Long-term exposure to air pollution and markers of inflammation, coagulation, and endothelial activation: a repeat-measures analysis in the Multi-Ethnic Study of Atherosclerosis (MESA)

Diesel exhaust particle extract elicits an oxPAPC-like transcriptomic profile in macrophages across multiple mouse strains

Air pollution is a prominent cause of cardiopulmonary illness, but uncertainties remain regarding the mechanisms mediating those effects as well as individual susceptibility. Macrophages are highly responsive to particles, and we hypothesized that their responses would be dependent on their genetic backgrounds. We conducted a genome-wide analysis of peritoneal macrophages harvested from 24 inbred strains of mice from the Hybrid Mouse Diversity Panel (HMDP). Cells were treated with a DEP methanol extract (DEPe) to elucidate potential mechanisms that mediate acute responses to air pollution exposures. This analysis showed that 1,247 genes were upregulated and 1,383 genes were downregulated with DEPe treatment across strains. Pathway analysis identified oxidative stress responses among the most prominent upregulated pathways; indeed, many of the upregulated genes included antioxidants such as Hmox1, Txnrd1, Srxn1, and Gclm, with NRF2 (official gene symbol: Nfe2l2) being the most significant driver. DEPe induced a Mox-like transcriptomic profile, a macrophage subtype typically induced by oxidized phospholipids and likely dependent on NRF2 expression. Analysis of individual strains revealed consistency of overall responses to DEPe and yet differences in the degree of Mox-like polarization across the various strains, indicating DEPe x genetic interactions. These results suggest a role for macrophage polarization in the cardiopulmonary toxicity induced by air pollution.

Indoor and ambient black carbon and fine particulate matter associations with blood biomarkers in COPD patients

BACKGROUND

Systemic inflammation contributes to cardiovascular risk and chronic obstructive pulmonary disease (COPD) pathophysiology. Associations between systemic inflammation and exposure to ambient fine particulate matter (PM ≤ 2.5 μm diameter; PM2.5), and black carbon (BC), a PM2.5 component attributable to traffic and other sources of combustion, infiltrating indoors are not well described.

METHODS

Between 2012 and 2017, COPD patients completed in-home air sampling over one-week intervals, up to four times (seasonally), followed by measurement of plasma biomarkers of systemic inflammation, C-reactive protein (CRP) and interleukin-6 (IL-6), and endothelial activation, soluble vascular adhesion molecule-1 (sVCAM-1). Ambient PM2.5, BC and sulfur were measured at a central site. The ratio of indoor/ambient sulfur in PM2.5, a surrogate for fine particle infiltration, was used to estimate indoor BC and PM2.5 of ambient origin. Linear mixed effects regression with a random intercept for each participant was used to assess associations between indoor and indoor of ambient origin PM2.5 and BC with each biomarker.

RESULTS

144 participants resulting in 482 observations were included in the analysis. There were significant positive associations between indoor BC and indoor BC of ambient origin with CRP [%-increase per interquartile range (IQR);95 % CI (13.2 %;5.2-21.8 and 11.4 %;1.7-22.1, respectively)]. Associations with indoor PM2.5 and indoor PM2.5 of ambient origin were weaker. There were no associations with IL-6 or sVCAM-1.

CONCLUSIONS

In homes of patients with COPD without major sources of combustion, indoor BC is mainly attributable to the infiltration of ambient sources of combustion indoors. Indoor BC of ambient origin is associated with increases in systemic inflammation in patients with COPD, even when staying indoors.

Long-term exposure to ambient air pollution and inflammatory response in the KORA study

Previous studies consistently showed an association between fine atmospheric particulate matter (PM2.5) and cardiovascular diseases. Concerns about adverse health effects of ultrafine particles (UFP) are growing but long-term studies are still scarce. In this study, we examined the association between long-term exposure to ambient air pollutants and blood biomarkers of inflammation and coagulation, including fibrinogen, high-sensitivity C-reactive protein (hs-CRP), serum amyloid A (SAA) adiponectin and interleukin-6 (IL-6), measured in the German KORA-S4 cohort study (1999-2001). IL-6 was available for older participants only, who were therefore considered as a subsample. Annual mean concentrations of UFP (as particle number concentration), particulate matter in different particles sizes (PM10, PMcoarse, PM2.5, PM2.5 absorbance), ozone (O3), and nitrogen oxides (NO2, NOX) were estimated by land-use regression models and assigned to participants' home addresses. We performed a multiple linear regression between each pollutant and each biomarker with adjustment for confounders. Per 1 interquartile range (IQR, 1945 particles/cm3) increase of UFP, fibrinogen increased by 0.70 % (0.04; 1.37) and hs-CRP increased by 3.16 % (-0.52; 6.98). Adiponectin decreased by -2.53 % (-4.78; -0.24) per 1 IQR (1.4 μg/m3) increase of PM2.5. Besides, PM2.5 was associated with increased IL-6 in the subsample. In conclusion, we observed that long-term exposure to air pollutants, including both fine and ultrafine particles, was associated with higher concentrations of pro-inflammatory and lower concentrations of an anti-inflammatory blood biomarkers, which is consistent with an increased risk for cardiovascular disease observed for long-term exposure to air pollutants.

Coarse Particulate Matter and Markers of Inflammation and Coagulation in the Multi-Ethnic Study of Atherosclerosis (MESA) Population: A Repeat Measures Analysis

BACKGROUND

In contrast to fine particles, less is known of the inflammatory and coagulation impacts of coarse particulate matter (PM 10 - 2.5 , particulate matter with aerodynamic diameter ≤ 10 μ m  and > 2.5 μ m ). Toxicological research suggests that these pathways might be important processes by which PM 10 - 2.5 impacts health, but there are relatively few epidemiological studies due to a lack of a national PM 10 - 2.5 monitoring network.

OBJECTIVES

We used new spatiotemporal exposure models to examine associations of both 1-y and 1-month average PM 10 - 2.5 concentrations with markers of inflammation and coagulation.

METHODS

We leveraged data from 7,071 Multi-Ethnic Study of Atherosclerosis and ancillary study participants 45-84 y of age who had repeated plasma measures of inflammatory and coagulation biomarkers. We estimated PM 10 - 2.5 at participant addresses 1 y and 1 month before each of up to four exams (2000-2012) using spatiotemporal models that incorporated satellite, regulatory monitoring, and local geographic data and accounted for spatial correlation. We used random effects models to estimate associations with interleukin-6 (IL-6), C-reactive protein (CRP), fibrinogen, and D-dimer, controlling for potential confounders.

RESULTS

Increases in PM 10 - 2.5 were not associated with greater levels of inflammation or coagulation. A 10 - μ g / m 3 increase in annual average PM 10 - 2.5 was associated with a 2.5% decrease in CRP [95% confidence interval (CI): - 5.5 , 0.6]. We saw no association between annual average PM 10 - 2.5 and the other markers (IL-6: - 0.7 % , 95% CI: - 2.6 , 1.2; fibrinogen: - 0.3 % , 95% CI: - 0.9 , 0.3; D-dimer: - 0.2 % , 95% CI: - 2.6 , 2.4). Associations consistently showed that a 1 0 - μ g / m 3 increase in 1-month average PM 10 - 2.5 was associated with reduced inflammation and coagulation, though none were distinguishable from no association (IL-6: - 1.2 % , 95% CI: - 3.0   , 0.5; CRP: - 2.5 % , 95% CI: - 5.3 , 0.4; fibrinogen: - 0.4 % , 95% CI: - 1.0 , 0.1; D-dimer: - 2.0 % , 95% CI: - 4.3 , 0.3).

DISCUSSION

We found no evidence that PM 10 - 2.5 is associated with higher inflammation or coagulation levels. More research is needed to determine whether the inflammation and coagulation pathways are as important in explaining observed PM 10 - 2.5 health impacts in humans as they have been shown to be in toxicology studies or whether PM 10 - 2.5 might impact human health through alternative biological mechanisms. https://doi.org/10.1289/EHP12972.

Exposure to residential traffic and trajectories of unhealthy ageing: results from a nationally-representative cohort of older adults

BACKGROUND

Traffic exposure has been associated with biomarkers of increased biological ageing, age-related chronic morbidities, and increased respiratory, cardiovascular, and all-cause mortality. Whether it is associated with functional impairments and unhealthy ageing trajectories is unknown.

METHODS

Nationally representative population-based cohort with 3,126 community-dwelling individuals aged ≥60 years who contributed 8,291 biannual visits over a 10 year period. Unhealthy ageing was estimated with a deficit accumulation index (DAI) based on the number and severity of 52 health deficits, including 22 objectively-measured impairments in physical and cognitive functioning. Differences in DAI at each follow-up across quintiles of residential traffic density (RTD) at 50 and 100 meters, and closest distance to a petrol station, were estimated using flexible marginal structural models with inverse probability of censoring weights. Models were adjusted for sociodemographic and time-varying lifestyle factors, social deprivation index at the census tract and residential exposure to natural spaces.

RESULTS

At baseline, the mean (SD) age and DAI score of the participants were 69.0 (6.6) years and 17.02 (11.0) %, and 54.0% were women. The median (IQR) RTD at 50 and 100 meters were 77 (31-467) and 509 (182-1802) vehicles/day, and the mean (SD) distance to the nearest petrol station of 962 (1317) meters. The average increase in DAI (95%CI) for participants in quintiles Q2-Q5 (vs Q1) of RTD at 50 meters was of 1.51 (0.50, 2.53), 0.98 (-0.05, 2.01), 2.20 (1.18, 3.21) and 1.98 (0.90, 3.05), respectively. Consistent findings were observed at 100 meters. By domains, most of the deficits accumulated with increased RTD were of a functional nature, although RTD at 50 meters was also associated with worse self-reported health, increased vitality problems and higher incidence of chronic morbidities. Living closer to a petrol station was associated with a higher incidence of functional impairments and chronic morbidities.

CONCLUSIONS

Exposure to nearby residential traffic is associated with accelerated trajectories of unhealthy ageing. Diminishing traffic pollution should become a priority intervention for adding healthy years to life in the old age.

Effects of fine particulate matter on bone marrow-conserved hematopoietic and mesenchymal stem cells: a systematic review

The harmful effects of fine particulate matter ≤2.5 µm in size (PM2.5) on human health have received considerable attention. However, while the impact of PM2.5 on the respiratory and cardiovascular systems has been well studied, less is known about the effects on stem cells in the bone marrow (BM). With an emphasis on the invasive characteristics of PM2.5, this review examines the current knowledge of the health effects of PM2.5 exposure on BM-residing stem cells. Recent studies have shown that PM2.5 enters the circulation and then travels to distant organs, including the BM, to induce oxidative stress, systemic inflammation and epigenetic changes, resulting in the reduction of BM-residing stem cell survival and function. Understanding the broader health effects of air pollution thus requires an understanding of the invasive characteristics of PM2.5 and its direct influence on stem cells in the BM. As noted in this review, further studies are needed to elucidate the underlying processes by which PM2.5 disturbs the BM microenvironment and inhibits stem cell functionality. Strategies to prevent or ameliorate the negative effects of PM2.5 exposure on BM-residing stem cells and to maintain the regenerative capacity of those cells must also be investigated. By focusing on the complex relationship between PM2.5 and BM-resident stem cells, this review highlights the importance of specific measures directed at safeguarding human health in the face of rising air pollution.

Age-Period-Cohort Analysis of Long-Term Trends in Ischemic Stroke Mortality in China Caused by Specific Risk Factors from 1990 to 2019

OBJECTIVE

The objective of this study was to study the primary risk factors for the long-term trends of mortality rates in ischemic stroke (IS) in China.

METHODS

Using the Global Burden of Disease Study 2019 (GBD 2019) database, research was conducted on the 11 primary risk factors for the mortality rates of IS in China from 1990 to 2019. This study employed joinpoint regression software and the age-period-cohort method to evaluate the trends of mortality rates divided by age, period, and cohort over time.

RESULTS

From 1990 to 2019, the age-standardized mortality rate (ASMR) caused by a diet high in red meat and high body mass index in China showed an upward trend. ASMR increased first and then decreased due to smoking, diet high in sodium, particulate matter pollution, high fasting plasma glucose, and high systolic blood pressure. Low-density lipoprotein cholesterol (LDL-C), kidney dysfunction, low temperature, and lead exposure remained relatively stable during this period. In the 35-45 age group, the mortality rate of IS due to high LDL-C was up to about 60%, and smoking affected men more than women. Overall, high LDL-C, high systolic blood pressure, and particulate matter pollution were the most common risk factors in patients with IS. The risk of death rose with age. The period and cohort relative risks showed that metabolic risk factors had the greatest impact on the mortality of IS.

CONCLUSION

Metabolic risk factors have become the primary risk factors for the ASMR of IS in China. Relevant authorities should pay attention to their long-term effects on IS. Effective public health policies and interventions should be implemented to reduce the burden of IS.

Association between Ambient Particulate Air Pollution and Soluble Biomarkers of Endothelial Function: A Meta-Analysis

BACKGROUND

The burden of cardiovascular diseases caused by ambient particulate air pollution is universal. An increasing number of studies have investigated the potential effects of exposure to particulate air pollution on endothelial function, which is one of the important mechanisms for the onset and development of cardiovascular disease. However, no previous study has conducted a summary analysis of the potential effects of particulate air pollution on endothelial function.

OBJECTIVES

To summarize the evidence for the potential effects of short-term exposure to ambient particulate air pollution on endothelial function based on existing studies.

METHODS

A systematic literature search on the relationship between ambient particulate air pollution and biomarkers of endothelial function including endothelin-1 (ET-1), E-selectin, intercellular cell adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) was conducted in PubMed, Scopus, EMBASE, and Web of Science up to 20 May 2023. Subsequently, a meta-analysis was conducted using a random effects model.

RESULTS

A total of 18 studies were included in this meta-analysis. A 10 μg/m3 increase in short-term exposure to ambient PM2.5 was associated with a 1.55% (95% CI: 0.89%, 2.22%) increase in ICAM-1 and a 1.97% (95% CI: 0.86%, 3.08%) increase in VCAM-1. The associations of ET-1 (0.22%, 95% CI: -4.94%, 5.65%) and E-selectin (3.21%, 95% CI: -0.90% 7.49%) with short-term exposure to ambient PM2.5 were statistically insignificant.

CONCLUSION

Short-term exposure to ambient PM2.5 pollution may significantly increase the levels of typical markers of endothelial function, including ICAM-1 and VCAM-1, suggesting potential endothelial dysfunction following ambient air pollution exposure.

Short-term air pollution exposure and mortality in Brazil: Investigating the susceptible population groups

This is the first study to examine the association between ambient air pollution (PM2.5, O3, and NO2) and mortality (in different population groups by sex and age) based on a nationwide death record across Brazil over a 15-year period (2003-2017). We used a time-series analytic approach with a distributed lag model. Our study population includes 2,872,084 records of deaths in Brazil between 2003 and 2017. Men accounted for a higher proportion of deaths, with 58% for all-cause mortality, 54% for respiratory mortality, and 52% for circulatory mortality. Most individuals were over 65 years of age. Our results suggest an association between air pollution and mortality in Brazil. The direction, statistical significance, and effect size of these associations varied considerably by type of air pollutant, region, and population group (sex and age group). In particular, the older population group (>65 years) was most affected. The national meta-analysis for the entire data set (without stratification by sex and age) showed that for every 10 μg/m3 increase in PM2.5 concentration, the risk of death from respiratory diseases increased by 2.93% (95%CI: 1.42; 4.43). For every 10 ppb increase in O3, there is a 2.21% (95%CI: 0.59; 3.83) increase in the risk of all-cause mortality for the group of all people between 46 and 65 years old, and a 3.53% (95%CI: 0.34; 6.72) increase in the risk of circulatory mortality for the group of women, all ages. For every 10 ppb increase in NO2, the risk of respiratory mortality increases by 17.56% (95%CI: 4.44; 30.64) and the risk of all-cause mortality by 5.63% (95%CI: 1.83; 9.44). The results of our study provide epidemiological evidence that air pollution is associated with a higher risk of cardiorespiratory mortality in Brazil. Given the lack of nationwide studies on air pollution in Brazil, our research is an important contribution to the local and international literature that can provide better support to policymakers to improve air quality and public health.

Duration-sensitive association between air pollution exposure and changes in cardiometabolic biomarkers: Evidence from a predominantly African American cohort

BACKGROUND

Ambient fine particulate matter (PM2.5) exposure has been related to cardiometabolic diseases, but the underlying biological pathways remain unclear at the population level.

OBJECTIVE

To investigate the effect of PM2.5 exposure on changes in multiple cardiometabolic biomarkers across different exposure durations.

METHOD

Data from a prospective cohort study were analyzed. Ten cardiometabolic biomarkers were measured, including ghrelin, resistin, leptin, C-peptide, creatine kinase myocardial band (CK-MB), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor alpha (TNF-alpha), N-terminal pro B-type natriuretic peptide (NT-proBNP), troponin, and interleukin-6 (IL-6). PM2.5 levels across exposure durations from 1 to 36 months were assessed. Mixed effect model was used to estimate changes in biomarker levels against 1 μg/m3 increase in PM2.5 level across different exposure durations.

RESULTS

Totally, 641 participants were included. The average PM2.5 exposure level was 9 μg/m3. PM2.5 exposure was inversely associated with ghrelin, and positively associated with all other biomarkers. The magnitudes of these associations were duration-sensitive and exhibited a U-shaped or inverted-U-shaped trend. For example, the association of resistin were β = 0.05 (95% CI: 0.00, 0.09) for 1-month duration, strengthened to β = 0.27 (95% CI: 0.14, 0.41) for 13-month duration, and weakened to β = 0.12 (95% CI: -0.03, 0.26) for 24-month duration. Similar patterns were observed for other biomarkers except for CK-MB, of which the association direction switched from negative to positive as the duration increased. Resistin, leptin, MCP-1, TNF-alpha, and troponin had a sensitive exposure duration of nearly 12 months. Ghrelin and C-peptide were more sensitive to longer-term exposure (>18 months), while NT-proBNP and IL-6 were more sensitive to shorter-term exposure (<6 months).

CONCLUSION

PM2.5 exposure was associated with elevated levels in cardiometabolic biomarkers related to insulin resistance, inflammation, and heart injury. The magnitudes of these associations depended on the exposure duration. The most sensitive exposure durations of different biomarkers varied.

Methylomic, Proteomic, and Metabolomic Correlates of Traffic-Related Air Pollution in the Context of Cardiorespiratory Health: A Systematic Review, Pathway Analysis, and Network Analysis

A growing body of literature has attempted to characterize how traffic-related air pollution (TRAP) affects molecular and subclinical biological processes in ways that could lead to cardiorespiratory disease. To provide a streamlined synthesis of what is known about the multiple mechanisms through which TRAP could lead to cardiorespiratory pathology, we conducted a systematic review of the epidemiological literature relating TRAP exposure to methylomic, proteomic, and metabolomic biomarkers in adult populations. Using the 139 papers that met our inclusion criteria, we identified the omic biomarkers significantly associated with short- or long-term TRAP and used these biomarkers to conduct pathway and network analyses. We considered the evidence for TRAP-related associations with biological pathways involving lipid metabolism, cellular energy production, amino acid metabolism, inflammation and immunity, coagulation, endothelial function, and oxidative stress. Our analysis suggests that an integrated multi-omics approach may provide critical new insights into the ways TRAP could lead to adverse clinical outcomes. We advocate for efforts to build a more unified approach for characterizing the dynamic and complex biological processes linking TRAP exposure and subclinical and clinical disease and highlight contemporary challenges and opportunities associated with such efforts.

Methylomic, proteomic, and metabolomic correlates of traffic-related air pollution: A systematic review, pathway analysis, and network analysis relating traffic-related air pollution to subclinical and clinical cardiorespiratory outcomes

A growing body of literature has attempted to characterize how traffic-related air pollution (TRAP) affects molecular and subclinical biological processes in ways that could lead to cardiorespiratory disease. To provide a streamlined synthesis of what is known about the multiple mechanisms through which TRAP could lead cardiorespiratory pathology, we conducted a systematic review of the epidemiological literature relating TRAP exposure to methylomic, proteomic, and metabolomic biomarkers in adult populations. Using the 139 papers that met our inclusion criteria, we identified the omic biomarkers significantly associated with short- or long-term TRAP and used these biomarkers to conduct pathway and network analyses. We considered the evidence for TRAP-related associations with biological pathways involving lipid metabolism, cellular energy production, amino acid metabolism, inflammation and immunity, coagulation, endothelial function, and oxidative stress. Our analysis suggests that an integrated multi-omics approach may provide critical new insights into the ways TRAP could lead to adverse clinical outcomes. We advocate for efforts to build a more unified approach for characterizing the dynamic and complex biological processes linking TRAP exposure and subclinical and clinical disease, and highlight contemporary challenges and opportunities associated with such efforts.

Vitamin D3 regulates PM-driven primary human neutrophil inflammatory responses

Recent evidence has demonstrated that both acute and chronic exposure to particulate air pollution are risk factors for respiratory tract infections and increased mortality from sepsis. There is therefore an urgent need to establish the impact of ambient particulate matter (PM) on innate immune cells and to establish potential strategies to mitigate against adverse effects. PM has previously been reported to have potential adverse effects on neutrophil function. In the present study, we investigated the impact of standard urban PM (SRM1648a, NIST) and PM2.5 collected from Chiang Mai, Thailand, on human peripheral blood neutrophil functions, including LPS-induced migration, IL-8 production, and bacterial killing. Both NIST and the PM2.5, being collected in Chiang Mai, Thailand, increased IL-8 production, but reduced CXCR2 expression and migration of human primary neutrophils stimulated with Escherichia coli LPS. Moreover, PM-pretreated neutrophils from vitamin D-insufficient participants showed reduced E. coli-killing activity. Furthermore, in vitro vitamin D3 supplementation attenuated IL-8 production and improved bacterial killing by cells from vitamin D-insufficient participants. Our findings suggest that provision of vitamin D to individuals with insufficiency may attenuate adverse acute neutrophilic responses to ambient PM.

Urban climate and cardiovascular health: Focused on seasonal variation of urban temperature, relative humidity, and PM2.5 air pollution

Seasonal effects on subclinical cardiovascular functions (CVFs) are an important emerging health issue for people living in urban environment. The objectives of this study were to demonstrate the effects of seasonal variations of temperature, relative humidity, and PM2.5 air pollution on CVFs. A total of 86 office workers in Taipei City were recruited, their arterial pressure waveform was recorded by cuff sphygmomanometer using an oscillometric blood pressure (BP) device for CVFs assessment. Results of paried t-test with Bonferroni correction showed significantly increased systolic and diastolic BP (SBP, DBP), central end-systolic and diastolic BP (cSBP, cDBP) and systemic vascular resistance, but decreased heart rate (HR), stroke volume (SV), cardio output (CO), and cardiac index in winter compared with other seasons. After controlling for related confounding factors, SBP, DBP, cSBP, cDBP, LV dp/dt max, and brachial-ankle pulse wave velocity (baPWV) were negatively associated with, and SV was positively associated with seasonal temperature changes. Seasonal changes of air pollution in terms of PM2.5 were significantly positively associated with DBP and cDBP, as well as negatively associated with HR and CO. Seasonal changes of relative humidity were significantly negatively associated with DBP, and cDBP, as well as positively associated with HR, CO, and baPWV. This study provides evidence of greater susceptibility to cardiovascular events in winter compared with other seasons, with ambient temperature, relative humidity, and PM2.5 as the major factors of seasonal variation of CVFs.

Are We Any Closer to Understanding How Chronic Pain Develops? A Systematic Search and Critical Narrative Review of Existing Chronic Pain Vulnerability Models

Identifying biopsychosocial factors underlying chronic pain vulnerability is essential for the design of preventative efforts. Multiple chronic pain vulnerability models exist, however, there is a lack of comprehensive evaluation of these models in the literature, potentially due to the lack of guidelines that specify the criteria by which these types of work should be assessed. In this work, we created evaluation criteria (based on the general goals of conceptual models), and we then used them to critically review the chronic pain vulnerability models available in the current peer-reviewed literature (identified through a systematic search). Particularly, we evaluated the models on the basis of conceptual clarity/specificity of measures, depth of description of aetiological and mechanistic factors, use of a whole system approach, and quality of the evidence associated with the models. We found nine conceptual models that have been explored in detail (eg, fear avoidance model, diathesis-stress model). These models excel at clarity and are supported mostly by self-report evidence of a psychological nature (anxiety sensitivity, pain catastrophizing, etc.), but provide little explanation of mechanistic and aetiological factors. In the future, models could be improved by complementing them with proposals from other models and exploring potential causal factors and mechanisms maintaining the condition. This task could be carried out through prospective cohort studies, and computational approaches, amongst others.

Short-term effects of air pollutant exposure on small airway dysfunction, spirometry, health-related quality of life, and inflammatory biomarkers in wildland firefighters: a pilot study

Clinical Trials Registry: Study ID: TCTR20200828005.

Particulate matter, traffic-related air pollutants, and circulating C-reactive protein levels: The Multiethnic Cohort Study

Inhaled particles and gases can harm health by promoting chronic inflammation in the body. Few studies have investigated the relationship between outdoor air pollution and inflammation by race and ethnicity, socioeconomic status, and lifestyle risk factors. We examined associations of particulate matter (PM) and other markers of traffic-related air pollution with circulating levels of C-reactive protein (CRP), a biomarker of systemic inflammation. CRP was measured from blood samples obtained in 1994-2016 from 7,860 California residents participating in the Multiethnic Cohort (MEC) Study. Exposure to PM (aerodynamic diameter ≤2.5 μm [PM2.5], ≤10 μm [PM10], and between 2.5 and 10 μm [PM10-2.5]), nitrogen oxides (NOx, including nitrogen dioxide [NO2]), carbon monoxide (CO), ground-level ozone (O3), and benzene averaged over one or twelve months before blood draw were estimated based on participants' addresses. Percent change in geometric mean CRP levels and 95% confidence intervals (CI) per standard concentration increase of each pollutant were estimated using multivariable generalized linear regression. Among 4,305 females (55%) and 3,555 males (45%) (mean age 68.1 [SD 7.5] years at blood draw), CRP levels increased with 12-month exposure to PM10 (11.0%, 95% CI: 4.2%, 18.2% per 10 μg/m3), PM10-2.5 (12.4%, 95% CI: 1.4%, 24.5% per 10 μg/m3), NOx (10.4%, 95% CI: 2.2%, 19.2% per 50 ppb), and benzene (2.9%, 95% CI: 1.1%, 4.6% per 1 ppb). In subgroup analyses, these associations were observed in Latino participants, those who lived in low socioeconomic neighborhoods, overweight or obese participants, and never or former smokers. No consistent patterns were found for 1-month pollutant exposures. This investigation identified associations of primarily traffic-related air pollutants, including PM, NOx, and benzene, with CRP in a multiethnic population. The diversity of the MEC across demographic, socioeconomic, and lifestyle factors allowed us to explore the generalizability of the effects of air pollution on inflammation across subgroups.

Assessing the timing and the duration of exposure to air pollution on cardiometabolic biomarkers in patients suspected of coronary artery disease

Air pollution can affect cardiometabolic biomarkers in susceptible populations, but the most important exposure window (lag days) and exposure duration (length of averaging period) are not well understood. We investigated air pollution exposure across different time intervals on ten cardiometabolic biomarkers in 1550 patients suspected of coronary artery disease. Daily residential PM_2.5 and NO₂ were estimated using satellite-based spatiotemporal models and assigned to participants for up to one year before the blood collection. Distributed lag models and generalized linear models were used to examine the single-day-effects by variable lags and cumulative effects of exposures averaged over different periods before the blood draw. In single-day-effect models, PM_2.5 was associated with lower apolipoprotein A (ApoA) in the first 22 lag days with the effect peaking on the first lag day; PM_2.5 was also associated with elevated high-sensitivity C-reactive protein (hs-CRP) with significant exposure windows observed after the first 5 lag days. For the cumulative effects, short- and medium-term exposure was associated with lower ApoA (up to 30wk-average) and higher hs-CRP (up to 8wk-average), triglycerides and glucose (up to 6 d-average), but the associations were attenuated to null over the long term. The impacts of air pollution on inflammation, lipid, and glucose metabolism differ by the exposure timing and durations, which can inform our understanding of the cascade of underlying mechanisms among susceptible patients.

The protective effect of p-Coumaric acid on hepatic injury caused by particulate matter in the rat and determining the role of long noncoding RNAs MEG3 and HOTAIR

Increasing air pollution is associated with serious human health problems. P-coumaric acid (PC) is a herbal phenolic compound that exhibits beneficial pharmacological potentials. Here, the protective effect of PC on liver injury induced by air pollution was examined. Thirty-two adult male Wistar rats (200-250 g) were divided randomly into four groups (n = 8). The groups were; Control (rats received DMSO and then exposed to clean air), PC (rats received PC and then exposed to clean air), DMSO + Dust (rats received DMSO and then exposed to dust), and PC + Dust (the animals received PC and then exposed to dust). The clean air, DMSO, PC, and dust were administrated 3 days a week for 6 consecutive weeks. The rats were anesthetized and their blood samples and liver sections were taken to conduct molecular, biomedical, and histopathological tests. Dust exposure increased the liver enzymes, bilirubin, triglyceride, cholesterol, and the production of liver malondialdehyde, and decreased in liver total anti-oxidant capacity and serum high-density lipoprotein. It also increased the mRNA expression of inflammatory-related cytokines, decreased the mRNA expression of SIRT-1, decreased the expression levels of miR-20b5p, and MEG3 while increased the expression levels of miR-34a, and HOTAIR. Dust exposure also increased the liver content of three cytokines TNF-α, NF-κB, HMGB-1, and ATG-7 proteins. PC enhanced liver function against adverse effects of dust through recovering almost all the studied variables. Exposure to dust damaged the liver through induction of oxidative stress, inflammation, and autophagy. PC protected the liver against dust-induced cytotoxicity.

The effects of fine particulate matter, solid fuel use and greenness on the risks of diabetes in middle-aged and older Chinese

BACKGROUND

Previous studies provided clues that environmental factors were closely related to diabetes incidence. However, the evidence from high-quality and large cohort studies about the effects of PM_2.5, solid fuel use and greenness on the development of diabetes among middle-aged and older adults in China was scarce.

OBJECTIVE

To separately investigate the independent effects of PM_2.5, solid fuel use and greenness on the development of diabetes among middle-aged and older adults.

METHODS

A total of 9242 participants were involved in this study extracted from the China Health and Retirement Longitudinal Study. Time-varying Cox regression was applied to detect the association of diabetes with PM_2.5, solid fuel use and greenness, separately. The potential interactive effect of air pollution and greenness were explored using the relative excess risk due to interaction (RERI).

RESULTS

Per 10 μg/m³ increases in PM_2.5 were associated with 6.0% (95% CI: 1.9, 10.2) increasing risks of diabetes incidence. Females seemed to be more susceptible to PM_2.5. However, the effects of solid fuel use only existed in older and lower BMI populations, with hazard ratios (HRs) of 1.404 (1.116, 1.766) and 1.346 (1.057, 1.715), respectively. In addition, exposure to high-level greenness might reduce the risks of developing diabetes [HR = 0.801 (0.687, 0.934)]. Weak evidence of the interaction effect of PM_2.5/solid fuel use and greenness on diabetes was found.

SIGNIFICANCE

Both PM_2.5 and solid fuel use were associated with the increasing incidence of diabetes. In addition, high-level greenness might be a beneficial environmental factor for reducing the risks of developing diabetes. All in all, our findings might provide valuable references for public health apartments to formulate very fruitful policies to reduce the burden of diabetes.

IMPACT STATEMENT

Both PM_2.5 and solid fuel use were associated with the increasing incidence of diabetes while high-level greenness was not, which might provide valuable references for public health apartments to make policies.

Noise, Air, and Heavy Metal Pollution as Risk Factors for Endothelial Dysfunction

During the last two decades, large epidemiological studies have shown that the physical environment, including noise, air pollution or heavy metals, have a considerable impact on human health. It is known that the most common cardiovascular risk factors are all associated with endothelial dysfunction. Vascular tone, circulation of blood cells, inflammation, and platelet activity are some of the most essential functions regulated by the endothelium that suffer negative effects as a consequence of environmental pollution, causing endothelial dysfunction. In this review, we delineate the impact of environmental risk factors in connection to endothelial function. On a mechanistic level, a significant number of studies suggest the involvement of endothelial dysfunction to fundamentally drive the adverse endothelium health effects of the different pollutants. We focus on well-established studies that demonstrate the negative effects on the endothelium, with a focus on air, noise, and heavy metal pollution. This in-depth review on endothelial dysfunction as a consequence of the physical environment aims to contribute to the associated research needs by evaluating current findings from human and animal studies. From a public health perspective, these findings may also help to reinforce efforts promoting the research for adequate promising biomarkers for cardiovascular diseases since endothelial function is considered a hallmark of environmental stressor health effects.

Short-term impacts of air pollution on the platelet-lymphocyte ratio and neutrophil-lymphocyte ratio among urban adults in China

The short-term impacts of urban air pollution on the platelet-lymphocyte ratio (PLR) and neutrophil-lymphocyte ratio (NLR) remain obscure. In this study, we included 3487 urban adults from the Wuhan-Zhuhai cohort. Individual inhalation exposure to air pollutants was estimated by combining participants' daily breath volume and ambient concentrations of six air pollutants (including fine particulate matter (PM_2.5), inhalable particulate matter (PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), carbon monoxide (CO) and ozone (O₃)). The cumulative impacts were assessed by applying lag structures of up to 7 days before the survey date. Associations of air pollutants with PLR and NLR were assessed using a linear mixed model and Bayesian kernel machine regression (BKMR) model. We found that PLR was negatively related to PM_2.5 (lag02-lag06), PM₁₀ (lag02-lag07), NO₂ (lag02-lag07), and SO₂ (lag03-lag05) and NLR was negatively related to PM₁₀ (lag05 and lag07). In the BKMR model, a negative joint association between the six-air-pollutant mixture and PLR and NLR was observed, whereas PM₁₀ and NO₂ appeared to be more important than the other pollutants in the mixture. The negative impact of air pollutants was stronger in males, participants with lower body mass index (< 24 kg/m²), those cooking meals at home, drinkers, and non-exercisers. In conclusion, short-term exposure to air pollutants is significantly related to PLR and NLR in peripheral blood. PLR and NLR may provide new insight into the molecular mechanism underlying the adverse health impact of air pollutants.

Fine Particulate Matter (PM2.5)-Induced Pulmonary Oxidative Stress Contributes to Changes in the Plasma Lipidome and Liver Transcriptome in Mice

Fine particulate matter (PM2.5) air pollution exposure increases the cardiovascular disease risk. Although the specific mechanisms remain elusive, it is thought that PM2.5-induced oxidative stress and endothelial dysfunction contribute to this pathogenesis. Our previous findings indicate that PM2.5 impairs vascular health via a circulating factor and that plasma lipid changes contribute to the observed vascular effects. In the current study, we extend on these findings by further characterizing PM2.5-induced changes in circulating lipids and examining whether the observed changes were accompanied by related alterations in the liver transcriptome. To address the role of pulmonary oxidative stress, we exposed wild-type (WT) mice and mice that overexpress extracellular superoxide dismutase (ecSOD-Tg) in the lungs to concentrated ambient PM2.5 (CAP, 9 days). We found that CAP decreased circulating complex lipids and increased free fatty acids and acylcarnitines in WT, but not ecSOD-Tg mice. These plasma lipid changes were accompanied by transcriptional changes in genes that regulate lipid metabolism (e.g., upregulation of lipid biosynthesis, downregulation of mitochondrial/peroxisomal FA metabolism) in the liver. The CAP-induced changes in lipid homeostasis and liver transcriptome were accompanied by pulmonary but not hepatic oxidative stress and were largely absent in ecSOD-Tg mice. Our results suggest that PM2.5 impacts hepatic lipid metabolism; however, it remains unclear whether the transcriptional changes in the liver contribute to PM2.5-induced changes in plasma lipids. Regardless, PM2.5-induced changes in the plasma lipidome and hepatic transcriptome are, at least in part, mediated by pulmonary oxidative stress.

Association of Ambient Air Pollution with Blood Pressure in Adolescence: A Systematic-review and Meta-analysis

We systematically reviewed the association of ambient air pollution with blood pressure (BP) as a primary outcome in adolescents (10-19 years). Five databases (Ovid Medline, Ovid Embase, Web of Science, The Cochrane Library, and LILACS) were searched for relevant articles published up to August 2022. Meta-analyses were conducted using STATA v17 (Protocol - OSF Registries https://doi.org/10.17605/OSF.IO/96G5Q). Eight studies (5 cohort, 3 cross-sectional) with approximately 15,000 adolescents were included. Data from 6 studies were suitable for inclusion in the meta-analyses. In sub-group analyses, non-significant positive associations were observed for cohort studies assessing long-term exposure to PM₁₀, PM_2.5, and NO₂ on systolic and diastolic BP. At age 12 years old (3702 adolescents), we found significant positive associations for long-term exposure to PM_2.5(β=5.33 (1.56, 9.09) mmHg) and PM₁₀ (β=2.47 (0.10, 4.85) mmHg) on diastolic BP. Significant positive associations were observed (3,592 adolescents) for long-term exposure to PM₁₀(β=0.34 (0.19, 0.50) mmHg) and NO₂ on diastolic BP (β=0.40 (0.09, 0.71) mmHg), and PM₁₀ on systolic BP (β=0.48 (0.19, 0.77) mmHg). The overall quality of evidence analysed was graded as "low/very low." Insufficient data for short-term exposures to PM₂.₅, PM₁₀, NO₂, CO on BP led to their exclusion from the meta-analysis. Inconsistent associations were reported for gender-stratified results. The evidence, though of low-quality and limited, indicated that ambient air pollution was positively associated with adolescent BP. Future studies need improved measures of air pollutant exposures, consideration of gender and socio-economic circumstances on the observed pollution effects, as well as adjustment for other potential confounding factors.

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.

Fine particulate matter and incident coronary heart disease events up to 10 years of follow-up among Deepwater Horizon oil spill workers

BACKGROUND

During the 2010 Deepwater Horizon (DWH) disaster, in-situ burning and flaring were conducted to remove oil from the water. Workers near combustion sites were potentially exposed to burning-related fine particulate matter (PM2.5). Exposure to PM2.5 has been linked to increased risk of coronary heart disease (CHD), but no study has examined the relationship among oil spill workers.

OBJECTIVES

To investigate the association between estimated PM2.5 from burning/flaring of oil/gas and CHD risk among the DWH oil spill workers.

METHODS

We included workers who participated in response and cleanup activities on the water during the DWH disaster (N = 9091). PM2.5 exposures were estimated using a job-exposure matrix that linked modelled PM2.5 concentrations to detailed DWH spill work histories provided by participants. We ascertained CHD events as the first self-reported physician-diagnosed CHD or a fatal CHD event that occurred after each worker's last day of burning exposure. We estimated hazard ratios (HR) and 95% confidence intervals (95%CI) for the associations between categories of average or cumulative daily maximum PM2.5 exposure (versus a referent category of water workers not near controlled burning) and subsequent CHD. We assessed exposure-response trends by examining continuous exposure parameters in models.

RESULTS

We observed increased CHD hazard among workers with higher levels of average daily maximum exposure (low vs. referent: HR = 1.26, 95% CI: 0.93, 1.70; high vs. referent: HR = 2.11, 95% CI: 1.08, 4.12; per 10 μg/m3 increase: HR = 1.10, 95% CI: 1.02, 1.19). We also observed suggestively elevated HRs among workers with higher cumulative daily maximum exposure (low vs. referent: HR = 1.19, 95% CI: 0.68, 2.08; medium vs. referent: HR = 1.38, 95% CI: 0.88, 2.16; high vs. referent: HR = 1.44, 95% CI: 0.96, 2.14; per 100 μg/m3-d increase: HR = 1.03, 95% CI: 1.00, 1.05).

CONCLUSIONS

Among oil spill workers, exposure to PM2.5 from flaring/burning of oil/gas was associated with increased risk of CHD.

Mining biomarkers from routine laboratory tests in clinical records associated with air pollution health risk assessment

Clinical laboratory in hospital can produce amounts of health data every day. The purpose of this study was to mine biomarkers from clinical laboratory big data associated with the air pollution health risk assessment using clinical records. 13, 045, 629 clinical records of all 27 routine laboratory tests in Changsha Central Hospital, including ALB, TBIL, ALT, DBIL, AST, TP, UREA, UA, CREA, GLU, CK, CKMB, LDL-C, TG, TC, HDL-C, CRP, WBC, Na, K, Ca, Cl, APTT, PT, FIB, TT, RBC and those daily air pollutants concentration monitoring data of Changsha, including PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃ from 2014 to 2016, were retrieved. The moving average method was used to the biological reference interval was established. The tests results were converted into daily abnormal rate. After data cleaning, GAM statistical model construction and data analysis, a concentration-response relationship between air pollutants and daily abnormal rate of routine laboratory tests was observed. Our study found that PM_2.5 had a stable association with TP (lag07), ALB (lag07), ALT (lag07), AST (lag07), TBIL (lag07), DBIL (lag07), UREA (lag07), CREA (lag07), UA (lag07), CK (lag 06), GLU (lag07), WBC (lag07), Cl (lag07) and Ca (lag07), (P < 0.05); O₃ had a stable association with AST (lag01), CKMB (lag06), TG (lag07), TC (lag05), HDL-C (lag07), K (lag05) and RBC (lag07) (P < 0.05); CO had a stable association with UREA (lag07), Na (lag7) and PT (lag07) (P < 0.05); SO₂ had a stable association with TP (lag07) and LDL-C (lag0) (P < 0.05); NO₂ had a stable association with APTT (lag7) (P < 0.05). These results showed that different air pollutants affected different routine laboratory tests and presented different pedigrees. Therefore, biomarkers mined from routine laboratory tests may potentially be used to low-cost assess the health risks associated with air pollutants.

Short-term air pollution and temperature exposure and changes in the extracellular microRNA profile of Normative Aging Study (NAS) participants

BACKGROUND

While the health effects of air pollution and temperature are widely studied, the molecular effects are poorly understood. Extracellular microRNAs (ex-miRNAs) have the potential to serve as diagnostic or prognostic biomarkers and/or to act as intercellular signaling molecules that mediate the effects of environmental exposures on health outcomes.

METHODS

We examined the relationship between short-term exposure to air pollution and ambient temperature and the ex-miRNA profiles of participants in the Normative Aging Study (NAS) from 1999 to 2015. Our exposures were defined as same-day, two-day, three-day, one-week, two-week, and three-week moving averages of PM2.5, NO2, O3, and temperature which were derived from high-resolution spatio-temporal models. The ex-miRNA profiles of the subjects were obtained during follow-up visits. We analyzed the data using a longitudinal quantile regression model adjusted for individual covariates, batch effects, and time trends. We adjusted for multiple comparisons using a false discovery rate (FDR) correction. Ex-miRNAs that were significantly associated with exposures were further investigated using pathway analyses.

RESULTS

We found that all the examined exposures were associated with changes in ex-miRNA profiles in our study, particularly PM2.5 which was responsible for most of the statistically significant results. We found 110 statistically significant exposure-outcome relationships that revealed associations with the levels of 52 unique ex-miRNAs. Pathway analyses showed these ex-miRNAs have been linked to target mRNAs, genes, and biological mechanisms that could affect virtually every organ system, and as such may be linked to multiple clinical disease presentations such as cardiovascular disease, respiratory disease, and neurological disease.

CONCLUSIONS

Air pollution and temperature exposures were significantly associated with alterations in the ex-miRNA profiles of NAS subjects with possible biological consequences.

Indoor air pollution from solid fuels use, inflammation, depression and cognitive function in middle-aged and older Chinese adults

BACKGROUND

Few studies have focused on the influence of indoor air pollution on depression and cognitive impairment; besides, the underlying mechanism is not well-established.

OBJECTIVE

This study aimed to fill the above gaps by exploring the underlying influence mechanism of solid fuel use, the major cause of indoor air pollution, with the risk of depression and cognitive impairment.

METHODS

This data came from China Health and Retirement Longitudinal Study (CHARLS) 2015 dataset. Self-reported household cooking fuels were collected and categorized as clean fuels and solid fuels. High-sensitivity C-reactive protein (CRP) and white blood cells (WBC) were used to measure inflammation. Depression and cognitive function were assessed by using standardized questionnaires.

RESULTS

Respondents had an average Center for Epidemiologic Studies Depression Scale (CESD-10) scores of 7.68 (SD = 6.14) and cognitive function scores of 15.97 (SD = 4.84). In the whole sample, 36.4 % of respondents used solid fuels use, but this proportion was much greater among those living in rural areas (78.38 %). Compared with clean fuel users, solid fuel users had more depression and worse cognitive function. After adjusting for confounders, indoor air pollution was significantly associated with depression and cognitive function respectively (β = -0.444, p < 0.001; β = 0.656, p < 0.001). Indoor air pollution was significantly related to the WBC (β = 0.170, p < 0.01), but not for the CRP. The WBC mediated the association between indoor air pollution and depression (β = 0.026, p < 0.01).

CONCLUSION

In conclusion, solid fuel use was significantly associated with a higher risk of depression and cognitive impairment. Furthermore, we found that solid fuel use influences depression partly via the inflammatory profile.

Kidney damage induced by repeated fine particulate matter exposure: Effects of different components

BACKGROUND

Exposure to fine particulate matter with an aerodynamic diameter of ≤2.5 μm (PM_2.5) is associated with adverse health effects. This study aimed to evaluate the toxic effects of the constituents of PM_2.5 on mouse kidneys.

METHODS

We collected PM_2.5 near an industrial complex located in southern Kaohsiung, Taiwan, that was divided into water extract and insoluble particles. Male C57BL/6 mice were divided into five groups: control, low- and high-dose insoluble particle exposure, and low- and high-dose water extract exposure. Biochemical analysis, Western blot analysis, histological examination, and immunohistochemistry were performed to evaluate the impact of PM_2.5 constituents on mice kidneys.

RESULTS

PM_2.5 was collected from January 1, 2021, to February 8, 2021, from an industrial complex in Kaohsiung, Taiwan. Metallic element analysis showed that Pb, Ni, V, and Ti were non-essential metals with enrichment factors >10. Polycyclic aromatic hydrocarbon and nitrate polycyclic aromatic hydrocarbon analyses revealed that the toxic equivalents are, in the order, benzo(a)pyrene (BaP), indeno(1,2,3-cd) pyrene (IP), dibenzo(a,h)anthracene (DBA), and benzo(b)fluoranthene (BbF), which are potential carcinogens. Both water extract and insoluble particle exposure induced inflammatory cytokine upregulation, inflammatory cell infiltration, antioxidant activity downregulation, and elevation of kidney injury molecule 1 (KIM-1) level in mouse kidneys. A dose-dependent effect of PM_2.5 water extract and insoluble particle exposure on angiotensin converter enzyme 2 downregulation in mouse kidneys was observed.

CONCLUSION

We found that water-soluble extract and insoluble particles of PM_2.5 could induce oxidative stress and inflammatory reactions, influence the regulation of renin-angiotensin system (RAS), and lead to kidney injury marker level elevation in mouse kidneys. The lowest-observed-adverse-effect level for renal toxicity in mice was 40 μg water-soluble extract/insoluble particle inhalation per week, which was approximately equal to the ambient PM_2.5 concentration of 44 μg/m³ for mice.

Association Between Long-term Ambient PM2.5 Exposure and Cardiovascular Outcomes Among US Hemodialysis Patients

RATIONALE & OBJECTIVE

Ambient PM_2.5 (particulate matter with a diameter of 2.5 microns) is a ubiquitous air pollutant with established adverse cardiovascular (CV) effects. However, quantitative estimates of the association between PM_2.5 exposure and CV outcomes in the setting of kidney disease are limited. This study assessed the association of long-term PM_2.5 exposure with CV events and cardiovascular disease (CVD)-specific mortality among patients receiving maintenance in-center hemodialysis (HD).

STUDY DESIGN

Retrospective cohort study.

SETTINGS & PARTICIPANTS

314,079 adult kidney failure patients initiating HD between 2011 and 2016 identified from the US Renal Data System.

EXPOSURE

Estimated daily ZIP code-level PM_2.5 concentrations were used to calculate each participant's annual average PM_2.5 exposure based on the dialysis clinics visited during the 365 days before the outcome.

OUTCOME

CV event and CVD-specific mortality were ascertained based on ICD-9/ICD-10 diagnostic codes and recorded cause of death from Centers for Medicare & Medicaid Services form 2746.

ANALYTICAL APPROACH

Discrete time hazards models were used to estimate hazards ratios per 1 μg/m³ greater annual average PM_2.5, adjusting for temperature, humidity, day of the week, season, age at baseline, race, employment status, and geographic region. Effect measure modification was assessed for age, sex, race, and baseline comorbidities.

RESULTS

Each 1 μg/m³ greater annual average PM_2.5 was associated with a greater rate of CV events (HR, 1.02 [95% CI, 1.01-1.02]) and CVD-specific mortality (HR, 1.02 [95% CI, 1.02-1.03]). The association was more pronounced for people who initiated dialysis at an older age, had chronic obstructive pulmonary disease (COPD) at baseline, or were Asian. Evidence of effect modification was also observed across strata of race, and other baseline comorbidities.

LIMITATIONS

Potential exposure misclassification and unmeasured confounding.

CONCLUSIONS

Long-term ambient PM_2.5 exposure was associated with CVD outcomes among patients receiving maintenance in-center HD. Stronger associations between long-term PM_2.5 exposure and adverse effects were observed among patients who were of advanced age, had COPD, or were Asian.

PLAIN-LANGUAGE SUMMARY

Long-term exposure to air pollution, also called PM_2.5, has been linked to adverse cardiovascular outcomes. However, little is known about the association of PM_2.5 and outcomes among patients receiving dialysis, who are individuals with high cardiovascular disease burdens. We conducted an epidemiological study to assess the association between the annual PM_2.5 exposure and cardiovascular events and death among patients receiving regular outpatient hemodialysis in the United States between 2011 and 2016. We found a higher risk of heart attacks, strokes, and related events in patients exposed to higher levels of air pollution. Stronger associations between air pollution and adverse health events were observed among patients who were older at the start of dialysis, had chronic obstructive pulmonary disease, or were Asian. These findings bolster the evidence base linking air pollution and adverse health outcomes and may inform policy makers and clinicians.

The effect of long-term exposure to air pollution and seasonal temperature on hospital admissions with cardiovascular and respiratory disease in the United States: A difference-in-differences analysis

BACKGROUND

Few studies have simultaneously examined the effect of long-term exposure to air pollution and ambient temperature on the rate of hospital admissions with cardiovascular and respiratory disease using causal inference methods.

METHODS

We used a variation of a difference-in-difference (DID) approach to assess the effects of long-term exposure to warm-season temperature, cold-season temperature, NO2, O3, and PM2.5 on the rate of hospital admissions for cardiovascular disease (CVD), myocardial infarction (MI), ischemic stroke, and respiratory diseases from 2001 to 2016 among Medicare beneficiaries who use fee-for-service programs. We computed the rate of admissions by zip code and year. Covariates included demographic and socioeconomic variables which were obtained from the decennial Census, the American Community Survey, the Behavioral Risk Factor Surveillance System, and the Dartmouth Health Atlas. As a secondary analysis, we restricted the analysis to zip code-years that had exposure to low concentrations of our pollutants.

RESULTS

PM2.5 was associated with a significant increase in the absolute rate of annual admissions with cardiovascular disease by 47.71 admissions (95 % CI: 41.25-56.05) per 100,000 person-years, myocardial infarction by 7.44 admissions (95 % CI: 5.53-9.63) per 100,000 person-years, and 18.58 respiratory admissions (95 % CI: 12.42-23.72) for each one μg/m3 increase in two-year average levels. O3 significantly increased the rates of all the studied outcomes. NO2 was associated with a decreased rate of admissions with MI by 0.83 admissions (95 % CI: 0.10-1.55) per 100,000 person-years but increased rate of admissions for respiratory disease by 3.16 admissions (95 % CI: 1.34-5.24) per 100,000 person-years. Warmer cold-season temperature was associated with a decreased admissions rate for all outcomes.

CONCLUSION

Air pollutants, particularly PM2.5 and O3, increased the rate of hospital admissions with cardiovascular and respiratory disease among the elderly, while higher cold-season temperatures decreased the rate of admissions with these conditions.

Time trends in the burden of stroke and subtypes attributable to PM2.5 in China from 1990 to 2019

Background

Increasing studies have found that PM2.5 has large adverse effects on stroke mortality. We want to investigate the long-term trends in the mortality of stroke attributable to ambient particulate matter pollution and household air pollution to provide evidence facilitating the design of policy.

Methods

The deaths data of stroke and its subtypes attributable to PM2.5 were obtained from the Global Burden of Disease (GBD) 2019, analyzed by Joinpoint regression software and the age-period-cohort (APC) method to assess the magnitude of the trends in mortality and the temporal trends in the mortality rate by age, period, and cohort.

Results

From 1990 to 2019, the age-standardized mortality rate (ASMR) attributable to PM2.5 exposure trended downwards, but the trends of ambient particulate matter pollution and household air pollution were opposite. The trends varied among subtypes, the AAPC of intracerebral hemorrhage, ischemic stroke, and subarachnoid hemorrhage attributable to PM2.5 were 0.7, 2.5, and-3.3%, respectively. The longitudinal age curve of the APC model showed that the mortality rates due to PM2.5 exposure increased with age. The period RRs of ischemic stroke due to ambient particulate matter pollution increased significantly. The cohort RRs of ambient particulate matter pollution increased among those born from 1905 to 1990. The net drifts of all subtypes attributable to PM2.5 were below 0, but owing to the increase of ambient particulate matter pollution, the range of the decline was small. Males had higher net drift values, compared with females.

Conclusions

Ambient particulate matter pollution has become the main type of PM2.5 leading to stroke in China. PM2.5 exposure is more harmful to ischemic stroke, males, and elderly. Chinese government should pay attention to the long-term impact of ambient air pollution on stroke and take effective public health policies and interventions.

Acute effects of exposure to fine particulate matter and ozone on lung function, inflammation and oxidative stress in healthy adults

Both fine particulate matter (PM_2.5) and ozone (O₃) may have adverse effects on human health. However, previous studies on the effects of air pollutants mainly have focused on susceptible population, and evidence on healthy young adults is limited. We aimed to examine the associations of the two main air pollutants (PM_2.5 and O₃) with lung function, inflammation and oxidative stress in healthy young adults. We recruited 30 healthy young adults for a longitudinal panel study in Beijing and implemented health examination seven times, including lung function (FEV₁ and PEF) and biomarkers of inflammation and oxidative stress (i.e. C-reactive protein, CRP; interleukin-6, IL-6; malondialdehyde, MDA) from December 2019 to May 2021. Hourly ambient air pollutants data were obtained from the closest air quality monitoring station. Linear mixed-effect model was applied to explore the associations between air pollutants and lung function, inflammation and oxidative stress. We observed higher PM_2.5 exposure was associated with decrement in lung function and increment in CRP and MDA. Each 10 μg/m³ increase in PM_2.5 (lag 2 day) is associated with a 17.06 ml (95% CI: -31.53, -2.58) decrease in FEV₁, 46.34 ml/s (95% CI: -76.41, -16.27) decrease in PEF and increments of 2.86% (95% CI: 1.47%, 4.27%) in CRP, 1.63% (95% CI: 0.14%, 3.14%) in MDA respectively. However, there is no significant association between ozone exposure and health indicators. The study suggested that short-term exposure to PM_2.5 may decrease lung function and induce inflammation and oxidative stress in healthy adults, but there is no association between O₃ and each outcome.

Long-Term Effects of Ambient Particulate and Gaseous Pollutants on Serum High-Sensitivity C-Reactive Protein Levels: A Cross-Sectional Study Using KoGES-HEXA Data

Ambient air pollutants reportedly increase inflammatory responses associated with multiple chronic diseases. We investigated the effects of long-term exposure to ambient air pollution on high-sensitivity C-reactive protein (hs-CRP) using data from 60,581 participants enrolled in the Korean Genome and Epidemiology Study-Health Examinees Study between 2012 and 2017. Community Multiscale Air Quality System with surface data assimilation was used to estimate the participants' exposure to criteria air pollutants based on geocoded residential addresses. Long-term exposure was defined as the 2-year moving average concentrations of PM₁₀, PM_2.5, SO₂, NO₂, and O₃. Multivariable linear and logistic regression models were utilized to estimate the percent changes in hs-CRP and odds ratios of systemic low-grade inflammation (hs-CRP > 3 mg/L) per interquartile range increment in air pollutants. We identified positive associations between hs-CRP and PM₁₀ (% changes: 3.75 [95% CI 2.68, 4.82]), PM_2.5 (3.68, [2.57, 4.81]), SO₂ (1.79, [1.10, 2.48]), and NO₂ (3.31, [2.12, 4.52]), while negative association was demonstrated for O₃ (-3.81, [-4.96, -2.65]). Elevated risks of low-grade inflammation were associated with PM₁₀ (odds ratio: 1.07 [95% CI 1.01, 1.13]), PM_2.5 (1.08 [1.02, 1.14]), and SO₂ (1.05 [1.01, 1.08]). The odds ratios reported indicated that the exposures might be risk factors for inflammatory conditions; however, they did not reflect strong associations. Our findings suggest that exposure to air pollutants may play a role in the inflammation process.

Multi-omics analysis unravels dysregulated lysosomal function and lipid metabolism involved in sub-chronic particulate matter-induced pulmonary injury

Particulate matter (PM) is a huge environmental threat and is of major public concern. Oxidative stress and systemic inflammation are known factors that contribute to PM- related damage; however, a systematic understanding of the deleterious pulmonary effects of PM using multi-omics analysis is lacking. In this study, we performed transcriptomic, proteomic, and metabolomic analyses in a mouse model exposed to PM for three months to identify molecular changes in lung tissues. We identified 1690 genes, 326 proteins, and 67 metabolites exhibiting significant differences between PM-challenged and control mice (p < 0.05). Differentially expressed genes and proteins regulated in PM-challenged mice were involved in lipid metabolism and in the immune and inflammatory response processes. Moreover, a comprehensive analysis of transcript, protein, and metabolite datasets revealed that the genes, proteins, and metabolites in the PM-treated group were involved in lysosomal function and lipid metabolism. Specifically, Cathepsin D (Ctsd), Ferritin light chain (Ftl), Lactotransferrin (Ltf), Lipocalin 2 (Lcn2), and Prosaposin (Psap) were major proteins/genes associated with PM-induced pulmonary damage, while two lipid molecules PC (18:1(11Z)/16:0) and PA (16:0/18:1(11Z)) were major metabolites related to PM-induced pulmonary injury. In summary, lipid metabolism might be used as successful precautions and therapeutic targets in PM-induced pulmonary injury to maintain the stability of cellular lysosomal function.

Potential urinary biomarkers in young adults with short-term exposure to particulate matter and bioaerosols identified using an unbiased metabolomic approach

Numerous epidemiological studies have shown a close relationship between outdoor air pollution and increased risks for cancer, infection, and cardiopulmonary diseases. However, very few studies have investigated the potential health effects of coexposure to airborne particulate matter (PM) and bioaerosols through the transmission of infectious agents, particularly under the current circumstances of the coronavirus disease 2019 pandemic. In this study, we aimed to identify urinary metabolite biomarkers that might serve as clinically predictive or diagnostic standards for relevant diseases in a real-time manner. We performed an unbiased gas/liquid chromatography-mass spectroscopy (GC/LC-MS) approach to detect urinary metabolites in 92 samples from young healthy individuals collected at three different time points after exposure to clean air, polluted ambient, or purified air, as well as two additional time points after air repollution or repurification. Subsequently, we compared the metabolomic profiles between the two time points using an integrated analysis, along with Kyoto Encyclopedia of Genes and Genomes-enriched pathway and time-series analysis. We identified 33 and 155 differential metabolites (DMs) associated with PM and bioaerosol exposure using GC/LC-MS and follow-up analyses, respectively. Our findings suggest that 16-dehydroprogesterone and 4-hydroxyphenylethanol in urine samples may serve as potential biomarkers to predict or diagnose PM- or bioaerosol-related diseases, respectively. The results indicated apparent differences between PM- and bioaerosol-associated DMs at five different time points and revealed dynamic alterations in the urinary metabolic profiles of young healthy humans with cyclic exposure to clean and polluted air environments. Our findings will help in investigating the detrimental health effects of short-term coexposure to airborne PM and bioaerosols in a real-time manner and improve clinically predictive or diagnostic strategies for preventing air pollution-related diseases.

Posttraumatic Stress Disorder Mediates the Association between Traumatic World Trade Center Dust Cloud Exposure and Ongoing Systemic Inflammation in Community Members

Exposure to World Trade Center (WTC) dust/fumes and traumas on 11 September 2001 has been reported as a risk factor for post-traumatic stress disorder (PTSD) and other mental/physical health symptoms in WTC-affected populations. Increased systemic inflammation and oxidative stress from the exposure and subsequent illnesses have been proposed as contributors to the underlying biological processes. Many blood-based biomarkers of systemic inflammation, including C-reactive protein (CRP), are useful for non-invasive diagnostic and monitoring of disease process, and also potential targets for therapeutic interventions. Twenty years after 9/11, however, the relationships between WTC exposure, chronic PTSD, and systemic inflammation are only beginning to be systematically investigated in the WTC-affected civilian population despite the fact that symptoms of PTSD and systemic inflammation are still common and persistent. This paper aims to address this knowledge gap, using enrollees of the WTC Environmental Health Center (EHC), a federally designated treatment and surveillance program for community members (WTC Survivors) exposed to the 9/11 terrorist attack. We conducted a mediation analysis to investigate the association between acute WTC dust cloud traumatic exposure (WDCTE) on 9/11, chronic PTSD symptoms, and levels of systemic inflammation. The data indicate that the chronic PTSD symptoms and some specific symptom clusters of PTSD significantly mediate the WDCTE on systemic inflammation, as reflected by the CRP levels. As both chronic PTSD and systemic inflammation are long-term risk factors for neurodegeneration and cognitive decline, further research on the implications of this finding is warranted.

Prenatal Exposure to Locally Emitted Air Pollutants Is Associated with Birth Weight: An Administrative Cohort Study from Southern Sweden

While prenatal exposure to ambient air pollution has been shown to be associated with reduced birth weight, there is substantial heterogeneity across studies, and few epidemiological studies have utilized source-specific exposure data. The aim of the present study was, therefore, to investigate the associations between local, source-specific exposure to fine particulate matter (PM2.5) during pregnancy and birth weight. An administrative cohort comprising 40,245 singleton births from 2000 to 2009 in Scania, Sweden, was combined with data on relevant covariates. Investigated sources of PM2.5 included all local sources together as well as tailpipe exhaust, vehicle wear-and-tear, and small-scale residential heating separately. The relationships between these exposures, represented as interquartile range (IQR) increases, and birth weight (continuous) and low birth weight (LBW; <2500 g) were analyzed in crude and adjusted models. Each local PM2.5 source investigated was associated with reduced birth weight; average decreases varied by source (12−34 g). Only small-scale residential heating was clearly associated with LBW (adjusted odds ratio: 1.14 (95% confidence interval: 1.04−1.26) per IQR increase). These results add to existing evidence that prenatal exposure to ambient air pollution disrupts fetal growth and suggest that PM2.5 from both vehicles and small-scale residential heating may reduce birth weight.

Fine particulate matter exposure aggravates ischemic injury via NLRP3 inflammasome activation and pyroptosis

Aims

Accumulating evidence has suggested that airborne fine particulate matter (PM2.5) exposure is associated with an increased risk of ischemic stroke. However, the underlying mechanisms have not been fully elucidated. In this study, we aim to investigate the role and mechanisms of NLRP3 inflammasome and pyroptosis in ischemic stroke after PM2.5 exposure.

Methods

The BV‐2 and HMC‐3 microglial cell lines were established and subjected to oxygen–glucose deprivation and reoxygenation (OGD/R) with or without PM2.5 exposure. We used the CCK‐8 assay to explore the effects of PM2.5 on cell viability of BV‐2 and HMC‐3 cells. Then, the effects of PM2.5 exposure on NLRP3 inflammasome and pyroptosis following OGD/R were detected by western blotting, ELISA, and the confocal immunofluorescence staining. Afterwards, NLRP3 was knocked down to further validate the effects of PM2.5 on cell viability, NLRP3 inflammasome activation, and pyroptosis after OGD/R in HMC‐3 cells. Finally, the intracellular reactive oxygen species (ROS) was measured and the ROS inhibitor N‐acetyl‐L‐cysteine (NAC) was used to investigate whether ROS was required for PM2.5‐induced NLRP3 inflammasome activation and pyroptosis under ischemic conditions.

Results

We found that PM2.5 exposure decreased the viability of BV‐2 and HMC‐3 cells in a dose‐ and time‐dependent manner under ischemic conditions. Furthermore, PM2.5 exposure aggravated NLRP3 inflammasome activation and pyroptosis after OGD/R, as indicated by an increased expression of NLRP3, ASC, pro‐caspase‐1, Caspase‐1, GSDMD, and GSDMD‐N; increased production of IL‐1β and IL‐18; and enhanced Caspase‐1 activity and SYTOX green uptake. However, shRNA NLRP3 treatment attenuated the effects of PM2.5 on cell viability, NLRP3 inflammasome activation, and pyroptosis. Moreover, we observed that PM2.5 exposure increased the production of intracellular ROS following OGD/R, while inhibiting ROS production with NAC partially attenuated PM2.5‐induced NLRP3 inflammasome activation and pyroptosis under ischemic conditions.

Conclusion

These results suggested that PM2.5 exposure triggered the activation of NLRP3 inflammasome and pyroptosis under ischemic conditions, which may be mediated by increased ROS production after ischemic stroke. These findings may provide a more enhanced understanding of the interplay between PM2.5 and neuroinflammation and cell death, and reveal a novel mechanism of PM2.5‐mediated toxic effects after ischemic stroke.

Long-term Air Pollution Exposure and Pneumonia-related Mortality in a Large Pooled European Cohort

Rationale: Ambient air pollution exposure has been linked to mortality from chronic cardiorespiratory diseases, while evidence on respiratory infections remains more limited. Objectives: We examined the association between long-term exposure to air pollution and pneumonia-related mortality in adults in a pool of eight European cohorts. Methods: Within the multicenter project ELAPSE (Effects of Low-Level Air Pollution: A Study in Europe), we pooled data from eight cohorts among six European countries. Annual mean residential concentrations in 2010 for fine particulate matter, nitrogen dioxide (NO₂), black carbon (BC), and ozone were estimated using Europe-wide hybrid land-use regression models. We applied stratified Cox proportional hazard models to investigate the associations between air pollution and pneumonia, influenza, and acute lower respiratory infections (ALRI) mortality. Measurements and Main Results: Of 325,367 participants, 712 died from pneumonia and influenza combined, 682 from pneumonia, and 695 from ALRI during a mean follow-up of 19.5 years. NO₂ and BC were associated with 10-12% increases in pneumonia and influenza combined mortality, but 95% confidence intervals included unity (hazard ratios, 1.12 [0.99-1.26] per 10 μg/m³ for NO₂; 1.10 [0.97-1.24] per 0.5 10^-5m^-1 for BC). Associations with pneumonia and ALRI mortality were almost identical. We detected effect modification suggesting stronger associations with NO₂ or BC in overweight, employed, or currently smoking participants compared with normal weight, unemployed, or nonsmoking participants. Conclusions: Long-term exposure to combustion-related air pollutants NO₂ and BC may be associated with mortality from lower respiratory infections, but larger studies are needed to estimate these associations more precisely.

Air pollution and biomarkers of cardiovascular disease and inflammation in the Malmö Diet and Cancer cohort

INTRODUCTION

Air pollution is associated with increased risk of cardiovascular disease, possibly through chronic systemic inflammation that promotes the progression of atherosclerosis and the risk of cardiovascular events. This study aimed to investigate the associations between air pollution and established biomarkers of inflammation and cardiovascular disease.

METHODS

The Cardiovascular Subcohort of the Malmö Diet and Cancer cohort includes 6103 participants from the general population of Malmö, Sweden. The participants were recruited 1991-1994. Annual mean residential exposure to particulate matter < 2.5 and < 10 μm (PM_2.5 and PM₁₀), and nitrogen oxides (NO_x) at year of recruitment were assigned from dispersion models. Blood samples collected at recruitment, including blood cell counts, and biomarkers (lymphocyte- and neutrophil counts, C-reactive protein (CRP), soluble urokinase-type plasminogen activator receptor (suPAR), lipoprotein-associated phospholipase A₂ (Lp-PLA₂), ceruloplasmin, orosomucoid, haptoglobin, complement-C3, and alpha-1-antitrypsin) were analyzed. Multiple linear regression models were used to investigate the cross-sectional associations between air pollutants and biomarkers.

RESULTS

The mean annual exposure levels in the cohort were only slightly or moderately above the new WHO guidelines of 5 μg/m³ PM_2.5 (10.5 μg/m³ PM_2.5). Residential PM_2.5 exposure was associated with increased levels of ceruloplasmin, orosomucoid, C3, alpha-1-antitrypsin, haptoglobin, Lp-PLA₂ and the neutrophil-lymphocyte ratio. Ceruloplasmin, orosomucoid, C3 and alpha-1-antitrypsin were also positively associated with PM₁₀. There were no associations between air pollutants and suPAR, leukocyte counts or CRP. The associations between particles and biomarkers were still significant after removing outliers and adjustment for CRP levels. The associations were more prominent in smokers.

CONCLUSION

Long-term residential exposure to moderate levels of particulate air pollution was associated with several biomarkers of inflammation and cardiovascular disease. This supports inflammation as a mechanism behind the association between air pollution and cardiovascular disease.

Exposure to air pollution is associated with an increased risk of metabolic dysfunction-associated fatty liver disease

BACKGROUND & AIMS

Accumulating animal studies have demonstrated the harmful contribution of ambient air pollution (AP) to metabolic dysfunction-associated fatty liver disease (MAFLD), but corresponding epidemiological evidence is limited. We examined the associations between long-term AP exposure and MAFLD prevalence in a Chinese population.

METHODS

We conducted a cross-sectional study of 90,086 participants recruited in China from 2018 to 2019. MAFLD was assessed based on radiologically diagnosed hepatic steatosis and the presence of overweight/obese status, diabetes mellitus, or metabolic dysregulation. Residence-specific levels of air pollutants, including particulate matter with aerodynamic diameters of ≤1 μm (PM₁), ≤2.5 μm (PM_2.5), and ≤10 μm (PM₁₀), and nitrogen dioxide (NO₂), were estimated by validated spatiotemporal models. We used logistic regression models to examine the AP-MAFLD associations and further evaluated potential effect modifications by demographics, lifestyle, central obesity, and diabetes status.

RESULTS

Increased exposure levels to all 4 air pollutants were significantly associated with increased odds of MAFLD, with odds ratios (ORs) of 1.13 (95% CI 1.10-1.17), 1.29 (1.25-1.34), 1.11 (1.09-1.14), and 1.15 (1.12-1.17) for each 10 μg/m³ increase in PM₁, PM_2.5, PM₁₀, and NO₂, respectively. Further stratified analyses revealed that individuals who are male, alcohol drinkers, and current and previous smokers, those who consume a high-fat diet, and those with central obesity experience more significant adverse effects from AP exposure than other individuals.

CONCLUSIONS

This study provides evidence that long-term exposure to ambient PM₁, PM_2.5, PM₁₀, and NO₂ may increase the odds of MAFLD in the real world. These effects may be exacerbated by unhealthy lifestyle habits and central obesity.

LAY SUMMARY

We conducted an epidemiological study on the potential effect of ambient air pollution on the risk of metabolic dysfunction-associated fatty liver disease (MAFLD) in approximately 90 thousand adults in China. We found that long-term exposure to ambient air pollution may increase the odds of MAFLD, especially in individuals who are male, smokers, and alcohol drinkers, those who consume a high-fat diet, and those with central obesity.

Inflammatory markers and lung function in relation to indoor and ambient air pollution

Ambient air pollution causes a range of adverse health effects, whereas effects of indoor sources of air pollution are not well described in high-income countries. We compared hazards of ambient air pollution and indoor sources with respect to important biomarkers of cardiorespiratory effects in terms of lung function and systemic inflammation in a middle-aged Danish cohort. Our cohort comprised 5199 men and women aged 49-63 years at the recruitment during April 2009 to March 2011, with information on exposure to second-hand smoke (SHS) and use of candles, wood stove, kerosene heater and gas cooker as well as relevant covariates. Ambient air pollution exposure was assessed as 2-year mean nitrogen dioxide (NO₂) at the address (mean ± SD: 17.1 ± 9.9 μg/m³) and 4-day average levels of particulate matter with diameter <2.5 μm (PM_2.5; mean ± SD: 12.5 ± 6.0 μg/m³) in urban background. Lung function was assessed as % predicted forced expiratory volume in the first second (FEV1) and inflammatory markers comprised interleukin-6 (IL-6), IL-10, IL-18, interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), and high sensitivity C-reactive protein (hs-CRP). We used random-effect regression models controlling for potential confounders as well as models with further adjustment for self-reported health or for all other exposures. In models adjusted for confounders FEV1 was inversely associated with exposure to NO₂, (-0,83% per 10 μg/m³; 95% CI: -1.26; -0.41%), SHS (-0.56% per 1 of 5 categories increment; 95% CI: -0.89; -0.23%), and gas cooker without hood (-0.89%; 95% CI: -1.62; -0.17%), whereas use of wood stove and candles showed positive associations, although these attenuated by mutual adjustment for all exposures or self-reported health. IL-6 showed positive associations with NO₂ (6.30% increase in log-transformed values per 10 μg/m³; 95% CI: 3.54; 9.05%), PM_2.5 (7.82% per 10 μg/m³; 95% CI: 3.35; 12.4%), SHS (4.38% per increase of 1 of 5 categories; 95% CI: 2.22; 6.54%) and use of kerosene (13.8%; 95% CI: 2.51; 25.1%), whereas the associations with use of wood stove and candles were inverse. PM_2.5 and NO₂ showed positive associations with IFN-γ and TNF-α, while PM_2.5 further associated with IL-10 and IL-18. Hs-CRP was inversely associated with use of candles. These results suggest that the levels of exposure to ambient air pollution and SHS are more harmful than are the levels of exposure to indoor combustion sources from candles and wood stoves in a high-income setting.

Association of Deepwater Horizon Oil Spill Response and Cleanup Work With Risk of Developing Hypertension

IMPORTANCE

Exposure to hydrocarbons, fine particulate matter (PM2.5), and other chemicals from the April 20, 2010, Deepwater Horizon disaster may be associated with increased blood pressure and newly detected hypertension among oil spill response and cleanup workers.

OBJECTIVE

To determine whether participation in cleanup activities following the disaster was associated with increased risk of developing hypertension.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted via telephone interviews and in-person home exams. Participants were 6846 adults who had worked on the oil spill cleanup (workers) and 1505 others who had completed required safety training but did not do cleanup work (nonworkers). Eligible participants did not have diagnosed hypertension at the time of the oil spill. Statistical analyses were performed from June 2018 to December 2021.

EXPOSURES

Engagement in cleanup activities following the Deepwater Horizon oil spill disaster, job classes, quintiles of cumulative total hydrocarbons exposure level, potential exposure to burning or flaring oil, and estimated PM2.5 were examined.

MAIN OUTCOMES AND MEASURES

Systolic and diastolic blood pressure measurements were collected during home exams from 2011 to 2013 using automated oscillometric monitors. Newly detected hypertension was defined as antihypertensive medication use or elevated blood pressure since the spill. Log binomial regression was used to calculate prevalence ratios (PR) and 95% CIs for associations between cleanup exposures and hypertension. Multivariable linear regression was used to estimate exposure effects on continuous blood pressure levels.

RESULTS

Of 8351 participants included in this study, 6484 (77.6%) were male, 517 (6.2%) were Hispanic, 2859 (34.2%) were non-Hispanic Black, and 4418 (52.9%) were non-Hispanic White; the mean (SD) age was 41.9 (12.5) years at enrollment. Among workers, the prevalence of newly detected hypertension was elevated in all quintiles (Q) of cumulative total hydrocarbons above the first quintile (PR for Q3, 1.29 [95% CI, 1.13-1.46], PR for Q4, 1.25 [95% CI, 1.10-1.43], and PR for Q5, 1.31 [95% CI, 1.15-1.50]). Both exposure to burning and/or flaring oil and gas (PR, 1.16 [95% CI, 1.02-1.33]) and PM2.5 from burning (PR, 1.26 [95% CI, 0.89-1.71]) for the highest exposure category were associated with increased risk of newly detected hypertension, as were several types of oil spill work including cleanup on water (PR, 1.34 [95% CI, 1.08-1.66]) and response work (PR, 1.51 [95% CI, 1.20-1.90]).

CONCLUSIONS AND RELEVANCE

Oil spill exposures were associated with newly detected hypertension after the Deepwater Horizon disaster. These findings suggest that blood pressure screening should be considered for workers with occupational hydrocarbon exposures.

Biomarkers for the adverse effects on respiratory system health associated with atmospheric particulate matter exposure

Large amounts of epidemiological evidence have confirmed the atmospheric particulate matter (PM_2.5) exposure was positively correlated with the morbidity and mortality of respiratory diseases. Nevertheless, its pathogenesis remains incompletely understood, probably resulting from the activation of oxidative stress, inflammation, altered genetic and epigenetic modifications in the lung upon PM_2.5 exposure. Currently, biomarker investigations have been widely used in epidemiological and toxicological studies, which may help in understanding the biologic mechanisms underlying PM_2.5-elicited adverse health outcomes. Here, the emerging biomarkers to indicate PM_2.5-respiratory system interactions were summarized, primarily related to oxidative stress (ROS, MDA, GSH, etc.), inflammation (Interleukins, FE_NO, CC16, etc.), DNA damage (8-OHdG, γH2AX, OGG1) and also epigenetic modulation (DNA methylation, histone modification, microRNAs). The identified biomarkers shed light on PM_2.5-elicited inflammation, fibrogenesis and carcinogenesis, thus may favor more precise interventions in public health. It is worth noting that some inconsistent findings may possibly relate to the inter-study differentials in the airborne PM_2.5 sample, exposure mode and targeted subjects, as well as methodological issues. Further research, particularly by -omics technique to identify novel, specific biomarkers, is warranted to illuminate the causal relationship between PM_2.5 pollution and deleterious lung outcomes.

Lung function and atherosclerosis: a cross-sectional study of multimorbidity in rural Uganda

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a leading cause of global mortality. In high-income settings, the presence of cardiovascular disease among people with COPD increases mortality and complicates longitudinal disease management. An estimated 26 million people are living with COPD in sub-Saharan Africa, where risk factors for co-occurring pulmonary and cardiovascular disease may differ from high-income settings but remain uncharacterized. As non-communicable diseases have become the leading cause of death in sub-Saharan Africa, defining multimorbidity in this setting is critical to inform the required scale-up of existing healthcare infrastructure.

METHODS

We measured lung function and carotid intima media thickness (cIMT) among participants in the UGANDAC Study. Study participants were over 40 years old and equally divided into people living with HIV (PLWH) and an age- and sex-similar, HIV-uninfected control population. We fit multivariable linear regression models to characterize the relationship between lung function (forced expiratory volume in one second, FEV₁) and pre-clinical atherosclerosis (cIMT), and evaluated for effect modification by age, sex, smoking history, HIV, and socioeconomic status.

RESULTS

Of 265 participants, median age was 52 years, 125 (47%) were women, and 140 (53%) were PLWH. Most participants who met criteria for COPD were PLWH (13/17, 76%). Median cIMT was 0.67 mm (IQR: 0.60 to 0.74), which did not differ by HIV serostatus. In models adjusted for age, sex, socioeconomic status, smoking, and HIV, lower FEV₁ was associated with increased cIMT (β = 0.006 per 200 mL FEV₁ decrease; 95% CI 0.002 to 0.011, p = 0.01). There was no evidence that age, sex, HIV serostatus, smoking, or socioeconomic status modified the relationship between FEV₁ and cIMT.

CONCLUSIONS

Impaired lung function was associated with increased cIMT, a measure of pre-clinical atherosclerosis, among adults with and without HIV in rural Uganda. Future work should explore how co-occurring lung and cardiovascular disease might share risk factors and contribute to health outcomes in sub-Saharan Africa.

Association between gaseous air pollutants and biomarkers of systemic inflammation: A systematic review and meta-analysis

BACKGROUND

Studies have linked gaseous air pollutants to multiple health effects via inflammatory pathways. Several major inflammatory biomarkers, including C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) have also been considered as predictors of cardiovascular disease. However, there has been no meta-analysis to evaluate the associations between gaseous air pollutants and these typical biomarkers of inflammation to date.

OBJECTIVES

To evaluate the overall associations between short-term and long-term exposures to ambient ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), carbon dioxide (CO) and major inflammatory biomarkers including CRP, fibrinogen, IL-6 and TNF-α.

METHODS

A meta-analysis was conducted for publications from PubMed, Web of Science, Scopus and EMBASE databases up to Feb 1st, 2021.

RESULTS

The meta-analysis included 38 studies conducted among 210,438 participants. Generally, we only observed significant positive associations between short-term exposures to gaseous air pollutants and inflammatory biomarkers. For a 10 μg/m³ increase in short-term exposure to O₃, NO₂, and SO₂, there were significant increases of 1.05% (95%CI: 0.09%, 2.02%), 1.60% (95%CI: 0.49%, 2.72%), and 10.44% (95%CI: 4.20%, 17.05%) in CRP, respectively. Meanwhile, a 10 μg/m³ increase in NO₂ was also associated with a 4.85% (95%CI: 1.10%, 8.73%) increase in TNF-α. Long-term exposures to gaseous air pollutants were not statistically associated with these biomarkers, but the study numbers were relatively small. Subgroup analyses found more apparent associations in studies with better study design, higher quality, and smaller sample size. Meanwhile, the associations also varied across studies conducted in different geographical regions.

CONCLUSION

Short-term exposure to gaseous air pollutants is associated with increased levels of circulating inflammatory biomarkers, suggesting that a systemic inflammatory state is activated upon exposure. More studies on long-term exposure to gaseous air pollutants and inflammatory biomarkers are warranted to verify the associations.

Surfaxin attenuates PM2.5-induced airway inflammation via restoring surfactant proteins in rats exposed to cigarette smoke

Epidemiologic studies have shown that the fine particulate matter 2.5 (PM2.5) exaggerates chronic airway inflammation involving in acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Surfactant proteins (SPs) decreases significantly related to airflow limitation and airway inflammation. However, how to restore the reduction of SPs levels in airway inflammation exposed to PM2.5 has not been well understood. In the present study, the SPs including SPA, SPB, SPC and SPD levels in bronchoalveolar lavage fluid (BALF) were detected from patients with stable COPD. Rats were exposed to cigarette smoke and PM2.5. After given with Surfaxin, the expression of SPs, protein kinase C (PKC) and tight junction protein (ZO-1) in lung tissue and the levels of C-reactive protein (CRP) and fibrinogen (FIB) in plasma was observed. The results showed that SPA, SPB and SPD were significantly lower than those of the control group (p < 0.01). PM2.5 aggravated smoking-induced airway inflammation and oxidative stress demonstrated by pathological changes of lung tissue and increased levels of CRP and PKC in vivo. PM2.5 decreased the expression of all the SPs and ZO-1, which could be significantly restored by Surfaxin. These findings indicate that Surfaxin protects the alveolar epithelium from PM2.5 in airway inflammation through increasing SPs.

Cumulative exposure amount of PM2.5 in the ambient air is associated with coronary atherosclerosis - Serial coronary CT angiography study

BACKGROUND

We investigated the change of coronary atherosclerosis with long-term exposure to fine particulate matter of aerodynamic diameter <2.5 ​μm (PM_2.5) using coronary computed tomography angiography (CCTA).

METHODS

Subjects undergoing serial CCTAs between January 2007 and December 2017 (n ​= ​3,127) were analyzed. Each individual's cumulative amount of PM_2.5 exposure between the two CCTAs was evaluated by Kriging interpolation and zonal analysis, considering the time interval between the two CCTAs. The main outcome was progression of coronary artery calcium (CAC) with additional semiquantitative analysis on the changes in the severity and composition of atherosclerotic plaques.

RESULTS

The CAC scores increased by 30.8 Agatston units per-year under a median PM_2.5 concentration 24.9 ​μg/m³ and tended to increase with the cumulative amount of PM_2.5 exposure (r ​= ​0.321, p ​<0.001). The CAC progressed in 1,361 (43.5%) subjects during a median 53 months follow-up. The cumulative amount of PM_2.5 exposure was independently associated with CAC progression (adjusted OR 1.09, p ​<0.001). By random forest analysis, the relative impact of cumulative amount of PM_2.5 exposure on CAC progression was higher than that of traditional cardiovascular risk factors and the average concentration of PM_2.5. The extent of coronary atherosclerosis and newly developed calcified plaque on follow-up were also significantly associated with the cumulative amount of PM_2.5 exposure.

CONCLUSIONS

Cumulative exposure to air pollution is associated with the progression of diffuse coronary calcification, the importance of which may be more significant than other traditional cardiovascular risk factors. Further investigations into the causality between PM_2.5 and coronary atherosclerosis are warranted to improve global cardiovascular health.