Role of autonomic reflex arcs in cardiovascular responses to air pollution exposure

Neuroendocrine contribution to sex-related variations in adverse air pollution health effects

Air pollution exposure is ranked as a leading environmental risk factor for not only cardiopulmonary diseases but also for systemic health ailments including diabetes, reproductive abnormalities, and neuropsychiatric disorders, likely mediated by central neural stress mechanisms. Current experimental evidence links many air pollution health outcomes with activation of neuroendocrine sympathetic-adrenal-medullary and hypothalamic-pituitary-adrenal (HPA) stress axes associated with resultant increases in adrenal-derived hormone levels acting as circulating mediators of multi-organ stress reactions. Epidemiological and experimental investigations also demonstrated sex-specific responses to air pollutant inhalation, which may be attributed to hormonal interactions within the stress and reproductive axes. Sex hormones (androgens and estrogens) interact with neuroendocrine functions to influence hypothalamic responses, subsequently augmenting stress-mediated metabolic and immune changes. These neurohormonal interactions may contribute to innate sex-specific responses to inhaled irritants, inducing differing individual susceptibility. The aim of this review was to: (1) examine neuroendocrine co-regulation of the HPA axis by gonadal hormones, (2) provide experimental evidence demonstrating sex-specific respiratory and systemic effects attributed to air pollutant inhalation exposure, and (3) postulate proposed mechanisms of stress and sex hormone interactions during air pollution-related stress.

Indoor air pollution impacts cardiovascular autonomic control during sleep and the inflammatory profile

The present study explores the modifications of cardiovascular autonomic control (CAC) during wake and sleep time and the systemic inflammatory profile associated with exposure to indoor air pollution (IAP) in a cohort of healthy subjects. Twenty healthy volunteers were enrolled. Indoor levels of fine particulate matter (PM2.5), nitrogen dioxide (NO2) and volatile organic compounds (VOCs) were monitored using a portable detector for 7 days. Together, a 7-day monitoring was performed through a wireless patch that continuously recorded electrocardiogram, respiratory activity and actigraphy. Indexes of CAC during wake and sleep time were derived from the biosignals: heart rate and low-frequency to high-frequency ratio (LF/HF), index of sympathovagal balance with higher values corresponding to a predominance of the sympathetic branch. Cyclic variation of heart rate index (CVHRI events/hour) during sleep, a proxy for the evaluation of sleep apnea, was assessed for each night. After the monitoring, blood samples were collected to assess the inflammatory profile. Regression and correlation analyses were performed. A positive association between VOC exposure and the CVHRI (Δ% = +0.2% for 1 μg/m3 VOCs, p = 0.008) was found. The CVHRI was also positively associated with LF/HF during sleep, thus higher CVHRI values corresponded to a shift of the sympathovagal balance towards a sympathetic predominance (r = 0.52; p = 0.018). NO2 exposure was positively associated with both the pro-inflammatory biomarker TREM-1 and the anti-inflammatory biomarker IL-10 (Δ% = +1.2% and Δ% = +2.4%, for 1 μg/m3 NO2; p = 0.005 and p = 0.022, respectively). The study highlights a possible causal relationship between IAP exposure and higher risk of sleep apnea events, associated with impaired CAC during sleep, and a pro-inflammatory state counterbalanced by an increased anti-inflammatory response in healthy subjects. This process may be disrupted in vulnerable populations, leading to a harmful chronic pro-inflammatory profile. Thus, IAP may emerge as a critical and often neglected risk factor for the public health that can be addressed through targeted preventive interventions.

Exploring the impact of occupational exposure: A study on cardiovascular autonomic functions of male gas station attendants in Sri Lanka

Fuel dispensing at fuel stations is performed manually by unprotected male gas station attendants in Sri Lanka, who have long working hours. These workers are exposed to hydrocarbon fuels associated with multiple health effects by modulation of the autonomic nervous system. This study was performed to determine cardiovascular autonomic functions among fuel pump attendants in Sri Lanka. Fuel pump attendants (n = 50) aged between 19 and 65 years were identified for the study from seven fuel stations. They were compared with age- and gender-matched controls (n = 46) without occupational exposure to fuel. A physical examination was performed before the autonomic function and heart rate variability (HRV) assessment. There were no significant differences in weight, height, or BMI between the study and the control populations (p > 0.05). Both the systolic blood pressure (SBP) (Mann Whitney U (MWU) = 743.5, p = 0.003) and diastolic blood pressure (DBP) (MWU = 686.5, p = 0.001) were significantly higher among the gas station attendants compared to controls. Valsalva ratio was significantly higher among the study group (MW U = 874.00, p = 0.043) compared to controls. The HRV analysis showed significantly higher SDNN and SD2 (MWU = 842.00, p = 0.034, and MWU = 843.50, p = 0.035 respectively) among the gas station attendants compared to controls. The changes to the cardiovascular autonomic parameters among those exposed to fuel vapor as a gas station attendant indicate an increase in sympathetic outflow to the vessels. In the occupational setting as fuel pump attendants need periodic monitoring.

Impact of Wildfire Smoke on Acute Illness

Climate change increases wildfire smoke exposure. Inhaled smoke causes inflammation, oxidative stress, and coagulation, which exacerbate cardiovascular and respiratory disease while worsening obstetric and neonatal outcomes.

Air Pollution Increases Risk of Occurrence of Intracerebral Haemorrhage but Not of Subarachnoid Haemorrhage: Time-Series Cross-Sectional Study

(1) Background: Haemorrhagic strokes (HS), including intracerebral (ICH) and subarachnoid haemorrhages (SAH), account for approximately 10-15% of strokes worldwide but are associated with worse functional outcomes and higher rates of mortality, and financial burden than ischemic stroke. There is evidence that confirmed poor air quality may increase the incidence of haemorrhagic strokes. The aim of our study was to evaluate the association between individual ambient air pollutants and the risk of haemorrhagic stroke in an urban environment without high levels of air pollution. (2) Methods: A time-series cross-sectional study design was used. A daily air pollution concentration (Agency of Regional Air Quality Monitoring in the Gdansk Metropolitan Area) and incidence of haemorrhagic strokes (National Health Fund) were obtained and covered the time period from 1 January 2014 to 31 December 2018. A generalised additive model with Poisson regression was used to estimate the associations between 24-h mean concentrations of SO2, NO, NO2, NOx, CO, PM10, PM2.5, and O3 and a daily number of haemorrhagic strokes. (3) Results: The single-day lag model results showed that NO2, NO and NOx exposure was associated with increased risk of ICH (88% events) with RR of 1.059 (95% CI: 1.015-1.105 for lag0), 1.033 (95% CI: 1.007-1.060 for lag0) and 1.031 (95% CI: 1.005-1.056 for lag0), but not for SAH (12% events). Exposure to CO was related to a substantial and statistically significant increase in incidence for 1.031 (95% CI: 1.002-1.061 for lag0) but not for SAH. Higher SO2, PM10, PM2.5, and O3 exposures were not significantly related to both ISC and SAH. (4) Conclusions: In this time-series cross-sectional study, we found strong evidence that supports the hypothesis that transient elevations in ambient NO2, NO and CO are associated with a higher relative risk of intracerebral but not subarachnoid haemorrhage.

Association between residential air pollution exposure and cardiovascular risk factors in adults living in northern France

Air pollution is associated with elevated cardiovascular mortality and an increase in cardiovascular risk factors. However, the literature data on associations between air pollution and cardiovascular risk factors are contradictory. To explore the relationship between residential exposure to atmospheric pollutants and cardiovascular risk factors (lipid biomarker and blood pressure levels). We studied a sample of 2339 adult participants in the ELISABET study from the Dunkirk and Lille urban areas of France. The mean annual exposure to atmospheric pollutants (PM10, NO2 and SO2) at the home address was estimated via an air dispersion model. The associations were probed in multivariate linear regression models. The mean NO2 level was 26.05 μg/m3 in Lille and 19.96 µg/m3 in Dunkirk. The mean PM10 level was 27.02 μg/m3 in Lille and 26.53 μg/m3 in Dunkirk. We detected a significant association between exposure to air pollutants and the high-density lipoprotein (HDL) (which is a protective factor against cardiovascular diseases) level: for a 2 µg/m3 increment in PM10, the HDL level decreased by 1.72% (p = 0.0037). None of the associations with other lipid variables or with blood pressure were significant. We didn't find evidence significant associations for most of the risk factors but, long-term exposure of adults to moderate levels of ambient air pollution was associated with a decrement in HDL.

Long-term exposure to PM2.5 and its components is associated with elevated blood pressure and hypertension prevalence: Evidence from rural adults

INTRODUCTION

The toxicity of fine particulate matter (PM2.5) is determined by its components, while the evidence regarding associations of PM2.5 components with blood pressure (BP) is limited, especially in rural areas.

OBJECTIVES

This study aimed to explore the associations of PM2.5 and its chemical components with systolic BP (SBP), diastolic BP (DBP), pulse pressure (PP), mean artery pressure (MAP) levels and hypertension prevalence, and to identify key components in Chinese rural areas.

METHODS

39,211 adults from the Henan Rural Cohort were included during 2015-2017. Different periods of PM2.5 and chemical components were estimated by hybrid satellite model. The single-pollutant, component-PM2.5 model, component-residual model and component-proportion model were applied to explore the associations of pollutants with BP levels and hypertension prevalence. Exposure-response (E-R) relationships, stratified analyses and sensitivity analyses were used to explore these associations further.

RESULTS

12,826 (32.71%) were identified with hypertension. For each 1 μg/m3 increase of pollutants, the adjusted odds ratio (OR) for hypertension prevalence was 1.03 for PM2.5 mass, 1.40 for BC, 1.16 for NH4+, 1.08 for NO3-, 1.17 for OM, 1.12 for SO42- and 1.25 for SOIL in the single-pollutant model. BC and SOIL were statistically significant in the component-PM2.5 model, component-residual model and component-proportion model. Similarly, associations of these pollutants with elevated BP levels were also found in aforementioned four models. These pollutants produced a stronger association with SBP than DBP, PP and MAP. Most of associations were non-linear in E-R relationships. The groups of older, the men, with lower per capita monthly income, lower educational level and higher BMI were more vulnerable to these pollutants in stratified analyses. The results remained stable in sensitivity analyses.

CONCLUSION

Long-term exposure to PM2.5 and its components, especially BC and SOIL, was associated with elevated BP and hypertension prevalence in rural adults, and decreasing pollutants may provide additional benefits.

Impact of Wildfires on Cardiovascular Health

Wildfire smoke (WFS) is a mixture of respirable particulate matter, environmental gases, and other hazardous pollutants that originate from the unplanned burning of arid vegetation during wildfires. The increasing size and frequency of recent wildfires has escalated public and occupational health concerns regarding WFS inhalation, by either individuals living nearby and downstream an active fire or wildland firefighters and other workers that face unavoidable exposure because of their profession. In this review, we first synthesize current evidence from environmental, controlled, and interventional human exposure studies, to highlight positive associations between WFS inhalation and cardiovascular morbidity and mortality. Motivated by these findings, we discuss preventative measures and suggest interventions to mitigate the cardiovascular impact of wildfires. We then review animal and cell exposure studies to call attention on the pathophysiological processes that support the deterioration of cardiovascular tissues and organs in response to WFS inhalation. Acknowledging the challenges of integrating evidence across independent sources, we contextualize laboratory-scale exposure approaches according to the biological processes that they model and offer suggestions for ensuring relevance to the human condition. Noting that wildfires are significant contributors to ambient air pollution, we compare the biological responses triggered by WFS to those of other harmful pollutants. We also review evidence for how WFS inhalation may trigger mechanisms that have been proposed as mediators of adverse cardiovascular effects upon exposure to air pollution. We finally conclude by highlighting research areas that demand further consideration. Overall, we aspire for this work to serve as a catalyst for regulatory initiatives to mitigate the adverse cardiovascular effects of WFS inhalation in the community and alleviate the occupational risk in wildland firefighters.

Effect of short-term exposure to air pollution on hospital admission for cardiovascular disease: A time-series study in Xiangyang, China

BACKGROUND

Data on the relationship between short-term exposure to air pollution and cardiovascular diseases (CVDs) and the potential modifying factors are limited and inconsistent.

OBJECTIVE

To explore the relationship between short-term exposure to air pollution and CVD risk, and potential modification effect factors.

METHOD

A time series study was conducted on 52,991 hospital admissions for CVD from 2015 to 2019 in Xiangyang City, China. Air pollution data from four national fixed monitoring stations were collected to estimate exposure level in Xiangyang City. A quasi-Poisson generalized additive model incorporating a distributed lag nonlinear model was applied to evaluate the association between air pollution and CVD risk. The potential modification effect of sex, age, and season on the above associations was also evaluated.

RESULTS

CVD risk was positively associated with air pollution. Peak associations in single lag day structures were observed for particulate matter ≤10 μm in aerodynamic (PM10; RR: 1.040, 95 % CI: 0.996-1.087), PM2.5 (1.025, 1.004-1.045), nitrogen dioxide (NO2; 1.074, 1.039-1.111), and sulfur dioxide (SO2; 1.079, 1.019-1.141) at Lag 0 and ozone (O3; 1.018, 1.004-1.031) at Lag 4. In cumulative lag day structures, the highest RRs were 1.225 (1.079,1.392) for PM10 at Lag 06, 1.054 (1.013, 1.098) for PM2.5 at Lag 03, 1.200 (1.119, 1.287) for NO2 at Lag 04, and 1.135 (1.025, 1.257) for SO2 at Lag 02. Moreover, the association between air pollution and CVD risk was modified by sex and age (P < 0.05). Females and individuals aged ≤65 years were more vulnerable to NO2 and had a higher CVD risk.

CONCLUSION

Short-term exposure to air pollution was positively associated with CVD risk. Moreover, sex and age could modify the effect of air pollution on CVD risk. Females and individuals aged ≤65 years had a higher NO2 exposure-induced CVD risk.

Long-term exposure to particulate matter is associated with elevated blood pressure: Evidence from the Chinese plateau area

Background

Ambient air pollution could increase the risk of hypertension; however, evidence regarding the relationship between long-term exposure to particulate matter and elevated blood pressure in plateau areas with lower pollution levels is limited.

Methods

We assessed the associations of long-term exposure to particulate matter (PM, PM1, PM2.5, and PM10) with hypertension, diastolic blood pressure (DBP), systolic blood pressure (SBP) and pulse pressure (PP) in 4.235 Tibet adults, based on the baseline of the China multi-ethnic cohort study (CMEC) in Lhasa city, Tibet from 2018-19. We used logistic regression and linear regression models to evaluate the associations of ambient PM with hypertension and blood pressure, respectively.

Results

Long-term exposure to PM1, PM2.5, and PM10 is positively associated with hypertension, DBP, and SBP, while negatively associated with PP. Among these air pollutants, PM10 had the strongest effect on hypertension, DBP, and SBP, while PM2.5 had the strongest effect on PP. The results showed for hypertension odds ratio (OR) = 1.99; 95% confidence interval (CI) = 1.58, 2.51 per interquartile range (IQR) μg/m3 increase in PM1, OR = 1.93; 95% CI = 1.55, 2.40 per IQR μg/m3 increase in PM2.5, and OR = 2.12; 95% CI = 1.67, 2.68 per IQR μg/m3 increase in PM10.

Conclusions

Long-term exposure to ambient air pollution was associated with an increased risk of hypertension, elevated SBP and DBP levels, and decreased PP levels. To reduce the risk of hypertension and PP reduction, attention should be paid to air quality interventions in plateau areas with low pollution levels.

Evaluation of neural reflex activation as a potential mode of action for respiratory and cardiovascular effects of fine particulate matter

OBJECTIVES

Mortality from respiratory and cardiovascular health conditions contributes largely to the total mortality that has been associated with exposure to PM2.5 in epidemiology studies. A mode of action (MoA) for these underlying morbidities has not been established, but it has been proposed that some effects of PM2.5 occur through activation of neural reflexes.

MATERIALS AND METHODS

We critically reviewed the experimental studies of PM2.5 (including ambient PM2.5, diesel exhaust particles, concentrated ambient particles, diesel exhaust, and cigarette smoke) and neural reflex activation, and applied the principles of the International Programme on Chemical Safety (IPCS) MoA/human relevance framework to assess whether they support a biologically plausible and human-relevant MoA by which PM2.5 could contribute to cardiovascular and respiratory causes of death. We also considered whether the evidence from these studies supports a non-threshold MoA that operates at low, human-relevant PM2.5 exposure concentrations.

RESULTS AND DISCUSSION

We found that the proposed MoA of neural reflex activation is biologically plausible for PM2.5-induced respiratory effects at high exposure levels used in experimental studies, but further studies are needed to fill important data gaps regarding the relevance of this MoA to humans at lower PM2.5 exposure levels. A role for the proposed MoA in PM2.5-induced cardiovascular effects is plausible for some effects but not others.

CONCLUSIONS

Further studies are needed to determine whether neural reflex activation is the MoA by which PM2.5 could cause either respiratory or cardiovascular morbidities in humans, particularly at the ambient concentrations associated with total mortality in epidemiology studies.

Prenatal Household Air Pollution Exposure and Childhood Blood Pressure in Rural Ghana

BACKGROUND

The association between prenatal household air pollution (HAP) exposure and childhood blood pressure (BP) is unknown.

OBJECTIVE

Within the Ghana Randomized Air Pollution and Health Study (GRAPHS) we examined time-varying associations between a) maternal prenatal and b) first-year-of-life HAP exposure with BP at 4 years of age and, separately, whether a stove intervention delivered prenatally and continued through the first year of life could improve BP at 4 years of age.

METHODS

GRAPHS was a cluster-randomized cookstove intervention trial wherein n = 1,414 pregnant women were randomized to one of two stove interventions: a) a liquefied petroleum gas (LPG) stove or improved biomass stove, or b) control (open fire cooking). Maternal HAP exposure over pregnancy and child HAP exposure over the first year of life was quantified by repeated carbon monoxide (CO) measurements; a subset of women (n = 368 ) also performed one prenatal and one postnatal personal fine particulate matter (PM 2.5 ) measurement. Systolic and diastolic BP (SBP and DBP) were measured in n = 667 4-y-old children along with their PM 2.5 exposure (n = 692 ). We examined the effect of the intervention on resting BP z -scores. We also employed reverse distributed lag models to examine time-varying associations between a) maternal prenatal and b) first-year-of-life HAP exposure and resting BP z -scores. Among those with PM 2.5 measures, we examined associations between PM 2.5 and resting BP z -scores. Sex-specific effects were considered.

RESULTS

Intention-to-treat analyses identified that DBP z -score at 4 years of age was lower among children born in the LPG arm (LPG β = - 0.20 ; 95% CI: - 0.36 , - 0.03 ) as compared with those in the control arm, and females were most susceptible to the intervention. Higher CO exposure in late gestation was associated with higher SBP and DBP z -score at 4 years of age, whereas higher late-first-year-of-life CO exposure was associated with higher DBP z -score. In the subset with PM 2.5 measurements, higher maternal postnatal PM 2.5 exposure was associated with higher SBP z -scores.

DISCUSSION

These findings suggest that prenatal and first-year-of-life HAP exposure are associated with child BP and support the need for reductions in exposure to HAP, with interventions such as cleaner cooking beginning in pregnancy. https://doi.org/10.1289/EHP13225.

Inhaled Volatile Molecules-Responsive TRP Channels as Non-Olfactory Receptors

Generally, odorant molecules are detected by olfactory receptors, which are specialized chemoreceptors expressed in olfactory neurons. Besides odorant molecules, certain volatile molecules can be inhaled through the respiratory tract, often leading to pathophysiological changes in the body. These inhaled molecules mediate cellular signaling through the activation of the Ca2+-permeable transient receptor potential (TRP) channels in peripheral tissues. This review provides a comprehensive overview of TRP channels that are involved in the detection and response to volatile molecules, including hazardous substances, anesthetics, plant-derived compounds, and pheromones. The review aims to shed light on the biological mechanisms underlying the sensing of inhaled volatile molecules. Therefore, this review will contribute to a better understanding of the roles of TRP channels in the response to inhaled molecules, providing insights into their implications for human health and disease.

Particulate Matter Air Pollution is a Significant Risk Factor for Cardiovascular Disease

Air pollution is responsible worldwide for 9-12 million deaths annually. The major contributor to air pollution is particulate matter ≤2.5 µg per cubic meter of air (PM2.5) from vehicles, industrial emissions, and wildfire smoke. United States ambient air standards recommend annual average PM2.5 concentrations of ≤12 μg/m³ while European standards allow an average annual PM2.5 concentration of ≤20 μg/m3. However, significant PM2.5 cardiovascular and pulmonary health risks exist below these concentrations. Chronic PM2.5 exposure significantly increases major cardiovascular and pulmonary event risks in Americans by 8 to more than 20% for each 10-μg/m3 increase in PM2.5. PM2.5-induced increases in lipid peroxidation, induction of vascular inflammation and endothelial cell injury initiate and propagate respiratory diseases, coronary and carotid atherosclerosis. PM2.5 can cause atherosclerotic vascular plaque rupture and myocardial infarction and stroke by activating metalloproteinases. This article discusses PM2.5 effects on the cardiovascular and pulmonary systems, specific PM2.5 pathophysiologic mechanisms contributing to cardiopulmonary disease, and preventive measures to limit the cardiovascular and pulmonary effects of PM2.5.

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.

Cigarette smoking and air pollution exposure and their effects on cardiovascular diseases

Cardiovascular disease (CVD) has no socioeconomic, topographical, or sex limitations as reported by the World Health Organization (WHO). The significant drivers of CVD are cardio-metabolic, behavioral, environmental, and social risk factors. However, some significant risk factors for CVD (e.g., a pitiable diet, tobacco smoking, and a lack of physical activities), have also been linked to an elevated risk of cardiovascular disease. Lifestyles and environmental factors are known key variables in cardiovascular disease. The familiarity with smoke goes along with the contact with the environment: air pollution is considered a source of toxins that contribute to the CVD burden. The incidence of myocardial infarction increases in males and females and may lead to fatal coronary artery disease, as confirmed by epidemiological studies. Lipid modification, inflammation, and vasomotor dysfunction are integral components of atherosclerosis development and advancement. These aspects are essential for the identification of atherosclerosis in clinical investigations. This article aims to show the findings on the influence of CVD on the health of individuals and human populations, as well as possible pathology and their involvement in smoking-related cardiovascular diseases. This review also explains lifestyle and environmental factors that are known to contribute to CVD, with indications suggesting an affiliation between cigarette smoking, air pollution, and CVD.

Exposure to urban nanoparticles at low PM[Formula: see text] concentrations as a source of oxidative stress and inflammation

Exposures to fine particulate matter (PM[Formula: see text]) have been associated with health impacts, but the understanding of the PM[Formula: see text] concentration-response (PM[Formula: see text]-CR) relationships, especially at low PM[Formula: see text], remains incomplete. Here, we present novel data using a methodology to mimic lung exposure to ambient air (2[Formula: see text] 60 [Formula: see text]g m[Formula: see text]), with minimized sampling artifacts for nanoparticles. A reference model (Air Liquid Interface cultures of human bronchial epithelial cells, BEAS-2B) was used for aerosol exposure. Non-linearities observed in PM[Formula: see text]-CR curves are interpreted as a result of the interplay between the aerosol total oxidative potential (OP[Formula: see text]) and its distribution across particle size (d[Formula: see text]). A d[Formula: see text]-dependent condensation sink (CS) is assessed together with the distribution with d[Formula: see text] of reactive species . Urban ambient aerosol high in OP[Formula: see text], as indicated by the DTT assay, with (possibly copper-containing) nanoparticles, shows higher pro-inflammatory and oxidative responses, this occurring at lower PM[Formula: see text] concentrations (< 5 [Formula: see text]g m[Formula: see text]). Among the implications of this work, there are recommendations for global efforts to go toward the refinement of actual air quality standards with metrics considering the distribution of OP[Formula: see text] with d[Formula: see text] also at relatively low PM[Formula: see text].

The mediation effect of lipids, blood pressure and BMI between air pollutant mixture and atherosclerotic cardiovascular disease: The CHCN-BTH cohort study

BACKGROUND

The combine effect of air pollutant mixture on atherosclerotic cardiovascular disease (ASCVD) remain undefined. This study aims to explore the association between long-term exposure of air pollutants and ASCVD, focusing on the mediating role of lipids, blood pressure and BMI.

METHODS

This study was based on the CHCN-BTH cohort study. The annual concentrations of air pollutants and PM2.5 constituents were sourced from in the Tracking Air Pollution in China (TAP) and ChinaHighAirPollutants (CHAP) datasets from 2014 to 2019. A Cox mixed-effects model was used to investigate the associations between long-term exposure of air pollutants and ASCVD. The combined impact of the air pollutant mixture was assessed using Quantile g-Computation. Stratified, sensitivity, and mediation analyses were conducted.

RESULTS

A total of 27,134 participants aged 18-80 were recruited in the present study. We found that each IQR increase of PM2.5, PM1, NO2, O3, BC, SO42-, and OM were significantly associated with the incidence of ASCVD, the hazard ratios (HRs) and 95 % confidence interval (CI) were 1.55 (1.35, 1.78), 1.46 (1.27, 1.67), 1.30 (1.21, 1.39), 1.66 (1.41,1.95), 2.14 (1.63, 2.83), 1.65 (1.25, 2.17) and 1.92(1.52, 2.45), respectively. The combined effect of air pollutant mixture on ASCVD was 1.79 (1.46, 2.20), PM2.5 contributed 83.3 % to this combined effect. Mediation effect models suggested that air pollutants and ASCVD might be mediated through SBP, DBP, HDL-C, LDL-C, hsCRP and BMI (mediation proportion range from 1.3 % to 26.1 %), Notably, HDL-C played mediation roles of 11.3 % (7.0 %, 18.4), 26.1 % (17.7 %, 38.1 %) and 25.4 % (15.4, 47.7 %) in the effects of long-term exposure to PM2.5, PM1 and OM on ASCVD, respectively.

CONCLUSIONS

Long-term, high-level air pollutant exposure was significantly associated with an elevated risk of ASCVD, particularly for PM2.5. Blood pressure, lipids and BMI, especially HDL-C, may mediate the effects of air pollutants exposure on ASCVD.

Impact of ultrafine particles and total particle number concentration on five cause-specific hospital admission endpoints in three German cities

INTRODUCTION

Numerous studies have shown associations between daily concentrations of fine particles (e.g., particulate matter with an aerodynamic diameter ≤2.5 µm; PM2.5) and morbidity. However, evidence for ultrafine particles (UFP; particles with an aerodynamic diameter of 10-100 nm) remains conflicting. Therefore, we aimed to examine the short-term associations of UFP with five cause-specific hospital admission endpoints for Leipzig, Dresden, and Augsburg, Germany.

MATERIAL AND METHODS

We obtained daily counts of (cause-specific) cardiorespiratory hospital admissions between 2010 and 2017. Daily average concentrations of UFP, total particle number (PNC; 10-800 nm), and black carbon (BC) were measured at six sites; PM2.5 and nitrogen dioxide (NO2) were obtained from monitoring networks. We assessed immediate (lag 0-1), delayed (lag 2-4, lag 5-7), and cumulative (lag 0-7) effects by applying station-specific confounder-adjusted Poisson regression models. We then used a novel multi-level meta-analytical method to obtain pooled risk estimates. Finally, we performed two-pollutant models to investigate interdependencies between pollutants and examined possible effect modification by age, sex, and season.

RESULTS

UFP showed a delayed (lag 2-4) increase in respiratory hospital admissions of 0.69% [95% confidence interval (CI): -0.28%; 1.67%]. For other hospital admission endpoints, we found only suggestive results. Larger particle size fractions, such as accumulation mode particles (particles with an aerodynamic diameter of 100-800 nm), generally showed stronger effects (respiratory hospital admissions & lag 2-4: 1.55% [95% CI: 0.86%; 2.25%]). PM2.5 showed the most consistent associations for (cardio-)respiratory hospital admissions, whereas NO2 did not show any associations. Two-pollutant models showed independent effects of PM2.5 and BC. Moreover, higher risks have been observed for children.

CONCLUSIONS

We observed clear associations with PM2.5 but UFP or PNC did not show a clear association across different exposure windows and cause-specific hospital admissions. Further multi-center studies are needed using harmonized UFP measurements to draw definite conclusions on the health effects of UFP.

The Effect of Ambient Air Pollution on Office, Home, and 24-Hour Ambulatory Blood Pressure Measurements

BACKGROUND

Air pollution has recently been linked to a number of cardiovascular diseases, particularly hypertension (HT). In our study, we aimed to evaluate the association between air pollution and blood pressure (BP) and compare the relationship of BP measurement results obtained using different methods (office, home, and 24-hour ambulatory BP monitoring [ABPM]).

METHODS

This retrospective nested panel study performed with prospective Cappadocia cohort data investigated the relationships between particulate matter (PM) 10 and sulfur dioxide (SO2) and concurrent home, office, and 24-hour ABPM data at each control performed over a 2-year period.

RESULTS

A total of 327 patients in the Cappadocia cohort were included in this study. On the day of office blood pressure measurement, there was an increase of 1.36 mm Hg in systolic BP and 1.18 mm Hg in diastolic BP for every 10 µm/m3 rise in SO2 values. A mean 3-day 10 µm/m3 increase in SO2 was linked to an increase of 1.60 mm Hg in systolic BP and 1.33 mm Hg in diastolic BP. A 10 µm/m3 rise in mean SO2 on the day of 24-hour ABPM measurement was found to be associated with an increase of 1.3 mm Hg in systolic BP and 0.8 mm Hg in diastolic BP. SO2 and PM 10 had no effect on home measurements.

CONCLUSION

In conclusion, increased SO2 levels, during winter months in particular, can be associated with an elevation in office BP values. Our study findings show that air pollution in the setting in which BP is measured may be associated with the results.

Short-term residential exposure to air pollution and risk of acute myocardial infarction deaths at home in China

Air pollution remains a major threat to cardiovascular health and most acute myocardial infarction (AMI) deaths occur at home. However, currently established knowledge on the deleterious effect of air pollution on AMI has been limited to routinely monitored air pollutants and overlooked the place of death. In this study, we examined the association between short-term residential exposure to China's routinely monitored and unmonitored air pollutants and the risk of AMI deaths at home. A time-stratified case-crossover analysis was undertaken to associate short-term residential exposure to air pollution with 0.1 million AMI deaths at home in Jiangsu Province (China) during 2016-2019. Individual-level residential exposure to five unmonitored and monitored air pollutants including PM1 (particulate matter with an aerodynamic diameter ≤ 1 μm) and PM2.5 (particulate matter with an aerodynamic diameter ≤ 2.5 μm), SO2 (sulfur dioxide), NO2 (nitrogen dioxide), and O3 (ozone) was estimated from satellite remote sensing and machine learning technique. We found that exposure to five air pollutants, even below the recently released stricter air quality standards of the World Health Organization (WHO), was all associated with increased odds of AMI deaths at home. The odds of AMI deaths increased by 20% (95% confidence interval: 8 to 33%), 22% (12 to 33%), 14% (2 to 27%), 13% (3 to 25%), and 7% (3 to 12%) for an interquartile range increase in PM1, PM2.5, SO2, NO2, and O3, respectively. A greater magnitude of association between NO2 or O3 and AMI deaths was observed in females and in the warm season. The greatest association between PM1 and AMI deaths was found in individuals aged ≤ 64 years. This study for the first time suggests that residential exposure to routinely monitored and unmonitored air pollutants, even below the newest WHO air quality standards, is still associated with higher odds of AMI deaths at home. Future studies are warranted to understand the biological mechanisms behind the triggering of AMI deaths by air pollution exposure, to develop intervention strategies to reduce AMI deaths triggered by air pollution exposure, and to evaluate the cost-effectiveness, accessibility, and sustainability of these intervention strategies.

Wildfire-related smoke inhalation worsens cardiovascular risk in sleep disrupted rats

Introduction

As a lifestyle factor, poor sleep status is associated with increased cardiovascular morbidity and mortality and may be influenced by environmental stressors, including air pollution.

Methods

To determine whether exposure to air pollution modified cardiovascular effects of sleep disruption, we evaluated the effects of single or repeated (twice/wk for 4 wks) inhalation exposure to eucalyptus wood smoke (ES; 964 μg/m3 for 1 h), a key wildland fire air pollution source, on mild sleep loss in the form of gentle handling in rats. Blood pressure (BP) radiotelemetry and echocardiography were evaluated along with assessments of lung and systemic inflammation, cardiac and hypothalamic gene expression, and heart rate variability (HRV), a measure of cardiac autonomic tone.

Results and Discussion

GH alone disrupted sleep, as evidenced by active period-like locomotor activity, and increases in BP, heart rate (HR), and hypothalamic expression of the circadian gene Per2. A single bout of sleep disruption and ES, but neither alone, increased HR and BP as rats transitioned into their active period, a period aligned with a critical early morning window for stroke risk in humans. These responses were immediately preceded by reduced HRV, indicating increased cardiac sympathetic tone. In addition, only sleep disrupted rats exposed to ES had increased HR and BP during the final sleep disruption period. These rats also had increased cardiac output and cardiac expression of genes related to adrenergic function, and regulation of vasoconstriction and systemic blood pressure one day after final ES exposure. There was little evidence of lung or systemic inflammation, except for increases in serum LDL cholesterol and alanine aminotransferase. These results suggest that inhaled air pollution increases sleep perturbation-related cardiovascular risk, potentially in part by increased sympathetic activity.

Association of SO2/CO exposure and greenness with high blood pressure in children and adolescents: A longitudinal study in China

Introduction

We aimed to investigate the association between greenness around schools, long-term gaseous air pollution exposure (SO₂ and CO), and blood pressure in children and adolescents.

Methods

From 2006 to 2018, a total of 219,956 Chinese children and adolescents aged 7-17 years in Beijing and Zhongshan were included in this longitudinal study. Annual average concentrations of SO₂ and CO and the mean values of normalized difference vegetation index around schools were calculated. We used the generalized estimation equation model, restricted cubic spline model, and Cox model to analyze the health effects.

Results

Among all the subjects, 52,515 had the first onset of HBP. During the follow-up, HBP's cumulative incidence and incidence density were 23.88% and 7.72 per 100 person-year respectively. Exposures to SO₂ and CO were significantly associated with SBP [β = 1.30, 95% CI: (1.26, 1.34) and 0.78 (0.75, 0.81)], DBP [β = 0.81 (0.79, 0.84) and 0.46 (0.44, 0.48)] and HBP [HR = 1.58 (1.57, 1.60) and 1.42 (1.41, 1.43)]. The risks of HBP attributed to SO₂ and CO pollution would be higher in school-aged children in the low greenness group: the attributable fractions (AFs) were 26.31% and 20.04%, but only 13.90% and 17.81% in the higher greenness group. The AFs were also higher for normal-BMI children and adolescents in the low greenness group (AFs = 30.90% and 22.64%, but 14.41% and 18.65% in the high greenness group), while the AFs were not as high as expected for obese children in the low greenness group (AFs = 10.64% and 8.61%), nor was it significantly lower in the high greenness group (AFs = 9.60% and 10.72%).

Discussion

Greenness could alleviate the damage effects of SO₂/CO exposure on the risks of HBP among children and adolescents, and the benefit is BMI sensitivity. It might offer insights for policymakers in making effective official interventions to prevent and control the prevalence of childhood HBP and the future disease burden caused by air pollution.

Impact of Ambient Ultrafine Particles on Cause-Specific Mortality in Three German Cities

Rationale: Exposure to ambient air pollution has been associated with adverse effects on morbidity and mortality. However, the evidence for ultrafine particles (UFPs; 10-100 nm) based on epidemiological studies remains scarce and inconsistent. Objectives: We examined associations between short-term exposures to UFPs and total particle number concentrations (PNCs; 10-800 nm) and cause-specific mortality in three German cities: Dresden, Leipzig, and Augsburg. Methods: We obtained daily counts of natural, cardiovascular, and respiratory mortality between 2010 and 2017. UFPs and PNCs were measured at six sites, and measurements of fine particulate matter (PM2.5; ⩽2.5 μm in aerodynamic diameter) and nitrogen dioxide were collected from routine monitoring. We applied station-specific confounder-adjusted Poisson regression models. We investigated air pollutant effects at aggregated lags (0-1, 2-4, 5-7, and 0-7 d after UFP exposure) and used a novel multilevel meta-analytical method to pool the results. Additionally, we assessed interdependencies between pollutants using two-pollutant models. Measurements and Main Results: For respiratory mortality, we found a delayed increase in relative risk of 4.46% (95% confidence interval, 1.52 to 7.48%) per 3,223-particles/cm3 increment 5-7 days after UFP exposure. Effects for PNCs showed smaller but comparable estimates consistent with the observation that the smallest UFP fractions showed the largest effects. No clear associations were found for cardiovascular or natural mortality. UFP effects were independent of PM2.5 in two-pollutant models. Conclusions: We found delayed effects for respiratory mortality within 1 week after exposure to UFPs and PNCs but no associations for natural or cardiovascular mortality. This finding adds to the evidence on the independent health effects of UFPs.

Intermittent Lead Exposure Induces Behavioral and Cardiovascular Alterations Associated with Neuroinflammation

The nervous system is the primary target for lead exposure and the developing brain appears to be especially susceptible, namely the hippocampus. The mechanisms of lead neurotoxicity remain unclear, but microgliosis and astrogliosis are potential candidates, leading to an inflammatory cascade and interrupting the pathways involved in hippocampal functions. Moreover, these molecular changes can be impactful as they may contribute to the pathophysiology of behavioral deficits and cardiovascular complications observed in chronic lead exposure. Nevertheless, the health effects and the underlying influence mechanism of intermittent lead exposure in the nervous and cardiovascular systems are still vague. Thus, we used a rat model of intermittent lead exposure to determine the systemic effects of lead and on microglial and astroglial activation in the hippocampal dentate gyrus throughout time. In this study, the intermittent group was exposed to lead from the fetal period until 12 weeks of age, no exposure (tap water) until 20 weeks, and a second exposure from 20 to 28 weeks of age. A control group (without lead exposure) matched in age and sex was used. At 12, 20 and 28 weeks of age, both groups were submitted to a physiological and behavioral evaluation. Behavioral tests were performed for the assessment of anxiety-like behavior and locomotor activity (open-field test), and memory (novel object recognition test). In the physiological evaluation, in an acute experiment, blood pressure, electrocardiogram, and heart and respiratory rates were recorded, and autonomic reflexes were evaluated. The expression of GFAP, Iba-1, NeuN and Synaptophysin in the hippocampal dentate gyrus was assessed. Intermittent lead exposure induced microgliosis and astrogliosis in the hippocampus of rats and changes in behavioral and cardiovascular function. We identified increases in GFAP and Iba1 markers together with presynaptic dysfunction in the hippocampus, concomitant with behavioral changes. This type of exposure produced significant long-term memory dysfunction. Regarding physiological changes, hypertension, tachypnea, baroreceptor reflex impairment and increased chemoreceptor reflex sensitivity were observed. In conclusion, the present study demonstrated the potential of lead intermittent exposure inducing reactive astrogliosis and microgliosis, along with a presynaptic loss that was accompanied by alterations of homeostatic mechanisms. This suggests that chronic neuroinflammation promoted by intermittent lead exposure since fetal period may increase the susceptibility to adverse events in individuals with pre-existing cardiovascular disease and/or in the elderly.

Associations between air pollutants and blood pressure in an ethnically diverse cohort of adolescents in London, England

Longitudinal evidence on the association between air pollution and blood pressure (BP) in adolescence is scarce. We explored this association in an ethnically diverse cohort of schoolchildren. Sex-stratified, linear random-effects modelling was used to examine how modelled residential exposure to annual average nitrogen dioxide (NO2), particulate matter (PM2.5, PM10) and ozone (O3), measures in μg/m3, associated with blood pressure. Estimates were based on 3,284 adolescents; 80% from ethnic minority groups, recruited from 51 schools, and followed up from 11-13 to 14-16 years old. Ethnic minorities were exposed to higher modelled annual average concentrations of pollution at residential postcode level than their White UK peers. A two-pollutant model (NO2 & PM2.5), adjusted for ethnicity, age, anthropometry, and pubertal status, highlighted associations with systolic, but not diastolic BP. A μg/m3 increase in NO2 was associated with a 0.30 mmHg (95% CI 0.18 to 0.40) decrease in systolic BP for girls and 0.19 mmHg (95% CI 0.07 to 0.31) decrease in systolic BP for boys. In contrast, a 1 μg/m3 increase in PM2.5 was associated with 1.34 mmHg (95% CI 0.85 to 1.82) increase in systolic BP for girls and 0.57 mmHg (95% CI 0.04 to 1.03) increase in systolic BP for boys. Associations did not vary by ethnicity, body size or socio-economic advantage. Associations were robust to adjustments for noise levels and lung function at 11-13 years. In summary, higher ambient levels of NO2 were associated with lower and PM2.5 with higher systolic BP across adolescence, with stronger associations for girls.

PM2.5 exposure exacerbates mice thoracic aortic aneurysm and dissection by inducing smooth muscle cell apoptosis via the MAPK pathway

Air pollution is a major public health concern worldwide. Exposure to fine particulate matter (PM2.5) is closely associated with cardiovascular diseases. However, the effect of PM2.5 exposure on thoracic aortic aneurysm and dissection (TAAD) has not been fully elucidated. Diesel exhaust particulate (DEP) is an important component of PM2.5, which causes health effects and is closely related to the incidence of cardiovascular disease. In the current study, we found that DEP exposure increased the incidence of aortic dissection (AD) in β-aminopropionitrile (BAPN)-induced thoracic aortic aneurysm (TAA). In addition, exposure to PM2.5 increased the diameter of the thoracic aorta in mice models. The number of apoptotic cells increased in the aortic wall of PM2.5-treated mice, as did the protein expression level of BAX/Bcl2 and cleaved caspase3/caspase3. Using a rhythmically stretching aortic mechanical simulation model, fluorescent staining indicated that PM2.5 administration could induce mitochondrial dysfunction and increase reactive oxygen species (ROS) levels in human aortic smooth muscle cells (HASMCs). Furthermore, ERK1/2 mitogen-activated protein kinase (MAPK) signaling pathways participated in the apoptosis of HASMCs after PM2.5 exposure. Therefore, we concluded that PM2.5 exposure could exacerbate the progression of TAAD, which could be induced by the increased apoptosis in HASMCs through the ERK1/2 MAPK signaling pathway.

Impact of air pollution on ischemic heart disease: Evidence, mechanisms, clinical perspectives

Ambient air pollution, and especially particulate matter (PM) air pollution <2.5 μm in diameter (PM_2.5), has clearly emerged as an important yet often overlooked risk factor for atherosclerosis and ischemic heart disease (IHD). In this review, we examine the available evidence demonstrating how acute and chronic PM_2.5 exposure clinically translates into a heightened coronary atherosclerotic burden and an increased risk of acute ischemic coronary events. Moreover, we provide insights into the pathophysiologic mechanisms underlying PM_2.5-mediated atherosclerosis, focusing on the specific biological mechanism through which PM_2.5 exerts its detrimental effects. Further, we discuss about the possible mechanisms that explain the recent findings reporting a strong association between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, increased PM_2.5 exposure, and morbidity and mortality from IHD. We also address the possible mitigation strategies that should be implemented to reduce the impact of PM_2.5 on cardiovascular morbidity and mortality, and underscoring the strong need of clinical trials demonstrating the efficacy of specific interventions (including both PM_2.5 reduction and/or specific drugs) in reducing the incidence of IHD. Finally, we introduce the emerging concept of the exposome, highlighting the close relationship between PM_2.5 and other environmental exposures (i.e.: traffic noise and climate change) in terms of common underlying pathophysiologic mechanisms and possible mitigation strategies.

Potential Biological Mediators of Myocardial and Vascular Complications of Air Pollution-A State-of-the-Art Review

Ambient air pollution is recognised globally as a significant contributor to the burden of cardiovascular diseases. The evidence from both human and animal studies supporting the cardiovascular impact of exposure to air pollution has grown substantially, implicating numerous pathophysiological pathways and related signalling mediators. In this review, we summarise the list of activated mediators for each pathway that lead to myocardial and vascular injury in response to air pollutants. We performed a systematic search of multiple databases, including articles between 1990 and Jan 2022, summarising the evidence for activated pathways in response to each significant air pollutant. Particulate matter <2.5 μm (PM_2.5) was the most studied pollutant, followed by particulate matter between 2.5 μm-10 μm (PM₁₀), nitrogen dioxide (NO₂) and ozone (O₃). Key pathogenic pathways that emerged included activation of systemic and local inflammation, oxidative stress, endothelial dysfunction, and autonomic dysfunction. We looked at how potential mediators of each of these pathways were linked to both cardiovascular disease and air pollution and included the overlapping mediators. This review illustrates the complex relationship between air pollution and cardiovascular diseases, and discusses challenges in moving beyond associations, towards understanding causal contributions of specific pathways and markers that may inform us regarding an individual's exposure, response, and likely risk.

The impact of PM2.5 on kidney

PM2.5 poses a severe risk to kidneys, inducing kidney function decline, increasing the risk of suffering from chronic kidney diseases and promoting the occurrence and development of various renal tumors. The mechanism of PM2.5-induced renal injury may involve oxidative stress, inflammatory response, and cytotoxicity. This paper elaborated PM2.5-induced kidney damage and the corresponding possible mechanism so as to raise awareness of air pollution and reduce the damage to human body.

[Environment and cardiovascular health: causes, consequences and opportunities in prevention and treatment]

The environment is a strong determinant of cardiovascular health. Environmental cardiology studies the contribution of environmental exposures with the aim of minimizing the harmful influences of pollution and promoting cardiovascular health through specific preventive or therapeutic strategies. The present review focuses on particulate matter and metals, which are the pollutants with the strongest level of scientific evidence, and includes possible interventions. Legislation, mitigation and control of pollutants in air, water and food, as well as environmental policies for heart-healthy spaces, are key measures for cardiovascular health. Individual strategies include the chelation of divalent metals such as lead and cadmium, metals that can only be removed from the body via chelation. The TACT (Trial to Assess Chelation Therapy, NCT00044213) clinical trial demonstrated cardiovascular benefit in patients with a previous myocardial infarction, especially in those with diabetes. Currently, the TACT2 trial (NCT02733185) is replicating the TACT results in people with diabetes. Data from the United States and Argentina have also shown the potential usefulness of chelation in severe peripheral arterial disease. More research and action in environmental cardiology could substantially help to improve the prevention and treatment of cardiovascular disease.

Environment and cardiovascular health: causes, consequences and opportunities in prevention and treatment

The environment is a strong determinant of cardiovascular health. Environmental cardiology studies the contribution of environmental exposures with the aim of minimizing the harmful influences of pollution and promoting cardiovascular health through specific preventive or therapeutic strategies. The present review focuses on particulate matter and metals, which are the pollutants with the strongest level of scientific evidence, and includes possible interventions. Legislation, mitigation and control of pollutants in air, water and food, as well as environmental policies for heart-healthy spaces, are key measures for cardiovascular health. Individual strategies include the chelation of divalent metals such as lead and cadmium, metals that can only be removed from the body via chelation. The TACT (Trial to Assess Chelation Therapy, NCT00044213) clinical trial demonstrated cardiovascular benefit in patients with a previous myocardial infarction, especially in those with diabetes. Currently, the TACT2 trial (NCT02733185) is replicating the TACT results in people with diabetes. Data from the United States and Argentina have also shown the potential usefulness of chelation in severe peripheral arterial disease. More research and action in environmental cardiology could substantially help to improve the prevention and treatment of cardiovascular disease.

Residential greenness attenuated association of long-term air pollution exposure with elevated blood pressure: Findings from polluted areas in Northern China

Background

Evidence on the hypertensive effects of long-term air pollutants exposure are mixed, and the joint hypertensive effects of air pollutants are also unclear. Sparse evidence exists regarding the modifying role of residential greenness in such effects.

Methods

A cross-sectional study was conducted in typically air-polluted areas in northern China. Particulate matter with diameter < 1 μm (PM₁), particulate matter with diameter < 2.5 μm (PM_2.5), particulate matter with diameter < 10 μm (PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and ozone (O₃) were predicted by space-time extremely randomized trees model. We used the Normalized Difference Vegetation Index (NDVI) to reflect residential green space. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were examined. We also calculated the pulse pressure (PP) and mean arterial pressure (MAP). Generalized additive model and quantile g-computation were, respectively, conducted to investigate individual and joint effects of air pollutants on blood pressure. Furthermore, beneficial effect of NDVI and its modification effect were explored.

Results

Long-term air pollutants exposure was associated with elevated DBP and MAP. Specifically, we found a 10-μg/m³ increase in PM_2.5, PM₁₀, and SO₂ were associated with 2.36% (95% CI: 0.97, 3.76), 1.51% (95% CI: 0.70, 2.34), and 3.54% (95% CI: 1.55, 5.56) increase in DBP; a 10-μg/m³ increase in PM_2.5, PM₁₀, and SO₂ were associated with 1.84% (95% CI: 0.74, 2.96), 1.17% (95% CI: 0.52, 1.83), and 2.43% (95% CI: 0.71, 4.18) increase in MAP. Air pollutants mixture (one quantile increase) was positively associated with increased values of DBP (8.22%, 95% CI: 5.49, 11.02) and MAP (4.15%, 95% CI: 2.05, 6.30), respectively. These identified harmful effect of air pollutants mainly occurred among these lived with low NDVI values. And participants aged ≥50 years were more susceptible to the harmful effect of PM_2.5 and PM₁₀ compared to younger adults.

Conclusions

Our study indicated the harmful effect of long-term exposure to air pollutants and these effects may be modified by living within higher green space place. These evidence suggest increasing residential greenness and air pollution control may have simultaneous effect on decreasing the risk of hypertension.

PM2.5-Induced Programmed Myocardial Cell Death via mPTP Opening Results in Deteriorated Cardiac Function in HFpEF Mice

PM2.5 exposure can induce or exacerbate heart failure and is associated with an increased risk of heart failure hospitalization and mortality; however, the underlying mechanisms remain unclear. This study focuses on the potential mechanisms underlying PM2.5 induction of cardiomyocyte programmed necrosis as well as its promotion of cardiac function impairment in a mouse model of heart failure with preserved ejection fraction (HFpEF). HFpEF mice were exposed to concentrated ambient PM2.5 (CAP) (CAP group) or filtered air (FA) (FA group) for 6 weeks. Changes in myocardial pathology and cardiac function were documented for comparisons between the two groups. In vitro experiments were performed to measure oxidative stress and mitochondrial permeability transition pore (mPTP) dynamics in H9C2 cells following 24 h exposure to PM2.5. Additionally, co-immunoprecipitation was conducted to detect p53 and cyclophilin D (CypD) interactions. The results showed exposure to CAP promoted cardiac function impairment in HFpEF mice. Myocardial pathology analysis and in vitro experiments demonstrated that PM2.5 led to mitochondrial damage in cardiomyocytes and, eventually, their necrosis. Moreover, our experiments also suggested that PM2.5 increases mitochondrial reactive oxygen species (ROS), induces DNA oxidative damage, and decreases the inner mitochondrial membrane potential (ΔΨm). This indicates the presence of mPTP opening. Co-immunoprecipitation results showed a p53/CypD interaction in the myocardial tissue of HFpEF mice in the CAP group. Inhibition of CypD by cyclosporin A was found to reverse PM2.5-induced mPTP opening and H9C2 cell death. In conclusion, PM2.5 induces mPTP opening to stimulate mitochondria-mediated programmed necrosis of cardiomyocytes, and it might exacerbate cardiac function impairment in HFpEF mice.

Associations of genetic risk factors and air pollution with incident hypertension among participants in the UK Biobank study

The purposes of this study were to quantify the association of the combination of air pollution and genetic risk factors with hypertension and explore the interactions between air pollution and genetic risk. This study included 391,366 participants of European ancestry initially free from pre-existing hypertension in the UK Biobank. Exposure to ambient air pollutants, including particulate matter (PM_2.5 PM_2.5-10, and PM₁₀), nitrogen dioxide (NO₂) and nitrogen oxides (NO_X), was estimated through land use regression modelling, and the associations between air pollutants and the incidence of hypertension were investigated using a Cox proportional hazards model adjusted for covariates. Furthermore, we established a polygenic risk score for hypertension and assessed the combined effect of genetic susceptibility and air pollution on incident hypertension. The results showed significant associations between the risk of hypertension and exposure to PM_2.5 (hazard ratio [HR]: 1.41, 95% confidence interval [CI]: 1.29-1.53; per 10 μg/m³), PM₁₀ (1.05, 1.00-1.09; per 10 μg/m³), and NO_X (1.01, 1.01-1.02 per 10 μg/m³). Additive effects of PM_2.5 and NO_X exposure and genetic risk were observed. Compared to individuals with a low genetic risk and low air pollution exposure, participants with high air pollution exposure and a high genetic risk had a significantly increased risk of hypertension (PM_2.5: 71% (66%-76%), PM₁₀: 59% (55%-64%), NO_X: 65% (60%-70%)). Our results indicate that long-term exposure to air pollution is associated with an increased risk of hypertension, especially in individuals with a high genetic risk.

Beta Blockers can mask not only Hypoglycemia, but also Hypotension

Background:

Beta-adrenergic (β-AR) receptor blockers (BBs) are an essential class of drugs as they have numerous indications. On the other hand, they have numerous unwanted effects which decrease the compliance, adherence, and persistence of this very useful group of drugs.

Objective:

The paper aims to analyze the possibility that an unnoticed side effect may contribute to a less favorable pharmacologic profile of BBs, e.g., a diminished reaction to a sudden fall in BP.

Methods:

We searched two medical databases for abstracts and citations (Medline and SCOPUS). Moreover, we searched the internet for drug prescription leaflets (of the individual BBs).

Results:

Whichever cause of stress is considered, the somatic manifestations of stress will be (partially) masked if a patient takes BB. Stress–induced hypercatecholaminemia acts on β-AR of cardiomyocytes; it increases heart rate and contractility, effects suppressed by BBs. The answers of the organism to hypoglycemia and hypotension share the main mechanisms such as sympathetic nervous system activation and hypercatecholaminemia. Thus, there is a striking analogy: BBs can cover up symptoms of both hypoglycemia (which is widely known) and of hypotension (which is not recognized). It is widely known that BBs can cause hypotension. However, they can also complicate recovery by spoiling the defense mechanisms in hypotension as they interfere with the crucial compensatory reflex to increase blood pressure in hypotension.

Conclusion:

Beta blockers can cause hypotension, mask it, and make recovery more difficult. This is clinically important and deserves to be more investigated and probably to be stated as a warning.

Food bioactives lowering risks of chronic diseases induced by fine particulate air pollution: a comprehensive review

Airborne particulate matter (PM) exerts huge negative impacts on human health worldwide, not only targeting the respiratory system but more importantly inducing and aggravating associated chronic diseases like asthma, lung cancer, atherosclerosis, diabetes mellitus and Alzheimer diseases. Food-derived bioactive compounds like vitamins, dietary polyphenols, omega-3 polyunsaturated fatty acids and sulforaphane are feasible alternative therapeutic approaches against PM-mediated potential health damages, drawing great attention in recent years. In this review, the association between PM exposure and risks of developing chronic diseases, and the detailed mechanisms underlying the detrimental effects of PM will be discussed. Subsequently, principal food-derived bioactive compounds, with emphasize on the preventative or protective effects against PM, along with potential mechanisms will be elucidated. This comprehensive review will discuss and present current research findings to reveal the nutritional intervention as a preventative or therapeutic strategy against ambient air pollution, thereby lowering the risk of developing chronic diseases.

Association between long-term exposure to PM2.5 and hypertension: A systematic review and meta-analysis of observational studies

BACKGROUND

Numerous studies have examined the association between long-term exposure to particulate matter with an aerodynamic diameter of ≤2.5 μm (PM_2.5) and hypertension. However, the results are inconsistent.

OBJECTIVES

Considering the limitations of previous meta-analyses and the publication of many new studies in recent years, we conducted this meta-analysis to assess the relationship between long-term PM_2.5 exposure and the incidence and prevalence of hypertension in a healthy population.

METHODS

We searched PubMed, Web of Science, Embase, and Scopus for relevant studies published until April 2, 2021 and reviewed the reference lists of previous reviews. A total of 28 observational studies reporting RR or OR with 95% CI for the association between long-term PM_2.5 exposure and the risk of hypertension were included.

RESULTS

After the sensitivity analysis, we excluded one study with a high degree of heterogeneity, resulting in 27 studies and 28 independent reports. Approximately 42 million participants were involved, and the cases of hypertension in cohort and cross-sectional studies were 508,749 and 1,793,003, respectively. The meta-analysis showed that each 10 μg/m³ increment in PM_2.5 was significantly associated with the risks of hypertension incidence (RR = 1.21, 95% CI: 1.07, 1.35) and prevalence (OR = 1.06, 95% CI: 1.03, 1.09). Subgroup analyses showed that occupational exposure had a significant effect on the association of PM_2.5 and hypertension incidence (p for interaction = 0.042) and that the PM_2.5 concentration level and physical activity had a noticeable effect on the association of PM_2.5 and hypertension prevalence (p for interaction = 0.005; p for interaction = 0.022).

CONCLUSIONS

A significantly positive correlation was observed between long-term PM_2.5 exposure and risks of hypertension incidence and prevalence, and a high PM_2.5 concentration resulted in an increased risk of hypertension.

Air Pollution Role as Risk Factor of Cardioinhibitory Carotid Hypersensitivity

Little is known about the impact of air pollution on neuroautonomic system. The authors have investigated possible influence of air pollution and outdoor temperature on the carotid sinus hypersensitivity (CSH), as main cause of neurally mediated syncope in forty-years-old subjects and older. Pollutants’ concentrations and outdoor temperature of days in which 179 subjects with recurrent syncope underwent carotid sinus massage (CSM) were analyzed. Before this manoeuvre, cardiovascular control by short period heart and blood pressure spectral duration of segment between the end of P and R ECG-waves (PeR) were registred; RR variability on the same short period ECG recordings and their spectral coherence were also analyzed. CSH was found in 57 patients (28 with cardioinhibitory response and 29 subjects showed vasodepressor reaction), while 122 subjects had a normal response. CSM performed during high ozone concentrations was associated with slightly higher risk of cardioinhibitory response (odd ratio 1.012, 95% CI 1.001–1.023, p < 0.05), but neither this or other polluting agent nor outdoor temperature seemed to influence autonomic control in basal resting condition. Thus, ozone seemed to influence response to the CSM in CSH patients and it is probably able to facilitate a cardioinhibitory response, perhaps through an increase of nerve acetylcholine release. P→PR coherence could be useful in predicting a sinus cardioinhibitory hypersensitivity in those cases when CSM is contraindicated.

The effects of exercise training on the lungs and cardiovascular function of animals exposed to diesel exhaust particles and gases

Air pollution has been identified as one of the main environmental risks to health. Since exercise training seems to act as an anti-inflammatory modulator, our hypothesis is that exercise training prevents damage to respiratory and cardiovascular function caused by diesel exhaust particle (DEP) exposure. This study aimed to evaluate whether aerobic exercise training prior to DEP exposure prevents inflammatory processes in the pulmonary and cardiovascular systems. Therefore, BALB/C male mice were or were not submitted to a 10-week exercise training protocol (5×/week, 1 h/d), and after four weeks, they were exposed to DEP in a chamber with 24 μg/m³ PM2.5 or filtered air. Heart rate variability, lung mechanics and bronchoalveolar lavage fluid, cytokines and polymorphonuclear cells in the lung parenchyma were evaluated. Exposure to DEPs reduced heart rate variability and the elastance of the respiratory system and increased the number of cells in bronchoalveolar lavage fluid, as well as macrophages, neutrophils and lymphocytes, the density of polymorphonuclear cells and the proportion of collagen fibres in the lung parenchyma. Additionally, DEP-exposed animals showed increased expression of IL-23 and IL-12p40 (proinflammatory cytokines) and inducible nitric oxide synthase. Exercise training avoided the increases in all these inflammatory parameters, except the elastance of the respiratory system, the amount of collagen fibres and the expression of inducible nitric oxide synthase. Additionally, trained animals showed increased expression of the anti-inflammatory cytokine IL-1ra. Although our data showed a reduction in proinflammatory markers and an increase in markers of the anti-inflammatory pathway, these changes were not sufficient to prevent damage to the lung and cardiovascular function induced by DEPs. Based on these data, we propose that aerobic exercise training prevents the lung inflammatory process induced by DEPs, although it was not sufficient to avoid chronic damage, such as a loss of lung function or cardiovascular events.

The impact of PM2.5 on children's blood pressure growth curves: A prospective cohort study

OBJECTIVE

The aim of this study was to explore the association between exposure to particulate matter with an aerodynamic diameter of 2.5 mm or less (PM2.5) and blood pressure (BP) levels in children and adolescents and to illustrate the impact of PM2.5 levels on BP growth curves in a cohort study.

METHODS

A longitudinal study was designed and included 4303 children (7617 BP measurements) living in the selected areas, and evaluations were conducted in 2014-2015 (visit 1) and followed up in 2019 (visit 2). Two-stage stratified cluster sampling was used to include urban-rural areas. A mixed linear regression model and mixed logistic regression model were used to analyze the effect of PM2.5 exposure on BP and the incidence of prehypertension and hypertension in children.

RESULTS

After adjusting for covariates, systolic blood pressure (SBP) (2.21 (95% CIs: 0. 81, 3.62), mmHg), diastolic blood pressure (DBP) (1.92 (95% CIs: 0.74, 3.11), mmHg), mean arterial pressure (MAP) (2.03 (95% CIs: 0.89, 3.17), mmHg) and heart rate (HR) (2.24 (95% CIs: 0.11, 4.37), beats/min) increased significantly in the fourth quartile of PM2.5 exposure levels compared with the first quartile (all P < 0.01). In addition, long-term exposure to PM2.5 was significantly positively correlated with SBP, DBP and MAP, and the effect was more notable in urban areas than that in rural areas. Moreover, the risk of prehypertension and hypertension incidence increased by 1.17 (95% CIs: 1.03, 1.33) fold with a one-quartile increase in PM2.5 exposure. The long-term effects of annual mean PM2.5 exposure on SBP, DBP and MAP were significant from pregnancy to 7, 3 and 4 years of age, respectively.

CONCLUSION

Long-term exposure to PM2.5 was positively associated with growth curves of hemodynamics indexed from pregnancy to childhood and adolescence, and the effect was more significant in urban areas than in rural areas.

The cardiovascular effects of air pollution: Prevention and reversal by pharmacological agents

Air pollution is associated with staggering levels of cardiovascular morbidity and mortality. Airborne particulate matter (PM), in particular, has been associated with a wide range of detrimental cardiovascular effects, including impaired vascular function, raised blood pressure, alterations in cardiac rhythm, blood clotting disorders, coronary artery disease, and stroke. Considerable headway has been made in elucidating the biological processes underlying these associations, revealing a labyrinth of multiple interacting mechanistic pathways. Several studies have used pharmacological agents to prevent or reverse the cardiovascular effects of PM; an approach that not only has the advantages of elucidating mechanisms, but also potentially revealing therapeutic agents that could benefit individuals that are especially susceptible to the effects of air pollution. This review gathers investigations with pharmacological agents, offering insight into the biology of how PM, and other air pollutants, may cause cardiovascular morbidity.

Key Characteristics of Cardiovascular Toxicants

BACKGROUND

The concept of chemical agents having properties that confer potential hazard called key characteristics (KCs) was first developed to identify carcinogenic hazards. Identification of KCs of cardiovascular (CV) toxicants could facilitate the systematic assessment of CV hazards and understanding of assay and data gaps associated with current approaches.

OBJECTIVES

We sought to develop a consensus-based synthesis of scientific evidence on the KCs of chemical and nonchemical agents known to cause CV toxicity along with methods to measure them.

METHODS

An expert working group was convened to discuss mechanisms associated with CV toxicity.

RESULTS

The group identified 12 KCs of CV toxicants, defined as exogenous agents that adversely interfere with function of the CV system. The KCs were organized into those primarily affecting cardiac tissue (numbers 1-4 below), the vascular system (5-7), or both (8-12), as follows: 1) impairs regulation of cardiac excitability, 2) impairs cardiac contractility and relaxation, 3) induces cardiomyocyte injury and death, 4) induces proliferation of valve stroma, 5) impacts endothelial and vascular function, 6) alters hemostasis, 7) causes dyslipidemia, 8) impairs mitochondrial function, 9) modifies autonomic nervous system activity, 10) induces oxidative stress, 11) causes inflammation, and 12) alters hormone signaling.

DISCUSSION

These 12 KCs can be used to help identify pharmaceuticals and environmental pollutants as CV toxicants, as well as to better understand the mechanistic underpinnings of their toxicity. For example, evidence exists that fine particulate matter [PM ≤2.5μm in aerodynamic diameter (PM2.5)] air pollution, arsenic, anthracycline drugs, and other exogenous chemicals possess one or more of the described KCs. In conclusion, the KCs could be used to identify potential CV toxicants and to define a set of test methods to evaluate CV toxicity in a more comprehensive and standardized manner than current approaches. https://doi.org/10.1289/EHP9321.

The Role of Hepatic Vagal Tone in Ozone-Induced Metabolic Dysfunction in the Liver

Air pollution has been associated with metabolic diseases and hepatic steatosis-like changes. We have shown that ozone alters liver gene expression for metabolic processes through neuroendocrine activation. This study aimed to further characterize ozone-induced changes and to determine the impact of hepatic vagotomy (HV) which reduces parasympathetic influence. Twelve-week-old male Wistar-Kyoto rats underwent HV or sham surgery 5-6 days before air or ozone exposure (0 or 1 ppm; 4 h/day for 1 or 2 days). Ozone-induced lung injury, hyperglycemia, glucose intolerance, and increases in circulating cholesterol, triglycerides, and leptin were similar in rats with HV and sham surgery. However, decreases in circulating insulin and increased HDL and LDL were observed only in ozone-exposed HV rats. Ozone exposure resulted in changed liver gene expression in both sham and HV rats (sham > HV), however, HV did not change expression in air-exposed rats. Upstream target analysis revealed that ozone-induced transcriptomic changes were similar to responses induced by glucocorticoid-mediated processes in both sham and HV rats. The directionality of ozone-induced changes reflecting cellular response to stress, metabolic pathways, and immune surveillance was similar in sham and HV rats. However, pathways regulating cell-cycle, regeneration, proliferation, cell growth, and survival were enriched by ozone in a directionally opposing manner between sham and HV rats. In conclusion, parasympathetic innervation modulated ozone-induced liver transcriptional responses for cell growth and regeneration without affecting stress-mediated metabolic changes. Thus, impaired neuroendocrine axes and parasympathetic innervation could collectively contribute to adverse effects of air pollutants on the liver.

Influence of the seasonality and of urban variables in the BTEX and PM2.5 atmospheric levels and risks to human health in a tropical coastal city (Fortaleza, CE, Brazil)

The International Agency for Research on Cancer (IARC) classifies benzene in group 1 (carcinogenic to humans). Particulate matter (PM) has recently also been classified in this category. This was an advance toward prioritizing the monitoring of particles in urban areas. The aim of the present study was to assess levels of PM_2.5 and BTEX (benzene, toluene, ethylbenzene, and xylene), the influence of meteorological variables, the planetary boundary layer (PBL), and urban variables as well as risks to human health in the city of Fortaleza, Brazil, in the wet and dry periods. BTEX compounds were sampled using the 1501 method of NIOSH and determined by GC-HS-PID/FID. PM_2.5 was monitored using an air sampling pump with a filter holder and determined by the gravimetric method. Average concentrations of BTEX ranged from 1.6 to 45.5 μg m^-3, with higher values in the wet period, which may be explained by the fact that annual distribution is influenced by meteorological variables and the PBL. PM_2.5 levels ranged from 4.12 to 33.0 μg m^-3 and 4.18 to 86.58 μg m^-3 in the dry and wet periods, respectively. No seasonal pattern was found for PM_2.5, probably due to the influence of meteorological variables, the PBL, and urban variables. Cancer risk ranged from 2.46E^-04 to 4.71E^-03 and 1.72E^-04 to 2.01E^-03 for benzene and from 3.07E^-06 to 7.04E^-05 and 3.08E^-06 to 2.85E^-05 for PM_2.5 in the wet and dry periods, respectively. Cancer risk values for benzene were above the acceptable limit established by the international regulatory agency in both the dry and wet periods. The results obtained of the noncarcinogenic risks for the compounds toluene, ethylbenzene, and xylene were within the limits of acceptability. The findings also showed that the risk related to PM is always greater among smokers than nonsmokers.

Air pollution-associated blood pressure may be modified by diet among children in Guangzhou, China

OBJECTIVES

To assess the associations between long-term air pollution exposure and blood pressure in children, and to explore the modifying effects of diet on prehypertension and hypertension.

METHODS

We evaluated 7225 primary school children aged 6-12 years from Guangzhou, China, in 2017. The blood pressure was measured objectively. The individual 1-year average concentration of particles with an aerodynamic diameter of 2.5 μm or less or 10 μm or less (PM2.5, PM10), sulfur dioxide (SO2), and ozone (O3) before each blood pressure measurement were calculated by inverse distance weighting interpolation according to each home address. Generalized linear mixed-effects models were used to examine the health effects and potential effect modifications by diet factors after adjusting for covariates.

RESULTS

The results showed that the estimated increase in mean SBP was 0.92 mmHg (95% CI 0.05-1.79) per interquartile range increase in O3. An interquartile range increase in the 1-year mean of SO2 and O3 was associated with odds ratios of 1.26 (95% CI 1.04-1.52) and 1.20 (95% CI 1.06-1.35) for prehypertension, respectively. In addition, an interquartile range increase in PM2.5, SO2, and O3 exposure was positively associated with hypertension, with odds ratios of 1.33 (95% CI 1.11-1.61), 1.70 (95% CI 1.33-2.16), and 1.48 (95% CI 1.20-1.83), respectively. Stronger effect estimates between PM2.5, SO2, and O3 concentration on prehypertension were exhibited among subgroups of children with a higher intake of sugar-sweetened beverages.

CONCLUSION

Long-term exposure to PM2.5, SO2, and O3 were associated with higher blood pressure levels in children, and dietary intake might modify these associations.

The Association Between Short-term Exposure to Ambient Air Pollution and Patient-Level Home Blood Pressure Among Patients With Chronic Cardiovascular Diseases in a Web-Based Synchronous Telehealth Care Program: Retrospective Study

BACKGROUND

The association between short-term exposure to ambient air pollution and blood pressure has been inconsistent, as reported in the literature.

OBJECTIVE

This study aimed to investigate the relationship between short-term ambient air pollution exposure and patient-level home blood pressure (HBP).

METHODS

Patients with chronic cardiovascular diseases from a telehealth care program at a university-affiliated hospital were enrolled as the study population. HBP was measured by patients or their caregivers. Hourly meteorological data (including temperature, relative humidity, wind speed, and rainfall) and ambient air pollution monitoring data (including CO, NO₂, particulate matter with a diameter of <10 µm, particulate matter with a diameter of <2.5 µm, and SO₂) during the same time period were obtained from the Central Weather Bureau and the Environmental Protection Administration in Taiwan, respectively. A stepwise multivariate repeated generalized estimating equation model was used to assess the significant factors for predicting systolic and diastolic blood pressure (SBP and DBP).

RESULTS

A total of 253 patients and 110,715 HBP measurements were evaluated in this study. On multivariate analysis, demographic, clinical, meteorological factors, and air pollutants significantly affected the HBP (both SBP and DBP). All 5 air pollutants evaluated in this study showed a significant, nonlinear association with both home SBP and DBP. Compared with demographic and clinical factors, environmental factors (meteorological factors and air pollutants) played a minor yet significant role in the regulation of HBP.

CONCLUSIONS

Short-term exposure to ambient air pollution significantly affects HBP in patients with chronic cardiovascular disease.

Effect of Air Quality on the Risk of Emergency Room Visits in Patients With Atrial Fibrillation

Background: We investigated the effect of particulate matter with aerodynamic diameter <2.5 μm (PM2.5) and meteorological conditions on the risk of emergency room visits in patients with atrial fibrillation (AF) in Beijing, which is considered as a monsoon climate region. Methods: In this case-crossover design study, medical records from patients with AF who visited the Critical Care Center in the Emergency Department of Anzhen Hospital from January 2011 through December 2014 and air quality and meteorological data of Beijing during the same period were collected and analyzed using Cox regression and time-series autocorrelation analyses. Results: A total of 8,241 patients were included. When the average PM2.5 concentration was >430 μg/m³, the risk of emergency room visits for patients with uncomplicated AF, AF combined with cardiac insufficiency, and AF combined with rheumatic heart disease increased by 12, 12, and 40%, respectively. When the average PM2.5 concentration was >420 μg/m³, patients with AF combined with diabetes mellitus had a 75% increased risk of emergency room visits, which was the largest increase in risk among all types of patients with AF. When the average PM2.5 concentration was >390 μg/m³, patients with AF combined with acute coronary syndrome had an approximately 30% increased risk of emergency room visits, which was the highest and fastest increase in risk among all types of patients with AF. The risk of emergency room visits for patients with AF was positively correlated with air quality as the time lag proceeded, with an autocorrelation coefficient of 0.223 between the risk of emergency room visits and air quality in patients with AF on day 6 of the time lag. Conclusion: Exposure to certain concentrations of PM2.5 in a monsoon climate region significantly increased the risk of emergency room visits in patients with AF.

Acute Exposure to Diesel Exhaust Increases Muscle Sympathetic Nerve Activity in Humans

Background

Diesel exhaust (DE) emissions are a major contributor to ambient air pollution and are strongly associated with cardiovascular morbidity and mortality. Exposure to traffic‐related particulate matter is linked with acute adverse cardiovascular events; however, the mechanisms are not fully understood. We examined the role of the autonomic nervous system during exposure to DE that has previously only been indirectly investigated.

Methods and Results

Using microneurography, we measured muscle sympathetic nerve activity (MSNA) directly in the peroneal nerve of 16 healthy individuals. MSNA, heart rate, and respiration were recorded while subjects rested breathing filtered air, filtered air with an exposure mask, and standardized diluted DE (300 µg/m³) through the exposure mask. Heart rate variability was assessed from an ECG. DE inhalation rapidly causes an increase in number of MSNA bursts as well as the size of bursts within 10 minutes, peaking by 30 minutes (P<0.001), compared with baseline filtered air with an exposure mask. No significant changes occurred in heart rate variability indices during DE exposure; however, MSNA frequency correlated negatively with total power (r²=0.294, P=0.03) and low frequency (r²=0.258, P=0.045). Heart rate correlated positively with MSNA frequency (r²=0.268, P=0.04) and the change in percentage of larger bursts (burst amplitude, height >50% of the maximum burst) from filtered air with an exposure mask (r²=0.368, P=0.013).

Conclusions

Our study provides direct evidence for the rapid modulation of the autonomic nervous system after exposure to DE, with an increase in MSNA. The quick increase in sympathetic outflow may explain the strong epidemiological data associating traffic‐related particulate matter to acute adverse cardiovascular events such as myocardial infarction.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02892279.

Effects of Ambient Air Pollution on Blood Pressure Among Children and Adolescents: A Systematic Review and Meta-Analysis

Background

Previous studies have investigated the association of ambient air pollution with blood pressure (BP) in children and adolescents, however, the results are not consistent. We conducted a systematic review and meta‐analysis to assess the relationship between short‐term and long‐term ambient air pollutant exposure with BP values among children and adolescents.

Methods and Results

We searched PubMed, Web of Science, and Embase before September 6, 2020. Two reviewers independently searched and selected studies, extracted data, and assessed study quality. The studies were divided into groups by composition of air pollutants (NO₂, particulate matter (PM) with diameter ≤10 μm or ≤2.5 μm) and length of exposure. The beta regression coefficients (β) and their 95% CIs were calculated to evaluate the strength of the effect with each 10 μg/m³ increase in air pollutants. Out of 36 650 articles, 14 articles were included in this meta‐analysis. The meta‐analysis showed short‐term exposure to PM with diameter ≤10 μm (β=0.267; 95% CI, 0.033‒0.501) was significantly associated with elevated systolic BP values. In addition, long‐term exposure to PM with diameter ≤2.5 μm (β=1.809; 95% CI, 0.962‒2.655), PM with diameter ≤10 μm (β=0.526; 95% CI, 0.095‒0.958), and NO₂ (β=0.754; 95% CI, 0.541‒0.968) were associated with systolic BP values and long‐term exposure to PM with diameter ≤2.5 μm (β=0.931; 95% CI, 0.157‒1.705), and PM with diameter ≤10 μm (β=0.378; 95% CI, 0.022‒0.735) was associated with diastolic BP.

Conclusions

Our study indicates that both short‐term and long‐term exposure to some ambient air pollutants may increase BP values among children and adolescents.