Chronic exposure to air pollution particles increases the risk of obesity and metabolic syndrome: findings from a natural experiment in Beijing

Maternal exposure to ambient particulate matter on the growth of twin fetuses after in vitro fertilization

BACKGROUND

While ambient air pollution has been associated with fetal growth in singletons, its correlation among twins is not well-established due to limited research in this area.

METHODS

The effects of exposure to PM2.5 particulate matter and its main components during pregnancy on birth weight and the incidence of large for gestational age (LGA) were investigated in 6177 twins born after in vitro fertilization at the Center for Reproductive Medicine of Shanghai Ninth People's Hospital (Shanghai, China) between 2007 and 2021. Other birth weight-related outcomes included macrosomia, low birth weight, very low birth weight, and small for gestational age (SGA). The associations of PM2.5 exposure with birth weight outcomes were analyzed using linear mixed-effect models and random-effect logistic regression models. Distributed lag models were incorporated to estimate the time-varying associations.

RESULTS

The findings revealed that an interquartile range (IQR) increase (18 μg/m3) in PM2.5 exposure over the entire pregnancy was associated with a significant increase (57.06 g, 95 % confidence interval [CI]: 30.91, 83.22) in the total birth weight of twins. The effect was more pronounced in larger fetuses (34.93 g, 95 % CI: 21.13, 48.72) compared to smaller fetuses (21.77 g, 95 % CI: 6.94, 36.60) within twin pregnancies. Additionally, an IQR increase in PM2.5 exposure over the entire pregnancy was associated with a 34 % increase in the risk of LGA (95 % CI: 11 %, 63 %). Furthermore, specific chemical components of PM2.5, such as sulfate (SO42-), exhibited effect estimates comparable to the PM2.5 total mass.

CONCLUSION

Overall, the findings indicate that exposures to PM2.5 and its specific components are associated with fetal overgrowth in twins.

Contribution of greenness, air pollution, and residential food environment to excess gestational weight gain: A cross-sectional study in Wuhan, China

OBJECTIVES

Our goal was to explore how greenness, air pollution, and residential food environment were linked to excessive gestational weight gain (EGWG), and to estimate their combined effects on this condition.

METHOD

This cross-sectional analysis included 51,507 pregnant women from the Wuhan Maternal and Child Health Management Information System between 2016 and 2019. Generalized linear mixed regression models were employed to explore the relationships between greenness, air pollution, residential food environmental exposure, and EGWG; and the combined effects were further estimated by cluster analysis and principal components analysis.

RESULT

We only found a significant association between convenience store density within the 250 m buffer zone (OR = 1.03 and 95% CI: 1.01,1.05) and EGWG. In terms of air pollution, sulfur dioxide(SO2), particulate matter with a diameter of 10 μm or less(PM10), and particulate matter with a diameter of 2.5 μm or less(PM2.5) were substantially correlated with a higher prevalence of EGWG and higher GWG, with (OR = 1.16 and 95% CI: 1.12,1.21; OR = 1.12 and 95% CI: 1.08,1.16; OR = 1.17 and 95% CI: 1.14,1.21, respectively) per interquartile range(IQR) increase. Cluster analysis revealed the presence of three clusters representing urban exposures. In contrast to urban environment clusters characterized by favourable conditions, those exhibiting elevated air pollution levels, high-density residential food environment and low levels of greenness were found to have increased odds of EGWG (OR = 1.10, 95% CI: 1.03, 1.19).

CONCLUSION

This study emphasizes that exposure to elevated air pollution, high-density residential neighbourhood food environments, and low levels of greenness is a neighbourhood obesogenic environment for pregnant women.

Prenatal and Early Life Exposure to Ambient Air Pollutants Is Associated with the Fecal Metabolome in the First Two Years of Life

Prenatal and early life air pollution exposure has been linked with several adverse health outcomes. However, the mechanisms underlying these relationships are not yet fully understood. Therefore, this study utilizes fecal metabolomics to determine if pre- and postnatal exposure to ambient air pollutants (i.e., PM10, PM2.5, and NO2) is associated with the fecal metabolome in the first 2 years of life in a Latino cohort from Southern California. The aims of this analysis were to estimate associations between (1) prenatal air pollution exposure with fecal metabolic features at 1-month of age, (2) prior month postnatal air pollution exposure with fecal metabolites from 1-month to 2 years of age, and (3) how postnatal air pollution exposure impacts the change over time of fecal metabolites in the first 2 years of life. Prenatal exposure to air pollutants was associated with several Level-1 metabolites, including those involved in vitamin B6 and tyrosine metabolism. Prior month air pollution exposure in the postnatal period was associated with Level-1 metabolites involved in histidine metabolism. Lastly, we found that pre- and postnatal ambient air pollution exposure was associated with changes in metabolic features involved in metabolic pathways including amino acid metabolism, histidine metabolism, and fatty acid metabolism.

Associations between exposure to various air pollutants and risk of metabolic syndrome: a systematic review and meta-analysis

BACKGROUND

Metabolic Syndrome (MetS) is a widely observed metabolic disorder that is increasingly prevalent worldwide, leading to substantial societal consequences. Previous studies have conducted two separate meta-analyses to investigate the relationship between MetS and air pollutants. However, these studies yielded conflicting results, necessitating a thorough systematic review and meta-analysis to reassess the link between different air pollutants and the risk of developing MetS.

METHODS

We conducted a comprehensive search of relevant literature in databases including PubMed, Embase, Cochrane Library, and Web of Science up to October 9, 2023. The search was specifically restricted to publications in the English language. Following the screening of studies investigating the correlation between air pollution and MetS, we utilized random-effects models to calculate pooled effect sizes along with their respective 95% confidence intervals (CIs). We would like to highlight that this study has been registered with PROSPERO, and it can be identified by the registration number CRD42023484421.

RESULTS

The study included twenty-four eligible studies. The results revealed that an increase of 10 μg/m3 in annual concentrations of PM1, PM2.5, PM10, NO2, SO2, and O3 was associated with a 29% increase in metabolic syndrome (MetS) risk for PM1 (OR = 1.29 [CI 1.07-1.54]), an 8% increase for PM2.5 (OR = 1.08 [CI 1.06-1.10]), a 17% increase for PM10 (OR = 1.17 [CI 1.08-1.27]), a 24% increase for NO2 (OR = 1.24 [CI 1.01-1.51]), a 19% increase for SO2 (OR = 1.19 [CI 1.04-1.36]), and a 10% increase for O3 (OR = 1.10 [CI 1.07-1.13]).

CONCLUSION

The findings of this study demonstrate a significant association between exposure to fine particulate matter (PM1, PM2.5, PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and the incidence of metabolic syndrome (MetS). Moreover, the results suggest that air pollution exposure could potentially contribute to the development of MetS in humans.

Environmental pollution to kidney disease: an updated review of current knowledge and future directions

Environmental pollution significantly impacts global disease burden. However, the contribution of environmental pollution to kidney disease is often overlooked in nephrology. This review examines the growing body of research demonstrating the significant impacts of environmental pollutants, with a focus on air pollution as a primary factor, and acknowledges the roles of other pollutants, such as heavy metals, in the development and progression of kidney diseases. Short-term exposure to air pollution is linked with an increased risk of kidney disease-related events, including hospital admissions, and death, predominantly occurring in vulnerable populations. In contrast, long-term exposure, even at low to moderate levels, may lead to progressive pathophysiological changes, such as chronic systemic inflammation and oxidative stress, that contribute to the development of kidney disease. In addition, air pollution may exacerbate traditional kidney disease risk factors such as hypertension and diabetes, thereby accelerating disease progression. The review also explores how climate change may interact with various pollutants, including air pollution, influencing kidney disease indirectly. The examined evidence underscores the urgent need for an interdisciplinary approach to research further into environmental kidney disease. Environmental health policies could play a crucial role in the prevention, intervention, and improvement of kidney health worldwide.

Prenatal exposure to PM2.5 and childhood body mass index growth trajectories from birth to 6 years old

This study aimed to determine the relationships between prenatal PM2.5 exposure and childhood growth trajectories during the first 6 years of life. A total of 47,625 pairs of mothers and children were recruited from a prospective birth cohort conducted between 2011 and 2013 in Wuhan, China, and followed for 6 years. We used the group-based trajectory models to classify the population into three trajectory groups: slow growth (n = 13,671, 28.7%), normal growth (n = 29,736, 62.4%), and rapid growth (n = 4218, 8.9%). Multinomial logistic regression models were used to determine the associations of prenatal PM2.5 exposure and childhood growth trajectories. Compared to normal growth trajectory, increased PM2.5 exposure in trimester 1, trimester 2 and the entire pregnancy showed significant associations with an increased risk of the slow growth trajectory but reduced the risk for the rapid growth trajectory, significant association of prenatal PM2.5 exposure with rapid growth trajectory was only observed in the trimester 3. Stratified analyses displayed relatively stronger associations among those mothers with maternal age over 35 years, pre-pregnancy BMI ≥ 25 kg/m2, and previous delivery experience. Prenatal exposure to PM2.5, particularly during the midpoint period of pregnancy, was more likely to have a slow growth trajectory and a lower risk of rapid growth trajectory. Maternal age, pre-pregnancy BMI, and previous delivery experience might modify these associations.

The association between air pollution and obesity: an umbrella review of meta-analyses and systematic reviews

The objective of this umbrella review was to investigate comprehensive and synthesized evidence of the association between ambient air pollution and obesity based on the current systematic reviews and meta-analyses. Related studies from databases including PubMed, EMBASE, Web of Science, and the Cochrane Library, published before July 16, 2023, were considered in the analysis. All selected systematic reviews and meta-analyses were included in accordance with PRISMA guidelines. The risk of bias and the methodological quality were evaluated using the AMSTAR 2 tool. The protocol for this umbrella review was documented in PROSPERO with the registration number: CRD42023450191. This umbrella review identified 7 studies, including 5 meta-analyses and 2 systematic reviews, to assess the impacts of air pollutants on obesity. Commonly examined air pollutants included PM1, PM2.5, PM10, NO2, SO2, O3. Most of the included studies presented that air pollution exposure was positively associated with the increased risk of obesity. The impact of air pollution on obesity varied by different ambient air pollutants. This study provided compelling evidence that exposure to air pollution had a positive association with the risk of obesity. These findings further indicate the importance of strengthening air pollution prevention and control. Future studies should elucidate the possible mechanisms and pathways linking air pollution to obesity.

Impact of green space and built environment on metabolic syndrome: A systematic review with meta-analysis

Metabolic Syndrome presents a significant public health challenge associated with an increased risk of noncommunicable diseases such as cardiovascular conditions. Evidence shows that green spaces and the built environment may influence metabolic syndrome. We conducted a systematic review and meta-analysis of observational studies published through August 30, 2023, examining the association of green space and built environment with metabolic syndrome. A quality assessment of the included studies was conducted using the Office of Health Assessment and Translation (OHAT) tool. The Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) assessment was used to evaluate the overall quality of evidence. Our search retrieved 18 studies that met the inclusion criteria and were included in our review. Most were from China (n = 5) and the USA (n = 5), and most used a cross-sectional study design (n = 8). Nine studies (50 %) reported only green space exposures, seven (39 %) reported only built environment exposures, and two (11 %) reported both built environment and green space exposures. Studies reported diverse definitions of green space and the built environment, such as availability, accessibility, and quality, particularly around participants' homes. The outcomes focused on metabolic syndrome; however, studies applied different definitions of metabolic syndrome. Meta-analysis results showed that an increase in normalized difference vegetation index (NDVI) within a 500-m buffer was associated with a lower risk of metabolic syndrome (odds ratio [OR] = 0.90, 95%CI = 0.87-0.93, I2 = 22.3 %, n = 4). A substantial number of studies detected bias for exposure classification and residual confounding. Overall, the extant literature shows a 'limited' strength of evidence for green space protecting against metabolic syndrome and an 'inadequate' strength of evidence for the built environment associated with metabolic syndrome. Studies with more robust study designs, better controlled confounding factors, and stronger exposure measures are needed to understand better what types of green spaces and built environment features influence metabolic syndrome.

Effects of exposure to environmental factors on obesity-related growth parameters and leptin (LEP) methylation in children

The prevalence of childhood obesity is rapidly increasing. Therefore, gaining more information on the role of environmental parameters is key. With overexpression of leptin (encoded by LEP) in obesity, LEP methylation might be altered by environmental exposures. This study aims to assess effects of ambient air pollution and nearby greenness on obesity-related growth and LEP methylation in early childhood. We monitored 120 mother-child pairs from conception until the age of five. Buccal swabs and anthropometric measurements of the children were taken at six months, one year, and five years old. Buccal DNA was extracted to determine LEP methylation levels. Estimates of air pollution and nearby greenness were calculated using high-resolution models. Effects of air pollution and nearby greenness on growth or LEP methylation were investigated using linear mixed effects models. Positive associations were shown for air pollution between conception and age one on impedance in six-month-olds and one-year-olds in the crude model. PM with aerodynamic diameter ≤10 (PM10) and ≤2.5 μm (PM2.5) positively associated with waist-hip-ratio and waist circumference at age five in the fully adjusted model. In early childhood, closest distance to forest negatively, and urban green and forest positively associated with weight-for-length, body mass index, and fat percentage in five-year-olds in the fully adjusted model. No significant associations for noise, and walkability on growth were seen. Negative associations were shown for smaller green clusters and positive associations for greater green clusters on LEP methylation in one-year-olds. For forest distance, walkability, noise, or all green on LEP methylation, no significant associations were found. Evidence is provided that ambient air pollution might have a significant effect on impedance and waist-hip-ratio, suggesting an increased risk of childhood obesity. Based on LEP methylation, greater green clusters might associate with a decreased risk of childhood obesity, while smaller green clusters showed the opposite.

The joint effects of prenatal exposure to PM2.5 constituents and reduced fetal growth on children's accelerated growth in the first 3 years: a birth cohort study

BACKGROUND

Prenatal fine particulate matter (PM2.5) constituents exposure and reduced fetal growth may be risk factors for accelerated growth in early childhood, an important indicator for lifelong health.

OBJECTIVE

The study investigated whether the joint effects are present between PM2.5 constituents and reduced fetal growth.

METHODS

The study was embedded in a birth cohort in China, including 5424 mother-child pairs. Prenatal PM2.5 and its constituents' [organic carbon (OC), elementary carbon (EC), ammonium (NH4+), nitrate (NO3-), and sulfate (SO42-)] concentrations were estimated based on maternal residential addresses. Fetal growth was evaluated by fetal growth trajectory in utero and preterm birth (PTB), low birth weight (LBW), and small for gestational age (SGA). Children's accelerated growth was defined as body mass index (BMI) Z-score change of >0.67 between birth and 3 years. Generalized logistic regression was used to analyze the effects of prenatal PM2.5 constituents exposure and fetal growth on children's accelerated growth. Joint effect was tested on multiplicative scale and additive scale with the relative excess risk due to interaction (RERI).

RESULTS

Children with lower fetal growth trajectory, PTB, LBW, and SGA had increased odds of children's accelerated growth, with odds ratios (ORs) ranging from 1.704 to 11.605. Compared with lower exposure (≤median), higher exposure (>median) of PM2.5, OC, and SO42- were significantly associated with increased odds of children's accelerated growth, varying in ORs from 1.163 to 1.478. Prenatal exposure to OC had joint effects with lower fetal growth on children's accelerated growth. We observed that the interaction was statistically significant on an additive scale in OC and lower fetal growth trajectory (RERI: 0.497, 95% CI: 0.033,0.962).

IMPACT

Fine particulate matter (PM2.5) is a huge threat to human health worldwide, causing 6.7 million death globally in 2019. According to the theory of DOHaD, prenatal PM2.5 exposure could influence early childhood growth, which is important for lifelong health. We found that prenatal exposure to PM2.5, OC, and SO42- was associated with higher risk of accelerated childhood growth in the first 3 years. More importantly, reduced fetal growth moderated these associations. Our findings highlight the need for policies and interventions on PM2.5 constituents to improve lifelong health, especially for those vulnerable populations with reduced fetal growth.

Association of volatile organic compound exposure with metabolic syndrome and its components: a nationwide cross-sectional study

BACKGROUND

Metabolic syndrome (MetS) is a health issue consisting of multiple metabolic abnormalities. The impact of exposure to volatile organic compounds (VOCs) on MetS and its components remains uncertain. This study aimed to assess the associations of individual urinary metabolites of VOC (mVOCs) and mVOC mixtures with MetS and its components among the general adult population in the United States.

METHODS

A total of 5345 participants with eligible data were filtered from the 2011-2020 cycles of the National Health and Nutrition Examination Survey. Multivariate logistic regression models were applied to assess the associations of individual mVOCs with MetS and its components. The least absolute shrinkage and selection operator (LASSO) regression models were constructed to identify more relevant mVOCs. The weight quantile sum regression model was applied to further explore the links between mVOC co-exposure and MetS and its components.

RESULTS

The results indicated positive associations between multiple mVOCs and MetS, including CEMA, DHBMA, and HMPMA. CEMA was found to be positively correlated with all components of MetS. HMPMA was associated with elevated triglyceride (TG), reduced high-density lipoprotein, and fasting blood glucose (FBG) impairment; 3HPMA was associated with an elevated risk of high TG and FBG impairment; and DHBMA had positive associations with elevated TG and high blood pressure. The co-exposure of LASSO-selected mVOCs was associated with an increased risk of elevated TG, high blood pressure, and FBG impairment.

CONCLUSION

Positive associations of certain individual urinary mVOCs and mVOC mixtures with MetS and its components were observed by utilizing multiple statistical models and large-scale national data. These findings may serve as the theoretical basis for future experimental and mechanistic studies and have important implications for public health.

Prenatal air pollution exposure and childhood obesity: Effect modification by maternal fruits and vegetables intake

BACKGROUND & AIMS

Prenatal exposure to air pollution is robustly associated with fetal growth restriction but the extent to which it is associated with postnatal growth and the risk of childhood obesity remains unknown. We examined the association of prenatal exposure to air pollution with offspring obesity related measures and evaluated the possible protective effect of maternal fruits and vegetables intake (FV).

METHODS

We included 633 mother-child pairs from the Rhea pregnancy cohort in Crete, Greece. Fine particles (PM2.5 and PM10) exposure levels during pregnancy were estimated using land-use regression models. We measured weight, height and waist circumference at 4 and 6 years of age, and body composition analysis was performed at 6 years using bioimpedance. Maternal diet was evaluated by means of a semi-quantitative food frequency questionnaire in mid-pregnancy. Adjusted associations were obtained via multivariable regression analyses and multiplicative interaction was used to evaluate the potential modifying role of FV intake.

RESULTS

Exposure to PMs in utero was not associated with measures of adiposity at 4 or 6 years of age. Associations at 4 years did not differ according to maternal consumption of FV. However, at 6 years, among children whose mothers reported consuming less than 5 servings of FV per day, one SD increase in PM10 during pregnancy was associated with increased BMI (beta 0.41 kg/m2, 95% CI: -0.06, 0.88, p-interaction = 0.037) and increased waist circumference (beta 0.83 cm, 95% CI: -0.38, 2.05, p-interaction = 0.043) and one SD increase in PM2.5 was associated with increased fat mass (beta 0.5 kg, 95% CI: 0.0, 0.99, p-interaction = 0.039) and increased percentage of body fat (beta 1.06%, 95% CI: -0.06, 2.17, p-interaction = 0.035). Similarly, higher prenatal PM2.5 and PM10 exposure was associated with increased risk for obesity and abdominal obesity at 6 years only in the low FV group.

CONCLUSIONS

Exposure to fine particulate matter during pregnancy was not associated with obesity-related measures at 4 and 6 years. However, only among offspring of mothers who consumed inadequate FV, we observed higher obesity-related measures at 6 years. Our results indicate that mothers' diet during pregnancy may play a role in the relationship between air-pollution and childhood obesity.

Disruption of phosphofructokinase activity and aerobic glycolysis in human bronchial epithelial cells by atmospheric ultrafine particulate matter

Exposure to ambient ultrafine particulate matter (UPM) causes respiratory disorders; however, the underlying molecular mechanisms remain unclear. In this study, we synthesized simulated UPM (sUPM) with controlled physicochemical properties using the spark-discharge method. Subsequently, we investigated the biological effects of sUPM using BEAS-2B human bronchial epithelial cells (HBECs) and a mouse intratracheal instillation model. High throughput RNA-sequencing and bioinformatics analyses revealed that dysregulation of the glycolytic metabolism is involved in the inhibited proliferation and survival of HBECs by sUPM treatment. Furthermore, signaling pathway and enzymatic analyses showed that the treatment of BEAS-2B cells with sUPM induces the inactivation of extracellular signal-regulated kinase (ERK) and protein kinase B (PKB, also known as AKT), resulting in the downregulation of phosphofructokinase 2 (PFK2) S483 phosphorylation, PFK enzyme activity, and aerobic glycolysis in HBECs in an oxidative stress-independent manner. Additionally, intratracheal instillation of sUPM reduced the phosphorylation of ERK, AKT, and PFK2, decreased proliferation, and increased the apoptosis of bronchial epithelial cells in mice. The findings of this study imply that UPM induces pulmonary toxicity by disrupting aerobic glycolytic metabolism in lung epithelial cells, which can provide novel insights into the toxicity mechanisms of UPM and strategies to prevent their toxic effects.

Association of air pollution exposure with overweight or obesity in children and adolescents: A systematic review and meta-analysis

Childhood overweight and obesity is a global problem. 38 million children under five years old were reported as being overweight/obese in 2019. However, current evidence regarding the effects of air pollution on children weight status remains scarce and inconsistent. This study aimed to determine the association between air pollutants and the weight status of children and adolescents. Four databases were searched up to August 9, 2023. Adjusted merged odds ratios (ORs), regression coefficients (β), and their 95 % confidence intervals (95 % CIs) were calculated and pooled. A total of 27 studies were included. The results showed that air pollutants had adverse effects on the body weight of children and adolescents. Exposure to PM1, PM2.5, PMcoarse, and PM10 were associated with increased risk of overweight/obesity, with pooled ORs (95 % CI) of 1.23 (1.09, 1.40), 1.18 (1.10, 1.28), 1.04 (1.03, 1.05) and 1.11 (1.06, 1.17) per 10 μg/m3 increment, respectively. Individuals with higher exposure levels to NOX, O3, SO2 and CO (per 10 μg/m3 increment) were associated with 12 %, 6 %, 28 % and 1 % increased odds of being overweight/obese, respectively. With respect to the level of body mass index, the pooled β (95 % CIs) for each 10 μg/m3 increase in PM1, PM2.5, PM10, and NOX exposure were 0.15 (0.12, 0.18), 0.11 (0.06, 0.16), 0.07 (0.03, 0.10), and 0.03 (0.01, 0.04), respectively. PM1 has relatively strong adverse effects on body weight status. The subgroup analysis revealed a significantly increase in the risk of overweight/obesity when the concentrations of PM2.5, PM10, and NO2 exceeded 35 μg/m3, 50 μg/m3, and 40 μg/m3, respectively. Exposure to PM2.5, PM10 and NOX increased the risk of overweight/obesity, especially in Asia. This study provides evidence of the association between air pollution and being overweight/obese in children and adolescents.

Beneficial associations between outdoor visible greenness at the workplace and metabolic syndrome in Chinese adults

BACKGROUND

Greenness surrounding residential places has been found to significantly reduce the risk of diseases such as hypertension, obesity, and metabolic syndrome (MetS). However, it is unclear whether visible greenness exposure at the workplace has any impact on the risk of MetS.

METHODS

Visible greenness exposure was assessed using a Green View Index (GVI) based on street view images through a convolutional neural network model. We utilized logistic regression to examine the cross-sectional association between GVI and MetS as well as its components among 51,552 adults aged 18-60 in the city of Hangzhou, China, from January 2018 to December 2021. Stratified analyses were conducted by age and sex groups. Furthermore, a scenario analysis was conducted to investigate the risks of having MetS among adults in different GVI scenarios.

RESULTS

The mean age of the participants was 40.1, and 38.5% were women. We found a statistically significant association between GVI and having MetS. Compared to the lowest quartile of GVI, participants in the highest quartile of GVI had a 17% (95% CI: 11-23%) lower odds of having MetS. The protective association was stronger in the males, but we did not observe such differences in different age groups. Furthermore, we found inverse associations between GVI and the odds of hypertension, low high-density lipoprotein cholesterol, obesity, and high levels of FPG.

CONCLUSIONS

Higher exposure to outdoor visible greenness in the workplace environment might have a protective effect against MetS.

Inflammatory response in mouse lungs to haze episodes under different backgrounds of particulate matter exposure

Particulate matter (PM) toxicity has mostly been investigated through in vitro exposure or tracheal infusion in animal models. However, given the complexity of ambient conditions, most animal studies do not mimic real-life PM exposure. In this work, we established a novel integrated exposure model to study the dynamic inflammatory response and defense strategies in ambient PM-exposed mice. Three groups of male C57BL/6 mice were kept in three chambers with pre-exposure to filtered air (FA), unfiltered air (UFA), or the air with a low PM concentration (PM2.5 ≤ 75 μg/m3) (LPM), respectively, for 37 days. Then all three groups of mice were exposed to haze challenge for 3 days, followed by exposure in filtered air for 7 days to allow recovery. Our results suggest that following a haze challenge, the defense strategies of mice of filtered air (FA) and low PM (LPM) groups comprised a form of "counterattack", whereas the response of the unfiltered air (UFA) group could be viewed as a "silence". While the latter strategy protected the lung tissues of mice from acute inflammatory damage, it also foreshadowed the development of chronic inflammatory diseases. These findings contribute to explaining previously documented PM-associated pathogenic mechanisms.

Redox and inflammatory mechanisms linking air pollution particulate matter with cardiometabolic derangements

Air pollution is the largest environmental risk factor for disease and premature death. Among the different components that are present in polluted air, fine particulate matter below 2.5 μm in diameter (PM2.5) has been identified as the main hazardous constituent. PM2.5 mainly arises from fossil fuel combustion during power generation, industrial processes, and transportation. Exposure to PM2.5 correlates with enhanced mortality risk from cardiovascular diseases (CVD), such as myocardial infarction and stroke. Over the last decade, it has been increasingly suggested that PM2.5 affects CVD already at the stage of risk factor development. Among the multiple biological mechanisms that have been described, the interplay between oxidative stress and inflammation has been consistently highlighted as one of the main drivers of pulmonary, systemic, and cardiovascular effects of PM2.5 exposure. In this context, PM2.5 uptake by tissue-resident immune cells in the lung promotes oxidative and inflammatory mediators release that alter tissue homeostasis at remote locations. This pathway is central for PM2.5 pathogenesis and might account for the accelerated development of risk factors for CVD, including obesity and diabetes. However, transmission and end-organ mechanisms that explain PM2.5-induced impaired function in metabolic active organs are not completely understood. In this review, the main features of PM2.5 physicochemical characteristics related to PM2.5 ability to induce oxidative stress and inflammation will be presented. Hallmark and recent epidemiological and interventional studies will be summarized and discussed in the context of current air quality guidelines and legislation, knowledge gaps, and inequities. Lastly, mechanistic studies at the intersection between redox metabolism, inflammation, and function will be discussed, with focus on heart and adipose tissue alterations. By offering an integrated analysis of PM2.5-induced effects on cardiometabolic derangements, this review aims to contribute to a better understanding of the pathogenesis and potential interventions of air pollution-related CVD.

The association between outdoor air pollution and body mass index, central obesity, and visceral adiposity index among middle-aged and elderly adults: a nationwide study in China

Background

Previous animal studies have suggested that air pollution (AP) exposure may be a potential risk factor for obesity; however, there is limited epidemiological evidence available to describe the association of obesity with AP exposure.

Methods

A retrospective cross-sectional study was conducted on 11,766 participants across mainland China in 2015. Obesity was assessed using body mass index (BMI), waist circumference (WC), and visceral adiposity index (VAI). The space-time extremely randomized tree (STET) model was used to estimate the concentration of air pollutants, including SO2, NO2, O3, PM1, PM2.5, and PM10, matched to participants' residential addresses. Logistic regression models were employed to estimate the associations of obesity with outdoor AP exposure. Further stratified analysis was conducted to evaluate whether sociodemographics or lifestyles modified the effects.

Results

Increased AP exposure was statistically associated with increased odds of obesity. The odds ratio (ORs) and 95% confidence interval (CI) of BMI-defined obesity were 1.21 (1.17, 1.26) for SO2, 1.33 (1.26, 1.40) for NO2, 1.15 (1.10, 1.21) for O3, 1.38 (1.29, 1.48) for PM1, 1.19 (1.15, 1.22) for PM2.5, and 1.11 (1.09, 1.13) for PM10 per 10 μg/m3 increase in concentration. Similar results were found for central obesity. Stratified analyses suggested that elderly participants experienced more adverse effects from all 6 air pollutants than middle-aged participants. Furthermore, notable multiplicative interactions were found between O3 exposure and females as well as second-hand smokers in BMI-defined obesity.

Conclusions

This study suggested that outdoor AP exposure had a significant association with the risk of obesity in the middle-aged and elderly Chinese population. Elderly individuals and women may be more vulnerable to AP exposure.

Dilemma of Epigenetic Changes Causing or Reducing Metabolic Disorders in Offsprings of Obese Mothers

Maternal obesity is associated with fetal complications predisposing later to the development of metabolic syndrome during childhood and adult stages. High-fat diet seems to influence individuals and their subsequent generations in mediating weight gain, insulin resistance, obesity, high cholesterol, diabetes, and cardiovascular disorder. Research evidence strongly suggests that epigenetic alteration is the major contributor to the development of metabolic syndrome through DNA methylation, histone modifications, and microRNA expression. In this review, we have discussed the outcome of recent studies on the adverse and beneficial effects of nutrients and vitamins through epigenetics during pregnancy. We have further discussed about the miRNAs altered during maternal obesity. Identification of new epigenetic modifiers such as mesenchymal stem cells condition media (MSCs-CM)/exosomes for accelerating the reversal of epigenetic abnormalities for the development of new treatments is yet another aspect of the present review.

The association of preconception paternal metabolic syndrome on early childhood emergency department visits and hospitalizations

BACKGROUND

Increasing preconception paternal comorbidity has been associated with adverse pregnancy outcomes. However, whether the father's health impacts the child after birth is uncertain.

OBJECTIVES

In the present study, we examined the association of preconception paternal metabolic syndrome status with childhood emergency department visits and hospitalizations.

MATERIALS AND METHODS

This is a longitudinal cohort study of children (295,355 boys and 278,735 girls) born to linked pairs of fathers and mothers in the United States between 2009 and 2016 within the IBM MarketScan Research database. Associations between paternal and maternal metabolic syndrome component diagnoses and subsequent hospitalizations and emergency department visits for offspring within the first 2 years of life were determined.

RESULTS

Note that, 35.5% (203,617/574,090) of children had at least one emergency room visit and 6.1% (35,141/574,090) of children had an inpatient admission. After adjustment, the odds of inpatient admission and emergency department visits increased in a dose-dependent fashion among fathers with higher comorbidities. Similar trends were seen for emergency department visit utilization.

DISCUSSION AND CONCLUSION

Increasing paternal preconception comorbidity is associated with a higher risk that a child requires the emergency department and inpatient care in the first years of life. An opportunity exists to engage men in preconception counseling to optimize their and their offspring's health.

Uncovering the link between air pollution and neurodevelopmental alterations during pregnancy and early life exposure: A systematic review

Air pollution plays, nowadays, a huge role in human's health and in the personal economy. Moreover, there has been a rise in the prevalence of neurodevelopmental disorders like the Autism Spectrum Disorder (ASD) in recent years. Current scientific studies have established a link between prenatal or perinatal exposure to environmental pollutants and ASD. This systematic review summarizes the current literature available about the relationship between exposure to air pollutants (particulate matter [PM], Second Organic Aerosols [SOA], Diesel Exhaust [DE], and Traffic Related Air Pollution [TRAP]) and neurodevelopmental disorders in preclinical models using rats and mice. The articles were selected and filtered using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology, and bias-evaluated using the SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE) tool. Overall, our findings suggest that air pollutants are associated with negative developmental outcomes characterized by ASD-like behaviors, abnormal biochemical patterns, and impaired achievement of developmental milestones in rodents. However, there is not sufficient information in certain domains to establish a clear relationship. Short phrases for indexing terms: Air pollution affects neurodevelopment; PM exposure modifies glutamate system; Prenatal exposure combined with postnatal affect more to behavioral / cognitive domain; Air pollution modifies social behavior in rodents; Cognitive deficits can be detected after gestational exposure to air pollution.

Maternal exposure to aircraft emitted ultrafine particles during pregnancy and likelihood of ASD in children

BACKGROUND

There is increasing evidence for adverse health effects associated with aircraft-emitted particulate matter (PM) exposures, which are largely in the ultrafine (PM0.1) size fraction, but no previous study has examined neurodevelopmental outcomes.

OBJECTIVE

To assess associations between maternal exposure to aircraft ultrafine particles (UFP) during pregnancy and offspring autism spectrum disorder (ASD) diagnosis.

METHODS

This large, representative cohort study included 370,723 singletons born in a single healthcare system. Demographic data, maternal health information, and child's ASD diagnosis by age 5 were extracted from electronic medical records. Aircraft exposure estimates for PM0.1 were generated by the University of California Davis/California Institute of Technology Source Oriented Chemical Transport model. Cox proportional hazard models were used to assess associations between maternal exposure to aircraft PM0·1 in pregnancy and ASD diagnosis, controlling for covariates.

RESULTS

Over the course of follow-up, 4,554 children (1.4 %) were diagnosed with ASD. Increased risk of ASD was associated with maternal exposure to aircraft PM0.1 [hazard ratio, HR: 1.02, (95 % confidence interval (CI): 1.01-1.03) per IQR = 0.02 µg/m3 increase during pregnancy. Associations were robust to adjustment for total PM0.1 and fine particulate matter (PM2.5), near-roadway air pollution, and other covariates. Noise adjustment modestly attenuated estimates of UFP effects, which remained statistically significant.

DISCUSSION

The results strengthen the emerging evidence that maternal particulate matter exposure during pregnancy is associated with offspring ASD diagnosis and identify aircraft-derived PM0.1 as novel targets for further study and potential regulation.

Ecological study on household air pollution exposure and prevalent chronic disease in the elderly

Older people spend most of their time indoors. Limited evidence demonstrates that exposure to indoor air pollutants might be related to chronic complications. This study aimed to estimate the correlation between household air pollution (HAP)'s long-term exposure and the prevalence of elevated hypertension, diabetes mellitus (DM), obesity, and low-density lipoprotein (LDL) cholesterol. From the Global Burden disease dataset, we extracted HAP, hypertension, DM, body mass index, and LDL cholesterol data from Iran from 1990 to 2019 to males and females in people over 50 years. We present APC and AAPC and their confidence intervals using Joinpoint Software statistical software. R software examined the correlation between HAP and hypertension, DM2, Obesity, and high LDL cholesterol. Our finding showed a significant and positive correlation between HAP exposure and prevalence of high low-density lipoprotein cholesterol (p ≤ 0.001, r = 0.70), high systolic blood pressure (p ≤ 0.001, r = 0.63), and high body mass index (p ≤ 0.001, r = 0.57), and DM2 (p ≤ 0.001, r = 0.38). The analysis results also illustrated a positive correlation between indoor air pollution and smoking (p ≤ 0.001, r = 0.92). HAP exposure might be a risk factor for elevated blood pressure, DM, obesity, and LDL cholesterol and, consequently, more serious health problems. According to our results, smoking is one of the sources of HAP. However, ecological studies cannot fully support causal relationships, and this article deals only with Iran. Our findings should be corroborated in personal exposure and biomonitoring approach studies.

Association between ambient air pollutants and lipid profile: A systematic review and meta-analysis

BACKGROUND

Studies of the effects of atmospheric pollutants on lipid profiles remain inconsistent and controversial.

AIM

The study was aimed to investigate the relationship between the exposure to ambient air pollutants and variations in the blood lipid profiles in the population.

METHODS

A comprehensive search of three different databases (PubMed, Web of Science, and the Cochrane Library) until December 17, 2022, yielded 17 origional studies fulfilling the inclusion criteria for a meta-analysis. Aggregate effect measures and 95% confidence intervals (95% CI) for the relevant ambient air pollutants were deduced employing random effects models.

RESULTS

The collective meta-analysis indicated that long-term exposure to PM₁, PM_2.5, PM₁₀ and CO showed a substantial correlation with TC (PM₁: β = 2.04, 95%CI = 0.15-3.94; PM_2.5: β = 1.11, 95%CI = 0.39-1.84; PM₁₀: β = 1.70, 95%CI = 0.67-2.73; CO: β = 0.08, 95%CI = 0.06-0.10), PM₁₀ exhibited a significant association with TG (β = 0. 537,95% CI = 0.09-0.97), whereas HDL-C demonstrated notable relationships with PM₁, PM₁₀, SO₂ and CO (PM₁: β = -2.38, 95%CI = -4.00 to -2.76; PM₁₀: β = -0.77, 95%CI = -1.33 to -0.21; SO₂: β = -0.91, 95%CI = -1.73 to -0.10; CO: β = -0.03, 95%CI = -0.05 to 0.00). PM_2.5, PM₁₀ also showed significant associations with LDL-C (PM_2.5: β = 1.44 95%CI = 0.48-2.40; PM₁₀: β = 1.62 95%CI = 0.90-2.34). Subgroup analysis revealed significant or stronger correlations predominantly in cohort study designs, with higher male comparisons, and in regions exhibiting elevated contaminant levels.

CONCLUSION

In summary, the analysis substantiates that ambient air pollutants can be recognized as potent contributors to alterations in lipid profiles, particularly particulate pollutants which exert more obvious effects on lipid profiles.

Prenatal exposure to PM2.5 and its constituents with children's BMI Z-score in the first three years: A birth cohort study

BACKGROUND

Limited studies evaluated the effect of prenatal exposure to fine particulate matter (PM_2.5) on childhood growth and no consensus reached yet. No study explored the effect of prenatal exposure to PM_2.5 and its constituents on childhood growth in a region with high PM_2.5 levels (>50 μg/m³). The present study aimed to examine the association of prenatal exposure to PM_2.5 and its constituents with children's BMI Z-score in the first three years.

METHODS

The present study was based on a birth cohort in Beijing, China, involving 15,745 mothers with their children who were followed to three years old. We estimated prenatal PM_2.5 and its constituents [organic carbon (OC), elemental carbon (EC), sulfate (SO₄^2-), nitrate (NO₃^-), and ammonium (NH₄⁺)] concentrations based on residential addresses at birth. Height (or length) and weight of children were repeatedly measured, and body mass index (BMI) Z-score was calculated at one, two, and three years old. Generalized linear regression and generalized estimating equation were used to examine the associations between prenatal exposure to PM_2.5 and its constituents with BMI Z-score in the first three years.

RESULTS

Prenatal exposure to PM_2.5 and its constituents was generally associated with higher BMI Z-score of children aged one, two, and three years. One IQR increase of PM_2.5, OC, EC, NO₃^-, NH₄⁺, and SO₄^2- (21.30 μg/m³, 11.52 μg/m³, 2.40 μg/m³, 8.28 μg/m³, 2.42 μg/m³, and 8.80 μg/m³, respectively) was associated with 0.13 (95%CI: 0.10, 0.16), 0.24 (95%CI: 0.19, 0.29), 0.12 (95%CI: 0.09, 0.16), 0.13 (95%CI: 0.09, 0.17), 0.11 (95%CI: 0.08, 0.13), and 0.24 (95%CI: 0.19, 0.30) increase in BMI Z-score from one to three years old, respectively.

CONCLUSION

The study suggested that prenatal exposure to PM_2.5 and its constituents was associated with higher BMI Z-score of children in the first three years. Public health policy for controlling harmful PM_2.5 constituents should be developed to promote child health.

Findings of indoor air pollution and childhood obesity in a cross-sectional study of Chinese schoolchildren

BACKGROUND

Air pollution exposures are increasingly suspected to influence the development of childhood adiposity, especially focusing on outdoor exposure, but few studies investigated indoor exposure and childhood obesity.

OBJECTIVES

We aimed to examine the association between exposure to multiple indoor air pollutants and childhood obesity in Chinese schoolchildren.

METHODS

In 2019, we recruited 6499 children aged 6-12 years from five Chinese elementary schools in Guangzhou, China. We measured age-sex-specific body mass index z score (z-BMI), waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR) on standard procedures. Four different indoor air pollution (IAP) exposures, including cooking oil fumes (COFs), home decoration, secondhand smoke (SHS), and incense burning, were collected by questionnaire and then converted into an IAP exposure index with four categories. Association between indoor air pollutants and childhood overweight/obesity as well as four obese anthropometric indices were assessed by logistic regression models and multivariable linear regression models, respectively.

RESULTS

Children exposed to ≥3 types of indoor air pollutants had higher z-BMI (coefficient [β]:0.142, 95% confidence interval [CI]:0.011-0.274) and higher risk of overweight/obesity (odd ratio [OR]:1.27, 95%CI:1.01-1.60). And a dose-response relationship was discovered between the IAP exposure index and z-BMI as well as overweight/obesity (p_{for trend}<0.05). We also found that exposure to SHS and COFs was positively associated with z-BMI and overweight/obesity (p < 0.05). Moreover, there was a significant interaction between SHS exposure and COFs on the higher risk of overweight/obesity among schoolchildren. Boys appear more susceptible to multiple indoor air pollutants than girls.

CONCLUSIONS

Indoor air pollution exposures were positively associated with higher obese anthropometric indices and increased odds of overweight/obesity in Chinese schoolchildren. More well-designed cohort studies are needed to verify our results.

Type 1 diabetes and diet-induced obesity predispose C57BL/6J mice to PM2.5-induced lung injury: a comparative study

BACKGROUND

Pre-existing metabolic diseases may predispose individuals to particulate matter (PM)-induced adverse health effects. However, the differences in susceptibility of various metabolic diseases to PM-induced lung injury and their underlying mechanisms have yet to be fully elucidated.

RESULTS

Type 1 diabetes (T1D) murine models were constructed by streptozotocin injection, while diet-induced obesity (DIO) models were generated by feeding 45% high-fat diet 6 weeks prior to and throughout the experiment. Mice were subjected to real-ambient PM exposure in Shijiazhuang City, China for 4 weeks at a mean PM2.5 concentration of 95.77 µg/m3. Lung and systemic injury were assessed, and the underlying mechanisms were explored through transcriptomics analysis. Compared with normal diet (ND)-fed mice, T1D mice exhibited severe hyperglycemia with a blood glucose of 350 mg/dL, while DIO mice displayed moderate obesity and marked dyslipidemia with a slightly elevated blood glucose of 180 mg/dL. T1D and DIO mice were susceptible to PM-induced lung injury, manifested by inflammatory changes such as interstitial neutrophil infiltration and alveolar septal thickening. Notably, the acute lung injury scores of T1D and DIO mice were higher by 79.57% and 48.47%, respectively, than that of ND-fed mice. Lung transcriptome analysis revealed that increased susceptibility to PM exposure was associated with perturbations in multiple pathways including glucose and lipid metabolism, inflammatory responses, oxidative stress, cellular senescence, and tissue remodeling. Functional experiments confirmed that changes in biomarkers of macrophage (F4/80), lipid peroxidation (4-HNE), cellular senescence (SA-β-gal), and airway repair (CCSP) were most pronounced in the lungs of PM-exposed T1D mice. Furthermore, pathways associated with xenobiotic metabolism showed metabolic state- and tissue-specific perturbation patterns. Upon PM exposure, activation of nuclear receptor (NR) pathways and inhibition of the glutathione (GSH)-mediated detoxification pathway were evident in the lungs of T1D mice, and a significant upregulation of NR pathways was present in the livers of T1D mice.

CONCLUSIONS

These differences might contribute to differential susceptibility to PM exposure between T1D and DIO mice. These findings provide new insights into the health risk assessment of PM exposure in populations with metabolic diseases.

Short-Term Ambient Air Ozone Exposure and Components of Metabolic Syndrome in a Cohort of Mexican Obese Adolescents

Ambient air pollution is a major global public health concern; little evidence exists about the effects of short-term exposure to ozone on components of metabolic syndrome in young obese adolescents. The inhalation of air pollutants, such as ozone, can participate in the development of oxidative stress, systemic inflammation, insulin resistance, endothelium dysfunction, and epigenetic modification. Metabolic alterations in blood in components of metabolic syndrome (MS) and short-term ambient air ozone exposure were determined and evaluated longitudinally in a cohort of 372 adolescents aged between 9 to 19 years old. We used longitudinal mixed-effects models to evaluate the association between ozone exposure and the risk of components of metabolic syndrome and its parameters separately, adjusted using important variables. We observed statistically significant associations between exposure to ozone in tertiles in different lag days and the parameters associated with MS, especially for triglycerides (20.20 mg/dL, 95% CI: 9.5, 30.9), HDL cholesterol (-2.56 mg/dL (95% CI: -5.06, -0.05), and systolic blood pressure (1.10 mmHg, 95% CI: 0.08, 2.2). This study supports the hypothesis that short-term ambient air exposure to ozone may increase the risk of some components of MS such as triglycerides, cholesterol, and blood pressure in the obese adolescent population.

Long-term effects of ambient PM2.5 constituents on metabolic syndrome in Chinese children and adolescents

Metabolic syndrome (MetS) is considered a main public health issue as it remarkably adds the risk of cardiovascular disease, leading to a heavy burden of disease. There is growing evidence linking fine particulate matter (PM_2.5) exposure to MetS. However, the influences of PM_2.5 constituents, especially in children and adolescents, remain unclear. Our study was according to a national analysis among Chinese children and adolescents to examine the associations between long-term exposure to PM_2.5 main constituents and MetS. A total of 10,066 children and adolescents aged 10-18 years were recruited in 7 provinces in China, with blood tests, health exams, and questionnaire surveys. We estimated long-term exposures to PM_2.5 mass and its five constituents, containing black carbon (BC), organic matter (OM), inorganic nitrate (NO₃^-), sulfate (SO₄^2-), and soil particles (SOIL) from multi-source data fusion models. Mixed-effects logistic regression models were used with the adjustment of a variety of covariates. In the surveyed populations, 2.9% were classified as MetS. From the single-pollutant models, we discovered that long-term exposures to PM_2.5 mass, BC, OM, NO₃^-, as well as SO₄^2-, were significantly associated with the prevalence of MetS, with odds ratios (ORs) per 1 μg/m³ that were 1.02 (95% confidence interval (CI): 1.01, 1.03) for PM_2.5 mass, 1.24 (95% CI: 1.14, 1.35) for BC, 1.07 (95% CI: 1.04, 1.11) for OM, 1.09 (95% CI: 1.04, 1.13) for NO₃^-, and 1.14 (95% CI:1.04, 1.24) for SO₄^2-. The influence of BC on the prevalence of MetS was robust in both the multi-pollutant model and the PM_2.5-constituent joint model. The paper indicates long-term exposure to PM_2.5 mass and specific PM_2.5 constituents, particularly for BC, was significantly associated with a higher MetS prevalence among children and adolescents in China. Our results highlight the significance of establishing further regulations on PM_2.5 constituents.

Ozone exposure induced risk of gestational diabetes mellitus

Numerous studies have shown that air pollution seems to be able to cause many diseases. Considering the possible mechanism of action and the same growth trend, the present study is designed to examine whether and how air pollutants, especially ozone (O₃) exposure, are associated with the incidence of gestational diabetes mellitus (GDM). By a retrospective cohort, we analyzed the records of 45439 pregnant women from 2013 to 2018 and matched them to maternal exposure to O₃. We found that the increased odds of GDM is associated with increased O₃ concentrations from the 1st month before pregnancy to the 3rd month during pregnancy. Specially, the odds ratios (ORs) of these associations were largest in the 1st month before pregnancy, suggesting that the effect of O₃ pollution on GDM occurred in pre-pregnancy period. Moreover, the exposure-response plot in the 1st month before pregnancy showed that the odds of GDM increased with the increasing concentration of O₃. Our findings provide the evidence that O₃ exposure in both pre-pregnancy and pregnancy period elevates the odds of GDM, suggesting that more intensive air pollution controls are needed to improve the health of pregnant women and their offspring.

Association between prenatal PM2.5 exposure and the risk of large for gestational age

BACKGROUND

The relationship between particulate matter <2.5 µm (PM2.5) and large for gestational age (LGA) is unclear, and studies conducted in highly polluted areas are lacking. We aimed to explore the association between PM2.5 and the risk of LGA in China.

METHODS

Maternal and neonatal characteristics were collected in the National Prepregnancy Examination Project. The definition of LGA was neonates with a weight over the 90th percentile for gestational age. Logistic regression was used to evaluate the relationship between PM2.5 exposure and the risk of LGA. The dose-response relationship was evaluated using a restricted cubic spline model.

RESULTS

There were 196,243 mother-neonate pairs included, among which the percentage of LGA was 15.3%. The average PM2.5 concentration was 75.29 µg/m³. A 10 µg/m³ increase in PM2.5 during the whole pregnancy was associated with an increased risk of LGA (odds ratio (OR) 1.097, 95% confidence interval (CI) 1.091-1.103). Pregnant women in the high-exposure group had a higher risk of giving birth to an LGA infant (OR 1.37, 95% CI 1.33-1.41). There was a nonlinear relationship between PM2.5 concentration and the risk of LGA, and the risk increased more rapidly at higher PM2.5 levels.

CONCLUSIONS

Prenatal exposure to PM2.5 was linked to an increased risk of LGA.

IMPACT

A nation-wide study in a highly polluted country suggested the association between prenatal PM2.5 exposure and LGA. A trimester-specific relationship between PM2.5 exposure and LGA was established. Call for attention on the pregnant women in highly polluted areas who were in high risk of giving birth to LGA.

Association of decreases in PM2.5 levels due to the implementation of environmental protection policies with the incidence of obesity in adolescents: A prospective cohort study

AIMS

To explore the association between decreased levels of particulate matter (≤2.5 µm; PM_2.5) due to the implementation of environmental protection policies and the incidence of obesity in adolescents in Chongqing, China through a prospective cohort study.

METHODS

A total of 2105 children (52.02% male; aged 7.33 ± 0.60 years at baseline) were enrolled from the Chongqing Children's Health Cohort. A mixed linear regression model was used to analyse the relationships of PM_2.5 levels with obesity indicators after adjusting for covariates. Additionally, a Poisson regression model was used to determine the relationship between PM_2.5 exposure and the incidence of overweight/obesity.

RESULTS

The average PM_2.5 exposure levels from participant conception to 2014, from 2015 to 2017, and from 2018 to 2019 were 66.64 ± 5.33 μg/m³, 55.49 ± 3.78 μg/m³, and 42.50 ± 1.87 μg/m³, respectively; these levels significantly decreased over time (P < 0.001). Throughout the entire follow-up period, the incidence of overweight/obesity after a ≥ 25 μg/m³ decrease in the PM_2.5 level was 4.57% among females; this incidence was the lowest among females who experienced remarkable decreases in PM_2.5 exposure. A 1-µg/m³ decrease in the PM_2.5 level significantly decreased the body mass index (BMI), BMI z score (BMI_z), and weight of adolescents (all P < 0.001). Compared with a < 20-μg/m³ decrease in the PM_2.5 level, a ≥ 25-μg/m³ decrease protected against increased BMI (net difference= -0.93; 95% confidence interval [CI]: (-1.23,-0.63) kg/m²), BMI_z (-0.28 (-0.39, -0.17)), weight (-1.59 (-2.44, -0.74) kg), and incidence of overweight/obesity (0.48 (0.37, 0.62), P < 0.001). Moreover, compared with a < 20-μg/m³ decrease in the PM_2.5 level, a ≥ 25-μg/m³ decrease resulted in significant absolute differences in BMI (-1.26 (-1.56, -0.96) kg/m²), BMI_z (-0.53 (-0.65, -0.40)) and weight (-3.01 (-3.8, -2.19) kg) (all P < 0.001).

CONCLUSIONS

This study showed the etiological relevance of declining PM_2.5 concentrations for the incidence of obesity in children and adolescents, suggesting that controlling ambient air pollutants may prevent the development of obesity in this age group. Continuous implementation of environmental protection policies in China has led to substantial health benefits.

How Does Environmental Information Disclosure Affect Public Health? Evidence from the New Ambient Air Quality Standards

Using a quasi-natural experiment of the implementation of the new Ambient Air Quality Standards in China, this paper assessed the impact of environmental information disclosure on public health. Our empirical results showed that environmental information disclosure (EID) largely improved both physical health and mental health. Moreover, we further investigated the air pollution channel, and the empirical results showed that EID could reduce the concentration of PM_2.5, which could cause an increase in public health as the concentration of PM_2.5 decreases. In addition, in terms of individual characteristics, the impact of EID was larger for men, people living in the countryside and people older than 60. In terms of the heterogeneity of cities, the impact of EID was larger in cities with higher public environmental concerns, and the impact of EID was more pronounced in core cities. For regional heterogeneity, the impact of EID on physical health was more pronounced in more developed regions, whereas the impact EID on mental health was higher in less developed regions.

Joint exposure to air pollution, ambient temperature and residential greenness and their association with metabolic syndrome (MetS): A large population-based study among Chinese adults

Previous studies assessing adverse health have traditionally focused on a single environmental exposure, failing to reflect the reality of various exposures present simultaneously. Air pollution, ambient temperature and greenness have been proposed as critical environmental factors associated with metabolic syndrome (MetS). However, evidence exploring their joint relationships with MetS is needed for identifying interactive factors and developing more targeted public health interventions. The baseline data was obtained from China Multi-Ethnic Cohort (CMEC). Environmental data of air pollutants (PM_2.5, O₃) and NDVI for greenness was calculated from satellites data. Ambient temperature data were obtained from European Center for Medium-Range Weather Forecasts (ECMWF). MetS was classified based on National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) using anthropometric measures and biomarkers. Logistic regression models were utilized to examine the combined relationship of MetS with three-year exposure to air pollutants, temperature and NDVI. Relative excess risk due to interaction (RERI) was calculated to evaluate interaction on an additive scale. We found associations between prevalent MetS and interquartile range (IQR) increases in PM_2.5 (OR: 1.38; 95% confidence interval [95% CI]: 1.23, 1.55) and O₃ (OR: 1.15; 95% CI: 1.09, 1.22). Additive and multiplicative interactions were observed between air pollutants and temperature exposure. Compared to low-temperature level, the relationship between PM_2.5 and MetS attenuated (RERI: 0.22, 95% CI: 0.44, -0.04) at high-temperature level, while the relationship between O₃ and MetS enhanced (RERI: 0.05, 95% CI: 0.02, 0.11). At low NDVI 250 m, the association between PM_2.5 and MetS was stronger (RERI: 0.13, 95% CI: 0.05, 0.19) with high NDVI 250 m as the reference group. Our findings showed that ambient temperature and residential greenness could affect the relationship between air pollutants and MetS.

Healthier Lifestyles Attenuated Association of Single or Mixture Exposure to Air Pollutants with Cardiometabolic Risk in Rural Chinese Adults

There is little research on how long-term exposure to independent and multiple air pollutants changes cardiometabolic risk in adults. In addition, previous studies focused on only the effect of one or two lifestyles on cardiometabolic risk. The evidence on the interactive effects of the lifestyle score and exposure to independent and mixtures of air pollutants on cardiometabolic risk is lacking. A total of 33,638 rural residents were included in the cross-sectional study. The three-year average concentrations of air pollutants for participants were predicted by using a satellite-based prediction. The air pollution score was created to assess the combined exposure of four air pollutants (PM1, PM2.5, PM10, and NO2). A gender−age-specific cardiometabolic risk score was calculated. Multivariable-adjusted linear regression and quantile g-computation were used to investigate the associations between air pollutants and cardiometabolic risk. Interaction plots were applied to describe the interactive effects of air pollution and the healthy lifestyle score on cardiometabolic risk. Per interquartile range (IQR) unit increases in PM1, PM2.5, PM10, or NO2 were associated with 0.162 (95% CI: 0.091, 0.233), 0.473 (95% CI: 0.388, 0.559), 0.718 (95% CI: 0.627, 0.810), and 0.795 (95% CI: 0.691, 0.898) unit increases in cardiometabolic risk score (all p < 0.05), respectively. A 0.854 (95% CI: 0.768, 0.940) unit increase in cardiometabolic risk was associated with each IQR increase in air pollution score. Furthermore, the strengths of associations of PM1, PM2.5, PM10, NO2, and the air pollution score on cardiometabolic risk score were attenuated with the healthy lifestyle score increase. In addition, there was no statistical significance after the lifestyle score equal to four scores for the effect of PM1 on the cardiometabolic risk score. In conclusions, individual or joint air pollutants were associated with an increased cardiometabolic risk. Improving the healthy lifestyle may be an effective method to improve cardiometabolic health in highly polluted rural regions.

Exposure to outdoor and indoor air pollution and risk of overweight and obesity across different life periods: A review

Due to the highly evolved industrialization and modernization, air quality has deteriorated in most countries. As reported by the World Health Organization (WHO), air pollution is now considered as one of the major threats to global health and a principal risk factor for noncommunicable diseases. Meanwhile, the increasing worldwide prevalence of overweight and obesity is attracting more public attentions. Recently, accumulating epidemiological studies have provided evidence that overweight and obesity may be partially attributable to environmental exposure to air pollution. This review summarizes the epidemiological evidence for the correlation between exposure to various outdoor and indoor air pollutants (mainly particulate matter (PM), nitrogen oxides (NO_x), ozone (O₃), and polycyclic aromatic hydrocarbons (PAHs)) and overweight and obesity outcomes in recent years. Moreover, it discusses the multiple effects of air pollution during exposure periods throughout life and sex differences in populations. This review also describes the potential mechanism underlying the increased risk of obesity caused by air pollution, including inflammation, oxidative stress, metabolic imbalance, intestinal flora disorders and epigenetic modifications. Finally, this review proposes macro- and micro-measures to prevent the negative effects of air pollution exposure on the obesity prevalence.

Chronic exposure to traffic-related air pollution reduces lipid mediators of linoleic acid and soluble epoxide hydrolase in serum of female rats

Chronic exposure to traffic-related air pollution (TRAP) is known to promote systemic inflammation, which is thought to underlie respiratory, cardiovascular, metabolic and neurological disorders. It is not known whether chronic TRAP exposure dampens inflammation resolution, the homeostatic process for stopping inflammation and repairing damaged cells. In vivo, inflammation resolution is facilitated by bioactive lipid mediators known as oxylipins, which are derived from the oxidation of polyunsaturated fatty acids. To understand the effects of chronic TRAP exposure on lipid-mediated inflammation resolution pathways, we measured total (i.e. free+bound) pro-inflammatory and pro-resolving lipid mediators in serum of female rats exposed to TRAP or filtered air (FA) for 14 months. Compared to rats exposed to FA, TRAP-exposed rats showed a significant 36-48% reduction in fatty acid alcohols, specifically, 9-hydroxyoctadecadienoic acid (9-HODE), 11,12-dihydroxyeicosatetraenoic acid (11,12-DiHETE) and 16,17-dihydroxydocosapentaenoic acid (16, 17-DiHDPA). The decrease in fatty acid diols (11,12-DiHETE and 16, 17-DiHDPA) corresponded to a significant 34-39% reduction in the diol to epoxide ratio, a marker of soluble epoxide hydrolase activity; this enzyme is typically upregulated during inflammation. The findings demonstrate that 14 months exposure to TRAP reduced pro-inflammatory 9-HODE concentration and dampened soluble epoxide hydrolase activation, suggesting adaptive immune changes in lipid mediator pathways involved in inflammation resolution.

Abnormal fasting blood glucose enhances the risk of long-term exposure to air pollution on dyslipidemia: A cross-sectional study

Both long-term exposure to air pollution and abnormal fasting blood glucose (FBG) are linked to dyslipidemia prevalence. However, the joint role of air pollution and FBG on dyslipidemia remains unknown clearly. In this study, we aimed to test whether abnormal FBG could enhance the risks of long-term exposure to air pollutants on dyslipidemia in general Chinese adult population. The present study recruited 8917 participants from 4 cities in Hebei province, China. Participants' individual exposure to air pollutants was evaluated by the Empirical Bayesian Kriging statistical model in ArcGIS10.2 geographic information system. Dyslipidemia was defined according to Guidelines for the Prevention and Treatment of Dyslipidemia in Chinese Adults. Subjects were grouped into normal, prediabetes, diabetes according to FBG level. Generalized linear models were applied to analyze the interaction of air pollutants and FBG on dyslipidemia prevalence. The prevalence of dyslipidemia was 43.83% in our investigation. After adjusting all covariates, we found the risk of four air pollutants (PM_2.5, PM₁₀, NO₂, SO₂) on dyslipidemia prevalence was stronger as higher FBG level, and the adjusted odd ratio of interaction (OR_inter (95% CI)) between PM_2.5, PM₁₀, NO₂, SO₂ and FBG levels on dyslipidemia was 1.171 (1.162, 1.189), 1.119 (1.111, 1.127), 1.124 (1.115, 1.130), 1.107 (1.098, 1.115), respectively. Stratified analyses indicated the modifying effects of FBG on the association of air pollution with dyslipidemia were stronger among male, less than 65 years old, overweight/obesity (all P_inter<0.1). Our study concluded that high FBG levels strengthened the risk of long-term exposure to air pollution on dyslipidemia, especially more noticeable in male, less than 65 years old, overweight.

Air pollution, residential greenness, and metabolic dysfunction biomarkers: analyses in the Chinese Longitudinal Healthy Longevity Survey

BACKGROUND

We hypothesize higher air pollution and fewer greenness exposures jointly contribute to metabolic syndrome (MetS), as mechanisms on cardiometabolic mortality.

METHODS

We studied the samples in the Chinese Longitudinal Healthy Longevity Survey. We included 1755 participants in 2012, among which 1073 were followed up in 2014 and 561 in 2017. We used cross-sectional analysis for baseline data and the generalized estimating equations (GEE) model in a longitudinal analysis. We examined the independent and interactive effects of fine particulate matter (PM_2.5) and Normalized Difference Vegetation Index (NDVI) on MetS. Adjustment covariates included biomarker measurement year, baseline age, sex, ethnicity, education, marriage, residence, exercise, smoking, alcohol drinking, and GDP per capita.

RESULTS

At baseline, the average age of participants was 85.6 (SD: 12.2; range: 65-112). Greenness was slightly higher in rural areas than urban areas (NDVI mean: 0.496 vs. 0.444; range: 0.151-0.698 vs. 0.133-0.644). Ambient air pollution was similar between rural and urban areas (PM_2.5 mean: 49.0 vs. 49.1; range: 16.2-65.3 vs. 18.3-64.2). Both the cross-sectional and longitudinal analysis showed positive associations of PM_2.5 with prevalent abdominal obesity (AO) and MetS, and a negative association of NDVI with prevalent AO. In the longitudinal data, the odds ratio (OR, 95% confidence interval-CI) of PM_2.5 (per 10 μg/m³ increase) were 1.19 (1.12, 1.27), 1.16 (1.08, 1.24), and 1.14 (1.07, 1.21) for AO, MetS and reduced high-density lipoprotein cholesterol (HDL-C), respectively. NDVI (per 0.1 unit increase) was associated with lower AO prevalence [OR (95% CI): 0.79 (0.71, 0.88)], but not significantly associated with MetS [OR (95% CI): 0.93 (0.84, 1.04)]. PM_2.5 and NDVI had a statistically significant interaction on AO prevalence (p_interaction: 0.025). The association between PM_2.5 and MetS, AO, elevated fasting glucose and reduced HDL-C were only significant in rural areas, not in urban areas. The association between NDVI and AO was only significant in areas with low PM_2.5, not under high PM_2.5.

CONCLUSIONS

We found air pollution and greenness had independent and interactive effect on MetS components, which may ultimately manifest in pre-mature mortality. These study findings call for green space planning in urban areas and air pollution mitigation in rural areas.

Obesity II: Establishing causal links between chemical exposures and obesity

Obesity is a multifactorial disease with both genetic and environmental components. The prevailing view is that obesity results from an imbalance between energy intake and expenditure caused by overeating and insufficient exercise. We describe another environmental element that can alter the balance between energy intake and energy expenditure: obesogens. Obesogens are a subset of environmental chemicals that act as endocrine disruptors affecting metabolic endpoints. The obesogen hypothesis posits that exposure to endocrine disruptors and other chemicals can alter the development and function of the adipose tissue, liver, pancreas, gastrointestinal tract, and brain, thus changing the set point for control of metabolism. Obesogens can determine how much food is needed to maintain homeostasis and thereby increase the susceptibility to obesity. The most sensitive time for obesogen action is in utero and early childhood, in part via epigenetic programming that can be transmitted to future generations. This review explores the evidence supporting the obesogen hypothesis and highlights knowledge gaps that have prevented widespread acceptance as a contributor to the obesity pandemic. Critically, the obesogen hypothesis changes the narrative from curing obesity to preventing obesity.

The Impact of PM2.5 on the Growth Curves of Children's Obesity Indexes: A Prospective Cohort Study

Aims

To explore the effect of long-term exposure to particulate matter with an aerodynamic diameter of 2.5 μm or less (PM2.5) on childhood obesity based on a cohort study in Chongqing.

Methods

A total of 4,284 children aged 6-8 years at baseline were enrolled from the Chongqing Children Health Cohort in 2014-2015 and were followed up in 2019. A stratified cluster sampling was applied to select the participants. A Mixed-effects linear regression model was used to examine the effect of long-term exposure to PM2.5 on the growth curve of obesity indicators [including body mass index (BMI), BMI Z-score (BMIz), and waist-to-height ratio (WHtR)]. A mixed-effects logistic regression model was used to study the dose relationship between PM2.5 exposure and the risk of obesity indicators.

Results

A higher level of accumulating exposure to PM2.5 was associated with an increased childhood obesity index, and the effect was the most significant for WHtR than BMI and BMIz. This effect was more pronounced in boys than in girls except for WHtR, and it was the most significant under the PM2.5 exposure period from pregnancy to 6 years old. Compared the annual average PM2.5 exposure level of <60 μg/m³, the WHtR and BMI were increased by 0.019 [(95% CIs): 0.014, 0.024] and 0.326 [(95% CIs): 0.037, 0.616] Kg/m² for participants living with the PM2.5 exposure level of 70-75 μg/m³, respectively. For every 5 μg/m³ increase in PM2.5 levels (from pregnancy to 6 years old), the risk of central obesity was increased by 1.26 {odds ratio [OR] (95% CIs): 1.26 (1.16, 1.37), p < 0.001} times.

Conclusions

This study confirmed a dose-response relationship between PM2.5 exposure and childhood obesity, especially central obesity, suggesting that controlling ambient air pollution can prevent the occurrence of obesity in children and adolescents.

The Association between Childhood Exposure to Ambient Air Pollution and Obesity: A Systematic Review and Meta-Analysis

Obesity has become a worldwide epidemic; 340 million of children and adolescents were overweight or obese in 2016, and this number continues to grow at a rapid rate. Epidemiological research has suggested that air pollution affects childhood obesity and weight status, but the current evidence remains inconsistent. Therefore, the aim of this meta-analysis was to estimate the effects of childhood exposure to air pollutants on weight. A total of four databases (PubMed, Web of Science, Embase, and Cochrane Library) were searched for publications up to December 31, 2021, and finally 15 studies met the inclusion criteria for meta-analysis. Merged odds ratios (ORs), coefficients (β), and 95% confidence intervals (95% CIs) that were related to air pollutants were estimated using a random-effects model. The meta-analysis indicated that air pollutants were correlated with childhood obesity and weight gain. For obesity, the association was considerable for PM₁₀ (OR = 1.12, 95% CI: 1.06, 1.18), PM_2.5 (OR = 1.28, 95% CI: 1.13, 1.45), PM₁ (OR = 1.41, 95% CI: 1.30, 1.53), and NO₂ (OR = 1.11, 95% CI: 1.06, 1.18). Similarly, BMI status increased by 0.08 (0.03-0.12), 0.11 (0.05-0.17), and 0.03 (0.01-0.04) kg/m² with 10 μg/m³ increment in exposure to PM₁₀, PM_2.5, and NO₂. In summary, air pollution can be regarded as a probable risk factor for the weight status of children and adolescents. The next step is to conduct longer-term and large-scale studies on different population subgroups, exposure concentrations, and pollutant combinations to provide detailed evidence. Meanwhile, integrated management of air pollution is essential.

Individual and joint effects of prenatal green spaces, PM2.5 and PM1 exposure on BMI Z-score of children aged two years: A birth cohort study

BACKGROUND

Few studies examined the association of prenatal exposure to green spaces with children's body mass index (BMI) Z-score, and no study evaluated the joint effect of prenatal green spaces and PM_2.5 or PM₁ exposure on children's BMI Z-score. We aimed to assess the individual and joint effects of prenatal green spaces, PM_2.5, and PM₁ exposure on BMI Z-score of children aged two years.

METHODS

The study was based on a birth cohort in Beijing, China, in which 13,253 mothers (LMP from 2014 to 2017) and their children were included. We estimated prenatal green spaces exposure by calculating average normalized difference vegetation index with 500 m buffers (NDVI-500), prenatal PM_2.5 and PM₁ exposure based on maternal residential addresses. Weight and height of children were measured at 2 years old. We calculated children's BMI Z-score based on the WHO Standards. Generalized linear regression was used to examine the individual and joint effects of prenatal NDVI-500, PM_2.5 and PM₁ exposure on children's BMI Z-score.

RESULTS

A 0.1 increase in prenatal NDVI-500 exposure, a 10 μg/m³ decrease in PM_2.5, a 10 μg/m³ decrease in PM₁ were associated with 0.185 [95% confidence interval (95%CI): 0.155, 0.216], 0.034 (95%CI: 0.015, 0.052) and 0.041 (95%CI: 0.020, 0.061) increase of children's BMI Z-score, respectively. Compared with those exposed to low-level NDVI-500 (not greater than median) and high-level PM_2.5 (greater than median), the BMI Z-score was higher in children whose mother exposed to high-level of NDVI-500 and low-level PM_2.5 [β:0.172 (95%CI: 0.131, 0.214), P_interaction = 0.003]. Compared with those exposed to low-level NDVI-500 and high-level PM₁, the BMI Z-score was higher in children whose mother exposed to high-level of NDVI-500 and low-level PM₁ [β:0.169 (95%CI: 0.127, 0.210), P_interaction<0.001]. In the trimester-specific analysis, NDVI-500 and PM exposure during the second trimester have a consistent individual effect, together with a joint effect, on child growth.

CONCLUSION

The study suggested the beneficial effect of prenatal exposure to green spaces on child growth and its interaction with PM_2.5 and PM₁, especially in the second trimester. The findings call for developing public health policy to improve green infrastructure and control PM_2.5 and PM₁ concentrations, in order to promote child growth.

Ambient air pollution during pregnancy and cardiometabolic biomarkers in cord blood

Prenatal air pollution exposure has been associated with adverse childhood cardiometabolic outcomes. It is unknown whether evidence of metabolic disruption associated with air pollution is identifiable at birth. We examined exposure to prenatal ambient air pollution and cord blood cardiometabolic biomarkers among 812 mother-infant pairs in the Healthy Start study.

Association between residential greenness and overweight/obesity among rural adults in northwestern China

BACKGROUND

Living in greener areas may reduce adiposity, but epidemiological evidence on this topic is still inconsistence and limited, especially in rural areas.

METHODS

We performed a cross-sectional study among 4651 Uyghur adults in rural areas in Xinjiang province, northwestern China, from May to September 2016. We measured residential greenness levels using satellite-derived Normalized Difference Vegetation Index (NDVI) and Soil Adjusted Vegetation Index (SAVI) in 100 m, 300 m, 500 m, and 1000 m buffers around each home address. Body height, weight, and waist circumference were assessed according to recommended guidelines. Data on baseline characteristics and confounders were collected using a questionnaire. We used generalized linear mixed models to estimate the associations of residential greenness with overweight/obesity prevalence and obesity-related anthropometric indices.

RESULTS

Higher residential greenness levels were associated with lower waist circumference and body mass index levels, as well as with a lower odds ratio of peripheral overweight/obesity prevalence. No significant association was found for greenness and central obesity prevalence. The associations persisted in magnitude and direction across several sensitivity analyses we performed. Stratified analysis suggested that the associations were generally stronger in older adults than those in younger adults. Additionally, neither air pollutants nor physical activity significantly mediated the associations between greenness and obesity.

CONCLUSIONS

Our results suggest that higher residential greenness were associated with lower odds of overweight/obesity and lower obesity-related anthropometric indices among rural Uyghur adults in China, especially for older adults.

Associations of perinatal exposure to PM2.5 with gestational weight gain and offspring birth weight

BACKGROUND

PM_2.5 have been associated with weight change in animal models and non-pregnant populations. Evidence of associations between PM_2.5 and gestational weight gain (GWG), an important determinant of course and outcomes of pregnancy, and subsequent birth outcomes is limited.

METHODS

The study was conducted among a subset of participants from the Omega Study, a prospective pregnancy cohort. Exposure to PM_2.5 (μg/m³) was ascertained for participants (N = 855) based on their residential address using a validated national spatiotemporal model. Adjusted multivariable linear regression models were used to estimate associations of trimester-specific and pregnancy-month PM_2.5 exposures with early (<20 weeks gestation), late (≥20 weeks gestation), and total GWG and infant birth weight. Stratified models and product terms were used to examine whether pre-pregnancy BMI (ppBMI) and infant sex modified the associations.

RESULTS

Average monthly PM_2.5 exposure during the first, second, and third trimesters were 7.3 μg/m³, 7.9 μg/m³, and 7.7 μg/m³, respectively. Higher third trimester PM_2.5 exposure was associated with higher late (0.40 kg per 5 μg/m (McDowell et al., 2018); 95%CI: 0.12, 0.67) and total (0.35 kg; 95%CI: 0.01, 0.70) GWG among participants with normal ppBMI. Higher second month PM_2.5 exposure was associated with lower early (-0.70 kg; 95%CI: 1.22, -0.18), late (-0.84 kg; 95% CI: 1.54, -0.14), and total (-1.70 kg; 95%CI: 2.57, -0.82) GWG among participants with overweight/obese ppBMI. Product terms between PM_2.5 and ppBMI were significant for second month PM_2.5 exposure and early (p-value = 0.01) and total GWG (p-value<0.01). Higher third trimester PM_2.5 exposure was associated with higher birth weight, though higher fourth month PM_2.5 exposure was associated with lower birth weight, particularly among those with normal ppBMI and male infants.

CONCLUSIONS

Associations of PM_2.5 with GWG vary by exposure window and ppBMI, while associations of PM_2.5 with birth weight potentially vary by exposure window, ppBMI and infant sex. Further exploration of associations between PM_2.5 and maternal/child health outcomes are needed.

Statistical Analysis of PM10 Concentration in the Monterrey Metropolitan Area, Mexico (2010–2018)

Air-quality monitoring and analysis are initial parts of a comprehensive strategy to prevent air pollution in cities. In such a context, statistical tools play an important role in determining the [d=R1]time-series trendstrend of time series, locating areas with high [d=R1]pollutant concentrationsconcentration of pollutants, and building predictive models. In this work, we analyzed the spatio-temporal behavior of the pollutant PM10 in the Monterrey Metropolitan Area (MMA), Mexico during the period 2010–2018 by applying statistical analysis to the time series of seven environmental stations. [d=R1]First, weWe used experimental variograms and scientific visualization to determine the general trends and variability in time. Then, fractal exponents (the Hurst rescaled range and Higuchi algorithm) were used to analyze the long-term dependence of the time series and characterize the study area by correlating that dependence with the geographical parameters of each environmental station. The results suggest a linear decrease in PM10 concentration, which showed an annual cyclicity[d=R1]. The, with the autumn-winter period [d=R1]wasas the most polluted and the spring-summer period [d=R1]wasas the least. Furthermore, it was found that the highest average concentrations are located in the western and high-altitude zones of the MMA, and that average concentration is related in a quadratic way to the Hurst and Higuchi exponents, which in turn are related to some geographic parameters. Therefore, [d=R1]in additionadditionally to the results for the MMA, the present paper shows three [d=R1]practicaluseful statistical methods for analyzing the spatio-temporal behavior of air quality.