elucidate the possible social and biological mechanisms (e.g., parenting, epigenetics) underlying the intergenerational transmission of the negative effects of pollution on mental health in caregiver-child dyads.

First Results From a Calibrated Network of Low-Cost PM2.5 Monitors in Mombasa, Kenya Show Exceedance of Healthy Guidelines

The paucity of fine particulate matter (PM2.5) measurements limits estimates of air pollution mortality in Sub-Saharan Africa. Well calibrated low-cost sensors can provide reliable data especially where reference monitors are unavailable. We evaluate the performance of Clarity Node-S PM monitors against a Tapered element oscillating microbalance (TEOM) 1400a and develop a calibration model in Mombasa, Kenya's second largest city. As-reported Clarity Node-S data from January 2023 through April 2023 was moderately correlated with the TEOM-1400a measurements (R 2 = 0.61) and exhibited a mean absolute error (MAE) of 7.03 μg m-3. Employing three calibration models, namely, multiple linear regression (MLR), Gaussian mixture regression and random forest (RF) decreased the MAE to 4.28, 3.93, and 4.40 μg m-3 respectively. The R 2 value improved to 0.63 for the MLR model but all other models registered a decrease (R 2 = 0.44 and 0.60 respectively). Applying the correction factor to a five-sensor network in Mombasa that was operated between July 2021 and July 2022 gave insights to the air quality in the city. The average daily concentrations of PM2.5 within the city ranged from 12 to 18 μg m-3. The concentrations exceeded the WHO daily PM2.5 limits more than 50% of the time, in particular at the sites nearby frequent industrial activity. Higher averages were observed during the dry and cold seasons and during early morning and evening periods of high activity. These results represent some of the first air quality monitoring measurements in Mombasa and highlight the need for more study.

Protective effects of docosahexaenoic acid supplementation on cognitive dysfunction and hippocampal synaptic plasticity impairment induced by early postnatal PM2.5 exposure in young rats

PM2.5 exposure is a challenging environmental issue that is closely related to cognitive development impairment; however, currently, relevant means for prevention and treatment remain lacking. Herein, we determined the preventive effect of docosahexaenoic acid (DHA) supplementation on the neurodevelopmental toxicity induced by PM2.5 exposure. Neonatal rats were divided randomly into three groups: control, PM2.5, and DHA + PM2.5 groups. DHA could ameliorate PM2.5-induced learning and memory dysfunction, as well as reverse the impairment of hippocampal synaptic plasticity, evidenced by enhanced long-term potentiation, recovered synaptic ultrastructure, and increased expression of synaptic proteins. Moreover, DHA increased CREB phosphorylation and BDNF levels and attenuated neuroinflammation and oxidative stress, reflected by lower levels of IBA-1, IL-1β, and IL-6 and increased levels of SOD1 and Nrf2. In summary, our findings demonstrated that supplementation of DHA effectively mitigated the cognitive dysfunction and synaptic plasticity impairment induced by early postnatal exposure to PM2.5. These beneficial effects may be attributed to the upregulation of the CREB/BDNF signaling pathway, as well as the reduction of neuroinflammation and oxidative stress.

Disease types and pathogenic mechanisms induced by PM2.5 in five human systems: An analysis using omics and human disease databases

Atmospheric fine particulate matter (PM2.5) can harm various systems in the human body. Due to limitations in the current understanding of epidemiology and toxicology, the disease types and pathogenic mechanisms induced by PM2.5 in various human systems remain unclear. In this study, the disease types induced by PM2.5 in the respiratory, circulatory, endocrine, and female and male urogenital systems have been investigated and the pathogenic mechanisms identified at molecular level. The results reveal that PM2.5 is highly likely to induce pulmonary emphysema, reperfusion injury, malignant thyroid neoplasm, ovarian endometriosis, and nephritis in each of the above systems respectively. The most important co-existing gene, cellular component, biological process, molecular function, and pathway in the five systems targeted by PM2.5 are Fos proto-oncogene (FOS), extracellular matrix, urogenital system development, extracellular matrix structural constituent conferring tensile strength, and ferroptosis respectively. Differentially expressed genes that are significantly and uniquely targeted by PM2.5 in each system are BTG2 (respiratory), BIRC5 (circulatory), NFE2L2 (endocrine), TBK1 (female urogenital) and STAT1 (male urogenital). Important disease-related cellular components, biological processes, and molecular functions are specifically induced by PM2.5. For example, response to wounding, blood vessel morphogenesis, body morphogenesis, negative regulation of response to endoplasmic reticulum stress, and response to type I interferon are the top uniquely existing biological processes in each system respectively. PM2.5 mainly acts on key disease-related pathways such as the PD-L1 expression and PD-1 checkpoint pathway in cancer (respiratory), cell cycle (circulatory), apoptosis (endocrine), antigen processing and presentation (female urogenital), and neuroactive ligand-receptor interaction (male urogenital). This study provides a novel analysis strategy for elucidating PM2.5-related disease types and is an important supplement to epidemiological investigation. It clarifies the risks of PM2.5 exposure, elucidates the pathogenic mechanisms, and provides scientific support for promoting the precise prevention and treatment of PM2.5-related diseases.

Predicting adverse birth outcome among childbearing women in Sub-Saharan Africa: employing innovative machine learning techniques

BACKGROUND

Adverse birth outcomes, including preterm birth, low birth weight, and stillbirth, remain a major global health challenge, particularly in developing regions. Understanding the possible risk factors is crucial for designing effective interventions for birth outcomes. Accordingly, this study aimed to develop a predictive model for adverse birth outcomes among childbearing women in Sub-Saharan Africa using advanced machine learning techniques. Additionally, this study aimed to employ a novel data science interpretability techniques to identify the key risk factors and quantify the impact of each feature on the model prediction.

METHODS

The study population involved women of childbearing age from 26 Sub-Saharan African countries who had given birth within five years before the data collection, totaling 139,659 participants. Our data source was a recent Demographic Health Survey (DHS). We utilized various data balancing techniques. Ten advanced machine learning algorithms were employed, with the dataset split into 80% training and 20% testing sets. Model evaluation was conducted using various performance metrics, along with hyperparameter optimization. Association rule mining and SHAP analysis were employed to enhance model interpretability.

RESULTS

Based on our findings, about 28.59% (95% CI: 28.36, 28.83) of childbearing women in Sub-Saharan Africa experienced adverse birth outcomes. After repeated experimentation and evaluation, the random forest model emerged as the top-performing machine learning algorithm, with an AUC of 0.95 and an accuracy of 88.0%. The key risk factors identified were home deliveries, lack of prenatal iron supplementation, fewer than four antenatal care (ANC) visits, short and long delivery intervals, unwanted pregnancy, primiparous mothers, and geographic location in the West African region.

CONCLUSION

The region continues to face persistent adverse birth outcomes, emphasizing the urgent need for increased attention and action. Encouragingly, advanced machine learning methods, particularly the random forest algorithm, have uncovered crucial insights that can guide targeted actions. Specifically, the analysis identifies risky groups, including first-time mothers, women with short or long birth intervals, and those with unwanted pregnancies. To address the needs of these high-risk women, the researchers recommend immediately providing iron supplements, scheduling comprehensive prenatal care, and strongly encouraging facility-based deliveries or skilled birth attendance.

Poor housing quality and the health of newborns and young children

This study uses linked administrative data on live births, hospital stays, and census records for children born in Hungary between 2006 and 2011 to examine the relationship between poor housing quality and the health of newborns and children aged 1-2 years. We show that poor housing quality, defined as lack of access to basic sanitation and exposure to polluting heating, is not a negligible problem even in a high-income EU country like Hungary. This is particularly the case for disadvantaged children, 20-25% of whom live in extremely poor-quality homes. Next, we provide evidence that poor housing quality is strongly associated with lower health at birth and a higher number of days spent in inpatient care at the age of 1-2 years. These results indicate that lack of access to basic sanitation, hygiene, and non-polluting heating and their health impacts cannot be considered as the exclusive problem for low- and middle-income countries. In high-income countries, there is also a need for public policy programs that identify those affected by poor housing quality and offer them potential solutions to reduce the adverse effects on their health.

Ambient Environment and the Epidemiology of Preterm Birth

Preterm birth (PTB) is associated with substantial mortality and morbidity. We describe environmental factors that may influence PTB risks. We focus on exposures associated with an individual's ambient environment, such as air pollutants, water contaminants, extreme heat, and proximities to point sources (oil/gas development or waste sites) and greenspace. These exposures may further vary by other PTB risk factors such as social constructs and stress. Future examinations of risks associated with ambient environment exposures would benefit from consideration toward multiple exposures - the exposome - and factors that modify risk including variations associated with the structural genome, epigenome, social stressors, and diet.

Climate change, air pollution and maternal and newborn health: An overview of reviews of health outcomes

Background

Climate change represents a fundamental threat to human health, with pregnant women and newborns being more susceptible than other populations. In this review, we aimed to describe the current landscape of available epidemiological evidence on key climate risks on maternal and newborn health (MNH).

Methods

We sought to identify published systematic and scoping reviews investigating the impact of different climate hazards and air pollution on MNH outcomes. With this in mind, we developed a systematic search strategy based on the concepts of 'climate/air pollution hazards, 'maternal health,' and 'newborn health,' with restrictions to reviews published between 1 January 2010 and 6 February 2023, but without geographical or language restriction. Following full text screening and data extraction, we synthesised the results using narrative synthesis.

Results

We found 79 reviews investigating the effects of climate hazards on MNH, mainly focussing on outdoor air pollution (n = 47, 59%), heat (n = 24, 30%), and flood/storm disasters (n = 7, 9%). Most were published after 2015 (n = 60, 76%). These reviews had consistent findings regarding the positive association of exposure to heat and to air pollution with adverse birth outcomes, particularly preterm birth. We found limited evidence for impacts of climate-related food and water security on MNH and did not identify any reviews on climate-sensitive infectious diseases and MNH.

Conclusions

Climate change could undermine recent improvements in maternal and newborn health. Our review provides an overview of key climate risks to MNH. It could therefore be useful to the MNH community to better understand the MNH needs for each climate hazard and to strengthen discussions on evidence and research gaps and potential actions. Despite the lack of comprehensive evidence for some climate hazards and for many maternal, perinatal, and newborn outcomes, we observed repeated findings of the impact of heat and air pollutants on birth outcomes, particularly preterm birth. It is time for policy dialogue to follow to specifically design climate policy and actions to protect the needs of MNH.

Exposure to indoor air pollution and adverse pregnancy outcomes in low and middle-income countries: a systematic review and meta-analysis

Introduction

Exposure to indoor air pollution such as biomass fuel and particulate matter is a significant cause of adverse pregnancy outcomes. However, there is limited information about the association between indoor air pollution exposure and adverse pregnancy outcomes in low and middle-income countries. Therefore, this meta-analysis aimed to determine the association between indoor air pollution exposure and adverse pregnancy outcomes in low and middle-income countries.

Methods

International electronic databases such as PubMed, Science Direct, Global Health, African Journals Online, HINARI, Semantic Scholar, and Google and Google Scholar were used to search for relevant articles. The study was conducted according to the updated Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. A random effect model at a 95% confidence interval was used to determine the association between indoor air pollution exposure and adverse pregnancy outcomes using STATA version 14. Funnel plot and Higgs I2 statistics were used to determine the publication bias and heterogeneity of the included studies, respectively.

Results

A total of 30 articles with 2,120,228 study participants were included in this meta-analysis. The pooled association between indoor air pollution exposure and at least one adverse pregnancy outcome was 15.5% (95%CI: 12.6-18.5), with significant heterogeneity (I2 = 100%; p < 0.001). Exposure to indoor air pollution increased the risk of small for gestational age by 23.7% (95%CI: 8.2-39.3) followed by low birth weight (17.7%; 95%CI: 12.9-22.5). Exposure to biomass fuel (OR = 1.16; 95%CI: 1.12-1.2), particulate matter (OR = 1.28; 95%CI: 1.25-1.31), and kerosene (OR = 1.38; 95%CI: 1.09-1.66) were factors associated with developing at least one adverse pregnancy outcomes.

Conclusions

We found that more than one in seven pregnant women exposed to indoor air pollution had at least one adverse pregnancy outcome. Specifically, exposure to particulate matter, biomass fuel, and kerosene were determinant factors for developing at least one adverse pregnancy outcome. Therefore, urgent comprehensive health intervention should be implemented in the area to reduce adverse pregnancy outcomes.

Ambient air pollution and adverse birth outcomes: A review of underlying mechanisms

Epidemiological data provide varying degrees of evidence for associations between prenatal exposure to ambient air pollutants and adverse birth outcomes (suboptimal measures of fetal growth, preterm birth and stillbirth). To assess further certainty of effects, this review examines the experimental literature base to identify mechanisms by which air pollution (particulate matter, nitrogen dioxide and ozone) could cause adverse effects on the developing fetus. It likely that this environmental insult impacts multiple biological pathways important for sustaining a healthy pregnancy, depending upon the composition of the pollutant mixture and the exposure window owing to changes in physiologic maturity of the placenta, its circulations and the fetus as pregnancy ensues. The current body of evidence indicates that the placenta is a target tissue, impacted by a variety of critical processes including nitrosative/oxidative stress, inflammation, endocrine disruption, epigenetic changes, as well as vascular dysregulation of the maternal-fetal unit. All of the above can disturb placental function and, as a consequence, could contribute to compromised fetal growth as well increasing the risk of stillbirth. Furthermore, given that there is often an increased inflammatory response associated with preterm labour, inflammation is a plausible mechanism mediating the effects of air pollution on premature delivery. In the light of increased urbanisation and an ever-changing climate, both of which increase ambient air pollution and negatively affect vulnerable populations such as pregnant individuals, it is hoped that the collective evidence may contribute to decisions taken to strengthen air quality policies, reductions in exposure to air pollution and subsequent improvements in the health of those not yet born.

Modulatory Effects of Vitamin D: A Possible Approach to Mitigate Air Pollution Related Pregnancy Complications

Approximately 99% of people on the planet breathe air that exceeds the World Health Organization's permitted threshold for pollution. South Asia is home to the world's most polluted cities. Population-based studies have suggested that women's reproductive health outcomes are worsening due to air pollution. Preeclampsia, miscarriage, gestational diabetes, high blood pressure, and unfavorable birth outcomes, including preterm birth, low birth weight, or even stillbirth are all linked to exposure to air pollution during pregnancy. It is estimated that 0.61 million deaths in India alone were related to indoor air pollution. Females frequently cook in the household using solid fuel as a primary combustion source. Women in the regions with the highest population density are disproportionately affected by high levels of poor-quality indoor air. Recently, it has been proposed that air pollution has a distinct role in the onset of vitamin D deficiency. Numerous studies have explored associations between low vitamin D level and various female reproductive health conditions since the discovery of the vitamin D receptor. It is worthy to note that some of these reproductive health conditions positively correlate with the severity of air pollution. In this study, the evidence has been synthesized on vitamin D's protective properties and dietary and pharmaceutical interventions have been discussed to show their beneficial effects in decreasing the long-term negative impacts of air pollution on women's health.

Effects of a liquefied petroleum gas stove intervention on stillbirth, congenital anomalies and neonatal mortality: A multi-country household air pollution intervention network trial

Household air pollution (HAP) from cooking with solid fuels used during pregnancy has been associated with adverse pregnancy outcomes. The Household Air Pollution Intervention Network (HAPIN) trial was a randomized controlled trial that assessed the impact of a liquefied petroleum gas (LPG) stove and fuel intervention on health in Guatemala, India, Peru, and Rwanda. Here we investigated the effects of the LPG stove and fuel intervention on stillbirth, congenital anomalies and neonatal mortality and characterized exposure-response relationships between personal exposures to fine particulate matter (PM2.5), black carbon (BC) and carbon monoxide (CO) and these outcomes. Pregnant women (18 to <35 years of age; gestation confirmed by ultrasound at 9 to <20 weeks) were randomly assigned to intervention or control arms. We monitored these fetal and neonatal outcomes and personal exposure to PM2.5, BC and CO three times during pregnancy, we conducted intention-to-treat (ITT) and exposure-response (E-R) analyses to determine if the HAPIN intervention and corresponding HAP exposure was associated with the risk of fetal/neonatal outcomes. A total of 3200 women (mean age 25.4 ± 4.4 years, mean gestational age at randomization 15.4 ± 3.1 weeks) were included in this analysis. Relative risks for stillbirth, congenital anomaly and neonatal mortality were 0.99 (0.60, 1.66), 0.92 (95 % CI 0.52, 1.61), and 0.99 (0.54, 1.85), respectively, among women in the intervention arm compared to controls in an ITT analysis. Higher mean personal exposures to PM2.5, CO and BC during pregnancy were associated with a higher, but statistically non-significant, incidence of adverse outcomes. The LPG stove and fuel intervention did not reduce the risk of these outcomes nor did we find evidence supporting an association between personal exposures to HAP and stillbirth, congenital anomalies and neonatal mortality.

Mortality risk of people living with HIV under hypothetical intervention scenarios of PM2.5 and HIV severity: a prospective cohort study

This study estimated and compared mortality risks among people living with HIV (PLWH) under the real-world and hypothetical scenarios of PM2.5 concentrations and HIV severity. An open cohort from all PLWH receiving antiretroviral therapy in Sichuan during 2010-2019 was constructed, resulting in 541,515 person-years. Annual mean concentrations of PM2.5 were estimated and linked to PLWH by their residential address. The parametric g-formula were used to assess 3- and 5-year mortality risks under the real-world and hypothetical scenarios of PM2.5 (10-35, 35-50, 50-75 μg/m3) and CD4 concentrations (0-200, 200-500, 500-800, 800-1100 counts/μl). The estimated 3- and 5-year mortality risks among the PLWH were 14.43 % and 19.38 %, respectively, which would decrease substantially when annual PM2.5 concentration were reduced to between 10 and 35 μg/m3 (risk difference [RD] = -3.23 % and - 4.06 %) and would increase when PM2.5 concentration were elevated to between 50 and 75 μg/m3 (RD = 3.59 % and 5.04 %). The mortality risk would increase when CD4 concentration were reduced to <200 counts/μl (RD = 15.90 % and 20.27 %) and would decrease when CD4 concentration were ≥ 200 counts/μl, especially to between 800 and 1100 counts/μl (RD = -9.01 % and - 11.75 %). The elevated concentration of PM2.5 may disproportionately affect individuals with immune deficiency, especially those with more severity. The findings would serve as justifications for future intervention design and policy making to alleviate air pollution and improve environmental justice and health equity.

Association of residential greenness, air pollution with adverse birth outcomes: Results from 61,762 mother‑neonatal pairs in project ELEFANT (2011-2021)

BACKGROUND

Emerging evidence has demonstrated the benefits of greenness exposure on human health, while conflicts remain unsolved in issue of adverse birth outcomes.

METHODS

Utilizing data from project ELEFANT spanning the years 2011 to 2021, we assessed residential greenness using the NDVI from MODIS data and residential PM2.5 exposure level from CHAP data. Our primary concerns were PTD, LBW, LGA, and SGA. Cox proportional hazard regression model was used to examine the association of residential greenness and air pollution exposure with risk of adverse birth outcomes. We performed mediation and modification effect analyses between greenness and air pollutant.

RESULTS

We identified 61,762 mother‑neonatal pairs in final analysis. For per 10 μg/m3 increase in PM2.5 concentration during entire pregnancy was associated with 19.8 % and 20.7 % increased risk of PTD and LGA. In contrast, we identified that an 0.1 unit increment in NDVI were associated with 24 %, 43 %, 26.5 %, and 39.5 % lower risk for PTD, LBW, LGA, and SGA, respectively. According to mediation analysis, NDVI mediated 7.70 % and 7.89 % of the associations between PM2.5 and PTD and LGA. Residential greenness could reduce the risk of PTD among mothers under 35 years old, living in rural areas, primigravidae and primiparity..

CONCLUSIONS

In summary, our results highlighted the potential of residential greenness to mitigate the risk of adverse birth outcomes, while also pointing to the adverse impact of PM2.5 on increased risk of multiple adverse birth outcomes (PTD and LGA). The significant mediation effect of NDVI emphasizes its potential as an important protective factor of PM2.5 exposure. Additionally, the identification of susceptible subgroups can inform targeted interventions to reduce adverse birth outcomes related to air pollution and lack of green spaces. Further research and understanding of these associations can contribute to better public health strategies aimed at promoting healthier pregnancies and birth outcomes.

Short-term effects of exposure to ambient PM2.5 and its components on hospital admissions for threatened and spontaneous abortions: A multicity case-crossover study in China

BACKGROUND

The adverse effects of short-term exposure to PM2.5 and its components on hospital admissions for threatened and spontaneous abortions (TSAB) are still controversial.

METHODS

Data on daily hospitalizations for TSAB and PM2.5 and its components, including sulfate (SO42-), nitrate (NO3-), ammonium salt (NH4+), organic matter (OM), and black carbon (BC), were collected from January 2015 to December 2021 (total 2,557 days) in five cities in China. Case-crossover analyses were conducted to investigate the short-term associations between PM2.5 and its components and TSAB. Additionally, the modification effects by age (<35 and ≥35 years), season (cold and warm seasons), and the "Three-Year Action Plan to Win the Blue Sky Defense War" (before and after implementation) on the above associations were further conducted.

RESULTS

For each 10 μg/m3 (1 μg/m3 for BC) increase, the strongest relative risks (95% confidence intervals) of hospitalization for TSAB were 1.011 (1.001-1.021) for PM2.5 in lag02, 1.060 (1.003-1.120) for SO42- in lag02, 1.035 (1.000-1.070) for NO3- in lag02, 1.065 (1.009-1.124) for NH4+ in lag02, 1.047 (1.008-1.088) for OM in lag01 and 1.029 (1.005-1.054) for BC in lag02 (all P <0.05). Furthermore, significant modifying effects of age and the Action Plan were found. The effects of NO3- (lag2), NH4+ (lag2), and BC (lag2) were more pronounced in mothers aged ≥35 years and the effects of PM2.5 (lag4), NO3- (lag4), NH4+ (lag4), OM (lag4), and BC (lag4) was more pronounced in the period before the Action Plan was implemented (all P modification <0.05).

CONCLUSION

Short-term exposure to ambient PM2.5 and its components (SO42-, NO3-, NH4+, OM, and BC) was related to increased risks of hospitalization for TSAB. The effects were more pronounced in mothers aged ≥35 years and the period before the Action Plan.

Adverse Health Impacts of Outdoor Air Pollution, Including from Wildland Fires, in the United States: "Health of the Air," 2018-2020

Rationale: Adverse health impacts from outdoor air pollution occur across the United States, but the magnitude of these impacts varies widely by geographic region. Ambient pollutant concentrations, emission sources, baseline health conditions, and population sizes and distributions are all important factors that need to be taken into account to quantify local health burdens. Objectives: To determine health impacts from ambient air pollution concentrations in the United States that exceed the levels recommended by the American Thoracic Society. Methods: Using a methodology that has been well established in previous "Health of the Air" reports, this study provides policy-relevant estimates for every monitored county and city in the United States for the adverse health impacts of outdoor pollution concentrations using U.S. Environmental Protection Agency design values for years 2018-2020. Additionally, for the first time, the report includes adverse birth outcomes as well as estimates of health impacts specifically attributable to wildland fires using an exposure dataset generated through Community Multiscale Air Quality simulations. Results: The adverse health burdens attributable to air pollution occur across the entire age spectrum, including adverse birth outcomes (10,660 preterm and/or low-weight births; 95% confidence interval [CI], 3,180-18,330), in addition to mortality impacts (21,300 avoidable deaths; 95% CI, 16,180-26,200), lung cancer incidence (3,000 new cases; 95% CI, 1,550-4,390), multiple types of cardiovascular and respiratory morbidity (748,660 events; 95% CI, 326,050-1,057,080), and adversely impacted days (52.4 million days; 95% CI, 7.9-92.4 million days). Two different estimates of mortality impacts from wildland fires were created based on assumptions regarding the underlying toxicity of particles from wildland fires (low estimate of 4,080 deaths, 95% CI, 240-7,890; middle estimate of 28,000 deaths, 95% CI, 27,300-28,700). Conclusions: This year's report identified sizable health benefits that would be expected to occur across the United States with compliance with more health-protective air quality standards such as those recommended by the American Thoracic Society. This study also indicates that a large number of excess deaths are attributable to emissions from wildland fires; air quality management strategies outside what is required by the Clean Air Act will be needed to best address this important source of air pollution and its associated health risks.

Exposure to ambient fine particulate matter components during pregnancy and early childhood and its association with asthma, allergies, and sensitization in school-age children

BACKGROUND

Exposure to fine particulate matter (PM2.5) has been associated with allergic diseases, including asthma. However, information about the effects of specific PM2.5 components is limited. This study aimed to investigate the relationship of exposure to chemical components of PM2.5 during pregnancy and early childhood with the development of asthma, allergies, and sensitization in school-age children.

METHODS

This study included 2,408 children in the second grade of elementary school. Questionnaire surveys of respiratory/allergic symptoms and measurements of serum total IgE and specific IgE levels to house dust mite (HDM) and animal proteins were conducted. Exposures to ambient PM2.5 mass, sulfate (SO42-), nitrate (NO3-), ammonium (NH4+), elemental carbon (EC), and organic carbon (OC) of PM2.5 in participants' residences from conception to age six were estimated using predictive models. Multiple logistic regression analysis was used to analyze the association of respiratory/allergic symptoms and allergen sensitization with estimated exposure concentrations, after adjustment for survey year, sex, season of birth, feeding method during infancy, presence of siblings, history of lower respiratory tract infection, use of childcare facilities, passive smoking, presence of pets, mother's age, history of allergic diseases, smoking during pregnancy, and annual household income.

RESULTS

No significant association was found between PM2.5 and its component concentrations and asthma. However, wheezing significantly increased with mean NO3- concentrations during pregnancy (odds ratio of 1.64 [95% confidence interval: 1.10, 2.47] for an interquartile range increase). Significant associations were also found between EC in the second trimester of pregnancy and PM2.5, NO3-, EC, and OC concentrations in early childhood. Higher PM2.5, SO4-, and NH4+ concentrations during the second trimester increased the risk of rhinitis. Sensitizations to HDM and animal proteins were significantly associated with exposure to components such as SO42- and NH4+ during pregnancy but not with postnatal exposure.

CONCLUSIONS

Exposures to NO3-, EC, and OC during pregnancy and early childhood were associated with wheezing. SO42- and NH4+ exposures during pregnancy were associated with sensitization to HDM and animal proteins. Asthma was not associated with exposure to PM2.5 and its main components at any period.

Estimating birthweight reduction attributable to maternal ozone exposure in low- and middle-income countries

The effect of O3 on birthweight in low- and middle-income countries (LMICs) remains unknown. A multicenter epidemiological study was conducted to evaluate the association between maternal peak-season O3 exposure and birthweight, using 697,148 singleton newborns obtained in 54 LMICs between 2003 and 2019. We estimated the birthweight reduction attributable to peak-season O3 exposure in 123 LMICs based on a nonlinear exposure-response function (ERF). With every 10-part per billion increment in O3 concentration, we found a reduction in birthweight of 19.9 g [95% confidence interval (CI): 14.8 to 24.9 g]. The nonlinear ERF had a monotonic decreasing curve, and no safe O3 exposure threshold was identified. The mean reduction in birthweight reduction attributable to O3 across the 123 LMICs was 43.8 g (95% CI: 30.5 to 54.3 g) in 2019. The reduction in O3-related birthweight was greatest in countries in South Asia, the Middle East, and North Africa. Effective O3 pollution control policies have the potential to substantially improve infant health.

Development of Spatio-Temporal Land Use Regression Models for Fine Particulate Matter and Wood-Burning Tracers in Temuco, Chile

Biomass burning is common in much of the world, and in some areas, residential wood-burning has increased. However, air pollution resulting from biomass burning is an important public health problem. A sampling campaign was carried out between May 2017 and July 2018 in over 64 sites in four sessions, to develop a spatio-temporal land use regression (LUR) model for fine particulate matter (PM) and wood-burning tracers levoglucosan and soluble potassium (Ksol) in a city heavily impacted by wood-burning. The mean (sd) was 46.5 (37.4) μg m-3 for PM2.5, 0.607 (0.538) μg m-3 for levoglucosan, and 0.635 (0.489) μg m-3 for Ksol. LUR models for PM2.5, levoglucosan, and Ksol had a satisfactory performance (LOSOCV R2), explaining 88.8%, 87.4%, and 87.3% of the total variance, respectively. All models included sociodemographic predictors consistent with the pattern of use of wood-burning in homes. The models were applied to predict concentrations surfaces and to estimate exposures for an epidemiological study.

PM2.5 pollution in Texas: a geospatial analysis of health impact functions

Background

Air pollution is the greatest environmental threat to human health in the world today and is responsible for an estimated 7-9 million deaths annually. One of the most damaging air pollutants is PM2.5 pollution, fine airborne particulate matter under 2.5 microns in diameter. Exposure to PM2.5 pollution can cause premature death, heart disease, lung cancer, stroke, diabetes, asthma, low birthweight, and IQ loss. To avoid these adverse health effects, the WHO recommends that PM2.5 levels not exceed 5 μg/m3.

Methods

This study estimates the negative health impacts of PM2.5 pollution in Texas in 2016. Local exposure estimates were calculated at the census tract level using the EPA's BenMAP-CE software. In BenMAP, a variety of exposure-response functions combine air pollution exposure data with population data and county-level disease and death data to estimate the number of health effects attributable to PM2.5 pollution for each census tract. The health effects investigated were mortality, low birthweight, stroke, new onset asthma, new onset Alzheimer's, and non-fatal lung cancer.

Findings

This study found that approximately 26.7 million (98.9%) of the 27.0 million people living in Texas in 2016 resided in areas where PM2.5 concentrations were above the WHO recommendation of 5 μg/m3, and that 2.6 million people (9.8%) lived in areas where the average PM2.5 concentration exceeded 10 μg/m3. This study estimates that there were 8,405 (confidence interval [CI], 5,674-11,033) premature deaths due to PM2.5 pollution in Texas in 2016, comprising 4.3% of all deaths. Statewide increases in air-pollution-related morbidity and mortality were seen for stroke (2,209 - CI: [576, 3,776]), low birthweight (2,841 - CI: [1,696, 3,925]), non-fatal lung cancers (636 - CI: [219, 980]), new onset Alzheimer's disease (24,575 - CI: [20,800, 27,540]), and new onset asthma (7,823 - CI: [7,557, 8,079]).

Conclusion

This study found that air pollution poses significant risks to the health of Texans, despite the fact that pollution levels across most of the state comply with the EPA standard for PM2.5 pollution of 12 μg/m3. Improving air quality in Texas could save thousands of lives from disease, disability, and premature death.

Quantifying the potential effects of air pollution reduction on population health and health expenditure in Taiwan

Air pollution, particularly ambient fine particulate matter (PM2.5) pollution, poses a significant risk to public health, underscoring the importance of comprehending the long-term impact on health burden and expenditure at national and subnational levels. Therefore, this study aims to quantify the disease burden and healthcare expenditure associated with PM2.5 exposure in Taiwan and assess the potential benefits of reducing pollution levels. Using a comparative risk assessment framework that integrates an auto-aggressive integrated moving average model, we evaluated the avoidable burden of cardiopulmonary diseases (including ischemic heart disease, stroke, chronic obstructive pulmonary disease, lung cancer, and diabetes mellitus) and related healthcare expenditure under different air quality target scenarios, including status quo and target scenarios of 15, 10, and 5 μg/m3 reduction in PM2.5 concentration. Our findings indicate that reducing PM2.5 exposure has the potential to significantly alleviate the burden of multiple diseases. Comparing the estimated attributable disease burden and healthcare expenditure between reference and target scenarios from 2022 to 2050, the avoidable disability-adjusted life years were 0.61, 1.83, and 3.19 million for the 15, 10, and 5 μg/m3 target scenarios, respectively. Correspondingly, avoidable healthcare expenditure ranged from US$ 0.63 to 3.67 billion. We also highlighted the unequal allocation of resources and the need for policy interventions to address health disparities due to air pollution. Notably, in the 5 μg/m3 target scenario, Kaohsiung City stands to benefit the most, with 527,368 disability-adjusted life years avoided and US$ 0.53 billion saved from 2022 to 2050. Our findings suggest that adopting stricter emission targets can effectively reduce the health burden and associated healthcare expenditure in Taiwan. Overall, this study provides policymakers in Taiwan with valuable insights for mitigating the negative effects of air pollution by establishing a comprehensive framework for evaluating the co-benefits of air pollution reduction on healthcare expenditure and disease burden.

Transcriptome sequencing analysis reveals a potential role of lncRNA NONMMUT058932.2 and NONMMUT029203.2 in abnormal myelin development of male offspring following prenatal PM2.5 exposure

Numerous epidemiological studies have shown that PM2.5 exposure in early life can influence brain development and increase the risk of neurodevelopmental disorders in boys, but the underlying molecular mechanisms remain unclear. In the current study, pregnant C57BL/6 J mice were oropharyngeally administered with PM2.5 suspension (3mg/kg/2 days) until the birth of offspring. Based on mRNA expression profiles, two-way analysis of variance (two-way ANOVA) and weighted gene co-expression network analysis (WGCNA) were conducted to explore the most impacted neurodevelopmental processes in male offspring and the most significantly associated gene modules. Gene Ontology (GO) enrichment and Encyclopedia of Genes and Genomes (KEGG) pathway analyses suggested that prenatal PM2.5 exposure significantly altered several biological processes (such as substrate adhesion-dependent cell spreading, myelination, and ensheathment of neurons) and KEGG pathways (such as tight junction and axon guidance). We further found that PM2.5 exposure significantly changed the expression of myelination-related genes in male offspring during postnatal development and impaired myelin ultrastructure on PNDs 14 and 21, as demonstrated by the decreased thickness of myelin sheaths in the optic nerves, and mild loss of myelin in the corpus callosum. Importantly, lncRNA NONMMUT058932.2 and NONMMUT029203.2 played key roles in abnormal myelination by regulating the expression of several myelination-related genes (Fa2h, Mal, Sh3tc2, Trf and Tppp) through the binding to transcription factor Ctcf. Our work provides genomic evidence for prenatal PM2.5 exposure-induced neurodevelopmental disorders in male offspring.

Ambient fine particulate matter and pregnancy outcomes: An umbrella review

The available evidence on the effects of ambient fine particulate matter (PM2.5) and pregnancy outcomes (birth outcomes and pregnancy complications) has increased substantially. The purpose of this umbrella review is to refine the evidence of the association between birth outcome (birth defects) and PM2.5; and summarize the credibility of existing research on the association between pregnancy complications and PM2.5. We searched PubMed, Web of Science, Embase, and Cochrane databases for relevant systematic reviews and meta-analyses up to March 16, 2022 in accordance with PRISMA guidelines. Two independent investigators conducted data extraction. AMSTAR 2 and GRADE assessment criteria were used to evaluate the methodological and evidence quality. We performed subgroup analyses by trimesters of pregnancy. The review protocol for this study has been registered in PROSPERO (CRD42022325550). This umbrella review identified a total of 41 systematic reviews, including 28 articles evaluating the influence of PM2.5 on birth outcomes and 13 on pregnancy complications. Positive associations between perinatal PM2.5 exposure and adverse birth outcomes were found, including low birth weight, preterm birth, stillbirth, small for gestational age, and birth defects. Pregnant women exposed to PM2.5 had a significantly higher risk of developing hypertensive disorder of pregnancy, gestational diabetes mellitus, gestational hypertension, and preeclampsia. The findings of subgroup analysis demonstrated that the effects of ambient PM2.5 exposure on pregnancy outcomes varied by trimesters. The findings of this extensive umbrella review provide convincing proof that exposure to ambient PM2.5 raises the risks of unfavorable birth outcomes and pregnancy complications. Some associations show considerable disparity between trimesters. These findings have implications for strengthen perinatal health care on air pollution and improving intergenerational equity.

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

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

PM2.5 leads to adverse pregnancy outcomes by inducing trophoblast oxidative stress and mitochondrial apoptosis via KLF9/CYP1A1 transcriptional axis

Epidemiological studies have demonstrated that fine particulate matter (PM2.5) is associated with adverse obstetric and postnatal metabolic health outcomes, but the mechanism remains unclear. This study aimed to investigate the toxicological pathways by which PM2.5 damaged placental trophoblasts in vivo and in vitro. We confirmed that PM2.5 induced adverse gestational outcomes such as increased fetal mortality rates, decreased fetal numbers and weight, damaged placental structure, and increased apoptosis of trophoblasts. Additionally, PM2.5 induced dysfunction of the trophoblast cell line HTR8/SVneo, including in its proliferation, apoptosis, invasion, migration and angiogenesis. Moreover, we comprehensively analyzed the transcriptional landscape of HTR8/SVneo cells exposed to PM2.5 through RNA-Seq and observed that PM2.5 triggered overexpression of pathways involved in oxidative stress and mitochondrial apoptosis to damage HTR8/SVneo cell biological functions through CYP1A1. Mechanistically, PM2.5 stimulated KLF9, a transcription factor identified as binding to CYP1A1 promoter region, which further modulated the CYP1A1-driven downstream phenotypes. Together, this study demonstrated that the KLF9/CYP1A1 axis played a crucial role in the toxic progression of PM2.5 induced adverse pregnancy outcomes, suggesting adverse effects of environmental pollution on pregnant females and putative targeted therapeutic strategies.

Climate Change, Air Quality, and Pulmonary Health Disparities

Climate change will alter environmental risks that influence pulmonary health, including heat, air pollution, and pollen. These exposures disproportionately burden populations already at risk of ill health, including those at vulnerable life stages, with low socioeconomic status, and systematically targeted by oppressive policies. Climate change can exacerbate existing environmental injustices by affecting future exposure, as well as through differentials in the ability to adapt; this is compounded by disparities in rates of underlying disease and access to health care. Climate change is therefore a dire threat not only to individual and population health but also to health equity.

Association of Fine Particulate Matter and Its Components with Macrosomia: A Nationwide Birth Cohort Study of 336 Chinese Cities

To examine the associations between macrosomia risk and exposure to fine particulate matter (PM2.5) and its chemical components during pregnancy, we collected birth records between 2010 and 2015 in mainland China from the National Free Preconception Health Examination Project and used satellite-based models to estimate concentrations of PM2.5 mass and five main components, namely, black carbon (BC), organic carbon (OC), nitrate (NO3-), sulfate (SO42-), and ammonium (NH4+). Associations between macrosomia risk and prenatal exposure to PM2.5 were examined by logistic regression analysis, and the sensitive subgroups were explored by stratified analyses. Of the 3,248,263 singleton newborns from 336 cities, 165,119 (5.1%) had macrosomia. Each interquartile range increase in concentration of PM2.5 during the entire pregnancy was associated with increased risk of macrosomia (odds ratio (OR) = 1.18; 95% confidence interval (CI), 1.17-1.20). Among specific components, the largest effect estimates were found on NO3- (OR = 1.36; 95% CI, 1.35-1.38) followed by OC (OR = 1.23; 95% CI, 1.22-1.24), NH4+ (OR = 1.22; 95% CI, 1.21-1.23), and BC (OR = 1.21; 95% CI, 1.20-1.22). We also that found boys, women with a normal or lower prepregnancy body mass index, and women with irregular or no folic acid supplementation experienced higher risk of macrosomia associated with PM2.5 exposure.

Does air pollution exposure affect semen quality? Evidence from a systematic review and meta-analysis of 93,996 Chinese men

Background

Air pollution may impair male fertility, but it remains controversial whether air pollution affects semen quality until now.

Objectives

We undertake a meta-analysis to explore potential impacts of six pollutants exposure during the entire window (0-90 days prior to ejaculation) and critical windows (0-9, 10-14, and 70-90 days prior to ejaculation) on semen quality.

Methods

Seven databases were retrieved for original studies on the effects of six pollutants exposure for 90 days prior to ejaculation on semen quality. The search process does not limit the language and search date. We only included original studies that reported regression coefficients (β) with 95% confidence intervals (CIs). The β and 95% CIs were pooled using the DerSimonian-Laird random effect models.

Results

PM2.5 exposure was related with decreased total sperm number (10-14 lag days) and total motility (10-14, 70-90, and 0-90 lag days). PM10 exposure was related with reduced total sperm number (70-90 and 0-90 lag days) and total motility (0-90 lag days). NO2 exposure was related with reduced total sperm number (70-90 and 0-90 lag days). SO2 exposure was related with declined total motility (0-9, 10-14, 0-90 lag days) and total sperm number (0-90 lag days).

Conclusion

Air pollution affects semen quality making it necessary to limit exposure to air pollution for Chinese men. When implementing protective measures, it is necessary to consider the key period of sperm development.

Spatial Patterns of Gallbladder and Biliary Tract Carcinoma in China From 1990 to 2019: An Analysis at the Provincial Level

Background Despite a high rate of fatal malignancy, little is known regarding the spatial and temporal patterns of the disease burden of gallbladder and biliary tract carcinoma in China, especially at the provincial level. Methodology Using data from the 2019 Global Burden of Diseases, Injuries, and Risk Factors Study, we estimated the temporal trend of the disease burden of gallbladder and biliary tract carcinoma from 1990 to 2019 as well as its incidence, mortality, prevalence, and disability-adjusted life-years (DALYs). We estimated the spatial pattern of the disease burden of gallbladder and biliary tract carcinoma at the provincial level. Results The disease burden of gallbladder and biliary tract carcinoma significantly increased from 1990 to 2019 in China. The age-standardized incidence, prevalence, mortality, and DALYs increased by 28.3%, 50.5%, 13.0%, and 7.0%, respectively. The disease burden of gallbladder carcinoma revealed substantial heterogeneity at the provincial level with a higher disease burden in developed provinces or cities than in developing provinces. The disease burden of gallbladder and biliary tract carcinoma was also heavier among males than among females (e.g., age-standardized DALYs: 42.60 per 100,000 people among males vs. 33.57 per 100,000 people among females in 2019). Conclusions The disease burden of gallbladder and biliary tract carcinoma has shown rapid changes during the past three decades, with a higher burden in economically advantaged regions than in disadvantaged regions in China. New public health policies and initiatives are needed to address this rising disease burden.

Impact of ambient temperature on adverse pregnancy outcomes: a birth cohort study in Fuzhou, China

Background

Previous studies have identified a series of specific adverse pregnancy outcomes (APOs) linked with temperature extremes. Most of them focus on preterm birth, low birth weight, and stillbirth. Other possible adverse outcomes were under-researched. This study aimed to investigate the impact of ambient temperature on maternal complications, white blood cell count (WBC), newborn hearing, and neonatal jaundice.

Methods

A total of 418 participants were recruited from Fuzhou Maternity & Child Healthcare Hospital in 2016. Participants were invited to fill out a structured questionnaire. The gridded near-surface air temperatures at a resolution of 0.1°* 0.1° for Fuzhou were extracted from a published dataset. Meteorological data and PM2.5 were extracted based on participants' residential addresses using R packages "ncdf4" and "raster." Multivariate logistic regression models were used to quantify the effects of ambient temperature on APOs after controlling for confounders.

Results

Overall, there were 107 APOs, accounting for 25.6% of all participants. Every 1°C increase in mean temperature was associated with a 10.0% increase in APOs (aOR = 1.100, 95%CI 1.006-1.203) during the period of early pregnancy. However, negative associations were observed in the middle pregnancy period, and a 1°C increase in mean temperature was associated 8.8% decrease in APOs (aOR = 0.912, 95%CI 0.846-0.982). Diurnal temperature variation had a significant impact on APOs in the third trimester. Infant jaundice was negatively associated with temperature exposure in the middle and late pregnancy periods. The risk of neonatal jaundice increased at lag weeks 2-9 in the first trimester, with the greatest lagged effect (aOR = 1.201, 95%CI 1.020-1.413) observed at lag week 3. A 1°C increase in mean temperature led to a 29.6% (aOR = 1.296, 95%CI 1.019-1.649) increase in high WBC. A 1°C increase in temperature variation was associated with more than two times (aOR = 2.469, 95%CI 1.001-6.089) increase of high WBC in the first trimester and about five times (aOR = 4.724, 95%CI 1.548-14.409) increase in the third trimester.

Conclusion

Ambient temperature affects neonatal jaundice, newborn hearing loss, and infections during pregnancy. In addition to the identified epidemiologic link and susceptible exposure windows, there is a need to understand the underlying biological mechanisms for better recommendations for climate change adaptation policies.

Prebirth effects of climate change on children's respiratory health

PURPOSE OF REVIEW

To date, there is no evidence that humanity will implement appropriate mitigation measures to avoid the catastrophic impact of climate change on the planet and human health. Vulnerable populations such as pregnant women and children will be the most affected. This review highlights epidemiologic data on climate change-related prenatal environmental exposures affecting the fetus and children's respiratory health.

RECENT FINDINGS

Research on outcomes of prenatal exposure to climate change-related environmental changes and pediatric pulmonary health is limited. In addition to adverse pregnancy outcomes known to affect lung development, changes in lung function, increased prevalence of wheezing, atopy, and respiratory infections have been associated with prenatal exposure to increased temperatures, air pollution, and maternal stress. The mechanisms behind these changes are ill-defined, although oxidative stress, impaired placental functioning, and epigenetic modifications have been observed. However, the long-term impact of these changes remains unknown.

SUMMARY

The detrimental impact of the climate crisis on pediatric respiratory health begins before birth, highlighting the inherent vulnerability of pregnant women and children. Research and advocacy, along with mitigation and adaptation measures, must be implemented to protect pregnant women and children, the most affected but the least responsible for the climate crisis.

Air pollution and child health impacts of decarbonization in 16 global cities: Modelling study

Most research on the air pollution-related health effects of decarbonization has focused on adults. We assess the potential health benefits that could be achieved in children and young people in a global sample of 16 cities through global decarbonization actions. We modelled annual average concentrations of fine particulate matter (PM_2.5) and nitrogen dioxide (NO₂) at 1x1 km resolution in the cities using a general circulation/atmospheric chemistry model assuming removal of all global combustion-related emissions from land transport, industries, domestic energy use and power generation. We modelled the impact on childhood asthma incidence and adverse birth outcomes (low birthweight, pre-term births) using published exposure-response relationships. Removal of combustion emissions was estimated to decrease annual average PM_2.5 by between 2.9 μg/m³ (8.4%) in Freetown and 45.4 μg/m³ (63.7%) in Dhaka. For NO₂, the range was from 0.3 ppb (7.9%) in Freetown to 18.8 ppb (92.3%) in Mexico City. Estimated reductions in asthma incidence ranged from close to zero in Freetown, Tamale and Harare to 149 cases per 100,000 population in Los Angeles. For pre-term birth, modelled impacts ranged from a reduction of 135 per 100,000 births in Dar es Salaam to 2,818 per 100,000 births in Bhubaneswar and, for low birthweight, from 75 per 100,000 births in Dar es Salaam to 2,951 per 100,000 births in Dhaka. The large variations chiefly reflect differences in the magnitudes of air pollution reductions and estimated underlying disease rates. Across the 16 cities, the reduction in childhood asthma incidence represents more than one-fifth of the current burden, and an almost 10% reduction in pre-term and low birthweight births. Decarbonization actions that remove combustion-related emissions contributing to ambient PM_2.5 and NO₂ would likely lead to substantial but geographically-varied reductions in childhood asthma and adverse birth outcomes, though there are uncertainties in causality and the precision of estimates.

Critical review on emerging health effects associated with the indoor air quality and its sustainable management

Indoor air quality (IAQ) is one of the fundamental elements affecting people's health and well-being. Currently, there is a lack of awareness among people about the quantification, identification, and possible health effects of IAQ. Airborne pollutants such as volatile organic compounds (VOCs), particulate matter (PM), sulfur dioxide (SO2), carbon monoxide (CO), nitrous oxide (NO), polycyclic aromatic hydrocarbons (PAHs) microbial spores, pollen, allergens, etc. primarily contribute to IAQ deterioration. This review discusses the sources of major indoor air pollutants, molecular toxicity mechanisms, and their effects on cardiovascular, ocular, neurological, women, and foetal health. Additionally, contemporary strategies and sustainable methods for regulating and reducing pollutant concentrations are emphasized, and current initiatives to address and enhance IAQ are explored, along with their unique advantages and potentials. Due to their longer exposure times and particular physical characteristics, women and children are more at risk for poor indoor air quality. By triggering many toxicity mechanisms, including oxidative stress, DNA methylation, epigenetic modifications, and gene activation, indoor air pollution can cause a range of health issues. Low birth weight, acute lower respiratory tract infections, Sick building syndromes (SBS), and early death are more prevalent in exposed residents. On the other hand, the main causes of incapacity and early mortality are lung cancer, chronic obstructive pulmonary disease, and cardiovascular disorders. It's crucial to acknowledge anticipated research needs and implemented efficient interventions and policies to lower health hazards.

Global, regional, and national burden of preterm birth attributable to ambient and household PM2.5 from 1990 to 2019: Worsening or improving?

BACKGROUND

Maternal exposure to fine particular matter (PM_2.5) during pregnancy, including ambient and household PM_2.5, has been linked with increased risk of preterm birth (PTB). However, the global spatio-temporal distribution of PTB-related deaths and disability-adjusted life years (DALYs) attributable to PM_2.5 is not well documented. We estimated the global, regional, and national patterns and trends of PTB burden attributable to both ambient and household PM_2.5 from 1990 to 2019.

METHODS

Based on the Global Burden of Disease Study (GBD) 2019 database, we obtained the numbers of deaths and DALYs as well as age-standardized mortality rate (ASMR) and age-standardized DALY rate (ASDR) of PTB attributable to total, ambient, and household PM_2.5 by socio-demographic index (SDI) and sex during 1990-2019. The average annual percentage changes (AAPCs) were calculated to assess the temporal trends of attributable burdens.

RESULTS

In 2019, 126,752 deaths and 11.3 million DALYs related to PTB worldwide (two-thirds in Western Sub-Saharan Africa and South Asia) could be caused by excess PM_2.5 above the theoretical minimum-risk exposure level (TMREL), of which 39 % and 61 % were attributable to ambient PM_2.5 and household PM_2.5, respectively. From 1990 to 2019, the global ASMR due to ambient PM_2.5 increased slightly by 7.08 % whereas that due to household PM_2.5 decreased substantially by 58.81 %, although the latter still dominated the attributable PTB burden, especially in low and low-middle SDI regions. Similar results were also observed for ASDRs. In addition, PTB burden due to PM_2.5 was higher in male infants and in lower SDI regions.

CONCLUSIONS

Globally in 2019, PM_2.5 remains a great concern on the PTB burden, especially in Western Sub-Saharan Africa and South Asia. Between 1990 and 2019, age-standardized burden of PTB due to ambient PM_2.5 increased globally, while that due to household PM_2.5 decreased markedly but still dominated in low and low-middle SDI regions.

Exposure-lag response of fine particulate matter on intrauterine fetal death: an analysis using a distributed lag non-linear model in Linxia Hui Autonomous Prefecture, China

The results of studies on intrauterine fetal death (IUFD) caused by exposure to fine particulate matter (PM_2.5) during pregnancy are inconsistent. Further exploration of the dose-response relationship and exposure window is required. We aimed to provide a reference for policy formulation by estimating the exposure-lag relationship of PM_2.5 on IUFD and looking for sensitive exposure windows. IUFD data was obtained from China Children Under 5 Death Surveillance Network in Linxia Hui Autonomous Prefecture from 2016 to 2020. Air pollution data and temperature data were obtained from ambient air monitoring stations and China Meteorological Data Network, respectively. The moving average is used to describe the trend and seasonality of PM_2.5 exposure; the distributed lag non-linear model (DLNM) is used to estimate the exposure-lag effect; the sandwich estimators are used to correct the variance-covariance matrix; and the model selected by Akaike's Information Criterion (AIC) finally adjusts gender, temperature, and district. About 180,622 infants were enrolled in the study, including 952 IUFDs (5.27‰). The median of PM_2.5 exposure is 34.08 μg/m³. There is an exposure-lag effect of PM_2.5 on IUFD approximate to a wavy shape; the concentration with effect is 40-90 μg/m³; and the sensitive lag time is 1, 2, 3, 8, 9, and 10 months. The maximum RR value of the exposure-lag effect of PM_2.5 on IUFD is 1.61 [95% CI 1.19, 2.19], in which the concentration of PM_2.5 is 62 μg/m³, and the lag month is 9 months. In the case of less than 6 months lag, the maximum RR value of the exposure-lag effect of PM_2.5 on IUFD is 1.43 [95% CI 1.24, 1.67], in which the concentration of PM_2.5 is 73 μg/m³, and the lag month is 3 months. Exposure to PM_2.5 concentrations above 40 μg/m³ may increase the risk of IUFD, especially in the first and third trimesters.

Aerosol physicochemical determinants of carbon black and ozone inhalation co-exposure induced pulmonary toxicity

Air pollution accounts for more than 7 million premature deaths worldwide. Using ultrafine carbon black (CB) and ozone (O3) as a model for an environmental co-exposure scenario, the dose response relationships in acute pulmonary injury and inflammation were determined by generating, characterizing, and comparing stable concentrations of CB aerosols (2.5, 5.0, 10.0 mg/m3), O3 (0.5, 1.0, 2.0 ppm) with mixture CB + O3 (2.5 + 0.5, 5.0 + 1.0, 10.0 + 2.0). C57BL6 male mice were exposed for 3 h by whole body inhalation and acute toxicity determined after 24 h. CB itself did not cause any alteration, however, a dose response in pulmonary injury/inflammation was observed with O3 and CB + O3. This increase in response with mixtures was not dependent on the uptake but was due to enhanced reactivity of the particles. Benchmark dose modeling showed several-fold increase in potency with CB + O3 compared with CB or O3 alone. Principal component analysis provided insight into response relationships between various doses and treatments. There was a significant correlation in lung responses with charge-based size distribution, total/alveolar deposition, oxidant generation, and antioxidant depletion potential. Lung tissue gene/protein response demonstrated distinct patterns that are better predicted by either particle dose/aerosol responses (interleukin-1β, keratinocyte chemoattractant, transforming growth factor beta) or particle reactivity (thymic stromal lymphopoietin, interleukin-13, interleukin-6). Hierarchical clustering showed a distinct signature with high dose and a similarity in mRNA expression pattern of low and medium doses of CB + O3. In conclusion, we demonstrate that the biological outcomes from CB + O3 co-exposure are significantly greater than individual exposures over a range of aerosol concentrations and aerosol characteristics can predict biological outcome.

Ambient fine particulate matter exposures and oxidative protein damage in early pregnant women

The association between oxidative protein damage in early pregnant women and ambient fine particulate matter (PM_2.5) is unknown. We estimated the effect of PM_2.5 exposures within seven days before blood collection on serum 3-nitrotyrosine (3-NT) and advanced oxidation protein products (AOPP) in 100 women with normal early pregnancy (NEP) and 100 women with clinically recognized early pregnancy loss (CREPL). Temporally-adjusted land use regression model was applied for estimation of maternal daily PM_2.5 exposure. Daily nitrogen dioxide (NO₂) exposure of each participant was estimated using city-level concentrations of NO₂. Single-day lag effect of PM_2.5 was analyzed using multivariable linear regression model. Net cumulative effect and distributed lag effect of PM_2.5 and NO₂ within seven days were analyzed using distributed lag non-linear model. In all 200 subjects, the serum 3-NT were significantly increased with the single-day lag effects (4.72%-8.04% increased at lag 0-2), distributed lag effects (2.32%-3.49% increased at lag 0-2), and cumulative effect within seven days (16.91% increased). The single-day lag effects (7.41%-10.48% increased at lag 0-1), distributed lag effects (3.42%-5.52% increased at lag 0-2), and cumulative effect within seven days (24.51% increased) of PM_2.5 significantly increased serum 3-NT in CREPL group but not in NEP group. The distributed lag effects (2.62%-4.54% increased at lag 0-2) and cumulative effect within seven days (20.25% increased) of PM_2.5 significantly increased serum AOPP in early pregnant women before the coronavirus disease (COVID-19) pandemic but not after that, similarly to the effects of NO₂ exposures. In conclusion, PM_2.5 exposures were associated with oxidative stress to protein in pregnant women in the first trimester, especially in CREPL women. Analysis of NO₂ exposures suggested that combustion PM_2.5 was the crucial PM_2.5 component. Wearing masks may be potentially preventive in PM_2.5 exposure and its related oxidative protein damage.

The association between ambient particulate matter exposure and the telomere-mitochondrial axis of aging in newborns

BACKGROUND

Particulate matter (PM) is associated with aging markers at birth, including telomeres and mitochondria. It is unclear whether markers of the core-axis of aging, i.e. tumor suppressor p53 (p53) and peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1α), are associated with prenatal air pollution and whether there are underlying mechanisms.

METHODS

556 mother-newborn pairs from the ENVIRONAGE birth cohort were recruited at the East Limburg Hospital in Genk (Belgium). In placenta and cord blood, telomere length (TL) and mitochondrial DNA content (mtDNAc) were measured using quantitative real-time polymerase chain reaction (qPCR). In cord plasma, p53 and PGC-1α protein levels were measured using ELISA. Daily ambient PM_2.5 concentrations during gestation were calculated using a spatial temporal interpolation model. Distributed lag models (DLMs) were applied to assess the association between prenatal PM_2.5 exposure and each molecular marker. Mediation analysis was performed to test for underlying mechanisms.

RESULTS

A 5 µg/m³ increment in PM_2.5 exposure was associated with -11.23 % (95 % CI: -17.36 % to -4.65 %, p = 0.0012) and -7.34 % (95 % CI: -11.56 % to -2.92 %, p = 0.0014) lower placental TL during the entire pregnancy and second trimester respectively, and with -12.96 % (95 % CI: -18.84 % to -6.64 %, p < 0.001) lower placental mtDNAc during the third trimester. Furthermore, PM_2.5 exposure was associated with a 12.42 % (95 % CI: -1.07 % to 27.74 %, p = 0.059) higher cord plasma p53 protein level and a -3.69 % (95 % CI: -6.97 % to -0.31 %, p = 0.033) lower cord plasma PGC-1α protein level during the third trimester. Placental TL mediated 65 % of the negative and 17 % of the positive association between PM_2.5 and placental mtDNAc and cord plasma p53 protein levels, respectively.

CONCLUSION

Ambient PM_2.5 exposure during pregnancy is associated with markers of the core-axis of aging, with TL as a mediating factor. This study strengthens the hypothesis of the air pollution induced core-axis of aging, and may unravel a possible underlying mediating mechanism in an early-life epidemiological context.

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

Introduction

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

Methods

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

Results

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

Conclusion

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

Association of ambient air pollution exposure with low birth weight

Increasing evidence has shown that exposure to air pollution is linked to adverse birth outcomes, but the results are not consistent. This study was performed on a subset of participants from the UK Biobank between 2006 and 2010. The land use regression (LUR) model was constructed to calculate the concentrations of particulate matter (PM2.5, PM2.5-10 and PM10), nitrogen oxides (NOx), and nitrogen dioxide (NO2). Binary logistic/multivariate linear regression models were applied to explore the potential linear relationships between air pollution exposure and newborn low birth weight (LBW) or BW. The Cochran-Armitage trend test was used to explore the possible association between the air pollution level and LBW. A restricted cubic spline (RCS) transformation of exposure variables was applied to visualize the relation of air pollutants to BW. Exposure to air pollutants, especially PM2.5 and PM10, was positively associated with LBW, and the odds ratios (ORs) and 95% confidence intervals (CIs) for each 10-μg/m3 increase in PM2.5 and PM10 were 1.25 ([1.03, 1.51], P = 0.025) and 1.12 ([1.02, 1.24], P = 0.021), respectively. A negative correlation was observed between the BW and PM2.5 (-0.05 [-0.08, -0.02], P = 0.001), PM10 (-0.03 [-0.05, -0.02], P < 0.001), PM2.5-10 (-0.04 [-0.07, -0.01], P < 0.001) and NOx (0.00 [0.00, 0.00], P = 0.021). Additionally, the BW changed dramatically up to a specific point (PM2.5 for 10.74 μg/m3, Pnonlinearity = 0.004; PM10 for 16.06 μg/m3, Pnonlinearity = 0.004; NO2 for 25.58 μg/m3, Pnonlinearity <0.001; and NOx for 39.88 μg/m3, Pnonlinearity <0.001), subsequently becoming relatively stable. PM2.5 and PM10 exposure were positively associated with LBW, and a negative correlation was observed between PM2.5, PM2.5-10, PM10 and NOx and BW.

Airway pollution and smoking in reproductive health

Environmental exposure refers to contact with chemical, biological, or physical substances found in air, water, food, or soil that may have a harmful effect on a person's health. Almost all of the global population (99%) breathe air that contains high levels of pollutants. Smoking is one of the most common forms of recreational drug use and is the leading preventable cause of morbidity and mortality worldwide. The small particles from either ambient (outdoor) pollution or cigarette smoke are inhaled to the lungs and quickly absorbed into the bloodstream. These substances can affect virtually every organ in our body and have been associated with various respiratory, cardiovascular, endocrine, and also reproductive morbidities, including decreased fertility, adverse pregnancy outcomes, and offspring long-term morbidity. This review summarizes the latest literature reporting the reproductive consequences of women exposed to ambient (outdoor) air pollution and cigarette smoking.

Prenatal Exposure to Ambient PM2.5 and Early Childhood Growth Impairment Risk in East Africa

Height for age is an important and widely used population-level indicator of children's health. Morbidity trends show that stunting in young children is a significant public health concern. Recent studies point to environmental factors as an understudied area of child growth failure in Africa. Data on child measurements of height-for-age and confounders were obtained from fifteen waves of the Demographic and Health Surveys (DHS) for six countries in East Africa. Monthly ambient PM_2.5 concentration data was retrieved from the Atmospheric Composition Analysis Group (ACAG) global surface PM_2.5 estimates and spatially integrated with DHS data. Generalized additive models with linear and logistic regression were used to estimate the exposure-response relationship between prenatal PM_2.5 and height-for-age and stunting among children under five in East Africa (EA). Fully adjusted models showed that for each 10 µg/m³ increase in PM_2.5 concentration there is a 0.069 (CI: 0.097, 0.041) standard deviation decrease in height-for-age and 9% higher odds of being stunted. Our study identified ambient PM_2.5 as an environmental risk factor for lower height-for-age among young children in EA. This underscores the need to address emissions of harmful air pollutants in EA as adverse health effects are attributable to ambient PM_2.5 air pollution.

Liquefied Petroleum Gas or Biomass for Cooking and Effects on Birth Weight

BACKGROUND

Exposure during pregnancy to household air pollution caused by the burning of solid biomass fuel is associated with adverse health outcomes, including low birth weight. Whether the replacement of a biomass cookstove with a liquefied petroleum gas (LPG) cookstove would result in an increase in birth weight is unclear.

METHODS

We performed a randomized, controlled trial involving pregnant women (18 to <35 years of age and at 9 to <20 weeks' gestation as confirmed on ultrasonography) in Guatemala, India, Peru, and Rwanda. The women were assigned in a 1:1 ratio to use a free LPG cookstove and fuel (intervention group) or to continue using a biomass cookstove (control group). Birth weight, one of four prespecified primary outcomes, was the primary outcome for this report; data for the other three outcomes are not yet available. Birth weight was measured within 24 hours after birth. In addition, 24-hour personal exposures to fine particulate matter (particles with a diameter of ≤2.5 μm [PM2.5]), black carbon, and carbon monoxide were measured at baseline and twice during pregnancy.

RESULTS

A total of 3200 women underwent randomization; 1593 were assigned to the intervention group, and 1607 to the control group. Uptake of the intervention was nearly complete, with traditional biomass cookstoves being used at a median rate of less than 1 day per month. After randomization, the median 24-hour personal exposure to fine particulate matter was 23.9 μg per cubic meter in the intervention group and 70.7 μg per cubic meter in the control group. Among 3061 live births, a valid birth weight was available for 94.9% of the infants born to women in the intervention group and for 92.7% of infants born to those in the control group. The mean (±SD) birth weight was 2921±474.3 g in the intervention group and 2898±467.9 g in the control group, for an adjusted mean difference of 19.6 g (95% confidence interval, -10.1 to 49.2).

CONCLUSIONS

The birth weight of infants did not differ significantly between those born to women who used LPG cookstoves and those born to women who used biomass cookstoves. (Funded by the National Institutes of Health and the Bill and Melinda Gates Foundation; HAPIN ClinicalTrials.gov number, NCT02944682.).

The Potential Role of PPARs in the Fetal Origins of Adult Disease

The fetal origins of adult disease (FOAD) hypothesis holds that events during early development have a profound impact on one’s risk for the development of future adult disease. Studies from humans and animals have demonstrated that many diseases can begin in childhood and are caused by a variety of early life traumas, including maternal malnutrition, maternal disease conditions, lifestyle changes, exposure to toxins/chemicals, improper medication during pregnancy, and so on. Recently, the roles of Peroxisome proliferator-activated receptors (PPARs) in FOAD have been increasingly appreciated due to their wide variety of biological actions. PPARs are members of the nuclear hormone receptor subfamily, consisting of three distinct subtypes: PPARα, β/δ, and γ, highly expressed in the reproductive tissues. By controlling the maturation of the oocyte, ovulation, implantation of the embryo, development of the placenta, and male fertility, the PPARs play a crucial role in the transition from embryo to fetus in developing mammals. Exposure to adverse events in early life exerts a profound influence on the methylation pattern of PPARs in offspring organs, which can affect development and health throughout the life course, and even across generations. In this review, we summarize the latest research on PPARs in the area of FOAD, highlight the important role of PPARs in FOAD, and provide a potential strategy for early prevention of FOAD.

Deaths attributable to anomalous temperature: A generalizable metric for the health impact of global warming

The U-shaped association between health outcomes and ambient temperatures has been extensively investigated. However, such analyses cannot fully estimate the mortality burden of climate change because the features of the association (e.g., minimum mortality temperature) vary with human adaptation; thus, they are not generalizable to different locations. In this study, we assumed that humans could adapt to regular temperature variations; and thus examined the all-cause mortality attributable to temperature anomaly (TA), an indicator widely utilized in climate science to measure irregular temperature fluctuations, across 115 cities in the United States (US). We first used quasi-Poisson regressions to obtain the city-specific TA-mortality associations, then used meta-regression to pool these city-specific estimates. Finally, we calculated the number of TA-related deaths using the uniform pooled association, then compared it to the estimates from city-specific associations, which had been controlled for adaptation. Meta-regression showed a U-shaped TA-mortality association, centered at a TA near 0. According to the pooled association, 0.579 % (95 % confidence interval [CI]: 0.465-0.681 %), 0.394 % (95 % CI: 0.332-0.451 %), and 0.185 % (95 % CI: 0.107-0.254 %) of all-cause deaths were attributable to all anomalous temperatures (TA ≠ 0), anomalous heat (TA > 0), and anomalous cold (TA < 0), respectively. At the city level, heat-related deaths estimated from the pooled association were in good agreement with heat-related deaths estimated from the city-specific associations (R² = 0.84). However, the cold-related deaths estimated from the two methods showed a weaker correlation (R² = 0.07). Our findings suggest that TA constitutes a generalizable indicator that can uniformly evaluate deaths attributable to anomalous heat in distinct geographical locations.

Health burden and economic loss attributable to ambient PM2.5 in Iran based on the ground and satellite data

We estimated mortality and economic loss attributable to PM_2·5 air pollution exposure in 429 counties of Iran in 2018. Ambient PM_2.5-related deaths were estimated using the Global Exposure Mortality Model (GEMM). According to the ground-monitored and satellite-based PM_2.5 data, the annual mean population-weighted PM_2·5 concentrations for Iran were 30.1 and 38.6 μg m^-3, respectively. We estimated that long-term exposure to ambient PM_2.5 contributed to 49,303 (95% confidence interval (CI) 40,914-57,379) deaths in adults ≥ 25 yr. from all-natural causes based on ground monitored data and 58,873 (95% CI 49,024-68,287) deaths using satellite-based models for PM_2.5. The crude death rate and the age-standardized death rate per 100,000 population for age group ≥ 25 year due to ground-monitored PM_2.5 data versus satellite-based exposure estimates was 97 (95% CI 81-113) versus 116 (95% CI 97-135) and 125 (95% CI 104-145) versus 149 (95% CI 124-173), respectively. For ground-monitored and satellite-based PM_2.5 data, the economic loss attributable to ambient PM_2.5-total mortality was approximately 10,713 (95% CI 8890-12,467) and 12,792.1 (95% CI 10,652.0-14,837.6) million USD, equivalent to nearly 3.7% (95% CI 3.06-4.29) and 4.3% (95% CI 3.6-4.5.0) of the total gross domestic product in Iran in 2018.

Prenatal exposure to ambient air pollution and adverse birth outcomes: An umbrella review of 36 systematic reviews and meta-analyses

Multiple systematic reviews and meta-analyses linked prenatal exposure to ambient air pollutants to adverse birth outcomes with mixed findings, including results indicating positive, negative, and null associations across the pregnancy periods. The objective of this study was to systematically summarise systematic reviews and meta-analyses on air pollutants and birth outcomes to assess the overall epidemiological evidence. Systematic reviews with/without meta-analyses on the association between air pollutants (NO₂, CO, O₃, SO₂, PM_2.5, and PM₁₀) and birth outcomes (preterm birth; stillbirth; spontaneous abortion; birth weight; low birth weight, LBW; small-for-gestational-age) up to March 30, 2022 were included. We searched PubMed, CINAHL, Scopus, Medline, Embase, and the Web of Science Core Collection, systematic reviews repositories, grey literature databases, internet search engines, and references of included studies. The consistency in the directions of the effect estimates was classified as more consistent positive or negative, less consistent positive or negative, unclear, and consistently null. Next, the confidence in the direction was rated as either convincing, probable, limited-suggestive, or limited non-conclusive evidence. Final synthesis included 36 systematic reviews (21 with and 15 without meta-analyses) that contained 295 distinct primary studies. PM_2.5 showed more consistent positive associations than other pollutants. The positive exposure-outcome associations based on the entire pregnancy period were more consistent than trimester-specific exposure averages. For whole pregnancy exposure, a more consistent positive association was found for PM_2.5 and birth weight reductions, particulate matter and spontaneous abortion, and SO₂ and LBW. Other exposure-outcome associations mostly showed less consistent positive associations and few unclear directions of associations. Almost all associations showed probable evidence. The available evidence indicates plausible causal effects of criteria air pollutants on birth outcomes. To strengthen the evidence, more high-quality studies are required, particularly from understudied settings, such as low-and-middle-income countries. However, the current evidence may warrant the adoption of the precautionary principle.